The surficial active centers of photocatalysts play a critical role in photocatalytic reactions and require rational design to optimize their adsorption and activation properties for substrates. Single atoms anchored to metal oxide semiconductors, forming asymmetric oxygen-bridged dual-metal sites (M1–O–M2), exhibit tunable electronic properties for adsorption and activation. However, the catalytic mechanisms of each site remain unclear, and their full performance potential has yet to be explored. Herein, we report oxygen-bridged reductive V4+ and oxidative Cuδ+ sites (Cu–O–V) for the photo-oxidative coupling of benzylamine (BA), enabled by the synthesis of single-atom Cu-anchored Na+ intercalated V2O5 (Cu-SA/NVO) nanoribbons. As characterized by electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS), and Raman spectroscopy, the introduction of Cuδ+ sites increases the density of nearby V4+ sites, thereby facilitating the directional migration of photoelectrons to V sites and photoholes to Cu sites. The synergistic effect of the promoted charge transfer and oxygen-bridged dual sites achieved a yield of 2.73 mmol g–1 h–1 for photo-oxidative BA to NBI, which was nearly 3 times that of NVO and 91 times that of Cu-SA/V2O5 with a selectivity of up to 99%. In situ infrared spectroscopy detected a stronger stretching vibration of *Ph–CH═NH intermediate on Cu-SA/NVO, indicating the Cu–O–V structure facilitated the nucleophilic reaction of the BA intermediate. Density functional theory (DFT) results revealed that the Cu–O–V bridge significantly enhanced the adsorption of O2 and BA, and lowered the reaction barrier for the conversion of *Ph–CH2NH2•+ to *Ph–CH═NH, thereby substantially improving the yield of NBI. Our work provides new insights into the design and optimization of photocatalysts.
{"title":"Oxygen-Bridged Cu and V Dual Metal Sites for Enhanced Photo-oxidative Coupling of Benzylamine","authors":"Bohan Wu, Xinyuan Li, Tailei Hou, Xingbao Chen, Jiale Wang, Shouyuan Li, Akang Chen, Chuwei Zhu, Xurui Zhang, Honghui Ou, Yiou Wang, Dingsheng Wang, Jiatao Zhang","doi":"10.1021/jacs.5c11918","DOIUrl":"https://doi.org/10.1021/jacs.5c11918","url":null,"abstract":"The surficial active centers of photocatalysts play a critical role in photocatalytic reactions and require rational design to optimize their adsorption and activation properties for substrates. Single atoms anchored to metal oxide semiconductors, forming asymmetric oxygen-bridged dual-metal sites (M<sub>1</sub>–O–M<sub>2</sub>), exhibit tunable electronic properties for adsorption and activation. However, the catalytic mechanisms of each site remain unclear, and their full performance potential has yet to be explored. Herein, we report oxygen-bridged reductive V<sup>4+</sup> and oxidative Cu<sup>δ+</sup> sites (Cu–O–V) for the photo-oxidative coupling of benzylamine (BA), enabled by the synthesis of single-atom Cu-anchored Na<sup>+</sup> intercalated V<sub>2</sub>O<sub>5</sub> (Cu-SA/NVO) nanoribbons. As characterized by electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS), and Raman spectroscopy, the introduction of Cu<sup>δ+</sup> sites increases the density of nearby V<sup>4+</sup> sites, thereby facilitating the directional migration of photoelectrons to V sites and photoholes to Cu sites. The synergistic effect of the promoted charge transfer and oxygen-bridged dual sites achieved a yield of 2.73 mmol g<sup>–1</sup> h<sup>–1</sup> for photo-oxidative BA to NBI, which was nearly 3 times that of NVO and 91 times that of Cu-SA/V<sub>2</sub>O<sub>5</sub> with a selectivity of up to 99%. In situ infrared spectroscopy detected a stronger stretching vibration of *Ph–CH═NH intermediate on Cu-SA/NVO, indicating the Cu–O–V structure facilitated the nucleophilic reaction of the BA intermediate. Density functional theory (DFT) results revealed that the Cu–O–V bridge significantly enhanced the adsorption of O<sub>2</sub> and BA, and lowered the reaction barrier for the conversion of *Ph–CH<sub>2</sub>NH<sub>2</sub><sup>•+</sup> to *Ph–CH═NH, thereby substantially improving the yield of NBI. Our work provides new insights into the design and optimization of photocatalysts.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"8 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrosynthesis of amino acids from abundant nitrogen sources and α-keto acids represents a sustainable route. Enhancing the reaction efficiency and exploring the mechanisms influencing the reaction are of great significance. Herein, we studied the effect of protons in the electrolyte on amino acid synthesis, which has been overlooked to date. Using the coreduction of oxalic acid and nitrate (NO3–) to glycine (Gly) on dendritic Bi as a model system, we found that optimal proton concentrations specifically enhance two key steps of the four-step reactions, governing Gly selectivity and production rate. One is that protons directly coordinate with key intermediates in NO3– reduction. Suitable proton concentration induces the desorption of *NH2OH (where * denotes an adsorption site) as protonated NH3OH+ from the catalyst surface. This desorption effectively prevents *NH2OH from further reduction to NH3, securing the essential intermediate (NH3OH+) for Gly synthesis. The other is that suitable proton concentration favors the proton-coupled electron transfer hydrogenation of glyoxylic acid oxime to Gly, which finally enhances the Gly selectivity and production rate. Guided by this mechanistic insight, we optimized the reaction conditions to precisely control each critical step, achieving excellent Gly electrosynthesis performance with an FEGly of 78.9% and a partial current density of 108.2 mA cm–2. The versatility of this approach was further demonstrated through efficient synthesis of diverse amino acids, including alanine, aspartic acid, and phenylglycine, delivering very high FEs and yield rates.
从丰富的氮源和α-酮酸中电合成氨基酸是一条可持续的途径。提高反应效率，探索影响反应的机理具有重要意义。在此，我们研究了电解质中质子对氨基酸合成的影响，这是迄今为止被忽视的。以草酸和硝酸（NO3 -）在树枝状铋上共还原为甘氨酸（Gly）为模型体系，我们发现最佳质子浓度特异性地增强了四步反应中的两个关键步骤，控制了甘氨酸的选择性和产率。一是在NO3 -还原过程中质子直接与关键中间体配合。合适的质子浓度诱导*NH2OH（*表示吸附位点）作为质子化的NH3OH+从催化剂表面解吸。这种解吸有效地阻止了*NH2OH进一步还原为NH3，确保了合成Gly所需的中间体（NH3OH+）。二是适宜的质子浓度有利于乙醛酸肟的质子偶联电子转移加氢生成甘氨酸，从而提高甘氨酸的选择性和产率。在此机制的指导下，我们优化了反应条件，以精确控制每个关键步骤，获得了优异的Gly电合成性能，FEGly为78.9%，分电流密度为108.2 mA cm-2。通过高效合成多种氨基酸，包括丙氨酸、天冬氨酸和苯基甘氨酸，进一步证明了这种方法的多功能性，并提供了非常高的FEs和产率。
{"title":"Proton-Regulated C–N Coupling for Efficient Amino Acid Electrosynthesis","authors":"Yong Wang, Xiang-Da Zhang, Pengsong Li, Congyang Wang, Yuqing Hou, Ran Duan, Jun Ma, Ganwen Zhang, Xihua Wang, Huizhen Liu, Yichao Zhang, Lihong Jing, Qingli Qian, Xiaofu Sun, Xinchen Kang, Qinggong Zhu, Buxing Han","doi":"10.1021/jacs.5c15446","DOIUrl":"https://doi.org/10.1021/jacs.5c15446","url":null,"abstract":"Electrosynthesis of amino acids from abundant nitrogen sources and α-keto acids represents a sustainable route. Enhancing the reaction efficiency and exploring the mechanisms influencing the reaction are of great significance. Herein, we studied the effect of protons in the electrolyte on amino acid synthesis, which has been overlooked to date. Using the coreduction of oxalic acid and nitrate (NO<sub>3</sub><sup>–</sup>) to glycine (Gly) on dendritic Bi as a model system, we found that optimal proton concentrations specifically enhance two key steps of the four-step reactions, governing Gly selectivity and production rate. One is that protons directly coordinate with key intermediates in NO<sub>3</sub><sup>–</sup> reduction. Suitable proton concentration induces the desorption of *NH<sub>2</sub>OH (where * denotes an adsorption site) as protonated NH<sub>3</sub>OH<sup>+</sup> from the catalyst surface. This desorption effectively prevents *NH<sub>2</sub>OH from further reduction to NH<sub>3</sub>, securing the essential intermediate (NH<sub>3</sub>OH<sup>+</sup>) for Gly synthesis. The other is that suitable proton concentration favors the proton-coupled electron transfer hydrogenation of glyoxylic acid oxime to Gly, which finally enhances the Gly selectivity and production rate. Guided by this mechanistic insight, we optimized the reaction conditions to precisely control each critical step, achieving excellent Gly electrosynthesis performance with an FE<sub>Gly</sub> of 78.9% and a partial current density of 108.2 mA cm<sup>–2</sup>. The versatility of this approach was further demonstrated through efficient synthesis of diverse amino acids, including alanine, aspartic acid, and phenylglycine, delivering very high FEs and yield rates.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"13 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhaofei Zhang, Arman Khosravi, Jagrut A. Shah, Kevin P. Quirion, Stephen C. Yachuw, Andrew T. Poore, Shiliang Tian, Peng Liu, Ming-Yu Ngai
Valence tautomerism, traditionally underexplored in asymmetric catalysis compared to the more familiar two-electron prototropic tautomerism like keto–enol, presents a promising avenue for novel chemical transformations. In this study, we harness one-electron valence tautomerism through a dual photoredox/nickel-catalyzed system to facilitate oxidant-free, enantioselective cross-nucleophile coupling (CNC). This method efficiently couples a diverse range of β-keto esters and amides with silyl enol ethers and allyl silanes, producing coupling products that feature a quaternary stereocenter with high stereocontrol. The reaction demonstrates broad tolerance for different functional groups and molecular architectures. Mechanistic investigations, including Stern–Volmer quenching, cyclic voltammetry, electron paramagnetic resonance (EPR), radical trapping, and density functional theory (DFT) calculations, corroborate a radical mechanism involving valence tautomerism. We anticipate that this mechanistic insight will inspire the discovery of new chemical transformations and provide a framework for describing key steps in future catalytic reactions.
{"title":"Catalytic Enantioselective Cross-Nucleophile Coupling via Valence Tautomerism","authors":"Zhaofei Zhang, Arman Khosravi, Jagrut A. Shah, Kevin P. Quirion, Stephen C. Yachuw, Andrew T. Poore, Shiliang Tian, Peng Liu, Ming-Yu Ngai","doi":"10.1021/jacs.5c16654","DOIUrl":"https://doi.org/10.1021/jacs.5c16654","url":null,"abstract":"Valence tautomerism, traditionally underexplored in asymmetric catalysis compared to the more familiar two-electron prototropic tautomerism like keto–enol, presents a promising avenue for novel chemical transformations. In this study, we harness one-electron valence tautomerism through a dual photoredox/nickel-catalyzed system to facilitate oxidant-free, enantioselective cross-nucleophile coupling (CNC). This method efficiently couples a diverse range of β-keto esters and amides with silyl enol ethers and allyl silanes, producing coupling products that feature a quaternary stereocenter with high stereocontrol. The reaction demonstrates broad tolerance for different functional groups and molecular architectures. Mechanistic investigations, including Stern–Volmer quenching, cyclic voltammetry, electron paramagnetic resonance (EPR), radical trapping, and density functional theory (DFT) calculations, corroborate a radical mechanism involving valence tautomerism. We anticipate that this mechanistic insight will inspire the discovery of new chemical transformations and provide a framework for describing key steps in future catalytic reactions.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"29 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xuqian Deng, Yan Li, Xiaolan Zhu, Yanlin Du, Hongli Chi, Ming Cheng, Yali Wang, Keli An, Penghui Zhang
Effectively and safely amplifying systemic immunity against heterogeneous and immunosuppressive cancers remains highly challenging. Here, we report a library of acylhydrazone-based ionizable lipids (AHzILs) that exploit pH-responsive E/Z isomerization to dynamically tune the membrane properties of mRNA-encapsulated lipid nanoparticles (LNPs), thereby achieving spleen targeting, efficient endosomal escape, and robust immune activation. These isomerizable mRNA vaccines acquired a protein corona enriched in mannose-binding protein A and vitronectin, promoting preferential uptake by antigen-presenting cells and granulocytes and facilitating immune-cell-mediated trafficking to the spleen. Once internalized, the acidic endosomal milieu triggered rapid pH-dependent E/Z isomerization of the acylhydrazone motif, inducing a cone-shaped lipid geometry that accelerated endosomal membrane destabilization. This disruption not only enabled efficient mRNA release and antigen expression but also activated the NLRP3 inflammasome pathway, thereby orchestrating both innate and adaptive immunity. Systemic immune activation expanded cDC1 subsets, enhanced antigen presentation, and T cell priming, thereby increasing the pool of antigen-specific TCF-1+PD-1+CD8+ T cells. This stem-like T cell subset synergized with anti-PD-1 checkpoint blockade to remodel the tumor microenvironment and ultimately confer durable systemic antitumor protection in a melanoma mouse model. Compared with conventional LNPs, our isomerizable vaccines uniquely integrate high transfection efficiency, intrinsic adjuvanticity, and spleen tropism, offering great promise for cancer immunotherapy and establishing a versatile modular platform adaptable to gene editing, T cell engineering, and targeted drug delivery against diverse malignant diseases.
{"title":"pH-Isomerizable Acylhydrazone-Based Ionizable Lipids for Spleen-Targeted mRNA Vaccines","authors":"Xuqian Deng, Yan Li, Xiaolan Zhu, Yanlin Du, Hongli Chi, Ming Cheng, Yali Wang, Keli An, Penghui Zhang","doi":"10.1021/jacs.5c16121","DOIUrl":"https://doi.org/10.1021/jacs.5c16121","url":null,"abstract":"Effectively and safely amplifying systemic immunity against heterogeneous and immunosuppressive cancers remains highly challenging. Here, we report a library of acylhydrazone-based ionizable lipids (AHzILs) that exploit pH-responsive <i>E</i>/<i>Z</i> isomerization to dynamically tune the membrane properties of mRNA-encapsulated lipid nanoparticles (LNPs), thereby achieving spleen targeting, efficient endosomal escape, and robust immune activation. These isomerizable mRNA vaccines acquired a protein corona enriched in mannose-binding protein A and vitronectin, promoting preferential uptake by antigen-presenting cells and granulocytes and facilitating immune-cell-mediated trafficking to the spleen. Once internalized, the acidic endosomal milieu triggered rapid pH-dependent <i>E</i>/<i>Z</i> isomerization of the acylhydrazone motif, inducing a cone-shaped lipid geometry that accelerated endosomal membrane destabilization. This disruption not only enabled efficient mRNA release and antigen expression but also activated the NLRP3 inflammasome pathway, thereby orchestrating both innate and adaptive immunity. Systemic immune activation expanded cDC1 subsets, enhanced antigen presentation, and T cell priming, thereby increasing the pool of antigen-specific TCF-1<sup>+</sup>PD-1<sup>+</sup>CD8<sup>+</sup> T cells. This stem-like T cell subset synergized with anti-PD-1 checkpoint blockade to remodel the tumor microenvironment and ultimately confer durable systemic antitumor protection in a melanoma mouse model. Compared with conventional LNPs, our isomerizable vaccines uniquely integrate high transfection efficiency, intrinsic adjuvanticity, and spleen tropism, offering great promise for cancer immunotherapy and establishing a versatile modular platform adaptable to gene editing, T cell engineering, and targeted drug delivery against diverse malignant diseases.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"224 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xue Zhang, Xin Li, Jie Li, Haoyang Pan, Minghui Yu, Yajie Zhang, Gui LinZhu, Zhen Xu, Ziyong Shen, Shimin Hou, Yaping Zang, Bingwu Wang, Kai Wu, Shang-Da Jiang, Ivano E. Castelli, Lianmao Peng, Per Hedegård, Song Gao, Peng He, Jing-Tao Lü, Yongfeng Wang
Spin coupling between magnetic metal atoms and organic radicals plays a pivotal role in high-performance magnetic materials. The complex interaction involving multispin centers in bulk materials makes it challenging to study spin coupling at the atomic scale. Here, we investigate the d–π–d spin interaction in well-defined metal–organic coordinated structures composed of two iron (Fe) atoms and four all-trans retinoic acid (ReA) molecules, using low-temperature scanning tunneling microscopy and atomic force microscopy. The ReA molecule is turned into a spin-1/2 radical state by dehydrogenation, facilitating strong magnetic coupling with the coordinated Fe atoms. Comprehensive theoretical analysis, based on density functional theory and valence bond theory, further elucidates the intrinsic mechanism of ferrimagnetic spin coupling in the coordination structure. Specifically, simultaneous antiferromagnetic coupling of an Fe dimer to ReA radicals parallelizes the dimer spin orientation. This work contributes to the fundamental understanding of the spin interaction in metal–organic coordination structures and provides microscopic insights for designing advanced magnetic materials.
{"title":"Atomic-Scale Engineering of d–π–d Spin Interaction in Metal–Organic Architectures","authors":"Xue Zhang, Xin Li, Jie Li, Haoyang Pan, Minghui Yu, Yajie Zhang, Gui LinZhu, Zhen Xu, Ziyong Shen, Shimin Hou, Yaping Zang, Bingwu Wang, Kai Wu, Shang-Da Jiang, Ivano E. Castelli, Lianmao Peng, Per Hedegård, Song Gao, Peng He, Jing-Tao Lü, Yongfeng Wang","doi":"10.1021/jacs.5c18517","DOIUrl":"https://doi.org/10.1021/jacs.5c18517","url":null,"abstract":"Spin coupling between magnetic metal atoms and organic radicals plays a pivotal role in high-performance magnetic materials. The complex interaction involving multispin centers in bulk materials makes it challenging to study spin coupling at the atomic scale. Here, we investigate the <i>d</i>–π–<i>d</i> spin interaction in well-defined metal–organic coordinated structures composed of two iron (Fe) atoms and four all-trans retinoic acid (ReA) molecules, using low-temperature scanning tunneling microscopy and atomic force microscopy. The ReA molecule is turned into a spin-1/2 radical state by dehydrogenation, facilitating strong magnetic coupling with the coordinated Fe atoms. Comprehensive theoretical analysis, based on density functional theory and valence bond theory, further elucidates the intrinsic mechanism of ferrimagnetic spin coupling in the coordination structure. Specifically, simultaneous antiferromagnetic coupling of an Fe dimer to ReA radicals parallelizes the dimer spin orientation. This work contributes to the fundamental understanding of the spin interaction in metal–organic coordination structures and provides microscopic insights for designing advanced magnetic materials.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"19 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Achieving stable and efficient alkaline water electrolysis (AWE) under fluctuating renewable energy inputs is essential for large-scale green hydrogen production. However, frequent shutdown-induced reverse current (RC) effects pose significant challenges to electrode durability. Here, we introduce a gradient interlayer engineering strategy to develop robust AWE electrodes that intrinsically resist both electrochemical reconstruction and mechanical fatigue. By constructing a dense interlayer with Ni(112̅)/Ni3S2(1̅20) heterointerfaces, the electrode demonstrates high catalytic activity (1.79 V @1000 mA cm-2─meeting the U.S. DOE 2026 target), excellent operational stability (>1500 h at 1000 mA cm-2 in 30 wt % KOH at 80 °C), and exceptional RC resistance for 3600 accelerated startup/shutdown cycles. Mechanistic studies through cross-sectional characterizations and theoretical calculations reveal that the seamless interlayer at the catalyst-substrate interface enhances interfacial adhesion, mitigates lattice mismatch, and facilitates charge redistribution, ensuring robust stability and integrity even under operational strains and potential reversals. This work establishes interface crystallography as a design paradigm for durable electrodes, potentially overcoming the stability-activity dilemma toward industrially relevant electrolyzers coupled with fluctuating renewable energy sources.
在波动的可再生能源投入下实现稳定高效的碱性水电解（AWE）对于大规模绿色制氢至关重要。然而，频繁的关断引起的反向电流（RC）效应对电极的耐用性提出了重大挑战。在这里，我们引入了一种梯度层间工程策略来开发坚固的AWE电极，该电极本质上可以抵抗电化学重构和机械疲劳。通过构建具有Ni（112℃）/Ni3S2（1℃）异质界面的致密中间层，该电极具有高催化活性（1.79 V @1000 mA cm-2，符合美国DOE 2026目标），优异的运行稳定性（在30 wt % KOH， 80°C下，1000 mA cm-2下>1500 h），以及在3600次加速启动/关闭循环中具有优异的RC电阻。通过截面表征和理论计算进行的机理研究表明，在催化剂-衬底界面处的无缝夹层增强了界面附着力，减轻了晶格失配，促进了电荷再分配，即使在操作应变和潜在逆转下也能确保强大的稳定性和完整性。这项工作建立了界面晶体学作为耐用电极的设计范例，有可能克服工业相关电解槽的稳定性-活性困境，以及波动的可再生能源。
{"title":"Heterointerface-Enabled Anti-Reverse-Current Electrodes for Alkaline Water Electrolyzers at 1000 mA cm<sup>-2</sup>.","authors":"Wenjun He, Yueshuai Wang, Yilong Zhao, Cheng Tang, Linchuan Cong, Changli Wang, Yue Lu, Xin Liu, Juncai Dong, Serhiy Cherevko, Qingsong Hua, Qiang Zhang","doi":"10.1021/jacs.5c17603","DOIUrl":"https://doi.org/10.1021/jacs.5c17603","url":null,"abstract":"<p><p>Achieving stable and efficient alkaline water electrolysis (AWE) under fluctuating renewable energy inputs is essential for large-scale green hydrogen production. However, frequent shutdown-induced reverse current (RC) effects pose significant challenges to electrode durability. Here, we introduce a gradient interlayer engineering strategy to develop robust AWE electrodes that intrinsically resist both electrochemical reconstruction and mechanical fatigue. By constructing a dense interlayer with Ni(112̅)/Ni<sub>3</sub>S<sub>2</sub>(1̅20) heterointerfaces, the electrode demonstrates high catalytic activity (1.79 V @1000 mA cm<sup>-2</sup>─meeting the U.S. DOE 2026 target), excellent operational stability (>1500 h at 1000 mA cm<sup>-2</sup> in 30 wt % KOH at 80 °C), and exceptional RC resistance for 3600 accelerated startup/shutdown cycles. Mechanistic studies through cross-sectional characterizations and theoretical calculations reveal that the seamless interlayer at the catalyst-substrate interface enhances interfacial adhesion, mitigates lattice mismatch, and facilitates charge redistribution, ensuring robust stability and integrity even under operational strains and potential reversals. This work establishes interface crystallography as a design paradigm for durable electrodes, potentially overcoming the stability-activity dilemma toward industrially relevant electrolyzers coupled with fluctuating renewable energy sources.</p>","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":" ","pages":""},"PeriodicalIF":15.6,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145720077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brandon H. Bowser, Jan Meisner, Omar Benallal, Tatiana B. Kouznetsova, Cameron L. Brown, Thomas J. Hicks, Todd J. Martinez, Stephen L. Craig
The reactivity of four-membered carbocycle mechanophores, such as cyclobutane (CB), cyclobutene (CBE), and benzocyclobutene (BCB), has been explored in the context of fundamental reaction mechanisms and the manipulation of polymer network properties. Despite their similar scaffolding, the mechanochemical reaction paths of these carbocycles are quite different due to the configuration or absence of π bonds opposite the sites of applied force. Here, we report a CBE diarylethene (DAE) mechanophore that can be reversibly toggled between open and bridged states, providing access to two reactivity patterns from a single species. The mechanochemical reactivity of both states is observed by single-molecule force spectroscopy (SMFS) and pulsed ultrasonication experiments. The two states give indistinguishable ring-opened products, but their reactivity differs significantly. The greater mechanochemical reactivity of the bridged state is evident in a lower transition force observed in the SMFS experiments (810 pN, vs 1520 pN for the open state) and by the greater conversion of bridged vs open isomers observed in pulsed sonication. The use of external triggers to switch between states of different reactivity offers promise as a quantitative probe of mechanochemical contributions to the performance of materials and devices.
{"title":"Switching and Quantifying the Single-Molecule Mechanochemical Reactivity of Four-Membered Carbocycle Mechanophores within a Single, Photoswitchable Polymer Strand","authors":"Brandon H. Bowser, Jan Meisner, Omar Benallal, Tatiana B. Kouznetsova, Cameron L. Brown, Thomas J. Hicks, Todd J. Martinez, Stephen L. Craig","doi":"10.1021/jacs.5c17630","DOIUrl":"https://doi.org/10.1021/jacs.5c17630","url":null,"abstract":"The reactivity of four-membered carbocycle mechanophores, such as cyclobutane (CB), cyclobutene (CBE), and benzocyclobutene (BCB), has been explored in the context of fundamental reaction mechanisms and the manipulation of polymer network properties. Despite their similar scaffolding, the mechanochemical reaction paths of these carbocycles are quite different due to the configuration or absence of π bonds opposite the sites of applied force. Here, we report a CBE diarylethene (DAE) mechanophore that can be reversibly toggled between open and bridged states, providing access to two reactivity patterns from a single species. The mechanochemical reactivity of both states is observed by single-molecule force spectroscopy (SMFS) and pulsed ultrasonication experiments. The two states give indistinguishable ring-opened products, but their reactivity differs significantly. The greater mechanochemical reactivity of the bridged state is evident in a lower transition force observed in the SMFS experiments (810 pN, vs 1520 pN for the open state) and by the greater conversion of bridged vs open isomers observed in pulsed sonication. The use of external triggers to switch between states of different reactivity offers promise as a quantitative probe of mechanochemical contributions to the performance of materials and devices.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"240 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Giovanni M Beneventi,Filip Božinović,Phillip M Greißel,Max M Martin,Frank Hampel,Alejandro Cadranel,Fabrizia Negri,Norbert Jux,Dirk M Guldi
Nanographenes (NGs) and graphene nanoribbons (GNRs) are molecular-level bridges to bulk-carbon materials. When synthesized with atomic precision via, for example, bottom-up strategies, a direct connection between the structure and properties is demonstrable. This is of key interest, especially considering practical applications. In the current work, we report the synthesis and comprehensive photophysical characterization of a full-benzenoid nanographene (NG-Br) and its covalent conjugate featuring a porphyrin (NG-(Zn)Por). Our synthetic approach relies on a cascade of Suzuki coupling, reduction, and Sandmeyer bromination reactions, starting from halogenated nitrobenzene derivatives. Knowing at which concentration aggregation occurs is important to study either monomers of NG-Br or its aggregates. In organic solvents, the association constant of NG-Br exceeds 1 × 106 M-1. Photophysical and theoretical analyses on the monomer revealed a subtle energy proximity between (S1)/(Lb) and (S2)/(La) that is the basis for strong vibronic coupling via the Herzberg-Teller mechanism, as well as (S1,1) and (S2,0) vibronic mixing. In NG-(Zn)Por, an ultrafast (S1-S1) energy transfer from NG to the porphyrin was observed. Our findings are essential for establishing an unambiguous structure-property relationship for NGs and 9-armchair GNRs, providing a blueprint for their use in optoelectronic devices ranging from single-electron transistors to OLEDs and organic solar cells.
{"title":"Synthesis and Excited-State Dynamics in Molecular Nanographene: Herzberg-Teller Vibronic Coupling and Energy Transfer to Porphyrins.","authors":"Giovanni M Beneventi,Filip Božinović,Phillip M Greißel,Max M Martin,Frank Hampel,Alejandro Cadranel,Fabrizia Negri,Norbert Jux,Dirk M Guldi","doi":"10.1021/jacs.5c14685","DOIUrl":"https://doi.org/10.1021/jacs.5c14685","url":null,"abstract":"Nanographenes (NGs) and graphene nanoribbons (GNRs) are molecular-level bridges to bulk-carbon materials. When synthesized with atomic precision via, for example, bottom-up strategies, a direct connection between the structure and properties is demonstrable. This is of key interest, especially considering practical applications. In the current work, we report the synthesis and comprehensive photophysical characterization of a full-benzenoid nanographene (NG-Br) and its covalent conjugate featuring a porphyrin (NG-(Zn)Por). Our synthetic approach relies on a cascade of Suzuki coupling, reduction, and Sandmeyer bromination reactions, starting from halogenated nitrobenzene derivatives. Knowing at which concentration aggregation occurs is important to study either monomers of NG-Br or its aggregates. In organic solvents, the association constant of NG-Br exceeds 1 × 106 M-1. Photophysical and theoretical analyses on the monomer revealed a subtle energy proximity between (S1)/(Lb) and (S2)/(La) that is the basis for strong vibronic coupling via the Herzberg-Teller mechanism, as well as (S1,1) and (S2,0) vibronic mixing. In NG-(Zn)Por, an ultrafast (S1-S1) energy transfer from NG to the porphyrin was observed. Our findings are essential for establishing an unambiguous structure-property relationship for NGs and 9-armchair GNRs, providing a blueprint for their use in optoelectronic devices ranging from single-electron transistors to OLEDs and organic solar cells.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"1 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Batuhan Balci, Eric M. Shepard, Alexander Marlott, Roark D. O’Neill, Michael T. Mock, William E. Broderick, Joan B. Broderick
The organometallic H-cluster of the [FeFe]-hydrogenase is assembled in vivo through a complex process requiring the action of three dedicated maturation enzymes, HydG, HydE, and HydF, as well as the aminomethyl-lipoyl-H-protein (Hmet) of the glycine cleavage system (GCS). Here we probe the role of HydF and its [4Fe-4S] cluster in [FeFe]-hydrogenase maturation by using a defined semisynthetic approach in which [FeI2(μ-SH)2(CO)4(CN)2]2– ([2Fe]E) is used to bypass HydE and HydG, and GCS components are used in place of cell lysate. We show that inclusion of the iron–sulfur carrier protein NfuA and the high-CO-affinity myoglobin variant MbH64L provides dramatically improved hydrogenase activities up to 828 μmol/min/mg, equivalent to the best reported activities for Chlamydomonas reinhardtii [FeFe]-hydrogenase isolated from the native organism. Apo-HydF lacking a [4Fe-4S] cluster provides very little hydrogenase activity; however, full maturation is restored with the addition of NfuA, which we demonstrate reconstitutes the [4Fe-4S] cluster of HydF. In addition, a HydF variant lacking a [4Fe-4S] cluster by changing two cysteine ligands to alanine is completely unable to support either semisynthetic maturation using [2Fe]E, or full maturation using HydG and HydE, even in the presence of NfuA, demonstrating that the HydF [4Fe-4S] cluster is absolutely essential for [FeFe]-hydrogenase maturation. The possibility that the HydF [4Fe-4S] cluster plays a role in direct binding of [2Fe]E is negated by our results with the HydFD311C variant, which demonstrate that the labile Asp311 cluster ligand is not essential for [2Fe]E binding and HydA maturation. We therefore conclude that [2Fe]E binds HydF adjacent to, but not directly coordinated to, the [4Fe-4S] cluster. The HydF [4Fe-4S] cluster is proposed to be essential due to its impact on the [2Fe]E binding orientation and the ability of the HydF/[2Fe]E complex to form productive interactions with Hmet or the Hmet/T-protein complex during DTMA ligand biosynthesis.
{"title":"The [4Fe-4S] Cluster of HydF Is Essential for [FeFe]-Hydrogenase Maturation","authors":"Batuhan Balci, Eric M. Shepard, Alexander Marlott, Roark D. O’Neill, Michael T. Mock, William E. Broderick, Joan B. Broderick","doi":"10.1021/jacs.5c18286","DOIUrl":"https://doi.org/10.1021/jacs.5c18286","url":null,"abstract":"The organometallic H-cluster of the [FeFe]-hydrogenase is assembled <i>in vivo</i> through a complex process requiring the action of three dedicated maturation enzymes, HydG, HydE, and HydF, as well as the aminomethyl-lipoyl-H-protein (H<sub>met</sub>) of the glycine cleavage system (GCS). Here we probe the role of HydF and its [4Fe-4S] cluster in [FeFe]-hydrogenase maturation by using a defined semisynthetic approach in which [Fe<sup>I</sup><sub>2</sub>(μ-SH)<sub>2</sub>(CO)<sub>4</sub>(CN)<sub>2</sub>]<sup>2–</sup> ([2Fe]<sub>E</sub>) is used to bypass HydE and HydG, and GCS components are used in place of cell lysate. We show that inclusion of the iron–sulfur carrier protein NfuA and the high-CO-affinity myoglobin variant Mb<sup>H64L</sup> provides dramatically improved hydrogenase activities up to 828 μmol/min/mg, equivalent to the best reported activities for <i>Chlamydomonas reinhardtii</i> [FeFe]-hydrogenase isolated from the native organism. Apo-HydF lacking a [4Fe-4S] cluster provides very little hydrogenase activity; however, full maturation is restored with the addition of NfuA, which we demonstrate reconstitutes the [4Fe-4S] cluster of HydF. In addition, a HydF variant lacking a [4Fe-4S] cluster by changing two cysteine ligands to alanine is completely unable to support either semisynthetic maturation using [2Fe]<sub>E</sub>, or full maturation using HydG and HydE, even in the presence of NfuA, demonstrating that the HydF [4Fe-4S] cluster is absolutely essential for [FeFe]-hydrogenase maturation. The possibility that the HydF [4Fe-4S] cluster plays a role in direct binding of [2Fe]<sub>E</sub> is negated by our results with the HydF<sup>D311C</sup> variant, which demonstrate that the labile Asp311 cluster ligand is not essential for [2Fe]<sub>E</sub> binding and HydA maturation. We therefore conclude that [2Fe]<sub>E</sub> binds HydF adjacent to, but not directly coordinated to, the [4Fe-4S] cluster. The HydF [4Fe-4S] cluster is proposed to be essential due to its impact on the [2Fe]<sub>E</sub> binding orientation and the ability of the HydF/[2Fe]<sub>E</sub> complex to form productive interactions with H<sub>met</sub> or the H<sub>met</sub>/T-protein complex during DTMA ligand biosynthesis.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"249 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Juan Zhu,Xingye Sun,Ningdong Feng,Bingbing Zhao,Ming Qiu,Jun Xu,Wei Luo
Rational engineering of the catalyst-electrolyte interface where the electrochemical processes occur to facilitate the proton transfer kinetics is crucial in various electrochemical reactions. Here, we show that the long-term stability of acidic oxygen evolution reaction (OER) catalyzed by RuO2 can be significantly promoted by engineering the interfacial water structure through interstitial boron (B) insertion (B-RuO2). Experimental results including in situ attenuated total reflectance-surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), local pH monitoring, and ab initio molecular dynamics (AIMD) simulations demonstrate that the insertion of boron atoms into the RuO2 lattice could facilitate the diffusion of protons across the interface by enhancing the connectivity of hydrogen-bond networks, thereby suppressing the continuous oxidative collapse of Ru. Moreover, the interstitial boron insertion could induce interfacial water reorientation and move nonbonding oxygen (ONB) away from Fermi level (Ef), resulting in decreased ONB and suppressed nucleophilic attack by interfacial H2O on ONB, further preventing structural corrosion caused by lattice oxygen loss. Consequently, the obtained B-RuO2 shows remarkable long-term operational stability, demonstrating over 1000 h of continuous operation at 10 mA cm-2. When applied in a practical proton exchange membrane water electrolyzer (PEMWE), it achieves a high current density of 3.0 A cm-2 at a voltage of 1.752 V and maintains stable performance at 4 A cm-2 for 200 h. This work provides a novel strategy for regulating the proton diffusion kinetics through engineering the interfacial water structure to promote acidic OER performance.
合理设计电化学过程发生的催化剂-电解质界面以促进质子转移动力学在各种电化学反应中是至关重要的。本研究表明，通过插入硼(B) （B-RuO2）来修饰界面水结构，可以显著提高RuO2催化酸性析氧反应（OER）的长期稳定性。包括原位衰减全反射-表面增强红外吸收光谱（ATR-SEIRAS）、局部pH监测和从头算分子动力学（AIMD）模拟在内的实验结果表明，在RuO2晶格中插入硼原子可以通过增强氢键网络的连连性来促进质子在界面上的扩散，从而抑制Ru的持续氧化坍塌。此外，硼的插入可以诱导界面水重定向，使非键氧（ONB）远离费米能级（Ef），从而减少ONB，抑制界面水对ONB的亲核攻击，进一步防止晶格氧损失引起的结构腐蚀。因此，得到的B-RuO2表现出显著的长期运行稳定性，在10 mA cm-2下连续运行超过1000小时。应用于质子交换膜水电解槽（PEMWE）中，在1.752 V电压下可获得3.0 a cm-2的高电流密度，并在4 a cm-2下保持200 h的稳定性能。本研究为通过设计界面水结构来调节质子扩散动力学以提高酸性OER性能提供了一种新的策略。
{"title":"Boosting Acidic Oxygen Evolution Electrocatalysis by Engineering the Interfacial Water at the Electrified RuO2-Electrolyte Interface.","authors":"Juan Zhu,Xingye Sun,Ningdong Feng,Bingbing Zhao,Ming Qiu,Jun Xu,Wei Luo","doi":"10.1021/jacs.5c16177","DOIUrl":"https://doi.org/10.1021/jacs.5c16177","url":null,"abstract":"Rational engineering of the catalyst-electrolyte interface where the electrochemical processes occur to facilitate the proton transfer kinetics is crucial in various electrochemical reactions. Here, we show that the long-term stability of acidic oxygen evolution reaction (OER) catalyzed by RuO2 can be significantly promoted by engineering the interfacial water structure through interstitial boron (B) insertion (B-RuO2). Experimental results including in situ attenuated total reflectance-surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), local pH monitoring, and ab initio molecular dynamics (AIMD) simulations demonstrate that the insertion of boron atoms into the RuO2 lattice could facilitate the diffusion of protons across the interface by enhancing the connectivity of hydrogen-bond networks, thereby suppressing the continuous oxidative collapse of Ru. Moreover, the interstitial boron insertion could induce interfacial water reorientation and move nonbonding oxygen (ONB) away from Fermi level (Ef), resulting in decreased ONB and suppressed nucleophilic attack by interfacial H2O on ONB, further preventing structural corrosion caused by lattice oxygen loss. Consequently, the obtained B-RuO2 shows remarkable long-term operational stability, demonstrating over 1000 h of continuous operation at 10 mA cm-2. When applied in a practical proton exchange membrane water electrolyzer (PEMWE), it achieves a high current density of 3.0 A cm-2 at a voltage of 1.752 V and maintains stable performance at 4 A cm-2 for 200 h. This work provides a novel strategy for regulating the proton diffusion kinetics through engineering the interfacial water structure to promote acidic OER performance.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"5 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145710808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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