Design Of High Efficient Ni Based Catalyst For Electrooxidation Of 5-hydroxymethylfurfural

Using renewable biomass resources to produce fine chemicals can effectively solve the problem of environmental pollution and excessive consumption of fossil energy.The conversion of 5-hydroxymethylfurfural（HMF）to 2,5-furanediformic acid（FDCA）by electrochemical oxidation has the advantages of mild conditions and high energy efficiency,which is of great significance for promoting the utilization and development of biomass energy.This thesis aims to design and prepare efficient HMF oxidation Nibased electrocatalysts and investigate the reaction mechanisms.The main research contents are as follows:（1）NiW composite catalyst was prepared on carbon paper by simple electrodeposition method.The effects of deposition time,temperature and the proportion of metal added on the reaction activity of the electrode were investigated,including water oxidation reaction（OER）and HMF electrocatalytic oxidation reaction（HMFOR）.The results show that when the deposition time is 60 min,the deposition temperature is 35℃and Ni:W is 1:2,the NiW composite electrode deposited on CP has the best OER and HMFOR activity.（2）WO_x doped Ni electrode was prepared by two-step electrodeposition method and applied to HMFOR to prepare FDCA system.By SEM,TEM,XPS and other characterization methods,it was proved that WO_x can be rapidly dissolved from the prepared NiW layer,resulting in a large number of lattice defects.The results of electrochemical test and density functional theory（DFT）calculation showed that the formation and stability of high valence Niwere promoted by the lattice defects,and the electrochemical oxidation activity of HMF is significantly enhanced.The experimental results showed that NiW/CP electrode possessed high activity and durability for HMFOR.Under the condition of 1.38 V vs RHE,the conversion of HMF to FDCA could be realized within 1.6 h.After at least 5 cycles,the yield of FDCA and Faraday efficiency both exceeded 90%.（3）NiMo/NF electrode catalyst were prepared by hydrothermal combined calcination.It was speculated by SEM,XRD and ICP that the rapid dissolution of Mo oxide in alkaline solution and Mo in NiMo O₄ compound in alkaline solution might lead to the change of catalyst structure and the formation of surface defects,promoting the formation of Niactive substance and enhancing the electrooxidation activity of HMF.According to electrochemical test results,the current density of HMFOR at NiMo/NF approached 200 m A·cm^-2at 1.37 V vs RHE.Through timing current measurement and product analysis,98.9%HMF conversion was achieved within 54 min at this voltage.At the same time,the electrode also had excellent electrooxidation activity on other biomass derivatives.