Preparation Of Cobalt Hydroxide Derivatization Catalyst And Study On Its Electrochemical Properties

Due to the increasing energy shortages today,it is extremely urgent to develop sustainable and alternative clean energy sources.Because of its high efficiency and environmental friendliness,hydrogen is used as a promising energy carrier and an important chemical component for future replacement of fossil fuels.In recent years,electrochemical splitting of water has provided a flexible and sustainable prospect.Precious metal-based materials such as Pt are electrocatalysts with active hydrogen evolution.However,scarcity and high costs limit their practical application in the energy sector.Therefore,the design and development of electrocata lysts for non-precious metal hydrogen evolution reactions are actively pursuing the future of the hydrogen energy economy and have attracted great research interest.Due to the limitation of reserves and cost of precious metal catalysts,transition metals typified by cobalt,nickel,iron,molybdenum,etc.,have attracted increasing attention due to their exhibited catalytic properties comparable to those of noble metals.Several classes of transition metal compounds,such as phosphides,selenides,sulfides,borides,carbides and metal alloys,have been identified as promising candidates for hydrogen evolution reactions.Fabricating and engineering heterointerface to modulate the atomic arrangement and chemical states of the catalysts was an effective approach to improve its electrochemical activity.Herein,a cobalt phosphide/cobalt sulfide?CoP/CoS_x?heterostructure hollow nanocone was fabricated by an ion intercalation in situ template method.The microstructure of the heterointerface can be adjusted by controlling the S/P ratio.The analysis of electrochemical test revealed that the disordered structure existing at the heterointerface could govern the catalytically active site,thus leading to an enhanced electrocatalytic activity in comparison with their crystalline counterparts.In addition,the impact of"current platform"induced by the unbalanced redox reaction or Faraday current in the value of Tafel slope was discussed in detail.It was found that,when"current platform"appeared,utilizing the value of Tafel slope as an activity kinetics standard was not accurate.On the other hand,compared with the monometallic phosphides,bimetallic phosphides can further improve the catalytic performance for hydrogen evolution reaction?HER?due to the synergistic effect of different components.As such,the rational design and facile synthesis of bimetallic-based phosphides with well controlled architectures and compositions is of scientific and technological importance.In this work,Fe-Co prussian blue analogue?PBA?nanocones?NCs?have been successfully fabricated via an intercalation reaction strategy by utilizing layer structured?-Co?OH?₂ NCs as self-sacrificing templates.After calcination and phosphorization process,Fe-Co PBA NCs can be converted to Fe doped Co_xP NCs without apparent shrinkage.Electrochemical tests show that Fe incorporation can effectively promote the electrocatalytic activities of Co_xP due to the synergistic effect.This simple and effective method will be helpful for the development of other functional Co based bimetallic compounds.Furthermore,this strategy can possibly be extended to fabricate a series of PBA material with special structure and novel morphology,which can serve as a promising platform for diverse applications,especially in energy storage and conversion.