Theoretical Design And Experimental Study Of Supported Low/Non-Noble Metal Electrolytic Water Catalyst

Finding clean and sustainable alternative energy has become a vital task.As a new generation of chemical energy carrier,hydrogen energy has recognized as an ideal candidate for fossil fuel owe to its advantages of high energy density,zero carbon emission,no pollution and sustainability.Electrolytic water hydrogen production technology can not only transform unsustainable energy such as solar energy and wind energy into chemical energy that can be stored and transported to make effective use of energy,but also effectively solve the problem of"where hydrogen comes from"in the green hydrogen energy industry,which has very important research significance.Electrolytic water consists of anodic oxygen evolution reaction（OER）and cathodic hydrogen evolution reaction（HER）,whose theoretical potential under standard conditions is 1.23 and 0 V,respectively.However,additional voltage（overpotential）needs to be applied to overcome the reaction barrier in the actual reaction process.Therefore,reducing the overpotential of electrolytic water reaction to reduce the energy loss is very important for the large-scale application of hydrogen energy,and reducing the overpotential needs to design and regulate the efficient electrocatalyst.At present,Pt-based precious metals and Ru/Ir-based precious metals show high activity in HER and OER,respectively,but their wide application in industrialization is limited by its high price and limited resources.Therefore,it is extremely important to design and develop bifunctional electrocatalysts with high activity and low price for the wide use of clean energy.In this paper,the theoretical design,preparation and structure-activity relationship of supported low content noble metal and non-noble metal base overall water spliiting catalysts were studied.The primary research contents and achievements are as follows:（1）Using density functional theory（DFT）calculation,36 nitrogen-doped graphene（NG）supported transition metal（TM）double atoms are designed in this paper.It is found that Cu Pd/NG has a good water splitting activity,with an overpotential of-0.73V and a Gibbs free energy(ΔG_*OOH)of 1.96 e V for OER.TheΔG_*H of HER is 0.29 e V.The reason for water splitting activity is explained by PDOS and ICOHP descriptors.（2）Low content Ru supported by CoP nanoflowers catalyst on carbon cloth（CC）is synthesized（Ru-Co P/CC）by hydrothermal and phosphating methods.The strong carrier metal interaction between Co P and Ru enables this catalyst to show excellent HER and OER activities.Through electrochemical testing suggest that Ru-Co P/CC is a good water splitting catalyst,which need 1.56 V battery voltage to realize the current density of 10 m A cm^-2,and can stay at least 120 h in 1 M KOH solution,the activity and stability is far superior to the Ru O₂/CC||Pt/C/CC.（3）The Co-phosphide supported Fe-phosphide non-noble metal bi-functional nanowire array catalyst on carbon cloth（Fe P-Co P/CC）is synthesized by simple two steps process.By electrochemical study suggest that the Fe P-Co P/CC is an extremely promising non-noble metal bifunctional catalysts,needing only 1.72 V battery voltage to achieve the current density of 50 m A cm^-2.Meanwhile,this catalyst remains outstanding stability for approximately 120 h,and the activity and stability are better than Ru O₂/CC||Pt/C/CC.XPS indicates that there is a strong electron interaction between Fe P and Co P components,which is beneficial to the redistribution of charge in the Fe P-Co P/CC surface,thus regulating the binding energy between the active site and the intermediate in the electrochemical process,and accelerating water splitting process.