Binary Metal Complex Catalysts Prepared By Magnetron Sputtering And Their Electrochemical Hydrogen Evolution Activity

With the increasing depletion of fossil energy and pollution caused by the use of fossil fuels,hydrogen has been paid more and more attention because of its high energy density,cleanness,and easy storage.The water electrolysis reaction is regarded as one of the most efficient,convenient and environmentally friendly methods for obtaining hydrogen.In the electrolysis process of water,the key factor is the electrode material.Thus,it is particularly important to obtain a high active and stable catalystfor hydrogen evolution reaction.In this paper,the electrode materials of hydrogen evolution reaction water electrolysis process have been studied.Several binary metal composites were prepared by magnetron sputteringin order to improve the hydrogen evolution activity of platinum group metals?Ir,Pd?by the interaction with other elements.The main content are listed as follows:?1?IrSi binary metal composites were prepared by magnetron sputtering.First,by calculating the double layer capacitance,we found that the electrochemical active area of Ir_91.04Si_8.96-MS/Ti was greatly increased by the addition of Si,which was 3.4 times larger than that of Ir-MS/Ti in 0.5 mol L^-1H₂SO₄.Secondly,with the increase of electrochemical active area,its electrochemical hydrogen evolution activity has also increased.When the overpotential was 0.2V,the apparenthydrogen evolution activity of Ir_91.04Si_8.96-MS/Ti was 107.40 mA cm^-2,which was 16.13 mA cm^-22 larger than that of Ir-MS/Ti.If the mass normalization of iridium metal was further performed,the hydrogen evolution activity per unit mass of IIr_91.04Si_8.96-MS/Ti was also excellent,which was 1.6 times higher thanthat of Ir-MS/Ti.In addition,Ir_91.04Si_8.96-MS/Ti had exhibited the excellent hydrogen evolution stability in the long-term variable potential and fixed constant potential scans.Finally,Ir_91.04Si_8.96-MS/Tihad also shown the excellent oxygen evolution activity in 0.5 mol L^-11 H₂SO₄,indicating that Ir_91.04Si_8.96-MS/Ti is a promising dual-effect catalyst for the hydrogen evolution reaction and oxygen evolution reaction.?2?In the study of electrochemical hydrogen evolution materials,amorphous electrode materials can show a larger electrochemical area,so the research on this aspect is a hot topic at present.In this paper,PdSi amorphous alloy was ingeniously prepared by magnetron sputtering.First,the amorphous Pd_71.78Si_28.22-MS/CP has a great deal of electrochemical active area,which is11.4 times bigger than that of Pd-MS/CP and 5.45 times biggerthan that of Pd/C.When the overpotential was 0.2V,the current density of Pd_71.78Si_28.22-MS/CP was 65.13mA cm^-2,which was 1.51 times that of Pd-MS/CP and 2.11 times that of Pd/C.It is due to the addition of Si has inhibited the hydrogen storage process and accelerated the reaction rate of hydrogen desorption step.In addition,the Pd_71.78Si_28.22-MS/CP has exhibited superior hydrogen evolution stability than Pd-MS/CP in both the long-term variable potential and constant potential scans.?3?The preparation of metal alloy materials is the most effective method for improving the electrocatalytic activity of single metals.In this paper,different proportions of PdFe alloy were prepared by magnetron sputtering.First,the XRD analysis has shownthat the position of the?110?plane positive has shifted by 0.5°,indicatingthat the lattice of Pdhas shrinken by the addition of Fe.With Fe content increased,the crystal surface displacement increased by follow.Second,the XPS analysis has shown thatthe binding energy of Pd had decreased,which indacted the electrons had transferred from Fe to Pd.The electrochemical area of Pd_73.28Fe_26.72-MS/CP was 4.89 times that of Pd-MS/C.Under acidic conditions,when the overpotential was 0.2V,the apparent current density of Pd_73.28Fe_26.72-MS/CP was70.40 mA cm^-2,which was 1.63 times that of Pd-MS/CP(43.19 mA cm^-2).After further normalizing that electrochemical area,the current density of Pd_73.28Fe_26.72-MS/CP was still 1.43 times that of Pd-MS/CP.This indicates that the increase in the electrochemical hydrogen evolution activity of PdFe is due to the increase of intrinsic activity.The Tafel slope of Pd_73.28Fe_26.72-MS/CP is also much lower than that of Pd-MS/CP,which further indicates that the addition of Fe increases the hydrogen desorption rate of the Pd surface.Similarly,in the alkaline environment,the electrochemical hydrogen evolution activity is also much higher than that of Pd.When the overpotential is 0.2V?vs.RHE?,the current density of Pd_73.28Fe_26.72-MS/CP(40.20mA cm^-2)was 2.19 times that of Pd-MS/CP.