Single Transition-Metal Atom Anchored on a Rhenium Disulfide Monolayer: An Efficient Bifunctional Electrocatalyst for the Oxygen Evolution and Oxygen Reduction Reactions.

Developing efficient oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) bifunctional electrocatalysts is attractive for rechargeable metal-air batteries. Meanwhile, single metal atoms embedded in 2D layered transition metal chalcogenides (TMDs) have become a very promising catalyst. Recently, many attentions have been paid to the 2D ReS 2 electrocatalyst due to its unique distorted octahedral 1T' crystal structure and thickness-independent electronic properties. Here, the catalytic activity of different transition metal (TM) atoms embedded in ReS 2 using the density functional theory is investigated. The results indicate that TM@ReS 2 exhibits outstanding thermal stability, good electrical conductivity, and electron transfer for electrochemical reactions. And the Ir@ReS 2 and Pd@ReS 2 can be used as OER/ORR bifunctional electrocatalysts with a lower overpotential for OER (η OER ) of 0.44 V and overpotentials for ORR (η ORR ) of 0.26 V and 0.27 V, respectively. The excellent catalytic activity is attributed to the optimal adsorption strength for oxygen intermediates coming from the effective modulation of the electronic structure of ReS 2 after Ir/Pd doping. The results can help to deeply understand the catalytic activity of TM@ReS 2 and develop novel and highly efficient OER/ORR electrocatalysts.