Controllable Preparation Of Heterostructured Palladium,Ruthenium-Nickel Hydroxide Catalysts With The Application Of Electrochemical Reforming Small Molecular

Starting from two-dimensional nanomaterials,this paper constructs heterostructures to improve catalytic performance and develop multifunctional electrocatalysts:First,heterostructured Ru/Ni（OH）₂ nanosheets are synthesized as bifunctional catalysts for cathode hydrogen reduction reaction and anodic ethanol oxidation reaction to achieve electrochemical reforming ethanol.Second,heterostructured Pd/Ni（OH）₂ nanosheets are synthesized as bifunctional catalysts for cathodic acetonitrile reduction reaction and anodic ethylamine oxidation reaction to achieve electrochemical reversible reforming acetonitrile-ethylamine.In this paper,new research ideas are provided for the construction of metal-metal hydroxide heterostructures,the exploration of electrocatalytic properties and electrochemical reforming reactions.The main research contents of this paper are as follows:Chapter 1.The classification of two-dimensional metal-based heterostructured nanomaterials is briefly reviewed,which are mainly divided into metal oxides,metal hydroxides,metal sulfides,metal phosphides,metal carbon/nitrides,etc.Furthermore,the application and research status of two-dimensional metal-based heterostructured nanomaterials as electrocatalysts in different catalytic reactions are introduced,and the research content and significance of this master’s thesis are clarified.Chapter 2.Electrochemical reforming ethanol to high value-added chemicals at the anode under green and mild conditions,while producing hydrogen at the cathode.Here,heterostructured Ru/Ni（OH）₂ nanosheets are successfully prepared by in-situ reduction strategy in this work,which exhibits an excellent bifunctional catalytic performance.In hydrogen evolution reaction,Ru/Ni（OH）₂ nanosheets show a small overpotential of 31 m V（vs.RHE,Reversible Hydrogen Electrode）at a current density of 10 m A cm^-2,which is better than commercial Pt/C.In ethanol oxidation reaction,Ru/Ni（OH）₂ nanosheets show excellent catalytic selectivity for ethanol oxidation to acetaldehyde products.At a current density of 50m A cm^-2,the potential required for ethanol electrocatalytic oxidation is only 0.34 V（vs.SCE,Saturated Calomel Electrode）.Density Functional Theory calculations show that the abundant active sites on the Ru-Ni（Ⅱ）heterostructure are the key to its excellent performance.Then,Ru/Ni（OH）₂ nanosheets are used as bifunctional catalysts to construct a two-electrode electrolytic cell for electrochemical reforming ethanol,which is driven by a 1.7 V solar cell.Hydrogen and acetaldehyde chemicals are generated at cathode and anode.This work provides forward-looking technical guidance for the design of new energy conversion systems.Chapter 3.Due to the strong hydrogen evolution properties of Ru,in order to further study the heterogeneous structural materials as cathode electrodes and electrochemical green synthesis of other compounds,this chapter uses Pd with weak hydrogen evolution ability as the main catalytic active site to achieve other cathodic reduction reactions.In addition,heterostructured Pd/Ni（OH）₂ nanosheets are synthesized by in-situ reduction strategy,and the electrochemical test results show excellent activity and selectivity for the electrochemical reversible reforming of acetonitrile and ethylamine.In acetonitrile reduction reaction,Pd acts as the reaction center,while Ni（OH）₂ provides proton hydrogen by facilitating the dissociation of water,reaching close to 100%FE at a potential of-0.15 V（vs.RHE）.In ethylamine oxidation reaction,abundant Ni（Ⅱ）defects on the surface of Pd/Ni（OH）₂ nanosheets.During oxidation,Ni（Ⅱ）defects are partially transformed into Ni（Ⅲ）defects,which acts as the active center of ethylamine oxidation,promotes the occurrence of ethylamine oxidation reaction,the FE reaches 96%at a potential of 1.44 V（vs.RHE）.Then,Pd/Ni（OH）₂ nanosheets are used as bifunctional catalysts to construct a two-electrode electrolytic cell,which is drived by a 2.0 V solar cell.Ethylamine is oxidized to acetonitrile at the anode and acetonitrile is reduced to ethylamine at the cathode,which are aimed to achieve electrochemical reversible reforming acetonitrile and ethylamine.This work demonstrates the importance of multifunctional catalysts prepared by heterostructure in the electrochemically rational synthesis of fine chemicals.Chapter 4.This paper successfully constructs heterostructured Ru/Ni（OH）₂ nanosheets and Pd/Ni（OH）₂ nanosheets by using a simple in-situ reduction strategy,which have different active sites as bifunctional catalysts,and are expected to promote the sustainable development of green energy by combining electrocatalytic reforming reaction technology and green synthesis of chemicals.At the same time,it opens up a new way for the rational preparation of cost-effective and high-efficiency multifunctional electrocatalysts for renewable energy conversion.