Design of active bifunctional electrocatalysts using single atom doped transition metal dichalcogenides

Single atom catalyst is designed to achieve high catalytic activity while extremely minimizing precious metal loadings for electrochemical energy conversion and storage applications. Using first-principles density functional theory calculations, we screen 48 combinations of single atom catalysts anchored at defective monolayer transition metal dichalcogenides (A ₁ /TMD; A = Ni, Cu, Pd, Ag, Pt and Au; TM = Mo, W, Nb and Ta; D = S and Se). With established methodologies, we identify five best catalysts for each of oxygen reduction/evolution and hydrogen evolution reactions among the stable candidates. A scaling relation between the Gibb's free energy for intermediates is figured out to understand the governing mechanism of single atom catalysts with varying transition metal dichalcogenides supports and to introduce key descriptor. Pt ₁ /MoS ₂ is proposed as the best bifunctional catalyst for oxygen reduction/evolution reaction. In addition, Pt ₁ /NbSe ₂ and Pt ₁ /TaS ₂ are promising candidates for oxygen and hydrogen evolution reactions. Treating the support itself as an active site for hydrogen evolution reaction, Pd ₁ /NbS ₂ and Pt ₁ /NbS ₂ are proposed as potential bifunctional catalysts toward oxygen reduction and evolution reaction, respectively. Conceptual design principle via high-throughput screening of single atom catalyst is demonstrated as a great approach to determine active and durable bifunctional single atom catalysts.