| Energy shortage and environmental pollution are the main challenges affecting the development of modern society based on fossil energy.Efficient and sustainable energy reform is the general trend.At this stage,the development of energy technologies such as direct methanol fuel cells（DMFC）fueled with methanol is an effective way of energy reform.However,the development of DMFC was inhibited by the high cost of precious metal anode materials,the easy to be poisoned,and the low performance and poor stability caused by the high anode overpotential of non-precious metal anode materials.Secondly,the electrocatalytic performance of anode material is mainly controlled by its microstructure and structure.Therefore,the design and development of high efficiency and low cost non-noble metal anode materials are very important for reducing overpotential,improving electrocatalytic performance and reducing cost.This paper takes the DMFC anode catalyst as the research background and the low-cost non-precious metal Ni-based anode material as the research object.Micro-nano anode materials such as nickel-based organic metal framework（Ni-MOF）and Ni O were prepared by solvothermal method,and used for methanol electrocatalysis research.On this basis,the effect of Co-doped Ni-based nanomaterials on the electrocatalytic performance of methanol was further discussed.The main findings are as follows:（1）Ni-MOF anode material was prepared by solvothermal method.The effect of reaction temperature on the morphology,structure and electrochemical performance of Ni-MOF materials was discussed.It was found that with the change of reaction temperature,the morphology and structure of Ni-MOF material changed significantly.When the reaction temperature is 150℃,the prepared Ni-MOF（Ni-MOF-150）is a layered microsphere composed of nanosheets,and its crystal structure is consistent with the simulated Ni-MOF structure（CCDC-638866）.Electrochemical tests show that Ni-MOF-150 has greater coverage of surface active species(9.12×10-7 mol·cm-2),proton diffusion coefficient(3.28×10-9 cm2·s-1)and relatively small charge transfer resistance（31.18Ωcm2）.In alkaline media,Ni-MOF-150 exhibits better electrocatalytic performance,with lower methanol oxidation peak potential（0.735 V vs.SCE）,greater mass specific activity(800.00 m A·g-1)and longer time stability.（2）Co-doped Ni-MOF composite material（Co-Ni-MOF）was prepared by solvothermal method.The effect of Co doping on the anode material structure and electrocatalytic performance was studied.The study found that the Co-doped Ni-MOF（Co-Ni-MOF-3）obtained when the amount of Co added is 0.6 mmol has a significantly improved electrochemical performance,and it has a larger coverage of surface active species(1.53×10-6 mol·cm-2),proton diffusion coefficient(5.62×10-7cm2·s-1)and relatively small charge transfer resistance（21.19Ωcm2）.In alkaline media,Co-Ni-MOF-3 as a methanol electrocatalytic material has a large mass specific activity(945.00 m A·g-1),which is comparable to commercial Pt/C(925.00 m A·g-1).In addition,it was found that Co doping significantly reduced the oxidation peak potential of Ni-MOF（0.680 V vs.SCE）.（3）Using nickel nitrate,cobalt nitrate,polyvinylpyrrolidone and urea as raw materials,Co-doped Ni O nanocomposite（Co-Ni O）was prepared by solvothermal method for methanol electrocatalysis.As a result,it was found that the Co-Ni O anode material had a higher catalytic activity for methanol than Ni O material.0The active species coverage of Co-Ni O-2(1.53×10-6 mol·cm-2)and proton diffusion coefficient(5.62×10-7 cm2·s-1)were 3.8 times and 2 times higher than that of undoped Ni O.The charge transfer resistance of Co-Ni O-2 is only 117.90Ωcm2,which is significantly lower than Ni O（288.30Ωcm2）.In alkaline media,the methanol oxidation peak potential of Co-Ni O-2 is only 0.610 V（vs.SCE）,which is significantly lower than that of Ni O（0.670 V vs.SCE）.At the same time,the mass specific activity of Co-Ni O-2 increased from 206.57 m A·g-1 of undoped Ni O to 262.95 m A·g-1. |
