Oxygen Evolution and Reduction on Two-Dimensional Transition Metal Dichalcogenides.

Motivated by the need to find good electrocatalysts for water oxidation and O 2 reduction, composed of nontoxic and earth-abundant elements, a systematic screening of two-dimensional (2D) transition metal dichalcogenides (TMDCs) is performed. To identify compounds that are intrinsically active and can fully take advantage of the high surface area of 2D catalysts, this study focuses on the properties of the ideal basal planes of 2D TMDCs, in the 2H, 1T, and 1T' phases. Over two hundred materials proposed in computational databases are studied by means of first-principles-based simulations coupled with continuum embedding models to account for the presence of electrochemical environments. The best candidates with overpotentials for the oxygen evolution and reduction reactions (OER and ORR) lower than 0.5 V under acidic conditions and higher stability against degradation in electrochemical environments are selected. For OER, the designed workflow identifies one active and thermodynamically stable material, and seven materials that are metastable at the oxidative potentials and acidic pH. On the other hand, for ORR, we identify 20 materials with overpotentials less than 0.5 V. Among these compounds, six bifunctional materials have been experimentally reported, with 1T-NbTe 2 and 1T'-MoTe 2 being the best performing catalysts for OER and ORR, respectively.