Theoretical Study On The Electrocatalytic Of CO₂ By Pd-based Bimetallic,and The Synthesis Of Methanol By Copper Alloy

An important sign of the rapid development of society is the rapid consumption ofenergy,and the pursuit of development has less attention to its consequences.The use of large-quantity stone energy has caused the concentration of carbon dioxide in the atmosphere to rise sharply,which has led to a series of environmental problems such as global warming.Therefore,finding renewable energy resources while reducing the amount of carbon dioxide in the atmosphere is extremely important for the sustainable development of society.One way to solve this problem is to hydrogenate CO₂ to make it a fuel or fuel precursor such as carbon monoxide,methanol or longer chain alcohols.Electrochemical conversion of CO₂ as a promising approach to simultaneous carbon recycling and renewable power storage has attracted considerable attention,so that it can simultaneously address two issues facing the energy and environmental sectors.At the same time,the hydrogenation of CO₂ to methanol is also one of the preferred options for reducing CO₂ content and storing energy.In the field of catalytic chemistry and chemical engineering,bimetallic clusters have become ideal catalysts,which can improve the reactivity and selectivity of each component,provide a solid and reliable theoretical basis for CO₂ hydrogenation,and simultaneously support cluster catalysts.In this paper,the catalytic performance of Pd-based bimetallic electrocatalysts and copper alloy catalysts for CO₂ hydrogenation reaction is studied in detail from the theoretical point of view,which provides theoretical guidance for the synthesis of high-efficiency,low-consumption water-gas shift catalysts.The main content is:1.Theoretical Insight in Electrocatalytic Reduction of CO₂ in Metal Ratio and Reaction Mechanism on Palladium-Copper Alloys.Environmental impacts of continued CO₂ production have led to an increased need for new methods of CO₂ removal and energy development.Recent studies have shown that electrochemical reduction of CO₂ is a good method of energy conversion.Alloys are of special interest for these applications,because of their unique chemical and physical properties that allow for highly active surfaces.Here,Pd_nCu_m?m+n=15 and n>m?bimetallic electrocatalysts were used for systematic studies to understand the effect of the composition of Pd and Cu on the electrochemical reduction of CO₂ to CO.In particular,PdCu alloys with a Pd/Cu molar ratio of 2/1 are most popular for CO conversion in terms of thermodynamics.This process can be achieved without any additional voltage assistance.Moreover,the detailed mechanism of electrochemical reduction of CO₂ to CH₃OH,CH₄ and C₂H₅OH compounds was studied using Pd₁₀Cu₅ as catalyst.Most importantly,the Micro-kinetic modeling was used to study the reaction mechanism.The findings revealed in this study may shed some light on the design of cost-effective and efficient electrocatalysts for CO₂ conversion to CO or to other useful hydrocarbons.2.A Tunable PdSn Alloy Electrocatalyst for CO₂ Reduction to value added products from DFT Study.Conversion of CO₂ into value added products by electroreduction is one of the attractive means to reduce CO₂ and it must trigger a sustainable solar-fuel-based economy.However,achieving this process requires catalysts with high activity,selectivity,and durability.Alloy catalysts can achieve superior performance to single metals while reducing the cost by finely tuning the composition and morphology.PdSn nanoparticles alloy is known currently as the most active electrocatalyst for CO₂ electroreduction reaction,but the reaction pathways to produce ethanol are not clear.In this work,we present the results of theoretical studies aimed at elucidating the optimal mechanism and the effects of the reaction environment of gas and liquid on the intrinsic activity and selectivity of alloy catalysts for the reduction of CO₂.In addition,through tuning PdSn catalyst with adding oxygen and sulfur atom,the reaction energy can be significantly reduced,eventually reducing the limiting voltage of the electrode reaction to-0.51 eV.Density functional theory calculations of the reaction free energy diagrams suggest that the the rate-determining step is hydrogenation of CO to CHO,this is easier than CO or CHO dimerization.The calculations also illustrate the rationality of the gas phase model compared to the liquid phase.3.DFT Comparison the Performance of bare Cu and Cu-Alloyed Co Single-Atom Catalyst for CO₂ synthesizing of methanol.Copper-based catalysts have been widely used for CO₂ synthesizing of methanol,while enhancing the productivity to methanol is challenging.In this section,density functional theory?DFT?is used to study the performance of CO₂ hydrogenation to CH₃OH on alloy catalysts with Co and Cu composition.Potential energy surface?PES?analysis confirmed that the favorable hydrogenation catalytic for CO₂ is the SAC of Cu₁₂Co,proceeds via CO₂?HCOO?H₂COO?H₂CO?H₃CO?CH₃OH.It has long been proposed that gas-phase atomic clusters that can be well characterized by computational method are the ultimate single-site catalysts.Br?nsted-Evans-Polanyi?BEP?relations perform adequately for exploring biomass-relevant chemical kinetics on metal surfaces with higher accuracy than the universal BEP relation.After analysis,the C-H formation and C-O bond scissions have showed good correlation within the range considered,for O-H the initial state representation seems more adequate.We hope that our work may be useful for designing and optimizing Cu-based catalysts for CO₂synthesizing of methanol.