Study On Electrochemical Hydrogen Evolution Activity Of RuW Composite

The production of hydrogen from electrolyzed water is simple,efficient and clean.The main problem faced by this method is the energy consumption caused by excessive overpotential during the hydrogen evolution process.Therefore,the need to find an efficient hydrogen evolution reaction catalyst is obviously particularly important.At present,Pt is the best hydrogen evolution reaction catalyst,but the high price of Pt limits its large-scale commercial application.Therefore,it is very important to find a suitable catalyst that can replace Pt.Ru is a 4d transition metal and a member of the precious metal series,but its price is 10 times lower than that of Pt,and the Ru-H bond energy is similar to the Pt-H bond energy.In theory,Ru is also an ideal HER catalyst.Based on the characteristics of Ru-based catalysts,this thesis prepares different RuM catalysts for the purpose of improving the hydrogen evolution reaction activity of the catalyst,and discusses the electrochemical hydrogen evolution reaction activity of Ru W in depth,and further improves the hydrogen evolution reaction of the catalyst through electrochemical phosphating.Finally,a very stable catalyst with extremely high apparent activity was obtained.The specific content of this paper is as follows:（1）Different RuM catalysts were prepared by magnetron sputtering,and the ratio of Ru-M was adjusted by changing the sputtering power of Ru and M.The research results show that when the content of the transition metal element M is 10%,the hydrogen evolution reaction activity of the catalyst is significantly better than that of the pure Ru catalyst regardless of whether it is under acidic or alkaline conditions.When the transition metal content M is 50%,the apparent activity of other catalysts except Ru Ni is better than that of the pure Ru catalyst.（2）In this chapter,a series of nano-Ru W composite electrodes with different proportions were prepared by high-vacuum magnetron sputtering.The loading capacity of precious metal Ru was only 78μg cm^-2.The hydrogen evolution activity of Ru W electrode under acidic and alkaline conditions is not only higher than that of Ru,but also higher than that of Pt/C.Different from Ru,the nano-Ru W electrode consists of many small sized nanoparticles arranged in sequence,which gives Ru W a huge electrochemical area,and is 3.2 times that of Ru.And then,due to the doping of W,the Ru unit cell becomes larger and the electronic structure is changed.The changes of Ru electronic structure and the increase of electrochemical area are the key factors to improve the hydrogen evolution activity of the catalyst.In the presence of0.5M H₂SO₄ at-0.2V,the HER activity of nano-Ru W composite electrode is 1.7 and1.1 times that of Ru and Pt/C electrode.In 1.0 M KOH,the HER activity of nano-Ru W composite electrode is 1.6 and 4.1 times higher than Ru and Pt/C electrodes.（3）The RuWP catalyst was prepared by electrochemically phosphating Ru W.The results show that the HER activity of Ru W is 96 m A cm^-2 and RuWP is 140 m A cm^-2 at an overpotential of 200 m V,and the activity is greatly improved.This is because the electrochemical phosphating generates Ru P and Ru₂P on the surface of Ru W,which makes the structure of the catalyst Ru_xP@Ru W,which has a larger electrochemical area,and the hydrogen adsorption free energy of Ru P and Ru₂P is closer to 0 e V,Which means better hydrogen evolution reaction activity.And further add a small amount of nickel chloride to the phosphating solution to obtain Ru_xNi_yP@Ru W catalyst.This method reduces the degradation loss of the catalyst during the catalysis process,and effectively improves the stability performance of the RuWP catalyst.