Metal oxide subnanometric size clusters can be “small” but “powerful” in suppressing side-reactions such as the hydrogen evolution reaction (HER), thereby improving ammonia (NH3) product during the nitrate reduction reaction (NO3-RR). This study presents the synthesis of a carbon-vulcanized (C)-defective TiO2 nanosheet (TNS) composite, modified with subnanometric WO3 clusters. It is found that among various loadings, the electrocatalyst with 3 wt % WO3 (C-3%WO3-TNS) suppresses HER. NH3 production higher than 97% is achieved by incorporating CuNi (40:60 wt %) onto C-3%WO3-TNS (Cu40Ni60/C-3%WO3-TNS), as confirmed by in situ differential electrochemical mass spectrometry (DEMS). Chemical characterizations reveal that WO3 clusters influence the Ti3+/Ti4+ ratio, thereby potentially suppressing HER. It has also been found that NH3 formation is further facilitated by Cu40Ni60, which promotes faster NO3– reduction via a multistep reaction on the C-WO3-TNS supports. The synergy between Cu40Ni60, C, WO3, and defective TNS modulates the production of H2 and NH3. This synergy can be attributed to the morphological and structural characteristics of the electrocatalyst, which indicate that Ni is positioned at specific edge sites over the C and TNS, while WO3 and Cu are well-distributed over the TNS. A mechanistic approach is proposed to explain the observed products by DEMS. This work highlights the dual potential of Cu40Ni60/C-3%WO3-TNS to suppress HER and promote NH3 synthesis, offering a promising strategy for tuning reaction pathways during NO3-RR.
{"title":"Bifunctional Catalyst Design Integrating Copper Nickel and Tungsten Trioxide on Defective Titanium Dioxide Enables Reaction Pathway Steering in Nitrate Electroreduction","authors":"Eleazar Castañeda-Morales, Xochiquetzalli González-Bautista, Francisco Ruiz-Zepeda, Arturo Susarrey-Arce, Martha Leticia Hernández-Pichardo, Arturo Manzo-Robledo","doi":"10.1021/acs.chemmater.5c02346","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c02346","url":null,"abstract":"Metal oxide subnanometric size clusters can be “small” but “powerful” in suppressing side-reactions such as the hydrogen evolution reaction (HER), thereby improving ammonia (NH<sub>3</sub>) product during the nitrate reduction reaction (NO<sub>3</sub>-RR). This study presents the synthesis of a carbon-vulcanized (C)-defective TiO<sub>2</sub> nanosheet (TNS) composite, modified with subnanometric WO<sub>3</sub> clusters. It is found that among various loadings, the electrocatalyst with 3 wt % WO<sub>3</sub> (C-3%WO<sub>3</sub>-TNS) suppresses HER. NH<sub>3</sub> production higher than 97% is achieved by incorporating CuNi (40:60 wt %) onto C-3%WO<sub>3</sub>-TNS (Cu<sub>40</sub>Ni<sub>60</sub>/C-3%WO<sub>3</sub>-TNS), as confirmed by in situ differential electrochemical mass spectrometry (DEMS). Chemical characterizations reveal that WO<sub>3</sub> clusters influence the Ti<sup>3+</sup>/Ti<sup>4+</sup> ratio, thereby potentially suppressing HER. It has also been found that NH<sub>3</sub> formation is further facilitated by Cu<sub>40</sub>Ni<sub>60</sub>, which promotes faster NO<sub>3</sub><sup>–</sup> reduction via a multistep reaction on the C-WO<sub>3</sub>-TNS supports. The synergy between Cu<sub>40</sub>Ni<sub>60</sub>, C, WO<sub>3</sub>, and defective TNS modulates the production of H<sub>2</sub> and NH<sub>3</sub>. This synergy can be attributed to the morphological and structural characteristics of the electrocatalyst, which indicate that Ni is positioned at specific edge sites over the C and TNS, while WO<sub>3</sub> and Cu are well-distributed over the TNS. A mechanistic approach is proposed to explain the observed products by DEMS. This work highlights the dual potential of Cu<sub>40</sub>Ni<sub>60</sub>/C-3%WO<sub>3</sub>-TNS to suppress HER and promote NH<sub>3</sub> synthesis, offering a promising strategy for tuning reaction pathways during NO<sub>3</sub>-RR.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"73 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147368220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-07DOI: 10.1021/acs.chemmater.5c03087
Wei Ge, Tania L. Class-Martínez, José Rebolledo-Oyarce, Alyssa McNarney, Songhyun Lee, Anshuman Goswami, Claire T. Nimlos, Ahmad Moini, Subramanian Prasad, Vivek Vattipalli, Anthony DeBellis, Sichi Li, Bradley F. Chmelka, Rajamani Gounder, William F. Schneider
Co2+ exchange is commonly used as a reporter of Al pair ensembles in zeolites. We combine density functional theory (DFT) calculations, statistical models, experimental titrations, and solid-state nuclear magnetic resonance (NMR) analyses to explore the utility of other 2+ ions as alternative reporters of proximal Al ensembles in the CHA zeolite. DFT calculations suggest that Ba2+ will exchange into both eight- (8MR) and six-membered (6MR) CHA rings equally effectively, distinct from Co2+, which exchanges solely into 6MR. Simulated titration curves highlight the potential for Co2+ and Ba2+ titrations to provide complementary information about specific proximal Al site ensembles as a function of Si/Al ratio. Experiments on CHA zeolites synthesized to express different Al distributions confirm that Ba2+ uptake exceeds that of Co2+ and that this uptake can be rationalized by Ba2+ ions that titrate both 8MR and 6MR Al pair sites. Comparisons of absolute ion uptakes and two-dimensional NMR analyses of Al proximity with predictions reveal previously unrecognized differences in Al siting rules under different syntheses. These findings demonstrate that complementary titrations using divalent cations of differing ionic radii provide additional resolution on Al–Al pair ensembles and the underlying rules that govern Al distributions on zeolite frameworks.
{"title":"Ba2+ Complements Co2+ Exchange as a Reporter of Al Proximity in CHA Zeolites","authors":"Wei Ge, Tania L. Class-Martínez, José Rebolledo-Oyarce, Alyssa McNarney, Songhyun Lee, Anshuman Goswami, Claire T. Nimlos, Ahmad Moini, Subramanian Prasad, Vivek Vattipalli, Anthony DeBellis, Sichi Li, Bradley F. Chmelka, Rajamani Gounder, William F. Schneider","doi":"10.1021/acs.chemmater.5c03087","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c03087","url":null,"abstract":"Co<sup>2+</sup> exchange is commonly used as a reporter of Al pair ensembles in zeolites. We combine density functional theory (DFT) calculations, statistical models, experimental titrations, and solid-state nuclear magnetic resonance (NMR) analyses to explore the utility of other 2+ ions as alternative reporters of proximal Al ensembles in the CHA zeolite. DFT calculations suggest that Ba<sup>2+</sup> will exchange into both eight- (8MR) and six-membered (6MR) CHA rings equally effectively, distinct from Co<sup>2+</sup>, which exchanges solely into 6MR. Simulated titration curves highlight the potential for Co<sup>2+</sup> and Ba<sup>2+</sup> titrations to provide complementary information about specific proximal Al site ensembles as a function of Si/Al ratio. Experiments on CHA zeolites synthesized to express different Al distributions confirm that Ba<sup>2+</sup> uptake exceeds that of Co<sup>2+</sup> and that this uptake can be rationalized by Ba<sup>2+</sup> ions that titrate both 8MR and 6MR Al pair sites. Comparisons of absolute ion uptakes and two-dimensional NMR analyses of Al proximity with predictions reveal previously unrecognized differences in Al siting rules under different syntheses. These findings demonstrate that complementary titrations using divalent cations of differing ionic radii provide additional resolution on Al–Al pair ensembles and the underlying rules that govern Al distributions on zeolite frameworks.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"6 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147371527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-06DOI: 10.1021/acs.chemmater.5c02896
Arseniy Bokov, Anna Shelyug, Liuda Mereacre, Michael Knapp, Helmut Ehrenberg
This study introduces halometallurgy, an approach for reducing common Li-ion cathode materials in air using a eutectic mixture of chloride salts, with direct implications for processing battery black mass containing NMC, NCA, LCO, LNMO, and LMO. In-depth analysis, including in situ XRD, SEM/EDX, and TGA-DSC, reveals that reduction in the presence of NaCl-KCl proceeds via distinct halothermal and carbothermal routes. During the halothermal stage, lithium migrates from cathode particles into the chlorides, leading to the decomposition of layered or spinel structures into a solid solution of cubic oxides. Lithium migration facilitates the melting of the salts, resulting in the encapsulation of the oxide phase and the creation of quasi-inert conditions. This enables further reduction during the carbothermal stage and promotes the nucleation of metallic crystallites. Upon washing with water, lithium predominantly remains in the saline solution, termed halothermal brine, while the insoluble fraction consists of porous transition metal oxides and graphite. Depending on cathode composition, halothermal reduction is observed at 460–640 °C, while carbothermal reduction occurs above 620–650 °C. Typical black-mass impurities, including current collectors, binders, and electrolyte residues, were also examined, demonstrating relevance for real waste streams. The proposed treatment offers a pathway toward decentralized battery recycling.
{"title":"Halometallurgy: Reduction of Battery Cathode Materials under a Quasi-Inert Environment of Alkali Chloride Salts","authors":"Arseniy Bokov, Anna Shelyug, Liuda Mereacre, Michael Knapp, Helmut Ehrenberg","doi":"10.1021/acs.chemmater.5c02896","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c02896","url":null,"abstract":"This study introduces halometallurgy, an approach for reducing common Li-ion cathode materials in air using a eutectic mixture of chloride salts, with direct implications for processing battery black mass containing NMC, NCA, LCO, LNMO, and LMO. In-depth analysis, including in situ XRD, SEM/EDX, and TGA-DSC, reveals that reduction in the presence of NaCl-KCl proceeds via distinct halothermal and carbothermal routes. During the halothermal stage, lithium migrates from cathode particles into the chlorides, leading to the decomposition of layered or spinel structures into a solid solution of cubic oxides. Lithium migration facilitates the melting of the salts, resulting in the encapsulation of the oxide phase and the creation of quasi-inert conditions. This enables further reduction during the carbothermal stage and promotes the nucleation of metallic crystallites. Upon washing with water, lithium predominantly remains in the saline solution, termed halothermal brine, while the insoluble fraction consists of porous transition metal oxides and graphite. Depending on cathode composition, halothermal reduction is observed at 460–640 °C, while carbothermal reduction occurs above 620–650 °C. Typical black-mass impurities, including current collectors, binders, and electrolyte residues, were also examined, demonstrating relevance for real waste streams. The proposed treatment offers a pathway toward decentralized battery recycling.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"32 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147360876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-06DOI: 10.1021/acs.chemmater.6c00566
Jared D. Fletcher, Marios Zacharias, Shoshanna Peifer, Jin Hou, Anastasia D. Pournara, Aditya D. Mohite, Richard D. Schaller, Jacky Even, Claudine Katan, Mercouri G. Kanatzidis
The CCDC numbers used in this publication were changed within the CCDC between the time of submission and publication. We request changing the numbers of 2483602–2483620 to 2483621–2483639. To list out all numbers impacted: Please change 2483602, 2483603, 2483604, 2483605, 2483606, 2483607, 2483608, 2483609, 2483610, 2483611, 2483612, 2483613, 2483614, 2483615, 2483616, 2483617, 2483618, 2483619, and 2483620 to 2483621, 2483622, 2483623, 2483624, 2483625, 2483626, 2483627, 2483628, 2483629, 2483630, 2483631, 2483632, 2483633, 2483634, 2483635, 2483636, 2483637, 2483638, and 2483639. This article has not yet been cited by other publications.
{"title":"Correction to “Polymorphism and Phase Control in Dion–Jacobson 2D 3-(Aminomethyl)piperidinium-Based Metal Iodide Perovskites”","authors":"Jared D. Fletcher, Marios Zacharias, Shoshanna Peifer, Jin Hou, Anastasia D. Pournara, Aditya D. Mohite, Richard D. Schaller, Jacky Even, Claudine Katan, Mercouri G. Kanatzidis","doi":"10.1021/acs.chemmater.6c00566","DOIUrl":"https://doi.org/10.1021/acs.chemmater.6c00566","url":null,"abstract":"The CCDC numbers used in this publication were changed within the CCDC between the time of submission and publication. We request changing the numbers of 2483602–2483620 to 2483621–2483639. To list out all numbers impacted: Please change 2483602, 2483603, 2483604, 2483605, 2483606, 2483607, 2483608, 2483609, 2483610, 2483611, 2483612, 2483613, 2483614, 2483615, 2483616, 2483617, 2483618, 2483619, and 2483620 to 2483621, 2483622, 2483623, 2483624, 2483625, 2483626, 2483627, 2483628, 2483629, 2483630, 2483631, 2483632, 2483633, 2483634, 2483635, 2483636, 2483637, 2483638, and 2483639. This article has not yet been cited by other publications.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"49 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147360877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Halide perovskites are crucial materials with broad applications owing to their exceptional optoelectronic properties. Vacancy-ordered double perovskites, featuring highly tunable transition metal sites, enable controllable optoelectronic properties through multielement compositional design. In this study, we introduced 18-crown-6 into the vacancy-ordered double perovskites system and developed two-dimensional ribbon-like single crystals (18C6@K)2{PtSnTeIrRe}1Cl6 via an antisolvent supramolecular assembly method, demonstrating morphology modulation through multielement composition design. The crystals crystallize in the centrosymmetric space group . The dumbbell-shaped structural units (crown ether@A)2MX6 pack along a and b axes to form a 2-dimensional (2D) monolayer, and these monolayers further stack along the c axis to generate the ribbon-like single crystals. Energy-dispersive X-ray spectroscopy (EDX) qualitatively confirmed the uniform distribution of the five transition metals throughout the crystal, while inductively coupled plasma atomic emission spectroscopy (ICP–AES) quantitatively verified their atomic ratios. We further investigated the origin of the morphology, distinct from the previously reported cube-like single crystals with the space group. When acetonitrile was used as the solvent, three-dimensional crystals with symmetry were obtained, whereas dimethylformamide (DMF) was essential for forming two-dimensional ribbon-like single crystals. The essential role of DMF could be ascribed to its capability to maintain a higher concentration of the building blocks. Moreover, Ir4+ and Pt4+ cations also played critical roles in inducing the two-dimensional ribbon-like morphology. The three-element (18C6@K)2{PtSnTe}1Cl6 single crystals exhibited bright yellow emission under 375 nm laser excitation, demonstrating the tunability of optoelectronic properties of this class of material.
{"title":"Supramolecular Assembly of Multielement Ribbon-like Structures Derived from Halide Perovskites","authors":"Heqing Zhu, Cheng Zhu, Yuxin Jiang, Chuxi Wen, Xinyu Chen, Peidong Yang","doi":"10.1021/acs.chemmater.5c03160","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c03160","url":null,"abstract":"Halide perovskites are crucial materials with broad applications owing to their exceptional optoelectronic properties. Vacancy-ordered double perovskites, featuring highly tunable transition metal sites, enable controllable optoelectronic properties through multielement compositional design. In this study, we introduced 18-crown-6 into the vacancy-ordered double perovskites system and developed two-dimensional ribbon-like single crystals (18C6@K)<sub>2</sub>{PtSnTeIrRe}<sub>1</sub>Cl<sub>6</sub> via an antisolvent supramolecular assembly method, demonstrating morphology modulation through multielement composition design. The crystals crystallize in the centrosymmetric space group <i></i><math display=\"inline\"><mi>P</mi><mover><mn>1</mn><mo accent=\"true\" stretchy=\"false\">¯</mo></mover></math>. The dumbbell-shaped structural units (crown ether@A)<sub>2</sub>MX<sub>6</sub> pack along a and <i>b</i> axes to form a 2-dimensional (2D) monolayer, and these monolayers further stack along the <i>c</i> axis to generate the ribbon-like single crystals. Energy-dispersive X-ray spectroscopy (EDX) qualitatively confirmed the uniform distribution of the five transition metals throughout the crystal, while inductively coupled plasma atomic emission spectroscopy (ICP–AES) quantitatively verified their atomic ratios. We further investigated the origin of the morphology, distinct from the previously reported cube-like single crystals with the <i></i><math display=\"inline\"><mi>R</mi><mover><mn>3</mn><mo accent=\"true\" stretchy=\"false\">¯</mo></mover></math> space group. When acetonitrile was used as the solvent, three-dimensional crystals with <i></i><math display=\"inline\"><mi>R</mi><mover><mn>3</mn><mo accent=\"true\" stretchy=\"false\">¯</mo></mover></math> symmetry were obtained, whereas dimethylformamide (DMF) was essential for forming two-dimensional ribbon-like single crystals. The essential role of DMF could be ascribed to its capability to maintain a higher concentration of the building blocks. Moreover, Ir<sup>4+</sup> and Pt<sup>4+</sup> cations also played critical roles in inducing the two-dimensional ribbon-like morphology. The three-element (18C6@K)<sub>2</sub>{PtSnTe}<sub>1</sub>Cl<sub>6</sub> single crystals exhibited bright yellow emission under 375 nm laser excitation, demonstrating the tunability of optoelectronic properties of this class of material.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"113 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147360881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05DOI: 10.1021/acs.chemmater.5c02749
Shintaro Tanaka, Yuta Kanao, Takaaki Tsuruoka, Kensuke Akamatsu, Yohei Takashima
Reversible structural transformations in metal–organic frameworks (MOFs) driven by bond-switching mechanisms offer a promising approach for dynamically controlling material properties, enhancing advanced functionality, and designing smart materials. However, most reported structural transformations have been serendipitous, posing significant challenges for their deliberate design and practical application. This study focuses on the structural interconversion between MIL-53 and MIL-68, two aluminum-based MOF structural isomers, investigating the effects of framework defects and particle size on their transformation behaviors. The findings of this study provide essential insights into the mechanisms underlying MOF structural transformations and lay the groundwork for developing responsive materials with precisely controlled structural dynamics.
{"title":"Impact of Defects and Particle Size on the Reversible Structural Transformation between Metal–Organic Frameworks","authors":"Shintaro Tanaka, Yuta Kanao, Takaaki Tsuruoka, Kensuke Akamatsu, Yohei Takashima","doi":"10.1021/acs.chemmater.5c02749","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c02749","url":null,"abstract":"Reversible structural transformations in metal–organic frameworks (MOFs) driven by bond-switching mechanisms offer a promising approach for dynamically controlling material properties, enhancing advanced functionality, and designing smart materials. However, most reported structural transformations have been serendipitous, posing significant challenges for their deliberate design and practical application. This study focuses on the structural interconversion between MIL-53 and MIL-68, two aluminum-based MOF structural isomers, investigating the effects of framework defects and particle size on their transformation behaviors. The findings of this study provide essential insights into the mechanisms underlying MOF structural transformations and lay the groundwork for developing responsive materials with precisely controlled structural dynamics.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"290 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147360879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05DOI: 10.1021/acs.chemmater.5c02738
Khabib Khumaini, Hye-Lee Kim, Taewook Nam, Won-Jun Lee
We elucidate the removal reaction mechanisms during isotropic atomic layer etching (ALE) of aluminum oxide (Al2O3) using density functional theory (DFT) calculations. Using amorphous aluminum fluoride (a-AlF3) surface models, we simulated reactions with various metal precursors: TiCl4, SiCl4, AlCl3, Al(CH3)3 (TMA), and AlCl(CH3)2 (DMAC). Our results indicate that the first two ligand-exchange steps involving TiCl4 and SiCl4 are favorable at 250 °C, releasing TiFCl3 and SiFCl3, respectively. However, the subsequent release of any Al-containing product is hindered by high activation barriers, which prevent net etching of the Al2O3 film. In contrast, we found that an alternative reaction pathway involving dimer formation is critical for successful etching processes. Although AlCl3 is ineffective via the simple ligand-exchange mechanism, it can etch the a-AlF3 layer effectively by forming a stable Al2F2Cl4 dimer product with low activation energies. The heteroleptic precursor DMAC is the most effective, offering multiple favorable reaction pathways that release various Al-containing dimers. DMAC features the lowest energy barriers, which explains its superior performance in experiments. Our calculations show that breaking the surface metal-fluoride bond is the most difficult part of the etching process, and dimer formation can offset this high-energy penalty by forming additional bonds. These theoretical results align well with experimental observations from in situ analyses, confirming that DFT is a powerful predictive tool for screening precursors and explaining reaction mechanisms in ALE processes.
{"title":"Dimer Formation as the Key Removal Pathway in the Isotropic Atomic Layer Etching of Al2O3: A First-Principles Study","authors":"Khabib Khumaini, Hye-Lee Kim, Taewook Nam, Won-Jun Lee","doi":"10.1021/acs.chemmater.5c02738","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c02738","url":null,"abstract":"We elucidate the removal reaction mechanisms during isotropic atomic layer etching (ALE) of aluminum oxide (Al<sub>2</sub>O<sub>3</sub>) using density functional theory (DFT) calculations. Using amorphous aluminum fluoride (a-AlF<sub>3</sub>) surface models, we simulated reactions with various metal precursors: TiCl<sub>4</sub>, SiCl<sub>4</sub>, AlCl<sub>3</sub>, Al(CH<sub>3</sub>)<sub>3</sub> (TMA), and AlCl(CH<sub>3</sub>)<sub>2</sub> (DMAC). Our results indicate that the first two ligand-exchange steps involving TiCl<sub>4</sub> and SiCl<sub>4</sub> are favorable at 250 °C, releasing TiFCl<sub>3</sub> and SiFCl<sub>3</sub>, respectively. However, the subsequent release of any Al-containing product is hindered by high activation barriers, which prevent net etching of the Al<sub>2</sub>O<sub>3</sub> film. In contrast, we found that an alternative reaction pathway involving dimer formation is critical for successful etching processes. Although AlCl<sub>3</sub> is ineffective via the simple ligand-exchange mechanism, it can etch the a-AlF<sub>3</sub> layer effectively by forming a stable Al<sub>2</sub>F<sub>2</sub>Cl<sub>4</sub> dimer product with low activation energies. The heteroleptic precursor DMAC is the most effective, offering multiple favorable reaction pathways that release various Al-containing dimers. DMAC features the lowest energy barriers, which explains its superior performance in experiments. Our calculations show that breaking the surface metal-fluoride bond is the most difficult part of the etching process, and dimer formation can offset this high-energy penalty by forming additional bonds. These theoretical results align well with experimental observations from <i>in situ</i> analyses, confirming that DFT is a powerful predictive tool for screening precursors and explaining reaction mechanisms in ALE processes.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"251 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147360878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05DOI: 10.1021/acs.chemmater.5c02918
Eve K. Stegner, Md Riad Sarkar Pavel, Anuluxan Santhiran, Jack Lawton, Juan-Pablo Correa-Baena, Aaron J. Rossini, Javier Vela
Chalcohalide semiconductors are rapidly gaining traction as stable, biocompatible materials for energy conversion applications. While the solid-state synthesis of bulk chalcohalides is relatively well-developed, the colloidal chemistry of these materials is still in its early stages. Colloidal semiconductors are often advantageous in device fabrication due to the cost effectiveness of solution processing. Thus, we aim to increase the utility of chalcohalides in device fabrication by establishing solution phase chemistry of promising compositions. We show that silyl hot-injection is a versatile and effective method of making colloidal PnChI (Pn = Sb, Bi; Ch = S, Se) and Sn2PnS2I3 (Pn = Sb, Bi) chalcohalides of tunable sizes and compositions. Furthermore, we demonstrate the preparation of mixed-pnictide chalcohalides through direct hot-injection and/or postsynthetic cation exchange, the latter being one of the few reported instances in chalcohalides. Additionally, we use the thiocyanate heat-up approach in combination with density functional theory to study halide mixing in quaternary tin chalcohalides. By pushing the limits of each synthetic technique, we have designed more soluble chalcohalides with tunable compositions while also gaining a better understanding of the efficacy of each procedure in respect to thin film and subsequent device fabrication. In addition to size and composition tuning, silyl hot-injection can help facilitate the future development and wide-scale application of chalcohalide-based devices by expanding the selection of solution-processable chalcohalides.
{"title":"Silyl Hot-Injection Versus Thiocyanate Heat-Up Synthesis of Chalcohalides: Pushing the Size and Composition Envelope","authors":"Eve K. Stegner, Md Riad Sarkar Pavel, Anuluxan Santhiran, Jack Lawton, Juan-Pablo Correa-Baena, Aaron J. Rossini, Javier Vela","doi":"10.1021/acs.chemmater.5c02918","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c02918","url":null,"abstract":"Chalcohalide semiconductors are rapidly gaining traction as stable, biocompatible materials for energy conversion applications. While the solid-state synthesis of bulk chalcohalides is relatively well-developed, the colloidal chemistry of these materials is still in its early stages. Colloidal semiconductors are often advantageous in device fabrication due to the cost effectiveness of solution processing. Thus, we aim to increase the utility of chalcohalides in device fabrication by establishing solution phase chemistry of promising compositions. We show that silyl hot-injection is a versatile and effective method of making colloidal PnChI (Pn = Sb, Bi; Ch = S, Se) and Sn<sub>2</sub>PnS<sub>2</sub>I<sub>3</sub> (Pn = Sb, Bi) chalcohalides of tunable sizes and compositions. Furthermore, we demonstrate the preparation of mixed-pnictide chalcohalides through direct hot-injection and/or postsynthetic cation exchange, the latter being one of the few reported instances in chalcohalides. Additionally, we use the thiocyanate heat-up approach in combination with density functional theory to study halide mixing in quaternary tin chalcohalides. By pushing the limits of each synthetic technique, we have designed more soluble chalcohalides with tunable compositions while also gaining a better understanding of the efficacy of each procedure in respect to thin film and subsequent device fabrication. In addition to size and composition tuning, silyl hot-injection can help facilitate the future development and wide-scale application of chalcohalide-based devices by expanding the selection of solution-processable chalcohalides.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"5 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147360880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-05DOI: 10.1021/acs.chemmater.5c03195
Dhritismita Sarma, Arup Mahata
The photophysical behavior of ns<sup>2</sup> metal-based zero-dimensional (0D) halides, particularly their broad emission driven by self-trapped excitons (STEs), makes them unique and promising for light-emitting technologies. The stereochemical activity of the ns<sup>2</sup> lone pair plays a decisive role in dictating the structural and photophysical properties of such metal halides. However, a systematic and generalized framework correlating the factors associated with ns<sup>2</sup> electron engineering, e.g., metal identity, local coordination geometry, electronic energy level of the organic cation, and dynamical off-centering in tuning the emission characteristics, remains limited. In this work, using state-of-the-art density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations on ns<sup>2</sup> metal (Pb<sup>2+</sup>, Sn<sup>2+</sup>, and Sb<sup>3+</sup>) bromides incorporating Cs<sup>+</sup>, aliphatic, and aromatic organic cations having octahedral, disphenoidal, and square-pyramidal coordination environments, we have studied the ground and excited-state behavior and framed a generalized structure–emission characteristic correlation. Our results demonstrate that, in higher-coordination environments, ns<sup>2</sup> lone pair exposure primarily determines the emission behavior, with Sn<sup>2+</sup> exhibiting more stable STE characteristics and Pb<sup>2+</sup> remaining largely inactive. However, in lower-coordination environments, the photophysical response appears as an interplay between ns<sup>2</sup> lone pair exposure and its coordination geometry; Sn<sup>2+</sup>, having disphenoidal coordination, displays a prominent emission characteristic compared to that of Pb<sup>2+</sup> disphenoidal and Sb<sup>3+</sup> square-pyramidal geometries. We find that the STE responses are largely hole-driven with a lesser role for electrons. Furthermore, our study reveals that, while A-site cation substitution has a minimal effect on ground-state hybridization, it profoundly alters excited-state behavior, where aromatic cations promote charge separation and non-STE-like excitons, whereas aliphatic cations favor STE formation. AIMD calculations further reveal that higher-coordination systems show lone pair activity through dynamic off-centering, whereas the lone pair of lower-coordination systems is stereochemically inactive to dynamic off-centering due to deviation from the optimal spatial availability of the lone pairs. Therefore, our results demonstrate that, despite the ns<sup>2</sup> lone pair’s population at the valence band edge, ground-state treatment is insufficient to fully capture the stereochemical nature; instead, it is dictated by the excited state and dynamical treatment. These insights establish a robust atomistic framework linking the stereochemical activity, coordination geometry, and exciton localization of the lone pair, thus providing atomistic interpretation of experimentally observed trends and offering a
{"title":"ns2 Electron Engineering in Zero-Dimensional Metal Halides for Modulating Emission Behavior","authors":"Dhritismita Sarma, Arup Mahata","doi":"10.1021/acs.chemmater.5c03195","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c03195","url":null,"abstract":"The photophysical behavior of ns<sup>2</sup> metal-based zero-dimensional (0D) halides, particularly their broad emission driven by self-trapped excitons (STEs), makes them unique and promising for light-emitting technologies. The stereochemical activity of the ns<sup>2</sup> lone pair plays a decisive role in dictating the structural and photophysical properties of such metal halides. However, a systematic and generalized framework correlating the factors associated with ns<sup>2</sup> electron engineering, e.g., metal identity, local coordination geometry, electronic energy level of the organic cation, and dynamical off-centering in tuning the emission characteristics, remains limited. In this work, using state-of-the-art density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations on ns<sup>2</sup> metal (Pb<sup>2+</sup>, Sn<sup>2+</sup>, and Sb<sup>3+</sup>) bromides incorporating Cs<sup>+</sup>, aliphatic, and aromatic organic cations having octahedral, disphenoidal, and square-pyramidal coordination environments, we have studied the ground and excited-state behavior and framed a generalized structure–emission characteristic correlation. Our results demonstrate that, in higher-coordination environments, ns<sup>2</sup> lone pair exposure primarily determines the emission behavior, with Sn<sup>2+</sup> exhibiting more stable STE characteristics and Pb<sup>2+</sup> remaining largely inactive. However, in lower-coordination environments, the photophysical response appears as an interplay between ns<sup>2</sup> lone pair exposure and its coordination geometry; Sn<sup>2+</sup>, having disphenoidal coordination, displays a prominent emission characteristic compared to that of Pb<sup>2+</sup> disphenoidal and Sb<sup>3+</sup> square-pyramidal geometries. We find that the STE responses are largely hole-driven with a lesser role for electrons. Furthermore, our study reveals that, while A-site cation substitution has a minimal effect on ground-state hybridization, it profoundly alters excited-state behavior, where aromatic cations promote charge separation and non-STE-like excitons, whereas aliphatic cations favor STE formation. AIMD calculations further reveal that higher-coordination systems show lone pair activity through dynamic off-centering, whereas the lone pair of lower-coordination systems is stereochemically inactive to dynamic off-centering due to deviation from the optimal spatial availability of the lone pairs. Therefore, our results demonstrate that, despite the ns<sup>2</sup> lone pair’s population at the valence band edge, ground-state treatment is insufficient to fully capture the stereochemical nature; instead, it is dictated by the excited state and dynamical treatment. These insights establish a robust atomistic framework linking the stereochemical activity, coordination geometry, and exciton localization of the lone pair, thus providing atomistic interpretation of experimentally observed trends and offering a","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"44 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147368132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flexible and wearable electronics demand stretchable sensors with polymer elastomers as key matrixes for mechanical flexibility and durability. However, despite their excellent elasticity, their limited mechanical strength remains a challenge. To address this limitation, in this study, we report the rational design of supramolecular polyurethane elastomers (SPUs) incorporating nucleobase-inspired aminopyrimidinedione with DDA-AAD (G-C mimic) reversible triple hydrogen bonds. This dual-domain architecture gives rise to a durable supramolecular network with enhanced mechanical properties, yielding elastomers that are soft, stretchable, and tough. By tuning of the density of dynamic cross-links, mechanical properties were systematically modulated. SPU-0.5 exhibited a maximum tensile strength of 16.14 MPa, representing a 67-fold strength enhancement over that of SPU-0. Although increasing the aminopyrimidinedione (APD) content reduced elongation, SPU-0.2 retained a high elongation of 1060% and showed the lowest residual strain during cyclic tests. To be of great interest, the activation energy increased with increasing hydrogen bonding content up to SPU-0.1, whereas beyond SPU-0.2 it decreased, likely due to extensive hydrogen bond formation. Furthermore, SPU-0.2-SP, a conductive variant, demonstrated a promising strain-sensing performance even after hundreds of cycles. Overall, the insights gained from this study advance the development of intelligent soft materials and lay the groundwork for next-generation flexible and wearable electronic devices.
{"title":"Dynamic Janus Hydrogen Bond Mimicry Unlocks Tough, Flexible Supramolecular Elastomers for Strain Sensing","authors":"Durga Lakshmi, Mahendra A. Wagh, Aakash Sharma, Md Shafi Alam, Muthamil Selvan T, Arun Torris, Titash Mondal, Gangadhar J. Sanjayan, Kiran Sukumaran Nair","doi":"10.1021/acs.chemmater.5c02829","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c02829","url":null,"abstract":"Flexible and wearable electronics demand stretchable sensors with polymer elastomers as key matrixes for mechanical flexibility and durability. However, despite their excellent elasticity, their limited mechanical strength remains a challenge. To address this limitation, in this study, we report the rational design of supramolecular polyurethane elastomers (SPUs) incorporating nucleobase-inspired aminopyrimidinedione with DDA-AAD (G-C mimic) reversible triple hydrogen bonds. This dual-domain architecture gives rise to a durable supramolecular network with enhanced mechanical properties, yielding elastomers that are soft, stretchable, and tough. By tuning of the density of dynamic cross-links, mechanical properties were systematically modulated. SPU-0.5 exhibited a maximum tensile strength of 16.14 MPa, representing a 67-fold strength enhancement over that of SPU-0. Although increasing the aminopyrimidinedione (APD) content reduced elongation, SPU-0.2 retained a high elongation of 1060% and showed the lowest residual strain during cyclic tests. To be of great interest, the activation energy increased with increasing hydrogen bonding content up to SPU-0.1, whereas beyond SPU-0.2 it decreased, likely due to extensive hydrogen bond formation. Furthermore, SPU-0.2-SP, a conductive variant, demonstrated a promising strain-sensing performance even after hundreds of cycles. Overall, the insights gained from this study advance the development of intelligent soft materials and lay the groundwork for next-generation flexible and wearable electronic devices.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"26 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147360998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：