Mechanism of electrochemical oxygen reduction reaction at two-dimensional Pt-doped MoSe2 material: an efficient electrocatalyst

Abstract

The O₂ reduction reaction (ORR) is a promising reaction in clean energy conversion systems such as fuel cells, metal–air batteries, and electrochemical reactions. Pt shows excellent electrocatalytic activities for ORR, but their high cost and poor durability hinder their wide application in electrochemistry for energy conversion. In this work, we have computationally designed a 2D monolayer Pt-doped MoSe₂ (noted by Pt–MoSe₂) material, and studied the structural and electronic properties with the ORR activities within the framework of first principles-based periodic hybrid Density Functional Theory (DFT). After doping the Pt atom in the pristine 2D monolayer MoSe₂ material, it became metallic with zero band gap and considerable electronic states at the Fermi energy (E_F) level, which were confirmed by performing the band structure and total density of states (DOS) calculations. A detailed reaction mechanism based on thermodynamic analysis of ORR on the surfaces of the 2D monolayer Pt–MoSe₂ material was carried out by performing quantum mechanical DFT calculations. We explored the electrocatalytic performance of the 2D monolayer Pt–MoSe₂ towards ORR, and full ORR pathways and reaction mechanism by computing the relative Gibb's free energy (ΔG) at the same DFT method. The present study shows how to design better electrocatalysts for ORR by understanding the chemical basis for Pt-doping in MoSe₂ and modification of the 2D layer structure, which paves the way to create high-performance and easily-accessible electrocatalysts. This work indicates that the 2D monolayer Pt–MoSe₂ is a promising candidate to substitute Pt electrodes, and an excellent electrocatalyst for fuel cell components in future applications.