| In order to solve the environmental pollution and energy consumption caused by traditional fossil fuels,it is urgent to develop clean and renewable energy.Hydrogen energy has been considered as a promising product that can replace traditional fossil fuels.Among various hydrogen production methods,hydrogen production by electrolysis of water is currently the most effective method for producing hydrogen.It contains two key half reactions:hydrogen evolution and oxygen evolution reactions(HER and OER).Currently noble metal-based compounds(such as IrO2/RuO2 and Pt)have excellent OER and HER electrocatalysts.However,their high cost and scarcity characteristics limit their large-scale application.Aiming at the problems of noble metal catalysts,this article prepares bimetallic compounds(especially bimetallic compounds with heterogeneous structure)on conductive substrates to improve catalytic activity,and explores OER,HER and total water dissolution performance.The specific research content is as follows:(1)Interface engineering has become an effective strategy to improve the electrocatalytic performance because of the strong coupling and synergistic effects between individual components.Herein,both interfacial FeOOH/CoO nanosheets(FeOOH/CoO-NSs)and nanowires array(FeOOH/CoO-NW s)were in situ constructed on nickel foam(NF)through a simple one-step hydrothermal approach.The rational selection of Fe(NO3)3ยท9H2O as a Fe source prevents the formation of nano sheet,and enables the generation of nano wire structure due to chemical affination.Benefiting from the synergistic interaction between FeOOH-CoO interface and the unique nano wires array structure,the resultant FeOOH/CoO-NWs/NF exhibits outstanding electrocatalytic activity towards both OER and HER.For the overall water splitting,the bifunctional FeOOH/CoO nanoneedle catalyst requires only a cell voltage of 1.61 V to achieve a current density of 10 mA cm-2,which is much lower than that required for IrO2//Pt/C(1.62 V).(2)Exploring highly active and stable hydrogen and oxygen evolving electrocatalysts is the key for electrochemical water splitting and renewable chemical conversion.Herein,a free-standing defective RuO2-TiO2 electrocatalyst on Ti mesh(D-RuO2/TiO2/TM)was prepared via a simple and easy industrial scale-up approach.Due to the interfacial interaction between RuO2 and TiO2 and the marginal defects on RuO2 nanoparticles,the catalyst showed good catalytic activity.It affords a current density of 50 mA cm-2 at low overpotential of 71 mV for Hydrogen Evolution Reaction(HER),and 10mA cm-2 at 296 mV for Oxygen Evolution Reaction(OER),respective.For overall water splitting,the electrolyzer assembled by D-RuO2/TiO2/TM bifunctional electrode only needs a cell voltage of 1.59 V to reach 10 mA cm-2.Moreover,such electrolyzer achieved an outstanding activity and stability at high current densities.Theoretical calculations revealed that the coupling of defect-rich RuO2 and TiO2 could greatly modulate electron structure of RuO2,accelerate the water dissociation on the catalyst,which consequently enhances the intrinsic activity toward both HER and OER. |
