Study On Her Performance Of 2-D Pt Based On Density Functional Theory

There are many ways to produce hydrogen energy,and water electrolysis has become the mainstream hydrogen production method.The cathode reaction of water electrolysis is called the hydrogen evolution reaction(HER),which is the key to the rate and efficiency of hydrogen production.According to the current research,the most efficient catalysts for HER are those precious metals such as Pt.Therefore,an in-depth understanding of HER principle for precious metals and the development of new precious metal catalysts have become the promising research direction to improve the hydrogen utilization rate and efficiency.At present,the researchers mainly focus on two-dimensional metals.Due to the characteristics of ultra-high specific surface area and the controllable strain,two-dimensional metals have great potential in catalysis compared with the three-dimensional counterparts.At present,for two-dimensional metal catalysts,the main problem lies in the lack of effective computational simulation data in the two-dimensional adsorption process to verify the catalytic potential.To solve the above problems,two-dimensional Pt is selected as the catalyst.Based on the density functional theory(DFT)calculation methods,the adsorptioninduced strain caused by hydrogen atoms,the surface deformation of two-dimensional Pt and d-band center of adsorption sites on Pt surfaces have been calculated.The data are used to study the catalysis of HER on two-dimensional(2-D)Pt surfaces.It mainly includes the following contents:(1)By calculating the Gibbs free energies of different adsorption sites on the 2-D Pt(111)surface,the instability of the optimal adsorption site due to the influence of quantum size effects and double-side-adsorption is revealed.(2)Through calculation of the strain and stress on the clean surface of 2-D Pt(111),it is revealed the expansion stress and strain are related to the location of adsorption site,the thickness of 2-D Pt and the surface coverage rate of hydrogen.(3)The influence of adsorption-induced stress on hydrogen adsorption energy is revealed by theoretical calculation of hydrogen adsorption energy at different adsorption sites and material thicknesses.The significant impacts caused by the adsorption-induced stress on the adsorption performance of materials under high coverage rate are emphasized.(4)By calculating the Gibbs adsorption free energy of different adsorption sites and material thickness on the 2-D Pt(111)surface at 100 % hydrogen coverage rate,the HER catalytic performance of the material is assessed.The results show that the designing scheme of 2-D Pt catalyst should be 4-atomic-layer thickness to reach the best performance of HER.