The Controllable Structure And Electrocatalytic Properties Of Transition Metal Cobalt Nickel Phosphorus (sulfur) Compounds

Traditional energy not only promotes economic development but also caused environmental pollution.So,it is very necessary to develop new clean energy.Representatives of clean energy include solar energy and hydrogen energy.Dye-sensitized solar cells?DSSC?and overall water splitting are two ideal ways to harness or generate clean energy.The effective DSSC counter electrode and the catalyst of overall water splitting both need the characteristics of low cost,fast photogenerated electron transfer rate,effective reduction of redox couple and excellent stability.The d orbital electrons or the empty d orbitals in the transition metal act as electrophiles or nucleophiles in the catalytic reaction,forming intermediate products to reduce the activation energy of the reaction and promoting the progress of the reaction.Therefore,this thesis mainly studies the transition metal cobalt-nickel-phosphorus?sulfur?compound as a research object to prepare a composite sulfide counter electrode,which solar energy converted to electrical energy;the multi-metal phosphide electrolyzed water catalyst converts electricity into hydrogen energy to realize energy conversion between the overall water splitting and the DSSC.1)Sulfides possessed resistivity and suitable band width,played a positive role in improving catalytic performance of DSSC.The CoS/MoS₂ microsphere composite were prepared by the hydrothermal and solvothermal reaction.The CoS nanoparticles provided active sites for catalytic reaction,while MoS₂ provided strong electron transport.CoS/MoS₂ achieved a photoelectric conversion efficiency of 7.48%.2)CoNiP/NF nanothorns were prepared by hydrothermal reaction and phosophorization,it has a highly dispersed structure.The rough surface of phosphide accelerated electron transport rate.In acidic electrolyte,when the current density is 10mA cm^-2,the overpotential of CoNiP/NF reaches 103 mV on HER;in alkaline electrolyte,the overpotential at the same current density is as low as 73 mV,and the overpotential of OER is 330 mV at the current density of 50 mA cm^-2.3)Zn-CoNiP/NF microspheres/thorns were synthesized by doping Zn on the basis of CoNiP/NF,which had better electrocatalytic activity than CoNiP/NF.Zn changed the electronic structure of CoNiP and optimized the reversible adsorption and desorption of hydrogen.The superior hydrophilicity enhances the interaction of the catalyst with water,the hierarchical structures with the superaerophobic multifold are in favor of removal of gas bubbles and more catalytic active sites to improve the electrochemical catalytic activity.