The catalytic activity and mechanism of oxygen reduction reaction on P-doped MoS2.

With the approaching commercialization of proton exchange membrane fuel cell technology, developing active, non-precious metal oxygen reduction reaction (ORR) catalyst materials to replace currently used Pt-based catalysts is a necessary and essential requirement in order to reduce the overall system cost. Here, we report a single-atom doped molybdenum disulfide sheet (short as X-MoS2) catalyst for the ORR using a dispersion-corrected density functional theory method. Of all the eleven X-MoS2 (X = B, C, N, O; Al, Si, P; Ga, Ge, As, and Se) systems, only the phosphorus atom doped molybdenum disulfide (P-MoS2) has an O2 adsorption energy close to that of a Pt(111) surface. We have further explored the detailed ORR mechanism of P-MoS2. Along the four-electron reaction pathway, the reduction of OH to H2O is the rate-limiting step with the largest diffusion barrier of 0.79 eV.