Transition metal atom anchored by defective WSSe monolayer as bifunctional single atom catalyst for ORR and OER

Abstract

• Pt@S-WSSe and Pt@Se-WSSe are found as bifuncational SACs with high ORR/OER catalytic activity. • The ORR and OER overpotential of Pt@S-WSSe are lower compared with the previous results. • The magnetic moment is identified as an effective descriptor to evaluate the catalytic activity of TM@S/Se-WSSe. Bifunctional electrocatalysts with high catalytic activity toward oxygen reduction reaction ( O R R ) and oxygen evolution reaction ( O E R ) are key for developing efficient energy conversion and storage technology. Here, we investigated the O R R and O E R electrocatalytic activity of transition metal atoms (TM) anchored at the S and Se vacancy sites of W S S e monolayer ( T M @ S - W S S e , T M @ S e - W S S e ) via performing the first-principles calculation. Our result shows that the single atom catalysts ( S A C s ) P t @ S - W S S e and P t @ S e - W S S e have low O R R / O E R overpotentials ( η O R R / η O E R ) of 0.31/0.36 V and 0.43/0.34 V, respectively. The η O R R and η O E R at SAC P t @ S - W S S e are even lower compared with the previously studied S A C s . Besides, the Gibbs free energy changes of the key intermediate adsorption are close to the values at ideal catalyst. Our calculations demonstrate the promising potential of P t @ S - W S S e and P t @ S e - W S S e as O R R and O E R bifunctional S A C s . More importantly, the superior O R R and O E R catalytic activity of T M @ S - W S S e and T M @ S e - W S S e are well explained via the intrinsic feature of S A C s as well as the interaction between the TM atom and the intermediates. Especially, we demonstrate that the magnetic moment and the catalytic activity of S A C s T M @ S - W S S e and T M @ S e - W S S e is closely correlated. Our result provides new idea for designing highly effectual O R R and O E R bifunctional SACs.