| Although nanoporous precious metal films show excellent and stable performance in electrocatalysis,the cost of nanoporous precious metal films is higher compared to nanoporous Cu films,and nanoporous copper films has the characteristics of high activity and easy to be oxidized.Therefore,it is significant to develop the preparation of nanoporous copper films and the study of electrocatalytic performance.In this paper,the Cu-Zn alloy was prepared by solid-solid thermal diffusion on the surface of a smooth copper foil,and nanoporous Cu thin films with different micromorphologies were prepared by dealloying method;and the nano-porous copper thin film was used as a substrate and heat-treated in air nanoporous Cu films with different morphologies were produced;the performance of electrocatalytic oxidation of methanol was measured by CV on the nanoporous copper films before and after heat treatment under alkaline conditions;the reaction rate constant of electrocatalysis oxidized methanol was measured by dual-potential amperometric chronometry,the results show that:Diffusion temperature affects the phase of the precursor and the microscopic morphology of the nanoporous copper film;diffusion time plays a key role in regulating the microscopic morphology of the nanoporous copper film and improving the uniformity of the overall sample;heat treatment conditions can effectively control the nanoporous copper film micro-morphology.The average size of the nanoporous copper film ligaments prepared by changing the diffusion conditions ranges from 111nm to 700nm,and the average pore size ranges from 185nm to 647nm;the average size of the nanoporous copper film ligaments prepared by changing the heat treatment conditions ranges from 110nm to 645nm,the average pore size ranges from 122nm to 288nm.The micromorphology of the nanoporous copper film before and after heat treatment has an important influence on the electrocatalytic methanol activity.The prepared nanoporous copper film catalyzes the oxidation of methanol under alkaline conditions;in the ten CV tests,the current density gradually decreases with the increase of the number of cycles,the peak potential gradually shifts negatively,and the initial potential gradually decreases;And after the fourth cycle,the peak current density tends to be flat;at this time,the peak current density of the nanoporous copper thin film continues to increase with the increase of the diffusion temperature,and it changes with the increase of the diffusion time and then increases and then decreases.Trend,the peak current density of the nanoporous copper film prepared under the condition of 360℃-80min increased to 49.75mA·cm-2;the peak current density of the nanoporous Cu film after heat treatment increased with the increase of the holding temperature and the holding time The trend of increasing first and then decreasing.The peak current of the nanoporous copper film prepared under heat treatment at 140°-20min increased to 86.00mA·cm-2,and the peak current density reached the maximum;while the nanoporous copper film before and after heat treatment The initial potential and the peak potential both decrease and shift to the left with the increase of the number of cycles;however,compared with the nanoporous copper film before heat treatment,the initial potential and the peak potential of the nanoporous copper film after heat treatment decreased gently.The reaction rate constant of the electrocatalytic oxidation of methanol on the nanoporous copper film before and after heat treatment was measured by dual-potential chronoamperometry;the slope of the nanoporous copper film before heat treatment reached the maximum when the diffusion condition was 360℃-80min The slope of the nanoporous copper film after heat treatment reached the maximum when the heat treatment conditions were 140℃-30min,the maximum slopes obtained were 67.05 and 36.04,and the corresponding maximum rate constants were 25.88 and 7.48 respectively. |
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