Pub Date : 2024-06-26DOI: 10.1021/acscatal.4c01477
Yu Wang, Zhuo-Ling Xie, Zhao-Lin Zeng, Cheng-Cheng Li, Jia-Hui An, Qing-Qing Hao, Hui-Bin Ge, Hui-Yong Chen, Xiao-Xun Ma, Qun-Xing Luo
A kinetic and mechanistic study of direct catalytic nitrilation from methyl salicylate and ammonia is conducted by using an amphoteric ZnAl2O4 spinel as a model catalyst. This overall process integrates the catalytic ammonolysis of esters with the dehydration of amides, proceeding stepwise over the concerted Lewis acid–base pairs of Zn–O–Al linkages. The chemisorption and activation of C–O bonds of the ester over Lewis acid–base pairs facilitate the leaving of the methoxy group, while Lewis basic oxygen (Zn–O*–Al) serves as the main hub station for multistep proton transportation, thus leading to the decreased apparent activation energy of nitrilation and ammonolysis. The combined experimental and computational evidence confirms that this direct nitrilation process follows a monomolecular surface adsorption model, i.e., the Eley–Rideal mechanism, involving eight elementary reaction steps in which chemisorbed surface species of methyl salicylate react with gaseous NH3 molecules via nucleophilic addition–elimination and multistep proton transfer to generate amides and nitriles in sequence. Microkinetic model discrimination and DFT calculations reveal that the formation of chemisorbed imine (C═N–H) via proton transfer from the Lewis basic oxygen atom (Zn–O*–Al) to the carbonyl oxygen (C═O*) is the rate-determining step, thereby providing a potential consideration of protonation and deprotonation ability to rationally design an improved catalyst.
{"title":"Kinetics and Mechanism of Integrated Catalytic Ammonolysis and Dehydration from Methyl Salicylate over ZnAl2O4 Spinel","authors":"Yu Wang, Zhuo-Ling Xie, Zhao-Lin Zeng, Cheng-Cheng Li, Jia-Hui An, Qing-Qing Hao, Hui-Bin Ge, Hui-Yong Chen, Xiao-Xun Ma, Qun-Xing Luo","doi":"10.1021/acscatal.4c01477","DOIUrl":"https://doi.org/10.1021/acscatal.4c01477","url":null,"abstract":"A kinetic and mechanistic study of direct catalytic nitrilation from methyl salicylate and ammonia is conducted by using an amphoteric ZnAl<sub>2</sub>O<sub>4</sub> spinel as a model catalyst. This overall process integrates the catalytic ammonolysis of esters with the dehydration of amides, proceeding stepwise over the concerted Lewis acid–base pairs of Zn–O–Al linkages. The chemisorption and activation of C–O bonds of the ester over Lewis acid–base pairs facilitate the leaving of the methoxy group, while Lewis basic oxygen (Zn–O*–Al) serves as the main hub station for multistep proton transportation, thus leading to the decreased apparent activation energy of nitrilation and ammonolysis. The combined experimental and computational evidence confirms that this direct nitrilation process follows a monomolecular surface adsorption model, <i>i.e.</i>, the Eley–Rideal mechanism, involving eight elementary reaction steps in which chemisorbed surface species of methyl salicylate react with gaseous NH<sub>3</sub> molecules <i>via</i> nucleophilic addition–elimination and multistep proton transfer to generate amides and nitriles in sequence. Microkinetic model discrimination and DFT calculations reveal that the formation of chemisorbed imine (C═N–H) <i>via</i> proton transfer from the Lewis basic oxygen atom (Zn–O*–Al) to the carbonyl oxygen (C═O*) is the rate-determining step, thereby providing a potential consideration of protonation and deprotonation ability to rationally design an improved catalyst.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461565","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}
Converting nitrate (NO3–) to ammonia (NH3) through the electrochemical reduction method offers an appealing approach for wastewater treatment and facilitates nitrogen cycling in nature. However, this electrolytic method involves a series of proton-coupled electron transfer processes and comes with severe competing reactions. Consequently, there is a significant demand for catalysts exhibiting good catalytic activities and selectivities. Here, a series of copper–cobalt binary sulfide nanosheets with varying Cu/Co compositions were prepared to investigate the synergy effects between the components copper sulfide and cobalt sulfide on their catalytic performance. As a result, a volcano-like correlation between the Cu/Co ratio and electrocatalytic performance was built. The optimal catalyst CuxS–Co0.5 exhibited a maximum Faradaic efficiency (FE) of ∼95.6% for ammonia at −1.4 V vs Ag/AgCl. The highest ammonia yield rate of 5.36 mg/h·cm2 was achieved at −1.6 V vs Ag/AgCl, which was 6.5- and 3.8-fold relative to those of pure CuxS and CoS2, respectively. By combining spectroscopy characterizations with theoretical calculations, we revealed that catalyst CuxS–Co0.5 with a built-in electric field confined to a few nanometers played a critical role in enhancing electron transfer and creating more active sites. Besides, its improved water dissociation capability was essential for the hydrogenation of reduction intermediates, collectively contributing to the enhanced catalytic performance.
{"title":"Efficient Electrochemical Nitrate Reduction to Ammonia Driven by a Few Nanometer-Confined Built-In Electric Field","authors":"Maolin Zhang, Zedong Zhang, Shaolong Zhang, Zechao Zhuang, Kepeng Song, Karthik Paramaiah, Moyu Yi, Hao Huang, Dingsheng Wang","doi":"10.1021/acscatal.4c02317","DOIUrl":"https://doi.org/10.1021/acscatal.4c02317","url":null,"abstract":"Converting nitrate (NO<sub>3</sub><sup>–</sup>) to ammonia (NH<sub>3</sub>) through the electrochemical reduction method offers an appealing approach for wastewater treatment and facilitates nitrogen cycling in nature. However, this electrolytic method involves a series of proton-coupled electron transfer processes and comes with severe competing reactions. Consequently, there is a significant demand for catalysts exhibiting good catalytic activities and selectivities. Here, a series of copper–cobalt binary sulfide nanosheets with varying Cu/Co compositions were prepared to investigate the synergy effects between the components copper sulfide and cobalt sulfide on their catalytic performance. As a result, a volcano-like correlation between the Cu/Co ratio and electrocatalytic performance was built. The optimal catalyst Cu<sub><i>x</i></sub>S–Co<sub>0.5</sub> exhibited a maximum Faradaic efficiency (FE) of ∼95.6% for ammonia at −1.4 V vs Ag/AgCl. The highest ammonia yield rate of 5.36 mg/h·cm<sup>2</sup> was achieved at −1.6 V vs Ag/AgCl, which was 6.5- and 3.8-fold relative to those of pure Cu<sub><i>x</i></sub>S and CoS<sub>2</sub>, respectively. By combining spectroscopy characterizations with theoretical calculations, we revealed that catalyst Cu<sub><i>x</i></sub>S–Co<sub>0.5</sub> with a built-in electric field confined to a few nanometers played a critical role in enhancing electron transfer and creating more active sites. Besides, its improved water dissociation capability was essential for the hydrogenation of reduction intermediates, collectively contributing to the enhanced catalytic performance.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462131","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}
Pub Date : 2024-06-26DOI: 10.1021/acscatal.4c02707
Eito Moriya, Kei Muto, Junichiro Yamaguchi
This manuscript describes the development of the Ni/dcype-catalyzed enolate dance/coupling reaction of alkenyl pivalates with nucleophiles, resulting in cine-substitution. Pivalates derived from 1-tetralone undergo this reaction to produce C2-functionalized dihydronaphthalenes. The direct utilization of 1-tetralone is also feasible, employing Piv2O to generate the corresponding enol pivalate in situ. Mechanistic investigations, including stoichiometric experiments, suggest that the reaction proceeds via C–O oxidative addition, nickel 1,2-translocation, and subsequent coupling with a nucleophile.
{"title":"Cine-Substitution of Enolates: Enolate Dance/Coupling of Cycloalkenyl Pivalates by Nickel Catalysis","authors":"Eito Moriya, Kei Muto, Junichiro Yamaguchi","doi":"10.1021/acscatal.4c02707","DOIUrl":"https://doi.org/10.1021/acscatal.4c02707","url":null,"abstract":"This manuscript describes the development of the Ni/dcype-catalyzed enolate dance/coupling reaction of alkenyl pivalates with nucleophiles, resulting in <i>cine</i>-substitution. Pivalates derived from 1-tetralone undergo this reaction to produce C2-functionalized dihydronaphthalenes. The direct utilization of 1-tetralone is also feasible, employing Piv<sub>2</sub>O to generate the corresponding enol pivalate <i>in situ</i>. Mechanistic investigations, including stoichiometric experiments, suggest that the reaction proceeds via C–O oxidative addition, nickel 1,2-translocation, and subsequent coupling with a nucleophile.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462100","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}
l-Threonine transaldolase (LTTA) is an attractive biocatalyst because of its potential diastereoselectivity in the synthesis of β-hydroxy-α-amino acids (βHAAs). However, prospective development of LTTA has been hampered by its low activity. Here, a combination of techniques involving structural comparison, computational analysis, Loop deletion, and alanine scanning was used to identify a key Loop region (Loop 1) regulating the catalytic ability of Chitiniphilus shinanonensis LTTA (CsLTTA). Saturation mutagenesis and iterative saturation mutagenesis at the hot spots in Loop 1 were performed, and the best variant containing an F70T/C57Q/Y69T (TQT) triple mutation was screened. The diastereoisomer excess (de) produced by the TQT variant (95.4%syn) was greater than that produced by the wild-type (WT) enzyme (75.2%syn), and the catalytic efficiency (kcat/Km) of the TQT variant was four times higher than that of the wild-type enzyme. Molecular dynamics simulations, metadynamics simulations, and CAVER analysis revealed the critical role of the Loop 1 structure in regulating the hydrogen bond network and thus reshaping the active-site pocket to control the syn-tunnel direction. Further engineering of Loop 1 in ObiH, an LTTA responsible for obafluorin biosynthesis, resulted in the development of the F70T-C57Q-H69T (ObiH-TQT) variant producing a de of 97%syn. Using the ObiH-TQT variant for kilogram-scale synthesis of l-syn-p-methylsulfonylphenylserine, coupled with acetaldehyde elimination, resulted in space–time yields of up to 12.7 g L–1 h–1. The method achieved 98.3% substrate conversion and 99.2%synde within 6 h, marking the highest reported levels to date. The above findings will contribute to the industrial production of β-hydroxy-α-amino acids, offer insights into the mechanism of Loop regions regulating the catalytic function of LTTAs, and provide ideas for engineering other enzymes.
{"title":"Deciphering the Key Loop: Enhancing l-Threonine Transaldolase’s Catalytic Potential","authors":"Zhiwen Xi, Jingxin Rao, Xinyi Zhang, Zhiyong Liu, Mingyue Zheng, Lihong Li, Wenchi Zhang, Yan Xu, Rongzhen Zhang","doi":"10.1021/acscatal.4c02049","DOIUrl":"https://doi.org/10.1021/acscatal.4c02049","url":null,"abstract":"<span>l</span>-Threonine transaldolase (LTTA) is an attractive biocatalyst because of its potential diastereoselectivity in the synthesis of β-hydroxy-α-amino acids (βHAAs). However, prospective development of LTTA has been hampered by its low activity. Here, a combination of techniques involving structural comparison, computational analysis, Loop deletion, and alanine scanning was used to identify a key Loop region (Loop 1) regulating the catalytic ability of <i>Chitiniphilus shinanonensis</i> LTTA (<i>Cs</i>LTTA). Saturation mutagenesis and iterative saturation mutagenesis at the hot spots in Loop 1 were performed, and the best variant containing an F70T/C57Q/Y69T (TQT) triple mutation was screened. The diastereoisomer excess (<i>de</i>) produced by the TQT variant (95.4%<i><sub>syn</sub></i>) was greater than that produced by the wild-type (WT) enzyme (75.2%<i><sub>syn</sub></i>), and the catalytic efficiency (<i>k</i><sub>cat</sub>/<i>K</i><sub>m</sub>) of the TQT variant was four times higher than that of the wild-type enzyme. Molecular dynamics simulations, metadynamics simulations, and CAVER analysis revealed the critical role of the Loop 1 structure in regulating the hydrogen bond network and thus reshaping the active-site pocket to control the <i>syn</i>-tunnel direction. Further engineering of Loop 1 in ObiH, an LTTA responsible for obafluorin biosynthesis, resulted in the development of the F70T-C57Q-H69T (ObiH-TQT) variant producing a <i>de</i> of 97%<i><sub>syn</sub></i>. Using the ObiH-TQT variant for kilogram-scale synthesis of <span>l</span>-<i>syn</i>-<i>p</i>-methylsulfonylphenylserine, coupled with acetaldehyde elimination, resulted in space–time yields of up to 12.7 g L<sup>–1</sup> h<sup>–1</sup>. The method achieved 98.3% substrate conversion and 99.2%<sub><i>syn</i></sub> <i>de</i> within 6 h, marking the highest reported levels to date. The above findings will contribute to the industrial production of β-hydroxy-α-amino acids, offer insights into the mechanism of Loop regions regulating the catalytic function of LTTAs, and provide ideas for engineering other enzymes.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461563","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}
Pub Date : 2024-06-26DOI: 10.1021/acscatal.4c00858
Bin Chen, Ya-Fei Jiang, Hai Xiao, Jun Li
The oxophilic elements may stabilize the O-intermediate in electrochemical CO2 reduction reaction (eCO2RR), yet their applications for formic acid (HCOOH) production may be limited by the Sabatier principle. Here we explore the bimetallic M1Ti3 (M = Ni, Pd, Pt, Cu, Ag, Au) single-cluster catalysts (SCCs) anchored on graphdiyne (GDY) for eCO2RR to produce HCOOH. First-principles calculations show that the M1Ti3/GDY SCCs prefer to activate and hydrogenate CO2 to the *OCHO intermediate (*denotes the active site of the catalyst) due to the oxophilic Ti sites, while the M1 site plays a key role in suppressing the adsorption of *H and tuning the adsorption of *OCHO and *HCOOH for the HCOOH production, which is attributed to the modulation of Ti–O bonding strength by the M1 atom. We predict that the Au1Ti3/GDY SCC is an efficient electrocatalyst for the selective eCO2RR to produce HCOOH. The directions for further improvements for the selective eCO2RR to produce HCOOH are discussed.
{"title":"Selective CO2-to-HCOOH Electroreduction on Graphdiyne-Supported Bimetallic Single-Cluster Catalysts","authors":"Bin Chen, Ya-Fei Jiang, Hai Xiao, Jun Li","doi":"10.1021/acscatal.4c00858","DOIUrl":"https://doi.org/10.1021/acscatal.4c00858","url":null,"abstract":"The oxophilic elements may stabilize the O-intermediate in electrochemical CO<sub>2</sub> reduction reaction (eCO<sub>2</sub>RR), yet their applications for formic acid (HCOOH) production may be limited by the Sabatier principle. Here we explore the bimetallic M<sub>1</sub>Ti<sub>3</sub> (M = Ni, Pd, Pt, Cu, Ag, Au) single-cluster catalysts (SCCs) anchored on graphdiyne (GDY) for eCO<sub>2</sub>RR to produce HCOOH. First-principles calculations show that the M<sub>1</sub>Ti<sub>3</sub>/GDY SCCs prefer to activate and hydrogenate CO<sub>2</sub> to the *OCHO intermediate (*denotes the active site of the catalyst) due to the oxophilic Ti sites, while the M<sub>1</sub> site plays a key role in suppressing the adsorption of *H and tuning the adsorption of *OCHO and *HCOOH for the HCOOH production, which is attributed to the modulation of Ti–O bonding strength by the M<sub>1</sub> atom. We predict that the Au<sub>1</sub>Ti<sub>3</sub>/GDY SCC is an efficient electrocatalyst for the selective eCO<sub>2</sub>RR to produce HCOOH. The directions for further improvements for the selective eCO<sub>2</sub>RR to produce HCOOH are discussed.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462056","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}
Metal hydrides are useful hydrogenation/dehydrogenation catalysts due to their reversible hydrogen absorption and desorption properties, especially in important energy-related reactions. However, the relationship between the structure of metal hydrides and their catalytic performance is still elusive. In this work, the critical role of electronic structure and H chemical potential of metal hydrides in catalysis is demonstrated by Al substitution of the classic hydrogen storage alloy LaNi5. Theoretical calculations reveal that electron transfer from Al to Ni reduces the adsorption energy of the partially hydrogenated intermediates and leads to lower reaction barriers. Al substitution also reduces the H chemical potential of LaNi5 and increases the availability of bulk-H in the catalytic process. The bulk-H serves as an extra hydrogen source for hydrogenation and facilitates the formation of H2 in dehydrogenation. Thus, the chemically synthesized LaNi4.5Al0.5 nanoparticles exhibit considerable bifunctional catalytic performance for the hydrogenation and dehydrogenation of carbazole-type liquid organic hydrogen carriers.
{"title":"Promoting Catalytic Performance of Metal Hydrides for Reversible Hydrogen Storage in N-ethylcarbazole by Electronic Structure and Hydrogen Chemical Potential Tuning","authors":"Hongen Yu, Zichang Zhang, Xu Jin, Xi Zhang, Rumei Jin, Youyu Lin, Zewei Xie, Yushen Huang, Tongyu Liu, Xingguo Li, Qiang Sun, Jie Zheng","doi":"10.1021/acscatal.4c02947","DOIUrl":"https://doi.org/10.1021/acscatal.4c02947","url":null,"abstract":"Metal hydrides are useful hydrogenation/dehydrogenation catalysts due to their reversible hydrogen absorption and desorption properties, especially in important energy-related reactions. However, the relationship between the structure of metal hydrides and their catalytic performance is still elusive. In this work, the critical role of electronic structure and H chemical potential of metal hydrides in catalysis is demonstrated by Al substitution of the classic hydrogen storage alloy LaNi<sub>5</sub>. Theoretical calculations reveal that electron transfer from Al to Ni reduces the adsorption energy of the partially hydrogenated intermediates and leads to lower reaction barriers. Al substitution also reduces the H chemical potential of LaNi<sub>5</sub> and increases the availability of bulk-H in the catalytic process. The bulk-H serves as an extra hydrogen source for hydrogenation and facilitates the formation of H<sub>2</sub> in dehydrogenation. Thus, the chemically synthesized LaNi<sub>4.5</sub>Al<sub>0.5</sub> nanoparticles exhibit considerable bifunctional catalytic performance for the hydrogenation and dehydrogenation of carbazole-type liquid organic hydrogen carriers.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462083","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}
Pub Date : 2024-06-26DOI: 10.1021/acscatal.4c02243
Zi-Zhan Liang, Xin-Ao Li, Qi-Ze Chen, Xiao-Lin Wang, Pei-Yang Su, Jian-Feng Huang, YeCheng Zhou, Li-Min Xiao, Jun-Min Liu
Overall water splitting into H2 and H2O2 via Z-scheme piezo-photocatalytic systems is an ideal method for renewable energy production. Herein, we have synthesized a triangular prism-shaped metal–organic cage (MOC-Q3) integrating three catalytic Pd2+ centers and two photosensitive ligands, which is successfully immobilized on a highly crystalline β-ketoenamine-linked covalent organic framework (EA-COF) to form a Z-scheme single-atom photosystem. The optimized MOC-Q3/EA-COF achieves a high H2 yield (26.17 mmol g–1 h–1) with a TONPd of 118,521 with ascorbic acid as sacrificial agent due to broad light absorption, effective carrier separation, and widely distributed Pd active sites, which is among the highest for COF-based solar H2 evolution photocatalysts. Interestingly, EA-COF is found to be a piezoelectric material and its piezoelectric performance is mainly due to the in-plane polarization of the 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde groups in the COF, which is confirmed by experimental observations and density functional theory calculations. The EA-COF shows H2 and H2O2 production rates of 239.94 and 400.38 μmol g–1 h–1, respectively, in pure water when excited by ultrasound coupled with light irradiation. The integration of MOC-Q3 can further enhance the efficiency of EA-COF in piezo-photocatalytic water splitting. The superior MOC-Q3/EA-COF exhibits H2 and H2O2 generation rates of 426.38 and 535.14 μmol g–1 h–1, respectively, outperforming pure EA-COF by 1.8 and 1.3 times. This is a pioneering work to construct a Z-scheme MOC/COF piezo-photocatalytic system, which provides an efficient way to use mechanical and solar energy to produce H2 and H2O2 through overall water splitting.
{"title":"A Direct Z-Scheme Single-Atom MOC/COF Piezo-Photocatalytic System for Overall Water Splitting","authors":"Zi-Zhan Liang, Xin-Ao Li, Qi-Ze Chen, Xiao-Lin Wang, Pei-Yang Su, Jian-Feng Huang, YeCheng Zhou, Li-Min Xiao, Jun-Min Liu","doi":"10.1021/acscatal.4c02243","DOIUrl":"https://doi.org/10.1021/acscatal.4c02243","url":null,"abstract":"Overall water splitting into H<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> via Z-scheme piezo-photocatalytic systems is an ideal method for renewable energy production. Herein, we have synthesized a triangular prism-shaped metal–organic cage (MOC-Q3) integrating three catalytic Pd<sup>2+</sup> centers and two photosensitive ligands, which is successfully immobilized on a highly crystalline β-ketoenamine-linked covalent organic framework (EA-COF) to form a Z-scheme single-atom photosystem. The optimized MOC-Q3/EA-COF achieves a high H<sub>2</sub> yield (26.17 mmol g<sup>–1</sup> h<sup>–1</sup>) with a TON<sub>Pd</sub> of 118,521 with ascorbic acid as sacrificial agent due to broad light absorption, effective carrier separation, and widely distributed Pd active sites, which is among the highest for COF-based solar H<sub>2</sub> evolution photocatalysts. Interestingly, EA-COF is found to be a piezoelectric material and its piezoelectric performance is mainly due to the in-plane polarization of the 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde groups in the COF, which is confirmed by experimental observations and density functional theory calculations. The EA-COF shows H<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> production rates of 239.94 and 400.38 μmol g<sup>–1</sup> h<sup>–1</sup>, respectively, in pure water when excited by ultrasound coupled with light irradiation. The integration of MOC-Q3 can further enhance the efficiency of EA-COF in piezo-photocatalytic water splitting. The superior MOC-Q3/EA-COF exhibits H<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> generation rates of 426.38 and 535.14 μmol g<sup>–1</sup> h<sup>–1</sup>, respectively, outperforming pure EA-COF by 1.8 and 1.3 times. This is a pioneering work to construct a Z-scheme MOC/COF piezo-photocatalytic system, which provides an efficient way to use mechanical and solar energy to produce H<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> through overall water splitting.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462074","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}
Pub Date : 2024-06-26DOI: 10.1021/acscatal.4c01446
Elijah Karvelis, Chloe Swanson, Bruce Tidor
The task of adapting enzymes for specific applications is often hampered by our incomplete ability to tune and tailor catalytic functions, particularly when seeking increased activity. Here, we develop and demonstrate a rational approach to address this challenge, applied to ketol-acid reductoisomerase (KARI), which has uses in industrial-scale isobutanol production. While traditional structure-based computational enzyme redesign strategies typically focus on the enzyme-bound ground state (GS) and transition state (TS), we postulated that additionally treating the underlying dynamics of complete turnover events that connect and pass through both states could further elucidate the structural properties affecting catalysis and help identify mutations that lead to increased catalytic activity. To examine the dynamics of substrate conversion with atomistic detail, we adapted and applied computational methods based on path sampling techniques to gather thousands of QM/MM simulations of attempted substrate turnover events by KARI: both productive (reactive) and unproductive (nonreactive) attempts. From these data, machine learning models were constructed and used to identify specific conformational features (interatomic distances, angles, and torsions) associated with successful, productive catalysis. Multistate protein redesign techniques were then used to select mutations that stabilized reactive-like structures over nonreactive-like ones while also meeting additional criteria consistent with enhanced specific activity. This procedure resulted in eight high-confidence enzyme mutants with a significant improvement in calculated specific activity relative to wild type (WT), with the fastest variant’s increase in calculated kcat being (2 ± 1) × 104-fold. Collectively, these results suggest that introducing mutations designed to increase the population of reaction-promoting conformations of the enzyme–substrate complex before it reaches the barrier can provide an effective approach to engineering improved enzyme catalysts.
{"title":"Substrate Turnover Dynamics Guide Ketol-Acid Reductoisomerase Redesign for Increased Specific Activity","authors":"Elijah Karvelis, Chloe Swanson, Bruce Tidor","doi":"10.1021/acscatal.4c01446","DOIUrl":"https://doi.org/10.1021/acscatal.4c01446","url":null,"abstract":"The task of adapting enzymes for specific applications is often hampered by our incomplete ability to tune and tailor catalytic functions, particularly when seeking increased activity. Here, we develop and demonstrate a rational approach to address this challenge, applied to ketol-acid reductoisomerase (KARI), which has uses in industrial-scale isobutanol production. While traditional structure-based computational enzyme redesign strategies typically focus on the enzyme-bound ground state (GS) and transition state (TS), we postulated that additionally treating the underlying dynamics of complete turnover events that connect and pass through both states could further elucidate the structural properties affecting catalysis and help identify mutations that lead to increased catalytic activity. To examine the dynamics of substrate conversion with atomistic detail, we adapted and applied computational methods based on path sampling techniques to gather thousands of QM/MM simulations of attempted substrate turnover events by KARI: both productive (reactive) and unproductive (nonreactive) attempts. From these data, machine learning models were constructed and used to identify specific conformational features (interatomic distances, angles, and torsions) associated with successful, productive catalysis. Multistate protein redesign techniques were then used to select mutations that stabilized reactive-like structures over nonreactive-like ones while also meeting additional criteria consistent with enhanced specific activity. This procedure resulted in eight high-confidence enzyme mutants with a significant improvement in calculated specific activity relative to wild type (WT), with the fastest variant’s increase in calculated <i>k</i><sub>cat</sub> being (2 ± 1) × 10<sup>4</sup>-fold. Collectively, these results suggest that introducing mutations designed to increase the population of reaction-promoting conformations of the enzyme–substrate complex before it reaches the barrier can provide an effective approach to engineering improved enzyme catalysts.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462049","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}
Pub Date : 2024-06-26DOI: 10.1021/acscatal.4c02203
Mengjie Zhou, Shuo Xu, Wenjie Zhang, Ge Shi, Yanjie He, Xiaoguang Qiao, Xinchang Pang
To provide some insights into the relationship between carbon dots’ optical properties and their photocatalytic ability, a series of silicon-doped carbon dots (SiCDs) featuring varying photoluminescence quantum yields (PLQYs) from 11.2 to 75.6% were synthesized, characterized, and employed in polymerization processes. The as-prepared samples exhibited varied structural and optical attributes and resulted in different reaction rates when utilized as cocatalysts for copper-catalyzed photoinduced atom transfer radical polymerization (photoATRP). Comparing the measured density of states, it was found that band gap reduction enhanced the photocatalytic capability of SiCDs. Besides, a negative correlation between the PLQY and polymerization rate was observed, while the latter saw a positive relationship with the nonradiative recombination rate. Both the doping effect and size effect account for the varied efficiency of photoreducing CuII to CuI complexes by SiCDs, thus resulting in variation in the reaction rate. The selected optimal SiCD was further investigated through kinetic study, on–off, and chain extension experiments to prove its feasibility on the aqueous photoATRP system. Remarkably, the SiCD-photocatalyzed approach exhibited an oxygen-tolerant feature and rapid reaction rate, allowing for 3D fabrication of complex structures with high precision and resolution.
{"title":"How Luminescence Performances of Silicon-Doped Carbon Dots Contribute to Copper-Catalyzed photoATRP?","authors":"Mengjie Zhou, Shuo Xu, Wenjie Zhang, Ge Shi, Yanjie He, Xiaoguang Qiao, Xinchang Pang","doi":"10.1021/acscatal.4c02203","DOIUrl":"https://doi.org/10.1021/acscatal.4c02203","url":null,"abstract":"To provide some insights into the relationship between carbon dots’ optical properties and their photocatalytic ability, a series of silicon-doped carbon dots (SiCDs) featuring varying photoluminescence quantum yields (PLQYs) from 11.2 to 75.6% were synthesized, characterized, and employed in polymerization processes. The as-prepared samples exhibited varied structural and optical attributes and resulted in different reaction rates when utilized as cocatalysts for copper-catalyzed photoinduced atom transfer radical polymerization (photoATRP). Comparing the measured density of states, it was found that band gap reduction enhanced the photocatalytic capability of SiCDs. Besides, a negative correlation between the PLQY and polymerization rate was observed, while the latter saw a positive relationship with the nonradiative recombination rate. Both the doping effect and size effect account for the varied efficiency of photoreducing Cu<sup>II</sup> to Cu<sup>I</sup> complexes by SiCDs, thus resulting in variation in the reaction rate. The selected optimal SiCD was further investigated through kinetic study, on–off, and chain extension experiments to prove its feasibility on the aqueous photoATRP system. Remarkably, the SiCD-photocatalyzed approach exhibited an oxygen-tolerant feature and rapid reaction rate, allowing for 3D fabrication of complex structures with high precision and resolution.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462067","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}
The CO2 oxidative dehydrogenation of propane (CO2–ODHP) is a highly important reaction for not only producing large amounts of propylene but also consuming the CO2 resource. GaN/zeolite catalysts deliver preferable activity in the reaction. However, similar to Pt- and Cr-based catalysts, there are shortcomings such as poor stability and coke accumulation, especially when operated at temperatures higher than 550 °C. Generally, carbon deposition is one of the main reasons for catalyst deactivation. The limited mass transfer greatly aggravates the deposited carbon formation, since carbon precursors could not be removed in time. In the present work, we modified zeolites with a short b-axis and hierarchical pores, which could offer a shorter diffusion distance and pore-rich structure to enhance the mass transfer. Thanks to this enhancement, the catalyst offers an initial propane conversion of 68.0% with a yield of 39.4% to propylene, surpassing other reported GaN/zeolite catalysts to data. Importantly, the catalyst showed a low loss rate of activity and a low amount of deposited carbon, which was easily regenerated compared with those of other catalysts without a short b-axis or hierarchical pores. Density functional theory (DFT) calculations and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) confirmed that the reaction involves a coupling reaction of direct dehydrogenation and CO2 reduction via reverse water–gas shift reaction, and CO2 participates in the reaction. The present work sheds light on designing an efficient catalyst for CO2–ODHP via a mass transfer-boosted strategy and, importantly, is expected to provide inspiration in constructing a zeolite with a short b-axis and hierarchical pores.
丙烷的二氧化碳氧化脱氢反应（CO2-ODHP）是一个非常重要的反应，不仅能生产大量丙烯，还能消耗二氧化碳资源。氮化镓/沸石催化剂在该反应中具有更高的活性。然而，与铂基和铬基催化剂类似，氮化镓/沸石催化剂也存在稳定性差和积炭等缺点，尤其是在温度高于 550 °C 时。一般来说，碳沉积是催化剂失活的主要原因之一。由于碳前体无法及时清除，有限的传质大大加剧了沉积碳的形成。在本研究中，我们对沸石进行了改性，使其具有短 b 轴和分层孔隙，从而缩短了扩散距离并丰富了孔隙结构，增强了传质能力。由于这种改进，催化剂的丙烷初始转化率达到 68.0%，丙烯产率为 39.4%，超过了其他已报道的 GaN/ 沸石催化剂。重要的是，与其他没有短 b 轴或分层孔的催化剂相比，该催化剂的活性损失率低，沉积碳量少，易于再生。密度泛函理论（DFT）计算和原位漫反射红外傅立叶变换光谱（DRIFTS）证实，该反应涉及直接脱氢和通过反向水气变换反应还原 CO2 的耦合反应，且 CO2 参与了反应。本研究揭示了如何通过传质增效策略设计 CO2-ODHP 的高效催化剂，更重要的是，有望为构建短 b 轴和分层孔隙的沸石提供启示。
{"title":"Mass-Transfer Enhancement in the CO2 Oxidative Dehydrogenation of Propane over GaN Supported on Zeolite Nanosheets with a Short b-Axis and Hierarchical Pores","authors":"Zhan-Jun Zhu, Zhen-Hong He, Yue Tian, Sen-Wang Wang, Yong-Chang Sun, Kuan Wang, Weitao Wang, Zhi-Fang Zhang, Jiajie Liu, Zhao-Tie Liu","doi":"10.1021/acscatal.4c02599","DOIUrl":"https://doi.org/10.1021/acscatal.4c02599","url":null,"abstract":"The CO<sub>2</sub> oxidative dehydrogenation of propane (CO<sub>2</sub>–ODHP) is a highly important reaction for not only producing large amounts of propylene but also consuming the CO<sub>2</sub> resource. GaN/zeolite catalysts deliver preferable activity in the reaction. However, similar to Pt- and Cr-based catalysts, there are shortcomings such as poor stability and coke accumulation, especially when operated at temperatures higher than 550 °C. Generally, carbon deposition is one of the main reasons for catalyst deactivation. The limited mass transfer greatly aggravates the deposited carbon formation, since carbon precursors could not be removed in time. In the present work, we modified zeolites with a short <i>b</i>-axis and hierarchical pores, which could offer a shorter diffusion distance and pore-rich structure to enhance the mass transfer. Thanks to this enhancement, the catalyst offers an initial propane conversion of 68.0% with a yield of 39.4% to propylene, surpassing other reported GaN/zeolite catalysts to data. Importantly, the catalyst showed a low loss rate of activity and a low amount of deposited carbon, which was easily regenerated compared with those of other catalysts without a short <i>b</i>-axis or hierarchical pores. Density functional theory (DFT) calculations and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) confirmed that the reaction involves a coupling reaction of direct dehydrogenation and CO<sub>2</sub> reduction via reverse water–gas shift reaction, and CO<sub>2</sub> participates in the reaction. The present work sheds light on designing an efficient catalyst for CO<sub>2</sub>–ODHP via a mass transfer-boosted strategy and, importantly, is expected to provide inspiration in constructing a zeolite with a short <i>b</i>-axis and hierarchical pores.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461623","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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