Theoretical Investigation On The 2D GeP₃-based Nanocatalysts For Hydrogen Evolution Reaction And The Correlative Catalytic Mechanism

With the rapid development of the world economy,the growing contradiction between energy and environment is becoming a great challenge facing all mankind.It is vital to search for alternative sources of energy to substitute the fossil fuel or reduce its dependency.Molecular hydrogen can be considered as one of the best energy carriers,due to the high energy density and calorific value as well as the environment-friendly combustion products.There are many ways to prepare hydrogen,the electrochemical water splitting is deemed to be a very promising technology to generate the fuel hydrogen,in view of the earth-abundant reactant water,high hydrogen production efficiency and no emission of greenhouse gases or other polluting gases.However,the hydrogen evolution reaction?HER,2H⁺+2e^-=H₂?,as the cathodic half reaction of water splitting,is a sluggish kinetic process,thus the core challenge is to develop the highly efficient catalyst to effectively minimize the necessary overpotential.Using first principles density functional theory?DFT?,this paper systematically investigate the catalytic activities for hydrogen evolution reaction?HER?of two-dimensional?2D?layered GeP₃ systems,through calculating electromagnetic properties and gibbs free energy?_H*value of the optimum H^*adsorption state.On this basis,the catalytic activity of two-dimensional GeP₃ was further enhanced by applying the surface strain or coupling with graphene.The following is a brief introduction of the specific content of this work.Under the DFT calculations,we systematically investigate the catalytic activities for hydrogen evolution reaction?HER?of two-dimensional?2D?layered GeP₃systems,viewed as the analogues of phosphorene.Our computed results reveal that the monolayer and few-layered GeP₃ systems can exhibit the good HER activity,where both the top sites over Ge and P atoms can serve as the most active sites.The correlative catalytic mechanisms are analyzed in detail.Further,we propose the effective strategy through applying the external strain to enhance the HER activity of these 2D layered GeP₃ systems by optimizing the adsorption state of H^*??_H*?or electronic property.Imposing the compressive strain on the monolayer GeP₃ and the tensile strain on the few-layered systems can simultaneously endow them with the optimum?_H*value and good conductivity,bringing higher HER activity.Moreover,we have also constructed series of new sandwich nanostructures by alternately stacking the monolayer GeP₃ and graphene,and all of them can uniformly exhibit the outstanding HER activity,due to the optimum?_H*value and good conductivity.Note that all of these systems can exhibit considerably high structure stabilities,as reflected by their large negative interlayer interaction energies.Obviously,all these fascinating findings can be advantageous for achieving the highly efficient and nonprecious HER electrocatalysts based on the excellent GeP₃ nanomaterials in the near future.