Pub Date : 2025-12-03DOI: 10.1016/j.mcat.2025.115630
Faiza Shafiq, Lei Yang, Jiake Fan, Weihua Zhu
One efficient technique for treating nitrate-induced environmental pollution and simultaneously producing valuable product ammonia (NH3) is to electrochemically catalyze nitrate reduction reaction (NO3RR) to synthesize ammonia. Using DFT calculations, single atoms supported on boron carbonitride (BC2N) monolayers as promising catalysts for NO3RR were investigated from their high activity, selectivity, and stability. We have thoroughly examined catalytic activity and selectivity using high-throughput six-step screening processes. It is found that two catalysts Cr@typeA VC2 and Cu@typeB VC1 can electrochemically convert nitrate to NH3, which possess very low limiting potentials (UL = - 0.07 and - 0.37 V, respectively) and high selectivity for NH3. The underlying reason is moderate adsorption strength between intermediate species and metal atoms, governed by their distinctive electronic properties. Additionally, the two catalysts exhibit outstanding structural stability at 500 K based on ab initio molecular dynamics simulations. Our work may offer basic insights for NO3RR and aid in the development of effective electrocatalysts for the production of NH3.
{"title":"Single metal atom supported on BC2N monolayers as promising electrochemical catalysts for nitrate reduction reaction: A theoretical study","authors":"Faiza Shafiq, Lei Yang, Jiake Fan, Weihua Zhu","doi":"10.1016/j.mcat.2025.115630","DOIUrl":"10.1016/j.mcat.2025.115630","url":null,"abstract":"<div><div>One efficient technique for treating nitrate-induced environmental pollution and simultaneously producing valuable product ammonia (NH<sub>3</sub>) is to electrochemically catalyze nitrate reduction reaction (NO<sub>3</sub>RR) to synthesize ammonia. Using DFT calculations, single atoms supported on boron carbonitride (BC<sub>2</sub>N) monolayers as promising catalysts for NO<sub>3</sub>RR were investigated from their high activity, selectivity, and stability. We have thoroughly examined catalytic activity and selectivity using high-throughput six-step screening processes. It is found that two catalysts Cr@typeA V<sub>C2</sub> and Cu@typeB V<sub>C1</sub> can electrochemically convert nitrate to NH<sub>3</sub>, which possess very low limiting potentials (<em>U</em><sub>L</sub> = - 0.07 and - 0.37 V, respectively) and high selectivity for NH<sub>3</sub>. The underlying reason is moderate adsorption strength between intermediate species and metal atoms, governed by their distinctive electronic properties. Additionally, the two catalysts exhibit outstanding structural stability at 500 K based on ab initio molecular dynamics simulations. Our work may offer basic insights for NO<sub>3</sub>RR and aid in the development of effective electrocatalysts for the production of NH<sub>3</sub>.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115630"},"PeriodicalIF":4.9,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mannose-6-phosphate (M6P) is a pivotal metabolic intermediate involved in lysosomal enzyme trafficking, glycosylation pathways, and multiple cellular processes, with growing relevance in both disease pathogenesis and industrial biomanufacturing. Despite its importance, microbial M6P production remains limited by low enzyme activity, narrow substrate specificity, and suboptimal conversion efficiency. To overcome these challenges, we engineered the polyphosphate-dependent mannose kinase (PPGMK) from Arthrobacter sp. I3 using a directed evolution strategy, guided by a high-throughput NADPH-coupled screening assay. Screening of over 4000 variants identified a triple mutant, Mut6 (L169I/L172I/I174L), which significantly improved substrate utilization and achieved a mannose-to-M6P conversion of 98.5 %, compared with 57.3 % for the wild-type enzyme. Molecular dynamics simulations revealed that Mut6 enhances active-site loop flexibility and strengthens hydrogen-bond networks, particularly involving residue D123, which promotes efficient proton transfer and stabilizes the substrate. Implementation of Mut6 in Escherichia coli enabled whole-cell biotransformation that reached an unprecedented M6P titer of 127.8 g/L with 98.2 % conversion within 8 h in a 1-L bioreactor, demonstrating excellent catalytic efficiency, operational robustness, and process scalability. This work establishes an environmentally friendly and industrially viable bioprocess for phosphorylated sugar production. Moreover, it highlights the power of rational and semi-rational enzyme engineering to optimize substrate binding, catalytic turnover, and operational performance, providing a versatile framework for the sustainable production of other sugar phosphates and value-added biochemicals.
{"title":"Directed evolution of Arthrobacter sp. polyphosphate-dependent mannose kinase enables efficient mannose-6-phosphate production","authors":"Dan Guan , Yingqi Ruan , Wenchi Zhang , Rongzhen Zhang , Zhiming Rao","doi":"10.1016/j.mcat.2025.115632","DOIUrl":"10.1016/j.mcat.2025.115632","url":null,"abstract":"<div><div>Mannose-6-phosphate (M6P) is a pivotal metabolic intermediate involved in lysosomal enzyme trafficking, glycosylation pathways, and multiple cellular processes, with growing relevance in both disease pathogenesis and industrial biomanufacturing. Despite its importance, microbial M6P production remains limited by low enzyme activity, narrow substrate specificity, and suboptimal conversion efficiency. To overcome these challenges, we engineered the polyphosphate-dependent mannose kinase (PPGMK) from <em>Arthrobacter</em> sp. I3 using a directed evolution strategy, guided by a high-throughput NADPH-coupled screening assay. Screening of over 4000 variants identified a triple mutant, Mut6 (L169I/L172I/I174L), which significantly improved substrate utilization and achieved a mannose-to-M6P conversion of 98.5 %, compared with 57.3 % for the wild-type enzyme. Molecular dynamics simulations revealed that Mut6 enhances active-site loop flexibility and strengthens hydrogen-bond networks, particularly involving residue D123, which promotes efficient proton transfer and stabilizes the substrate. Implementation of Mut6 in <em>Escherichia coli</em> enabled whole-cell biotransformation that reached an unprecedented M6P titer of 127.8 g/L with 98.2 % conversion within 8 h in a 1-L bioreactor, demonstrating excellent catalytic efficiency, operational robustness, and process scalability. This work establishes an environmentally friendly and industrially viable bioprocess for phosphorylated sugar production. Moreover, it highlights the power of rational and semi-rational enzyme engineering to optimize substrate binding, catalytic turnover, and operational performance, providing a versatile framework for the sustainable production of other sugar phosphates and value-added biochemicals.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115632"},"PeriodicalIF":4.9,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.mcat.2025.115591
Zhouxuan Zang, Ningke Pang, Ziyue Zhang, Yi Yu, Li Xu, Guoji Liu
Hydroxypivalaldehyde (HPA) is an important intermediate in the fine chemical industry, making the development of high-performance catalysts for its preparation a significant research goal. In this study, we synthesized mixed metal oxides with a high concentration of the metal oxide phase by calcining Mg-Al layered double hydroxides (LDHs) modified with IPA. The catalytic performance of all catalysts was evaluated in the aldol condensation reaction of formaldehyde (FA) and isobutyraldehyde (IBD) for the production of HPA. The morphology and structure of the catalysts were characterized by BET, XRD, TG, TEM, SEM, and TPD. The results indicated that the treatment with isopropanol significantly increased the specific surface area of the mixed metal oxides. The specific surface area of the AMO-Mg2AlO-8 h catalyst reached 281 m2/g. XPS analysis confirmed that the modification with isopropanol enhanced the proportion of metal oxide phases in the LDH-derived catalysts. The reaction results demonstrated that the AMO-Mg2AlO-8 h catalyst exhibited high catalytic activity and selectivity. Under optimal conditions, an IBD conversion of 67.9 % and an HPA selectivity of 97.8 % were achieved. Combined characterization, experimental, and theoretical studies revealed that the AMO-Mg2AlO-8 h catalyst, with a higher exposure of the (220) crystal plane, possesses high surface adsorption energy and excellent acid-base properties. These properties effectively facilitate the adsorption and activation of both FA and IBD molecules. This efficient adsorption and activation effectively suppresses side reactions, thereby enhancing the selectivity toward HPA.
{"title":"Study on the role of crystal face on aldol condensation over LDH-derived mixed oxides","authors":"Zhouxuan Zang, Ningke Pang, Ziyue Zhang, Yi Yu, Li Xu, Guoji Liu","doi":"10.1016/j.mcat.2025.115591","DOIUrl":"10.1016/j.mcat.2025.115591","url":null,"abstract":"<div><div>Hydroxypivalaldehyde (HPA) is an important intermediate in the fine chemical industry, making the development of high-performance catalysts for its preparation a significant research goal. In this study, we synthesized mixed metal oxides with a high concentration of the metal oxide phase by calcining Mg-Al layered double hydroxides (LDHs) modified with IPA. The catalytic performance of all catalysts was evaluated in the aldol condensation reaction of formaldehyde (FA) and isobutyraldehyde (IBD) for the production of HPA. The morphology and structure of the catalysts were characterized by BET, XRD, TG, TEM, SEM, and TPD. The results indicated that the treatment with isopropanol significantly increased the specific surface area of the mixed metal oxides. The specific surface area of the AMO-Mg<sub>2</sub>AlO-8 h catalyst reached 281 m<sup>2</sup>/g. XPS analysis confirmed that the modification with isopropanol enhanced the proportion of metal oxide phases in the LDH-derived catalysts. The reaction results demonstrated that the AMO-Mg<sub>2</sub>AlO-8 h catalyst exhibited high catalytic activity and selectivity. Under optimal conditions, an IBD conversion of 67.9 % and an HPA selectivity of 97.8 % were achieved. Combined characterization, experimental, and theoretical studies revealed that the AMO-Mg2AlO-8 h catalyst, with a higher exposure of the (220) crystal plane, possesses high surface adsorption energy and excellent acid-base properties. These properties effectively facilitate the adsorption and activation of both FA and IBD molecules. This efficient adsorption and activation effectively suppresses side reactions, thereby enhancing the selectivity toward HPA.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115591"},"PeriodicalIF":4.9,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.mcat.2025.115629
Kimia Keshavarz, Najmeh Nowrouzi
A novel light-driven strategy for efficient C–S bond formation has been developed using a Cu₂O/THPP nanocatalyst. Operated under ambient conditions and white LED irradiation, this method enables the smooth conversion of carboxylic acids or aldehydes into thioethers in high yields via disulfide activation. This radical-mediated transformation offers a green, selective, and practical approach for the synthesis of bioactive sulfur-containing compounds, underscoring its strong potential in sustainable organic synthesis.
{"title":"Photoredox-catalyzed C–S bond formation using a Cu₂O/THPP nanocomposite under visible light: A practical approach to thioether synthesis","authors":"Kimia Keshavarz, Najmeh Nowrouzi","doi":"10.1016/j.mcat.2025.115629","DOIUrl":"10.1016/j.mcat.2025.115629","url":null,"abstract":"<div><div>A novel light-driven strategy for efficient C–S bond formation has been developed using a Cu₂O/THPP nanocatalyst. Operated under ambient conditions and white LED irradiation, this method enables the smooth conversion of carboxylic acids or aldehydes into thioethers in high yields <em>via</em> disulfide activation. This radical-mediated transformation offers a green, selective, and practical approach for the synthesis of bioactive sulfur-containing compounds, underscoring its strong potential in sustainable organic synthesis.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115629"},"PeriodicalIF":4.9,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alginate oligosaccharides (AOS), produced by the catalytic degradation of sodium alginate via alginate lyases, have garnered significant interest owing to their diverse biological activities. In industrial applications, enzymes characterized by high catalytic efficiency and excellent thermostability possess greater practical value. In this study, we performed molecular engineering on the alginate lyase Alg-7 derived from Pseudoalteromonas sp. Alg6B. Through sequence alignment to identify conserved residues and the application of multiple computer-assisted semi-rational design strategies, we systematically modified amino acid residues near the enzyme’s active pocket and optimized its surface charge distribution. The final combinatorial mutant, E353Y/D317T, exhibited a 193 % increase in specific activity (9220.89 U·mg-1), compared to the wild-type enzyme and demonstrated a 4.76-fold extension in half-life at 40°C. Molecular docking and molecular dynamics simulations revealed that the E353Y/D317T mutant significantly reduced the desolvation penalty. Furthermore, newly formed hydrogen bonds replaced unfavorable binding interactions, thereby enhancing the catalytic efficiency. Additionally, optimization of the enzyme’s surface charge distribution reduced the binding free energy of the mutant protein conformation and enhanced its overall structural stability.
{"title":"Enhancing the specific activity and thermostability of alginate lyase via semi-rational design","authors":"Chenglin Su , Shuoqi Jiang , Qiuya Gu , Xiaobin Yu","doi":"10.1016/j.mcat.2025.115635","DOIUrl":"10.1016/j.mcat.2025.115635","url":null,"abstract":"<div><div>Alginate oligosaccharides (AOS), produced by the catalytic degradation of sodium alginate via alginate lyases, have garnered significant interest owing to their diverse biological activities. In industrial applications, enzymes characterized by high catalytic efficiency and excellent thermostability possess greater practical value. In this study, we performed molecular engineering on the alginate lyase Alg-7 derived from <em>Pseudoalteromonas</em> sp. Alg6B. Through sequence alignment to identify conserved residues and the application of multiple computer-assisted semi-rational design strategies, we systematically modified amino acid residues near the enzyme’s active pocket and optimized its surface charge distribution. The final combinatorial mutant, E353Y/D317T, exhibited a 193 % increase in specific activity (9220.89 U·mg<sup>-1</sup>), compared to the wild-type enzyme and demonstrated a 4.76-fold extension in half-life at 40°C. Molecular docking and molecular dynamics simulations revealed that the E353Y/D317T mutant significantly reduced the desolvation penalty. Furthermore, newly formed hydrogen bonds replaced unfavorable binding interactions, thereby enhancing the catalytic efficiency. Additionally, optimization of the enzyme’s surface charge distribution reduced the binding free energy of the mutant protein conformation and enhanced its overall structural stability.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115635"},"PeriodicalIF":4.9,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-02DOI: 10.1016/j.mcat.2025.115634
Xiaodong Hao , Xuan Zhao , Yuhao Zhou , Yang Xu , Jiahao Xia , Lei Wu , Tingting Wei , Zhen-Hong He , Shufang Ma , Bingshe Xu
The catalytic dehydrogenation of propane, a critical process, is conventionally hampered by the high energy demands of the direct route and the poor selectivity associated with oxidative dehydrogenation using molecular oxygen. This work presents a strategic synthesis of Zr and Co co-doped CeO2 nanorods, fabricated through a combination of hydrothermal and atomization-drying techniques, for application in photothermal CO2-mediated oxidative dehydrogenation of propane (CO2ODHP). The optimized Co/Zr-CeO2 catalyst exhibits markedly enhanced performance under low-temperature illumination, delivering a high propane conversion of 230.04 μmol·gcat-1 while maintaining 90.3 % selectivity toward propylene. Comprehensive characterization and analysis reveal that the co-doping strategy simultaneously introduces abundant oxygen vacancies and electronically modifies the CeO2 host. The resultant tailored band structure promotes the separation and utilization of photogenerated carriers under light irradiation, which synergizes with the defect-mediated thermal catalysis to drive the efficient dehydrogenation of propane. This study highlights the effectiveness of coupled structural and electronic engineering in developing high-performance photothermal catalysts for alkane valorization.
{"title":"Boosting photothermal propane dehydrogenation via synergistic Co-Zr doping in CeO2 nanorods","authors":"Xiaodong Hao , Xuan Zhao , Yuhao Zhou , Yang Xu , Jiahao Xia , Lei Wu , Tingting Wei , Zhen-Hong He , Shufang Ma , Bingshe Xu","doi":"10.1016/j.mcat.2025.115634","DOIUrl":"10.1016/j.mcat.2025.115634","url":null,"abstract":"<div><div>The catalytic dehydrogenation of propane, a critical process, is conventionally hampered by the high energy demands of the direct route and the poor selectivity associated with oxidative dehydrogenation using molecular oxygen. This work presents a strategic synthesis of Zr and Co co-doped CeO<sub>2</sub> nanorods, fabricated through a combination of hydrothermal and atomization-drying techniques, for application in photothermal CO<sub>2</sub>-mediated oxidative dehydrogenation of propane (CO<sub>2</sub><sub><img></sub>ODHP). The optimized Co/Zr-CeO<sub>2</sub> catalyst exhibits markedly enhanced performance under low-temperature illumination, delivering a high propane conversion of 230.04 μmol·g<sub>cat</sub><sup>-1</sup> while maintaining 90.3 % selectivity toward propylene. Comprehensive characterization and analysis reveal that the co-doping strategy simultaneously introduces abundant oxygen vacancies and electronically modifies the CeO<sub>2</sub> host. The resultant tailored band structure promotes the separation and utilization of photogenerated carriers under light irradiation, which synergizes with the defect-mediated thermal catalysis to drive the efficient dehydrogenation of propane. This study highlights the effectiveness of coupled structural and electronic engineering in developing high-performance photothermal catalysts for alkane valorization.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115634"},"PeriodicalIF":4.9,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One possible method for sustainable energy conversion is heterogeneous photocatalysis, which stores solar energy in chemical bonds. Large-scale uses of highly active photocatalysts are hampered by issues such as ineffective solar energy consumption, poor mass transfer, photocatalyst instability, and cost constraints, despite notable breakthroughs in their design. In order to overcome these problems, we have created a polymer-based photocatalyst by effectively combining polypyrrole (Ppy) with a metal-free dopant, fast green (FG), via a supramolecular self-assembly approach to create a polymeric hydrogel (Ppy@FG). In addition to producing 3,4-dihydropyrimidin-2(1H)-thiones (DHPMs) efficiently, Ppy@FG demonstrates exceptional photocatalytic efficiency for the regeneration of nicotinamide adenine dinucleotide phosphate (NADPH), attaining an impressive yield. Mechanistic insights into the photoinduced electronic dynamics underlying the Ppy@FG system's macroscopic photocatalytic performance are obtained through systematic spectroscopic studies. Our research indicates that a 3D-network-based design integrated into the photocatalyst for artificial photosynthesis presents a viable and sustainable approach to regioselective NADPH regeneration and organic transformation. This current work is a novel approach for carrying out solar light-mediated highly selective NADPH regeneration (55.94 ± 2.1 %) and DHPMs synthesis (98.1 ± 1.3 %) in the presence of Ppy@FG hydrogel photocatalyst, which plays a crucial role in pharmacological activities, including antioxidant, antimicrobial, anti-inflammatory, mitotic kinesin inhibition and calcium channel modulation. This research work contributes to the comprehension of metal-free systems for greener, cost-effective enzymatic processes, including chemical and energy industries.
一种可能的可持续能量转换方法是多相光催化，它将太阳能储存在化学键中。尽管高活性光催化剂在设计上取得了显著的突破，但由于太阳能消耗效率低、传质差、光催化剂不稳定性和成本限制等问题，它们的大规模使用受到了阻碍。为了克服这些问题，我们通过超分子自组装方法，将聚吡咯（Ppy）与无金属掺杂剂fast green （FG）有效结合，创造了一种聚合物基光催化剂（Ppy@FG）。除了有效地生产3,4-二氢嘧啶-2(1H)-硫酮（dhpm）外，Ppy@FG还表现出对烟酰胺腺嘌呤二核苷酸磷酸（NADPH）再生的特殊光催化效率，获得了令人印象深刻的产量。通过系统光谱研究获得了Ppy@FG系统宏观光催化性能的光致电子动力学机制。我们的研究表明，基于3d网络的设计集成到人工光合作用的光催化剂中，为区域选择性NADPH再生和有机转化提供了一种可行且可持续的方法。目前的研究是在Ppy@FG水凝胶光催化剂的存在下进行太阳能光介导的高选择性NADPH再生（55.94±2.1%）和dhpm合成（98.1±1.3%）的新方法，它在抗氧化，抗菌，抗炎，有丝分裂运动蛋白抑制和钙通道调节等药理活性中起着至关重要的作用。这项研究工作有助于理解无金属系统的绿色，具有成本效益的酶的过程，包括化学和能源工业。
{"title":"Solar light-driven supramolecular hydrogel photocatalyst for efficient organic transformation and NADPH regeneration","authors":"Tanya Dhar Dubey , Rehana Shahin , Shaifali Mishra , Kanchan Sharma , Chandani Singh , Mohamed Abbas , Ghadah Shukri Albakri , Krishna Kumar Yadav , Rajesh K. Yadav , Jin-Ook Baeg","doi":"10.1016/j.mcat.2025.115619","DOIUrl":"10.1016/j.mcat.2025.115619","url":null,"abstract":"<div><div>One possible method for sustainable energy conversion is heterogeneous photocatalysis, which stores solar energy in chemical bonds. Large-scale uses of highly active photocatalysts are hampered by issues such as ineffective solar energy consumption, poor mass transfer, photocatalyst instability, and cost constraints, despite notable breakthroughs in their design. In order to overcome these problems, we have created a polymer-based photocatalyst by effectively combining polypyrrole (Ppy) with a metal-free dopant, fast green (FG), via a supramolecular self-assembly approach to create a polymeric hydrogel (Ppy@FG). In addition to producing 3,4-dihydropyrimidin-2(1H)-thiones (DHPMs) efficiently, Ppy@FG demonstrates exceptional photocatalytic efficiency for the regeneration of nicotinamide adenine dinucleotide phosphate (NADPH), attaining an impressive yield. Mechanistic insights into the photoinduced electronic dynamics underlying the Ppy@FG system's macroscopic photocatalytic performance are obtained through systematic spectroscopic studies. Our research indicates that a 3D-network-based design integrated into the photocatalyst for artificial photosynthesis presents a viable and sustainable approach to regioselective NADPH regeneration and organic transformation. This current work is a novel approach for carrying out solar light-mediated highly selective NADPH regeneration (55.94 ± 2.1 %) and DHPMs synthesis (98.1 ± 1.3 %) in the presence of Ppy@FG hydrogel photocatalyst, which plays a crucial role in pharmacological activities, including antioxidant, antimicrobial, anti-inflammatory, mitotic kinesin inhibition and calcium channel modulation. This research work contributes to the comprehension of metal-free systems for greener, cost-effective enzymatic processes, including chemical and energy industries.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115619"},"PeriodicalIF":4.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.mcat.2025.115621
Gyula Novodárszki , Adél Pakuts , Blanka Szabó , Hanna E. Solt , Anna Vikár , Ferenc Lónyi , Yuting Shi , Amosi Makoye , Róbert Barthos
Acetaldehyde has been identified as a key intermediate in the catalytic conversion of ethanol into butadiene or butanol. A variety of methodologies have been implemented to enhance the yield, including the promotion of in situ catalytic generation of acetaldehyde and the direct addition of acetaldehyde to the ethanol reactant. In the present study, molybdenum-promoted, partially silica-coated magnesium oxide catalysts (Mo/MgO-SiO2) were prepared and utilized. The initiation of an intermolecular redox reaction by molybdenum led to the conversion of ethanol to acetaldehyde and ethane. However, the Mo-promoted catalyst exhibited lower basicity and, consequently, reduced activity in aldol coupling when compared to the supporting oxide. The conversion of ethanol and the yield of C4 were found to be higher in the presence of the Mo-promoted catalysts in comparison to the MgO-SiO2 support, yet butadiene selectivity was observed to be lower. The conversion of an ethanol/acetaldehyde mixture resulted in a substantial butadiene yield, accompanied by notable crotonaldehyde and crotyl alcohol yields. It is noteworthy that the latter two products were not obtained from pure ethanol. At elevated space velocities, two additional condensation products, ethyl vinyl ether and ethyl acetate, were obtained from the mixture. This suggests that the coupled products are formed not only by the condensation of two acetaldehyde molecules, but also by other coupling pathways occurring between intermediate products that are adsorbed on the catalyst surface.
{"title":"Coupling reactions of ethanol and an ethanol/acetaldehyde mixture over Mo/MgO-SiO2 catalysts","authors":"Gyula Novodárszki , Adél Pakuts , Blanka Szabó , Hanna E. Solt , Anna Vikár , Ferenc Lónyi , Yuting Shi , Amosi Makoye , Róbert Barthos","doi":"10.1016/j.mcat.2025.115621","DOIUrl":"10.1016/j.mcat.2025.115621","url":null,"abstract":"<div><div>Acetaldehyde has been identified as a key intermediate in the catalytic conversion of ethanol into butadiene or butanol. A variety of methodologies have been implemented to enhance the yield, including the promotion of in situ catalytic generation of acetaldehyde and the direct addition of acetaldehyde to the ethanol reactant. In the present study, molybdenum-promoted, partially silica-coated magnesium oxide catalysts (Mo/MgO-SiO<sub>2</sub>) were prepared and utilized. The initiation of an intermolecular redox reaction by molybdenum led to the conversion of ethanol to acetaldehyde and ethane. However, the Mo-promoted catalyst exhibited lower basicity and, consequently, reduced activity in aldol coupling when compared to the supporting oxide. The conversion of ethanol and the yield of C<sub>4</sub> were found to be higher in the presence of the Mo-promoted catalysts in comparison to the MgO-SiO<sub>2</sub> support, yet butadiene selectivity was observed to be lower. The conversion of an ethanol/acetaldehyde mixture resulted in a substantial butadiene yield, accompanied by notable crotonaldehyde and crotyl alcohol yields. It is noteworthy that the latter two products were not obtained from pure ethanol. At elevated space velocities, two additional condensation products, ethyl vinyl ether and ethyl acetate, were obtained from the mixture. This suggests that the coupled products are formed not only by the condensation of two acetaldehyde molecules, but also by other coupling pathways occurring between intermediate products that are adsorbed on the catalyst surface.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115621"},"PeriodicalIF":4.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.mcat.2025.115623
Zong-Lin Li , Li-Man Gu , Zhi-Min Li , Wei-Hua Xiong
The practical implementation of aerobic photo-enzymatic cascades is severely limited by inherent incompatibilities among system components, including enzyme inactivation by photocatalytic species and reduced light penetration due to enzyme precipitation. Here, we present an orthogonal platform that overcomes these limitations by integrating intracellular, material-free enzyme anchoring with extracellular cofactor stabilization. Enzymes fused to cationic θ-defensin tags were anchored onto microbial membranes via electrostatic interactions, yielding optically clear, membrane-associated biocatalysts that retain high activity. A biocompatible Ni(II) catalyst redirected vulnerable NAD• radicals into productive NAD+ regeneration through a Ni(II)/Ni(III) redox cycle. Membrane-anchored enzymes tolerated both Ni(II) mediation and light exposure, avoiding the deactivation observed with soluble enzymes. Coupling membrane-anchored aldehyde dehydrogenase with TiO2 photocatalysis and the Ni(II) mediator enabled the aerobic conversion of R-glyceraldehyde to glyceric acid with 82% yield, while maintaining NAD+/NADH stability. This strategy addresses enzyme protection, cofactor stability, and light accessibility simultaneously, offering a practical and scalable solution for solar-driven biocatalysis without external fixation materials.
{"title":"Spatially integrated photo-enzymatic cascade enables aerobic cofactor self-recycling via intracellular biocatalysis and extracellular photocatalysis","authors":"Zong-Lin Li , Li-Man Gu , Zhi-Min Li , Wei-Hua Xiong","doi":"10.1016/j.mcat.2025.115623","DOIUrl":"10.1016/j.mcat.2025.115623","url":null,"abstract":"<div><div>The practical implementation of aerobic photo-enzymatic cascades is severely limited by inherent incompatibilities among system components, including enzyme inactivation by photocatalytic species and reduced light penetration due to enzyme precipitation. Here, we present an orthogonal platform that overcomes these limitations by integrating intracellular, material-free enzyme anchoring with extracellular cofactor stabilization. Enzymes fused to cationic θ-defensin tags were anchored onto microbial membranes via electrostatic interactions, yielding optically clear, membrane-associated biocatalysts that retain high activity. A biocompatible Ni(II) catalyst redirected vulnerable NAD• radicals into productive NAD<sup>+</sup> regeneration through a Ni(II)/Ni(III) redox cycle. Membrane-anchored enzymes tolerated both Ni(II) mediation and light exposure, avoiding the deactivation observed with soluble enzymes. Coupling membrane-anchored aldehyde dehydrogenase with TiO<sub>2</sub> photocatalysis and the Ni(II) mediator enabled the aerobic conversion of <em>R</em>-glyceraldehyde to glyceric acid with 82% yield, while maintaining NAD<sup>+</sup>/NADH stability. This strategy addresses enzyme protection, cofactor stability, and light accessibility simultaneously, offering a practical and scalable solution for solar-driven biocatalysis without external fixation materials.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115623"},"PeriodicalIF":4.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-29DOI: 10.1016/j.mcat.2025.115627
Yan Li, Hecheng Hu, Zhiqiang Zhang
The catalytic mechanism and origins of stereoselectivity for the reactions of bromoenals and pyrazoles to synthesize pyrazolo [3,4-b]pyridones catalyzed by a chiral NHC (NHC: N-heterocyclic carbene) catalyst were analyzed using density functional theory computations. Possible reaction pathways were examined. The results suggest that pyrazolo [3,4-b]pyridones formation occurs via nine steps, involving nucleophilic addition, 1,2-proton transfer, CBr bond dissociation, 1,3-proton transfer, CC bond formation, deprotonation, protonation, cycloaddition and regeneration of catalyst. The stereoselectivity of the reaction is determined in the step involving CC bond formation and R-pyrazolo [3,4-b]pyridone is the major product. The computed enantioselectivity of this reaction is in agreement with experiment. The observed enantioselectivity is derived from the differential interactions (CH⋯O, CH⋯π, and CH⋯CH) of stereocontrolling transition states. The effects of substituent and solvation as well as the role of the NHC have also been explored. This study might be helpful in understanding this kind of reactions and designing new reactions.
采用密度泛函理论计算分析了溴烯醛与吡唑手性NHC （NHC: n -杂环碳）催化剂催化合成吡唑[3,4-b]吡啶酮的催化机理和立体选择性的来源。研究了可能的反应途径。结果表明，吡唑[3,4-b]吡啶酮的生成过程包括亲核加成、1,2质子转移、CBr键解离、1,3质子转移、CC键形成、去质子化、质子化、环加成和催化剂再生等9个步骤。反应的立体选择性在形成CC键的步骤中决定，r -吡唑[3,4-b]吡酮是主要产物。该反应的对映选择性计算结果与实验结果一致。观察到的对映体选择性源于立体控制过渡态的微分相互作用（CH⋯O， CH⋯π和CH⋯CH）。探讨了取代基和溶剂化的影响以及NHC的作用。这项研究可能有助于理解这类反应并设计新的反应。
{"title":"NHCcatalyzed [3 + 3] cycloaddition of bromoenals and pyrazoles: Insights into reaction mechanism, regio- and stereoselectivities","authors":"Yan Li, Hecheng Hu, Zhiqiang Zhang","doi":"10.1016/j.mcat.2025.115627","DOIUrl":"10.1016/j.mcat.2025.115627","url":null,"abstract":"<div><div>The catalytic mechanism and origins of stereoselectivity for the reactions of bromoenals and pyrazoles to synthesize pyrazolo [3,4-b]pyridones catalyzed by a chiral NHC (NHC: N-heterocyclic carbene) catalyst were analyzed using density functional theory computations. Possible reaction pathways were examined. The results suggest that pyrazolo [3,4-b]pyridones formation occurs via nine steps, involving nucleophilic addition, 1,2-proton transfer, C<img>Br bond dissociation, 1,3-proton transfer, C<img>C bond formation, deprotonation, protonation, cycloaddition and regeneration of catalyst. The stereoselectivity of the reaction is determined in the step involving C<img>C bond formation and <em>R</em>-pyrazolo [3,4-b]pyridone is the major product. The computed enantioselectivity of this reaction is in agreement with experiment. The observed enantioselectivity is derived from the differential interactions (CH⋯O, CH⋯π, and CH⋯CH) of stereocontrolling transition states. The effects of substituent and solvation as well as the role of the NHC have also been explored. This study might be helpful in understanding this kind of reactions and designing new reactions.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"590 ","pages":"Article 115627"},"PeriodicalIF":4.9,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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