Effect Of Crystal Plane Regulation On The Olefin Hydrogenation Performance Of Au-based Alloy SPE Membrane Electrod

As the world’s energy demand and consumption continue to increase,fossil energy can not meet the energy demand indefinitely.Hydrogen energy has the advantages of high calorific value of combustion,cleanliness and abundant reserves,showing the trend of replacing traditional fossil energy,and is known as the key to sustainable development in the future.However,the production and storage of hydrogen energy restricts the development of hydrogen energy,and efficient hydrogen production and storage can be achieved through the coupling of electrolyzed water technology and liquid organic hydrogen storage technology.The core of this technology lies in the SPE membrane electrode composed of proton exchange membrane and catalytic layer,in which the structure,morphology,exposed crystal face and composition of the catalytic layer will directly affect the catalytic performance of the membrane electrode.In this paper,Au-based alloy catalyst was prepared by ion beam sputtering technology,and the sample was modified by controlling electrochemical dealloying,corrosion fluid type,concentration,temperature,time and electrochemical dealloying steps to form a pore structure,increase the number of exposed high exponential crystal surfaces on the sample surface,and optimize and improve the hydrogenation performance of the sample.The effects of electrochemical dealloying on the composition,specific surface area,phase structure,surface morphology,exposed crystal surface and chemical state of Au-based alloy SPE membrane electrode on hydrogenation performance were analyzed by ICP-OES,BET,XRD,TEM,XPS,GC-MS and other detection methods.The conclusions are as follows:1.Electrochemical analysis showed that the preferred condition for good hydrogenation performance in Au-Ni/NC system was 30s（H-6）treated at 50°C at0.5mol HCl system.9000s（P-9）treated at 50°C under 0.65mol HCl O₄ system;The combined preferred sample was 30s treated at 50°C under 0.5mol HCl system+the preferred sample obtained by 9000s at 50°C under 0.65mol HCl O₄ system（A-B-4）;The Au-Ni-Ce/NC system is:treated at 50°C for 40s（CH-3）under 0.25mol HCl system;5400s（CP-3）treated at 60°C under 0.15mol HCl O₄ system;The preferred sample was 40s treated at 50°C under 0.25mol HCl system+sample obtained by60°C treatment at 0.15mol HCl O₄system for 2700s（C-D-3）.The results of ICP,BET and electric double-layer capacitance showed that the Ni content in the sample decreased by more than 99%after electrochemical dealloying,the geometric specific surface area（SSA）and active specific surface area（ESA）were improved,and the hydrogenation performance of the sample increased with the increase of SSA and ESA.The combined series A-B-4 and C-D-3 have the highest current efficiency of 61.38%and 67.84%in each system,while the cyclohexane conversion rate is increased by 24.62%and 24.38%compared with the original system.2.Electrochemical dealloying causes compression strain on the surface of A-B-4 and C-D-3 samples,and the improvement of SSA of the sample is attributed to the fact that electrochemical dealloying causes the surface of A-B-4 to form a network pore structure,while C-D-3 forms a three-dimensional double continuous structure,which effectively increases the SSA of the sample;A partial ligament structure composed entirely of（220）bare crystal faces appeared on the surface of C-D-3,and Au nanoparticles had a large number of low-coordination atoms that could act as active sites;However,the surface of A-B-4 ligament has a reduced low index crystal facet,and（311）high index crystal plane appears exposed,and there are a large number of atomic steps and high index crystal plane at the edge of the ligament,which effectively increases the number of active sites of the sample and promotes the hydrogenation reaction.