Transition metal anchored C2N monolayers as efficient bifunctional electrocatalysts for hydrogen and oxygen evolution reactions

Abstract

Developing highly active non-noble catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for overall water splitting. In this work, by means of first-principles computations, we screened a series of transition metal atom anchored C₂N monolayers (TM_x@C₂N, TM = Ti, Mn, Fe, Co, Ni, Cu, Mo, Ru, Rh, Pd, Ag, Ir, Pt, or Au) as electrocatalysts for both HER and OER. Almost all TM_x@C₂N composites show metallic properties, indicating outstanding charge transfer for efficient electrochemical procedures. Ti₁@C₂N, Mn₁@C₂N, Co₂@C₂N, Ni₂@C₂N, Cu₂@C₂N, Mo₁@C₂N, Ru₂@C₂N and Ir₁@C₂N exhibit high catalytic activity toward the HER. Among them, Ti₁@C₂N would be the best HER catalyst since both N and Ti atoms are active sites. Unfortunately, Ti₁@C₂N exhibits no OER activity. Instead, only Mn₁@C₂N could perform as a bifunctional electrocatalyst with N and Mn atoms as active sites for the HER and OER, respectively. This work would open a new door for the development of non-noble metal bifunctional electrocatalysts for overall water splitting and also shed light on C₂N-supported nanomaterials as advanced catalysts.