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The role of CO_(2)dissociation in CO_(2)hydrogenation to ethanol on CoCu/silica catalysts

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Nano Research 2023年第5期16卷 6128-6133页

作者： Zhongyan Wang Chengsheng Yang Xianghong Li Xiwen Song Chunlei Pei zhi-jian zhao Jinlong Gong Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyCollaborative Innovation Center of Chemical Science and EngineeringTianjin UniversityTianjin 300072China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou 350207China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

CoCu-based catalysts are widely used in CO_(x) hydrogenation reactions to produce higher alcohols due to the C–C coupling ability of Co and the ability of Cu to produce alcohols.This work describes the role of easily happened CO_(2)dissociation on the CoCu surface during the reaction,using different silica support to tune the metal–support interaction,reaches different selectivity to ethanol.CoCu supported on mesoporous silica MCM-41 shows ethanol selectivity as high as 85.3%,the ethanol space-time yield(STY)is 0.229 mmol/(gmetal∙h),however,poor selectivity to ethanol as low as 28.8%is observed on CoCu supported on amorphous silica.The different selectivity is due to the different intensities of CO_(2)dissociation on the catalysts.The adsorbed O*produced via CO_(2)dissociation can occupy the cobalt hollow sites on CoCu surfaces,which are also the adsorption sites of C1 intermediates for further C–C coupling.

关键词： CO_(2)hydrogenation bimetallic catalysts cobalt catalysts CO_(2)dissociation ethanol synthesis

Chemical looping oxidative propane dehydrogenation controlled by oxygen bulk diffusion over FeVO_(4)oxygen carrier pellets

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Chinese Journal of Chemical Engineering 2023年第1期53卷 409-420页

作者： Hongbo Song Wei Wang Jiachen Sun Xianhui Wang Xianhua Zhang Sai Chen Chunlei Pei zhi-jian zhao Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhejiang Institute of Tianjin University Ningbo 315201China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China Department of Chemistry National University of Singapore3 Science Drive 3117543Singapore

The oxygen distribution and evolution within the oxygen carrier exert significant influence on chemical looping processes.This paper describes the influence of oxygen bulk diffusion within FeVO4 oxygen carrier pellets on the chemical looping oxidative propane dehydrogenation(CL-ODH).During CL-ODH,the oxygen concentration at the pellet surface initially decreased and then maintained stable before the final decrease.At the stage with the stable surface oxygen concentration,the reaction showed a stable C3H6 formation rate and high C3H6 selectivity.Therefore,based on Fick’s second law,the oxygen distribution and evolution in the oxygen carrier at this stage were further analyzed.It was found that main reactions of selective oxidation and over-oxidation were controlled by the oxygen bulk diffusion.C3H8 conversion rate kept decreasing during this stage due to the decrease of the oxygen flux caused by the decline of oxygen gradient within the oxygen carrier,while C3H6 selectivity increased due to the decrease of overoxidation.In addition,reaction rates could increase with the propane partial pressure due to the increase of the oxygen gradient within the oxygen carrier until the bulk transfer reached its limit at higher propane partial pressure.This study provides fundamental insights for the diffusion-controlled chemical looping reactions.

关键词： Chemical looping Diffusion Reaction kinetics Oxygen carriers Oxidation

Electrochemical Approaches to CO_(2) Conversion on Copper-Based Catalysts

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Accounts of Materials Research 2023年第3期4卷 212-222页

作者： Gong Zhang Lulu Li zhi-jian zhao Tuo Wang Jinlong Gong School of Chemical Engineering and Technology Key Laboratory for Green Chemical Technology of Ministry of EducationTianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China

CONSPECTUS:As one of the essential pathways to carbon neutrality or carbon negativity,the electrochemical reduction of CO_(2) offers tremendous prospects for platform chemicals and fuel production.Copper(Cu)is currently the only metal material that is able to reduce CO_(2) to multicarbon(C2+)products.Despite the fact that copper-based materials have been investigated for decades,we still confront numerous challenges on the path to the fundamental understanding and large-scale deployment of copper-based electrocatalysts for CO_(2) reduction.For fundamental investigations,it remains a variety of open questions about the CO_(2) reduction mechanisms.The convoluted C−C coupling pathways and product bifurcation processes confuse the design of efficient catalysts.The active sites of copper-based catalysts remain ambiguous due to surface reconstruction.As for theoretical calculations,the construction of electrolyte−electrode models and the investigation of solvation effects are premature for obtaining confident conclusions.In addition,simple and easily scalable techniques for catalyst synthesis still need to be continuously developed.For practical applications,the CO_(2) electrolyzer with copper-based materials must be operated with high current densities,high Faradaic efficiencies,high energetic efficiencies,high single-pass conversion rates(high product concentration),and long stability.Nevertheless,due to the intricate nature of electrochemical systems,a high-performance copper-based electrocatalyst alone is not sufficient to meet all of the above commercialization requirements.Therefore,reactor design involving mass transfer enhancement calls for more research input.Based on the above background and the urgency of the net-zero goal,we initiated our research on CO_(2) electrolysis using copper-based materials with an emphasis on active site identification and mass transfer enhancement.This Account describes our contribution to the field of C_(2+)products formation.We first discuss the synthesis of copper-based materia

关键词： stability catalyst Copper

Wide-pH-range adaptable ammonia electrosynthesis from nitrate on Cu-Pd interfaces

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Science China Chemistry 2023年第3期66卷 913-922页

作者： Yongtao Wang Peng Zhang Xiaoyun Lin Gong Zhang Hui Gao Qingzhen Wang zhi-jian zhao Tuo Wang Jinlong Gong Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China

Ammonia production via electrochemical nitrate reduction is essential for environmental protection and the emerging hydrogen economy. Complex nitrate wastewater with a wide pH range calls for flexible catalysts with high selectivity. A high Faradaic efficiency(FE) of NH3 cannot be obtained under strong acid or alkaline conditions due to the uncontrollable adsorption energy and coverage of hydrogen species(H*) on active sites. This article describes the design and fabrication of a copper-palladium(Cu-Pd) alloy nanocrystal catalyst that inhibits H2 and nitrite generation in electrolytes with different nitrate concentrations and varied pH. The interfacial sites of Cu-Pd alloys could enhance the adsorption energy and coverage of H* while increasing the reaction rate constant of NO_(2)*-to-NO*, which achieves a rapid conversion of NO_(2)* along with a decreased FE of NO_(2)-. Under ambient conditions, optimal FE(NH3) is close to 100% at a wide pH range, with the solar-to-chemical conversion efficiency approaching 4.29%. The combination of thermodynamics and kinetics investigations would offer new insights into the reduction mechanism of NO_(2)* for further development of nitrate reduction.

关键词： nitrate reduction ammonia synthesis Cu-Pd interfaces reaction kinetics break p H limitation

Exploring the initial oxidation of Pt,Pt_(3)Ni,Pt_(3)Au(111)surfaces:a genetic algorithm based global optimization with density functional theory

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Green Chemical Engineering 2020年第1期1卷 56-62页

作者： Sihang Liu Jie Zong zhi-jian zhao Jinlong Gong School of Chemical Engineering and Technology Key Laboratory for Green Chemical Technology of Ministry of EducationTianjin UniversityTianjin300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin300072China Department of Chemistry The Pennsylvania State UniversityUniversity ParkPA 16802USA Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou350207China

Noble metal alloys are one of the most commonly used heterogeneous catalysts.During many reactions,the surface composition and oxidation states of the noble metal alloy particles have been reported to be dynamic.This paper describes a density functional theory study to explore the initial oxidation stages of the Ptbased surfaces,which are widely-used catalysts in various clean energy conversion processes.By applying a genetic algorithm based global optimization,we identified new surface phases at relatively high O coverages,1 ML and 3/2 ML,on Pt and Pt alloy(111)surfaces.The existence of O transforms the metallic surfaces,creating oxide skins with different morphology and composition.Metals with higher reducibility are pulled out to the outmost surface,to bind with O atoms.The lattice constant affects the binding strength of O atoms over certain oxide skins.Moreover,the strain effect plays a crucial role in the formation of oxide overlayers.

关键词： alloy theory optimization

Neural Network Accelerated Investigation of the Dynamic Structure-Performance Relations of Electrochemical CO_(2) Reduction over SnO_(x),Surfaces

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Research 2023年第2期2023卷 351-360页

作者： Lulu Li zhi-jian zhao Gong Zhang Dongfang Cheng Xin Chang Xintong Yuan Tuo Wang Jinlong Gong School of Chemical Engineering and Technology Key Laboratory for Green Chemical Technology of Ministry of EducationTianjin UniversityTianjin 300072China Collaborative Innovation Center for Chemical Science and Engineering(Tianjin) Tianjin 300072China National Industry-Education Platform of Energy Storage Tianjin UniversityTianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China

Heterogeneous catalysts,especially metal oxides,play a curial role in improving energy conversion efficiency and production of valuable chemicals.However,the surface structure at the atomic level and the nature of active sites are still ambiguous due to the dynamism of surface structure and difficulty in structure characterization under electrochemical conditions.

关键词： conditions structure difficulty

Theory assisted design of N-doped tin oxides for enhanced electrochemical CO2 activation and reduction

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Science China Chemistry 2019年第8期62卷 1030-1036页

作者： Congling Hu Lei Zhang Lulu Li Wenjin Zhu Wanyu Deng Hao Dong zhi-jian zhao Jinlong Gong Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityCollaborative Innovation Center of Chemical Science and Engineering (Tianjin)Tianjin 300072China Department of Mechanical and Materials Engineering Western UniversityLondonON N6A 5B9Canada

Clearly understanding the structure-function relationship and rational design of efficient CO2 electrocatalysts are still the challenges.This article describes the molecular origin of high selectivity of formic acid on N-doped SnO2 nanoparticles,which obtained via thermal treatment of g-C3N4 and SnCl2·2H2O precursor.Combined with density functional theory(DFT)calculations,we discover that N-doping effectively introduces oxygen vacancies and increases the charge density of Sn sites,which plays a positive role in CO2 activation.In addition,N-doping further regulates the adsorption energy of^*OCHO,^*COOH,^*H and promotes HCOOH generation.Benefited from above modulation,the obtained N-doped SnO2 catalysts with oxygen vacancies(Ov-N-SnO2)exhibit faradaic efficiency of 93% for C1 formation,88% for HCOOH production and well-suppression of H2 evolution over a wide range of potentials.

关键词： N-doped SnO2 oxygen vacancy charge density CO2 activation electrochemical CO2 reduction

Fabrication of bilayer Pd-Pt nanocages with sub-nanometer thin shells for enhanced hydrogen evolution reaction

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Nano Research 2019年第9期12卷 2268-2274页

作者： Yihe Wang Lei Zhang Congling Hu Shengnan Yu Piaoping Yang Dongfang Cheng zhi-jian zhao Jinlong Gong Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityCollaborative Innovation Center of Chemical Science and Engin eeringTianjin 300072China

The hydrogen evolution reaction (HER),which generates molecular hydrogen through the electrochemical reduction of water,is an important clean-energy technology.Platinum (Pt) is an ideal material for HER electrocatalysts in terms of low overpotential and fast kinetics.An effective method to improve the atom utilization efficiency of Pt is to fabricate Pt-based core-shell or nanocage structures with ultra-thin walls.This paper describes the construction of bilayer palladium (Pd)-Pt alloy nanocages catalyst with enhanced HER catalytic activity.The nanocages were fabricated by etching away the Pd templates of multishelled nanocubes composed of alternate shells of Pd and Pt with well-defined (100) facets.The bilayer Pd-Pt nanocages with sub-nanometer shells have a high dispersion of the active atoms on the outside and inside surfaces of outer layer and inner layer,respectively.Moreover,the Pd-Pt alloy lowers the overpotential for HER and speeds up the reaction rate of HER due to the synergies between Pd and Pt.The rational design of bilayer nanocages provided a novel route for boosting the atom utilization efficiency of Pt catalysts.

关键词： Pd-Pt alloy multishelled nanocubes nanocages hydrogen evolution reaction electrocatalysis

Nanostructured Catalysts toward Efficient Propane Dehydrogenation

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Accounts of Materials Research 2020年第1期1卷 30-40页

作者： Sai Chen Chunlei Pei Guodong Sun zhi-jian zhao Jinlong Gong Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering&TechnologyTianjin UniversityTianjin 300072China Collaborative Innovation Center for Chemical Science&Engineering(Tianjin) Tianjin 300072China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China

CONSPECTUS:Propylene serves as one of the most significant compounds in the chemical industry.Propane dehydrogenation(PDH),an“on purpose”propylene production technology is developing.Pt-and CrOx-based catalysts are widely applied in commercialized PDH processes,and both exhibit high activity and propylene yields.However,as an intensively endothermic process,PDH requires operation at high temperatures(generally above 500°C),which restricts the C3H6 selectivity and catalyst structure stability on account of coking side reactions,particle sintering,and so forth.Nanostructured catalysts(NCs)based on metals and/or metal oxides with tunable geometric and electronic properties play significant roles because such features intrinsically influence the adsorption of propyl intermediates on the catalyst surface.However,thermodynamical metastability of these NCs results in grand challenges in their structure-controlled preparation.The regulation of material structure and reaction performance at the molecular and atomic levels has attracted extended attention over the past few years.This Account describes our recent advances in controllable regulation of metal and oxide NCs toward efficient propane dehydrogenation.As a structure-insensitive reaction,the dehydrogenation of propane can occur on an individual active site,while larger ensembles of active sites also induce structure-sensitive side reactions,leading to C−C cracking and coke deposition.This paper is aimed at delivering general fundamentals for rational design of NCs in PDH reactions.We start with the catalytic kinetics on the active sites regarding the adsorption of key propyl intermediates on the surface.In subsequent sections,we present the effective regulation strategies for metal and oxide NCs by promoter and support effects.Upon metal NCs,coke deposition and nanoparticles(NPs)sintering tend to occur,which can be suppressed with the increase of geometric separation and charge density of surface active sites by changing alloy compositions,ordered intermetallic all

关键词： surface. stability. propylene