| With the rapid development of economy,the demand for energy is increasing.However,the traditional energy sources of coal,oil and natural gas have limited reserves and serious environmental pollutions due to the long-term overuse.Therefore,it is urgent to develop clean and renewable energy,such as hydrogen energy,which can effectively solve the energy crisis and environmental problems at present.At present,the electrolysis of water is widely considered as the most promising green hydrogen production method for large-scale industrial application.The key issue is to develop efficient hydrogen evolution catalyst to solve the problems of large energy consumption and high reaction energy barrier.It is well known that platinum group precious metals are the best catalysts for hydrogen evolution,but their limited reserves and high price make them difficult to be widely used.Among many metal-based catalysts,cobalt phosphide（CoP）is very popular because of its excellent catalytic activity,good stability,low price and abundant reserves.However,in comparison with platinum group noble metals,its intrinsic catalytic activity and stability are still poor and need to be further improved.Therefore,it is greatly important to improve the catalytic activity and stability of cobalt phosphide by diverse modification strategies.In view of the above situation,we have carried out the following research:（1）Co-Ni bimetallic precursor was synthesized on nickel foam substrate by simple hydrothermal and water bath method,and then Co-Ni bimetallic phosphide was synthesized by the following low temperature phosphating method.By adjusting the concentration of nickel source in water bath,the effect of nickel introduction on hydrogen evolution performance of single-phase CoP electrocatalysis was investigated.The electrochemical test results show that the best Co Ni P electrode obtained at 0.1 M of nickel source has the lowest overpotential of only 38.2 m V at the current density of 10 m A·cm-2.This is mainly due to the synergistic effect between the introducing Ni atoms and Co atoms,and the effective increase of the electrochemical active surface area,which leads to a significant improvement in catalytic performance.（2）CoFeP nanostructures with controllable iron content were synthesized by simple ion exchange method,and tested their electrochemical performance under alkaline conditions.The results show that the sample obtained with ion exchange for 30 min in 30m M iron source concentration has the lowest overpotential of only 29.8 m V at the current density of 10 m A·cm-2.This is mainly due to the doping of an appropriate amount of iron atoms in the Co Fe P electrode.It not only changes the electronic structure of the CoP surface which could improves its catalytic performance,but also effectively improves the stability of single-phase CoP,especially under high current density.（3）WP/CoO/COP composite nano-catalysts were prepared on the Co（OH）F/NF precursor by water bath,air annealing and low temperature phosphating.The electrochemical test showed that the catalysts improved the electrochemical hydrogen evolution performance of single-phase CoP at high current density while maintaining good stability,with overpotential of only 163.9 m V at a current density of 500 m A·cm-2.The results show that the improvement of the performance can be attributed to the introduction of proper amount of W atoms and the formation of WP/CoO/CoP composite phase,which effectively accelerates the reaction process. |
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