Preparation,Modification And Photoelectrochemical Properties Of Cobalt Foam-base SbVO₄ Composites

The development of a renewable,clean andcost-effective energy source had become important in order to meet the growing global demand for energy and the environmental problems caused by rapid development and population growth.Hydrogen energy had good combustion performance,clean products and environmental protection,and is currently the most ideal new energy.Photoelectrochemical water splitting using solar energy has aroused strong interest among scientists as a future energy conversion technology,and extensive research had proved that the oxygen evolution reaction（OER）is the performance-limiting stage of this technology.Therefore,it is an important subject of photoelectrochemical technology to study efficient,inexpensive and environmentally friendly photoelectrochemical catalytic materials to reduce the overpotential of hydrogen（oxygen）evolution and improve the photoelectric conversion efficiency.In this thesis,three kinds of multicomponent composites,SbVO₄@Co,SbVO₄/Mo S₂@Co and SbVO₄/FeOOH@Co were prepared using three-dimensional porous cobalt foam as the substrate.The elemental composition,morphology,light absorption characteristics and photoelectrochemical OER properties of the composites were investigated by a series of physical characterization and photoelectrochemical performance tests.The main work included the following parts:（1）SbVO₄ were prepared through hydrothermal treatment of the mixture of SbCl₃and Na VO₃.The as-prepared SbVO₄were further employed as photoelectrocatalysts which were deposited on cobalt foam to synthesized the SbVO₄@Co composites by immersion method.The SbVO₄@Co were characterized by XRD,XPS,SEM,EDS and DRS,and it was proved that SbVO₄nanoparticles was deposited on the cobalt foam.The photoelectrochemical performance were tested in 1.0 M KOH electrolyte using SbVO₄@Co as the working electrode.The results indicated that at a current density of 50 m A·cm^-2,the overpotential was 387 m V and the Tafel slope was 72.9 m V·dec^-1.In the meantime,under AM 1.5G simulated solar illumination,the overpotential of SbVO₄@Co went down from 387 to 318 at 50 m A·cm^-2.When the potential was1.62 V vs.RHE,the maximum ISTC efficiency was 0.23%and the charge transfer resistance was 2.89Ω,and it exhibited good stability.（2）SbVO₄ were prepared through hydrothermal treatment of the mixture SbCl₃and Na VO₃.Mo S₂were prepared through hydrothermal treatment of the mixture of（NH₄）₆Mo₇O₂₄·4H₂O and NH₂CSNH₂.The as-prepared SbVO₄and Mo S₂were uniformly dispersed in ethylene glycol where supported on cobalt foam to synthesized the SbVO₄/Mo S₂@Co composites by drop coating and programmed roasting method.The SbVO₄/Mo S₂@Co were characterized by XRD,XPS,SEM,EDS and DRS,and it was proved that SbVO₄/Mo S₂@Co composites were prepared.The photoelectrochemical performance were tested in 1.0 M KOH electrolyte using SbVO₄/Mo S₂@Co as the working electrode.The results indicated that that at a current density of50 m A·cm^-2,the overpotential was 217 m V,which is 170 m V lower than that of SbVO₄@Co,and the Tafel slope was 20.2 m V·dec^-1.In the meantime,under AM 1.5G simulated solar illumination,When the potential was 1.24 V vs.RHE,the maximum ISTC efficiency was about 0.38%,the ISTC efficiency was 0.15%higher than SbVO₄@Co,and the charge transfer resistance was 6.14Ω.and it exhibited good stability.（3）SbVO₄ was synthesized through hydrothermal treatment of the mixture SbCl₃and Na VO₃.Then the as-prepared SbVO₄were deposited on cobalt foam by immersion method to prepared the SbVO₄@Co.Finally,the SbVO₄@Co was put into 0.01 M Fe（NO₃）₃·9H₂O solution to synthesized the SbVO₄/FeOOH@Co composites by immersion self-growth method.The SbVO₄/FeOOH@Co were characterized by XRD,XPS,SEM,EDS and DRS,and it was proved that SbVO₄/FeOOH@Co composite was constructed.The photoelectrochemical performance were tested in 1.0 M KOH electrolyte using SbVO₄/FeOOH@Co as the working electrode.The results indicated that at a current density of 100 m A·cm^-2,the overpotential was 303 m V and the Tafel slope was 15.1 m V·dec^-1.At the same time,under AM 1.5G simulated solar illumination,the overpotential of SbVO₄/FeOOH@Co went down from 303 to 267 at 100 m A·cm^-2.When the potential was 1.21 V vs.RHE,exhibiting a maximum ISTC efciency of 0.084%and the charge transfer resistance was 0.67Ω,and it exhibited good stability.