Preparation And Electrocatalytic Performance Of Pd-based Bimetallic Catalysts Supported By Hollow Cage NiCo-LDHs

Direct ethanol fuel cell is an effective technology to alleviate energy shortage and environmental pollution.Catalyst is the key to control the direct ethanol fuel cell.Aiming at the problem of expensive cost and scarce resources of traditional noble metal catalysts,as well as the problem of poor conductivity and easy agglomeration of layered double metal hydroxides（LDHs）materials,this paper takes LDHs as the research object,carbon nanotubes（CNTs）as the carrier,and uses ZIF-67 sacrificial template method to design and prepare hollow cage structure NiCo-LDH@CNTs.The performance of loaded Pd-based bimetallic nanoparticles electrocatalyst for ethanol electrocatalytic oxidation was studied,and the structure-activity relationship between catalyst structure and electrocatalytic performance was explored.The main research contents and results are as follows:（1）The sacrificial template method was employed.In situ growth of ZIF-67 particles on CNTs（ZIF@CNTs）,and ZIF-67 was converted to NiCo-LDH by etching to produce a hollow cage like structure NiCo-LDH@CNTs-2.5%Catalysts.The electronic structure of Co element,which plays an active site role in the electrocatalytic oxidation of ethanol,changed,the hollow cage structure provided more active sites for NiCo-LDH,and the CNTs provided structural support to the catalyst and enhanced its electrical conductivity,thus achieving the promotion of ethanol electrocatalytic oxidation performance.The NiCo-LDH@CNTs-2.5%catalyst showed high performance for the electrocatalytic oxidation of ethanol,and the peak current density for ethanol oxidation can reach 11.5 m A·cm^-2.（2）MPd/NiCo-LDH@CNTs（M=Ru,Ag and Cr）composites were prepared by loading MPd bimetallic nanoparticles on the surface of 3D NiCo-LDH@CNTs materials via a simple and rapid impregnation reduction method using hollow caged NiCo-LDH@CNTs as a support.CrPd/NiCo-LDH@CNTs exhibited high electrocatalytic oxidation performance for ethanol,and its ethanol oxidation current density can reach 46.2 m A·cm^-2.The ethanol electrocatalytic oxidation current density retention was 80%after 8000 s stability test.In addition,the incorporation of Cr changed the electronic structure of Pd,which improves its anti-toxicity and stability in the electrocatalytic process of ethanol.