Preparation And Electrocatalytic Performance Of Cobalt-based Binary Metal Sulfide/oxide Composite Materials

The development of highly efficient water-splitting catalysts has become a core issue of renewable energy technologies.The noble metal and oxides have very high electrocatalytic water-splitting activity under both acidic and alkaline conditions.However,the practical applications are extremely limited due to the high price.Cobalt is a very cheap transition metal element,and its various forms of compounds show good electrocatalytic properties.In this thesis,a high-efficiency cobalt-based catalyst was prepared by a simple electrodeposition method,and its electrocatalytic performance was studied.(1)Amorphous sulfide nanoparticles were prepared byelectroposited preparing nanofiber-like conductive substrates on the surface of polyaniline.The morphology and chemical composition of the samples were characterized.The results showed that prepared CoMoSx/NCNFs/CP has a tight and coarse three-dimensional network nanofiber structure It also showed excellent catalytic activity for HER with a low overpotential(117 mV)and a low Tafel slope(75 mV dec-1).This is due to the abundance of catalytic active sites on the surface of the amorphous CoMoSx and the flow charge transfer to the underlying NCNF skeleton.(2)A simple and rapid CV electrodeposition method was used to fabricate amorphous NiCoOx and CoOx thin films.A self-supporting NiCoOx/NF composites were further prepared.The morphology and chemical composition of the films were characterized.OER performance was tested by CV method.The SEM results showed that a variable morphology can be realized by strictly optimizing the Ni/Co ratio of the metal ions in the precursor solution.The optimized NiCoOx(2:1)/ITO showed the highest OER activity in 1 M KOH,with the overpotential(250 mV),a slope(48 mV dec-1),and an overpotential(364 mV at 10 mA cm).This nanostructured NiCoOx(2:1)/ITO also showed excellent stability during WOR.