Preparation And Electrochemical Performance Of Anodic Catalyst For Water Splitting

Hydrogen is considered as one of the most ideal green energy sources.In the water electrolysis for hydrogen production,the high overpotential of oxygen evolution has resulted in the low energy conversion efficiency.Therefore,it is quite critical to research and develop anodic catalytic materials with high performance and to reduce the overpotential of oxygen evolution.In this paper,we chose cheap transition metals and special foam substrates to prepare FeCoNi/nickel foam and Cu nanowires/copper foam,acting as anodic catalytic materials for electrochemical water splitting.Meanwhile,the WO₃/FeOOH photoanode material was prepared by the combination of FeOOH with good electrocatalytic activity and semiconductor WO₃ for photoelectrochemical water splitting.The results have produced the theoretical significance for the preparation and application of anodic catalysts in?photo?electrochemical water splitting.The main results were as follows:?1?The tri-component FeCoNi composite anodic materials was prepared by one-step electrochemical deposition using foam nickel?NF?as the substrate.The composite anodic materials were systematically characterized by X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,field emission scanning electron microscopy?FESEM?,energy dispersive spectrometer?EDS?,transmission electron microscopy?TEM?and electrochemical tests,respectively.The results have indicated that the current density of FeCoNi/NF composite as anode reaches up to 126.90 mA/cm² at bias potential of 1.55 V?vs.RHE?.After 8 h of continuous electrolysis,the current density of FeCoNi did not significantly decay.?2?Cu nanowire anodic materials was prepared by the chemical immersion and electrochemical cathodization using copper foam?CF?as substrate.Then,the composite anodic materials were systematically characterized by XRD,FESEM and electrochemical tests,respectively.The results have demonstrated that the current density of Cu nanowire as anode reaches up to 214 mA/cm² at bias potential of 1.80 V?vs.RHE?.Moreover,the current density of Cu nanowire was quite stable and more than 84%of the initial value was still sustained after continuous electrolysis of 2,000 s.?3?WO₃/FeOOH photoanode materials was prepared by deposition-annealing process and electrochemical deposition using fluorine-doped tin oxide?FTO?as substrate.The composite anodic materials were systematically characterized by XRD,FESEM,UV-Vis diffuse reflectance spectra?UV-Vis DRS?,incident photon to current efficiency?IPCE?and electrochemical tests,respectively.The results have indicated that the current density of WO₃/FeOOH as photoanode reaches up to 0.67 mA/cm²,which is 2-fold that of pure WO₃ at bias potentials of 1.23 V?vs.RHE?.The current density of WO₃/FeOOH was quite stable and more than 88%of the initial value was still sustained after continuous electrolysis of 3 h.The origin of the performance enhancement for photoelectrochemical seawater splitting was also analyzed by electrochemical impedance spectroscopy?EIS?and Mott-Schottky?MS?decay measurements.The reaction mechanism of photoelectrochemical water splitting was proposed.