Design, Preparation And Characterization Of Electrode With Catalytic Activity For Hydrogen Evolution Reaction

Hydrogen is of great interest as an ideal and clean source of energy in the future,and concerned by most scientists. Water electrolysis is an important technique forhydrogen production. Photo splitting of water to hydrogen is a perfect project of"Sunlight Economy". Research and exploitation of electrode with catalytic activityfor hydrogen evolution reaction (HER) is important and effective to reduce the lossof energy. In this paper, many kinds of cathodes for hydrogen evolution were prepared.SEM, TEM, XRD, XPS and STM were used for characterization of those electrodes.The catalytic activity and mechanism for HER were researched by polarizationcurves and alternating current impedance measurements. Crystalline and nanocrystalline metal were deposited on p-Si byelectrodeposition and electroless plating. After deposition of Ni-W-P, the HERovervoltage of Ni-W-P/p-Si electrode was about 200~350mV lower than p-Si whenthe current density is 80A/m2. Nanocrystalline Ni-W-P alloy had the best activityfor the HER. Overpotential of HER decreased about 50mV after illumination by500W iodine-tungsten lamp. AES and XPS showed that Fe was dissolved and semi-conductor of WO3 filmwas formed when Fe-W deposit was dipped in H2SO4 solution. The thickness ofWO3 film was about 720nm. Nanometer Pd particle was prepared on WO3 film byelectroless deposition. SEM and STM showed that the size of Pd was about 10nm.After modification of Pd, the photoelectrochemical catalytic property for hydrogenevolution reaction of WO3 electrode was improved. A Schottky barrier was formedat the interface of Pd/WO3 that drives electrons toward the Pd and holes towardWO3. WO3 film was prepared on the surface of nanocrystalline Ni-W-P and Ni-Moalloys by sol-gel method. The influences of thickness and the heat treatmenttechniques on the catalytic activity of HER were researched. After heat treatment 6h at 600 ℃ , H2WO4 was decomposed to WO3.Nanometer WO3 particle was obtained after grinding 24h, and diameter of particlewas about 61nm. For Ni-W-P/WO3 composite layers prepared by electrodeposition,with the increase of WO3 in bath, the apparent activation energy of HER wasdecreased but the exchange current density i0 and apparent area were increased. Nanometer CdS particle was prepared by chemical precipitation method.Ni/CdS composite deposit was electrodeposited on Cu substrate from a solutioncontaining CdS particles suspended by stirring. When the current density was80A/m2, overpotential of HER moved near 100mV towards more positive values.Compared with Ni electrode, the rate of HER was increased remarkably. The HER had been studied on various Nickel based alloy electrode materials inalkaline water electrolysis in order to find better electrocatalysis. NanocrystallineNi-W-P and Ni-Mo alloys were selected as activity cathode materials in chlor-alkaliindustry. The optimal technological conditions were made certain by orthogonalexperiment. High electrocatalytic activity electrodes used for chlor-alkali industry wereprepared by electrodeposition of nanocrystalline Ni-W-P and Ni-Mo alloys on steel.The electrolysis voltages were decreased 150mV(Ni-W-P alloy) and 280mV(Ni-Moalloy) under industrial conditions. It was shown from continuous electrolysis testthat Ni-W-P alloy cathode had long life and steady performance.