ACS Catalysis 最新文献

{"title":"Elementary Steps, Site Requirements, and Support Effects in Methylcyclohexane Dehydrogenation Reactions on Dispersed Pd Nanoparticles","authors":"Zhongyao Zhang, Sai Chen, Trenton Otto, Enrique Iglesia","doi":"10.1021/acscatal.4c07240","DOIUrl":"https://doi.org/10.1021/acscatal.4c07240","url":null,"abstract":"Hydrogenation-dehydrogenation cycles enable the efficient storage, transport, and release of hydrogen via chemical means. Practical kinetic, thermodynamic, and H-density considerations make cyclic hydrocarbons the preferred organic hydrogen carriers. This study addresses the mechanism of methylcyclohexane (MCH) dehydrogenation to toluene (TOL), through methylcyclohexene (MCHE) intermediates on Pd nanoparticles (2–11 nm diameter) dispersed on Al₂O₃, SiO₂, MgO, and CeO₂. Turnovers occur on Pd surfaces densely covered with MCH-derived intermediates differing in isomeric structure and reactivity via sequential C–H activation elementary events, irrespective of nanoparticle size or support. The kinetically relevant step shifts from the second to the first H-abstraction step in MCH as temperature increases (from 453 to 553 K). The reactivity of Pd nanoparticle surfaces is insensitive to their size but supports with more competent Lewis acid–base (LAB) pairs lead to higher rates and stronger rate enhancements (relative to SiO₂) with decreasing temperatures, which reflect the lower coverages of less reactive intermediates when supports can scavenge desorbable species. These dense adlayers retain interstices within which dehydrogenation turnovers occur, but no longer expose the most distinctive low-coordination atoms prevalent on small nanoparticles, leading to the observed structure insensitivity of turnover rates. The prevalence of such adlayers leads to surfaces without the saturation hydrogen coverages expected for Pd surfaces devoid of such organic species. These mechanistic insights are consistent with (i) the elimination of support effect by titration of LAB pairs; (ii) initial rate transients that are inhibited by competent supports; (iii) the relative reactivity of metal-free supports for dehydrogenation of MCHE and methylcyclohexadienes (but not MCH); and (iv) measured kinetic effects of MCH, MCHE, and H₂ on turnover rates. The support effects provide strategies for maximizing the exposure of bare atom ensembles during dehydrogenation reactions. Its conceptual impact and practical significance are not restricted to the subject reaction in this study.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"23 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142880022","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}

{"title":"Synergistic Dual-Atom Catalysts on Ceria for Enhanced CO Preferential Oxidation: Insights from High-Throughput First-Principles Microkinetics","authors":"Zhang Liu, Yanwei Wen, Zhaojie Wang, Limin Guo, Rong Chen, Aimin Zhang, Bin Shan","doi":"10.1021/acscatal.4c05779","DOIUrl":"https://doi.org/10.1021/acscatal.4c05779","url":null,"abstract":"Highly dispersed transition metal atoms supported by reducible ceria have garnered considerable attention as CO preferential oxidation (PROX) catalysts. Dual-atom catalysts (DACs), which effectively balance activity and selectivity through synergistic effects, are promising candidates for PROX catalysis. We report here the high-throughput screening of CeO₂(110)-supported DACs (M_A-M_B/CeO₂, M_A(B) = 3d, 4d, 5d transition metal) based on first-principles microkinetics. Reduced electronegativity and d-orbital population of metal atoms favor the stability of loaded DACs via binding energy and aggregation energy analyses. A state-to-state microkinetic analysis of the full PROX reaction network identifies that the O₂ -predissociated Mars–van Krevelen (MvK) pathway, characterized by direct oxidation, carbonate formation, and interfacial oxygen migration, is the predominant mechanism on M_A-M_B/CeO₂ under low temperatures. The key energetic routes of homogeneous DACs reveal that the oxygen removal energy of dissociated O₂ and adsorption energies of CO and H on transition metal sites serve as effective descriptors of PROX performance. Following these insights, high-throughput computations of PROX descriptors are carried out on a combination of 435 heterogeneous DACs to screen catalysts with balanced activity and selectivity. Au-based DACs, notably Fe–Au, stand out at room temperature for their facile activation of dissociated oxygen and moderated hydrogen affinity. Our study harnesses the unique properties of dual-atom configurations and paves way for the rational design of efficient PROX catalysts.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"14 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142880021","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}

{"title":"Highly Stable Subnanometric Pt Clusters in All Silica K-Doped Zeolites: Implications for the CO Oxidation Reaction","authors":"Benjamin Bohigues, Isabel Millet, Patricia Concepción, Avelino Corma, Manuel Moliner, Pedro Serna","doi":"10.1021/acscatal.4c04758","DOIUrl":"https://doi.org/10.1021/acscatal.4c04758","url":null,"abstract":"Small metal clusters can provide improved catalytic activity compared with single metal atoms and larger metal nanoparticles of the same element. The stabilization of metal ensembles of a few atoms is extremely challenging, however, because reductive sintering and oxidative fragmentation are phenomena that often occur at low temperatures in reactive atmospheres. In this regard, the CO oxidation reaction is particularly challenging because CO tends to aggregate noble metals on nonreducible supports, such as SiO₂, whereas O₂ triggers the formation of (less active) single atoms on reducible supports, such as CeO₂. Accordingly, state-of-the-art Pt/CeO₂ catalysts undergo severe deactivation under practical CO oxidation conditions in excess of O₂. In this contribution, we report a highly active CO oxidation catalyst that is able to overcome both sintering and fragmentation instabilities under conditions that make other alternatives fail. The catalyst is based on small Pt clusters inside K-MFI that benefit from both strong metal/support interactions at defective sites of the zeolite and strong electronic promotion by the support, to attain highly stable, highly active, electron-rich Pt clusters.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"32 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142873846","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}

{"title":"Catalytic Resonance Theory: Turnover Efficiency and the Resonance Frequency","authors":"Jesse R. Canavan, Justin A. Hopkins, Brandon L. Foley, Omar A. Abdelrahman, Paul J. Dauenhauer","doi":"10.1021/acscatal.4c06623","DOIUrl":"https://doi.org/10.1021/acscatal.4c06623","url":null,"abstract":"Programmable catalysts exhibiting forced oscillation in the free energy of reacting surface species were simulated to understand the general mechanisms leading to efficient use of the input energy. Catalytic ratchets with either positive or negative adsorbate scaling exhibited oscillation conditions of both high and low turnover efficiency, yielding catalytic turnover frequencies either close to or significantly lower than the applied catalyst oscillation frequency, respectively. The “effective rate”, defined as the product of the catalytic turnover frequency and the turnover efficiency (η_TOE), was limited via two catalytic mechanisms: a leaky catalytic ratchet existed when molecules repeatedly traversed backward through the catalytic transition state upon catalyst oscillation, while a catalytic ratchet with low surface participation exhibited reduced formation of a gas-phase final product due to low surface product coverage. A single applied frequency yielding a maximum effective catalytic rate defined as the “resonance frequency” provided maximum combined benefit for catalytic rate and efficiency.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"58 3 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142880024","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}

{"title":"Bis(oxazoline) Iron Complexes Enable Tuning of Lewis Acidity for Catalytic Carbonyl–Olefin Metathesis","authors":"Jessica L. Gomez-Lopez, Ashlee J. Davis, Timothy J. McClure, Mina Son, Daniel Steigerwald, Rebecca B. Watson, Mu-Hyun Baik, Corinna S. Schindler","doi":"10.1021/acscatal.3c04684","DOIUrl":"https://doi.org/10.1021/acscatal.3c04684","url":null,"abstract":"Carbonyl–olefin metathesis reactions are powerful transformations for carbon–carbon bond formation. Despite recent progress, limitations exist that hamper the synthetic generality of the reported approaches. Catalytic systems that will enable tuning of their Lewis acidity and consequently the selective activation of specific substrate classes are expected to greatly enhance the current scope. We herein report the development of cationic iron-bis(oxazoline) complexes as powerful catalysts that enable the alteration of Lewis acidity to efficiently convert substrate types that were previously found to be incompatible with existing catalytic systems in carbonyl–olefin ring-closing metathesis.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"28 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142873845","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}

{"title":"Modulating Lattice Oxygen through an Alkaline Earth Metal Promoter for Chemical Looping Oxidative Dehydrogenation of Propane","authors":"Wei Wang, Sai Chen, Jiachen Sun, Ziyi Li, Xianhui Wang, Yiyi Xu, Zelin Wu, Donglong Fu, Chunlei Pei, Zhi-Jian Zhao, Jinlong Gong","doi":"10.1021/acscatal.4c06614","DOIUrl":"https://doi.org/10.1021/acscatal.4c06614","url":null,"abstract":"Rational design of metal oxide-type redox catalysts for selective propylene production is of paramount importance, yet remains challenging. This paper describes the structural and electronic effect of an alkaline earth metal promoter on lattice oxygen reactivity for chemical looping oxidative dehydrogenation (CL-ODH) of propane through the configuration of core–shell-type redox catalysts, which consist of a redox-active FeVO₄ core and a selective mixed alkaline earth metal oxide shell. A systematic study demonstrates that Mg is the optimal promoter among all alkali and alkaline earth metals investigated, and the formed Mg₂V₂O₇ outer shell provides a catalytic surface for C–H activation while blocking the nonselective sites for FeVO₄, typically as an oxygen carrier. The core–shell redox catalyst with a higher coverage of the Mg₂V₂O₇ layer achieves an enhanced propylene selectivity of 80.8% at an operation temperature of 550 °C. The design strategy highlights the exploration of alkaline earth metals in redox catalysts for chemical looping processes.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"20 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142873848","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}

{"title":"Site-Selective Magnesiation of Multifluorinated Arenes Catalyzed by Rhodium–Aluminum Bimetallic Complexes","authors":"Ikuya Fujii, Kazuhiko Semba, Yoshiaki Nakao","doi":"10.1021/acscatal.4c06676","DOIUrl":"https://doi.org/10.1021/acscatal.4c06676","url":null,"abstract":"We report the site-selective C–F magnesiation of multifluorinated arenes catalyzed by Rh–Al bimetallic complexes to prepare synthetically important fluorine-containing organomagnesium reagents. We clarified that the catalyst-control site-selectivity stems from the steric and electronic environments of the substrates. The protocol can be applied to the efficient synthesis of fluorine-containing pharmaceuticals and liquid crystal molecules.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"2 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142873850","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}

{"title":"Identifying Reactive Trends in Glycerol Electro-Oxidation Using an Automated Screening Approach: 28 Ways to Electrodeposit an Au Electrocatalyst","authors":"Raghuram Gaddam, Zirui Wang, Yichen Li, Lauren C. Harris, Michael A. Pence, Efren R. Guerrero, Paul J. A. Kenis, Andrew A. Gewirth, Joaquín Rodríguez-López","doi":"10.1021/acscatal.4c04190","DOIUrl":"https://doi.org/10.1021/acscatal.4c04190","url":null,"abstract":"Automated, rapid electrocatalyst discovery techniques that comprehensively address the exploration of chemical spaces, characterization of catalyst robustness, reproducibility, and translation of results to (flow) electrolysis operation are needed. Responding to the growing interest in biomass valorization, we studied the glycerol electro-oxidation reaction (GEOR) on gold in alkaline media as a model reaction to demonstrate the efficacy of such methodology introduced here. Our platform combines individually addressable electrode arrays with HardPotato, a Python application programming interface for potentiostat control, to automate electrochemical experiments and data analysis operations. We systematically investigated the effects of reduction potential (<i>E</i>_l) and pulse width (PW) on GEOR activity during the electrodeposition (Edep) of gold, evaluating 28 different conditions in triplicate measurements with great versatility. Our findings reveal a direct correlation between <i>E</i>_l and GEOR activity. Upon CV cycling, we recorded a 52% increase in peak current density and a −0.25 V shift in peak potential as <i>E</i>_l varied from −0.2 to −1.4 V. We also identified an optimal PW of ∼1.0 s, yielding maximum catalytic performance. The swift analysis enabled by our methodology allowed us to correlate performance enhancements with increased electrochemical surface area and preferential deposition of Au(110) and Au(111) sites, even in disparate Edep conditions. We validate our methodology by scaling the Edep process to larger electrodes and correlating intrinsic activity with product speciation via flow electrolysis measurements. Our platform highlights opportunities in automation for electrocatalyst discovery to address pressing needs toward industrial decarbonization, such as biomass valorization.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"27 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142880023","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}

{"title":"Cu-Catalyzed Diastereo- and Enantioselective Synthesis of Homopropargyl Amines Bearing All-Carbon Quaternary Stereocenters via Chirality Transfer of Hindered Allenylcopper Species","authors":"Jing He, Wan Seok Yoon, Jaesook Yun","doi":"10.1021/acscatal.4c06631","DOIUrl":"https://doi.org/10.1021/acscatal.4c06631","url":null,"abstract":"The construction of congested acyclic stereocenters with high stereoselectivity is a significant challenge in synthetic chemistry. Herein, we report an efficient method for diastereo- and enantioselective C–C coupling of 1,3-disubstituted enynes with imines for the asymmetric construction of vicinal stereogenic centers, including an all-carbon quaternary center. This coupling was accomplished by chirality transfer from axial-to-central of fully substituted axially chiral allenylcopper intermediates formed in situ from branched enynes with concomitant diastereoselective formation of an additional stereocenter in imine addition enabled by a chiral C₁-symmetric <i>N</i>-heterocyclic carbene (NHC) copper catalyst. DFT calculations provided an enhanced understanding of the silyl effect of allenylcopper nucleophiles on reactivity and the origin of stereoselectivity. Synthetic versatility of the resulting products bearing densely functionalized groups could amplify the significance of the current method.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"83 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142873849","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}

{"title":"Ancestral Sequence Reconstruction Reveals Determinants of Regioselectivity in C(sp3)-H Oxyfunctionalization Reactions by CYP505Es","authors":"Ana C. Ebrecht, Jasmin C. Aschenbrenner, Yosephine Gumulya, Martha S. Smit, Diederik J. Opperman","doi":"10.1021/acscatal.4c06260","DOIUrl":"https://doi.org/10.1021/acscatal.4c06260","url":null,"abstract":"Regioselective C–H functionalization of fatty acids and alcohols is a challenging reaction, especially in-chain/midchain hydroxylation. These hydroxy fatty acids or diols offer a synthetic route to valuable δ- and γ-lactones. Although terminal and subterminal hydroxylation of fatty acids and alcohols by cytochrome P450 monooxygenases have been extensively explored, the molecular determinants of in-chain hydroxylation are unknown. Here we performed ancestral sequence reconstruction (ASR) of the subfamily of CYP505Es, able to perform in-chain hydroxylation, together with their closest related subterminal hydroxylases. Three ancestors were resurrected, which represented the in-chain and subterminal hydroxylases, as well as their common ancestor, which displayed little regioselectivity. Mutations were introduced to investigate the divergence in regioselectivity observed in the natural evolution. Whereas subterminal hydroxylation appears to be through multiple additive mutations in the active site, in-chain hydroxylation was greatly affected by the BC-loop. ASR provides not only insight for directed evolution studies but also more promiscuous ancestors as templates for the starting point for laboratory evolution.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"60 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142873847","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}