Study On Electrocatalytic Performances Of Co-MOFs-based Composites And Their Deriratives

In this paper,carbon nitride?g-C₃N₄?doped cobalt derivative composite molybdenum disulfide?Co₃O₄/mC@MoS₂@g-C₃N₄?,porouscobaltironprussianblue selenium/phosphatization(porous Co_xFe_1-x-Se-P)and fluorine-doped cobalt-nickel bimetallic organic framework derivatives(CoO_xNiO_y@m C₇₀₀-F)composites were prepared based on Co-MOF.The prepared composites were used as electrocatalysts to study the catalytic activity toward hydrogen evolution reaction?HER?,oxygen evolution reaction?OER?and oxygen reduction reaction?ORR?.And the overall water splitting properties of the latter two samples were futher studied.1.Co-MOFs@MoS₂@MA composite was obtained by adding MoS₂ nanosheets and melamine?MA?during the preparation of Co-MOFs by stirring at room temperature and growing in situ.After calcination,Co₃O₄/mC@MoS₂@g-C₃N₄ composites were obtained.The electrocatalytic analysis show that the composites have good HER and ORR performance,with a low onset potentials of 31 mV and 0.89 V,and Tafel slopes were 66 and84 mV·dec^-1,respectively.The results indicates that the as-prepared material can be used in fuel cells.2.A Co Fe prussian blue with hollow structure was prepared by hydrothermal method.Porous Co_xFe_1-x-Se-P composite was obtained by selenization and phosphating under high temperature.The developed composite exhibit excellent electrocatalytic activity for HER with 172.5 mV at a current density of 10 mA·cm^-2 and the Tafel slopes of 58 mV·dec^-11 and OER with 144.2 mV at a current density of 10 mA·cm^-2 and the Tafel slopes of 106 mV·dec^-1,respectively.Further,overall water splitting was examined in an alkaline solution and?E value was 1.66 V,which is close to 1.63 V of Pt/C catalyst.It showed that the developed composite is a promising electrocatalyst in water splliting.3.The CoO_xNiO_y@mC₇₀₀-F composites with excellent HER and OER properties are obtained by the calcining F-doping bimetallic CoNi-MOFs at different temperatures which prepared via hydrothermal method.The onset potentials and Tafel slope for HER are 25.4 mV respectively,and 29 mV·dec^-11 and for OER are 1.11 V and 78 mV·dec^-1,respectively.Furthermore,when used in a two-electrode alkaline electrolyzer,the resulting composite possess superior water electrocatalysis performance with a?E value of 1.81 V.It is proved that the introduction of heteroatoms and the high-temperature calcination will favor to improve the electrocatalytic performance..The study expanded the application of cobalt-based catalysts and provides a reference for the development of highly efficient and stable electrocatalysts.