Electron-rich interface of Cu-Co heterostructure nanoparticle as a cocatalyst for enhancing photocatalytic hydrogen evolution

Heterogeneous nano-metal structures are widely used in the field of photocatalysis as an efficient cocatalyst, but the structure–activity relationship has not been elucidated clearly. In this work, a classical CuCo@C nanoparticle with a core of bimetallic CuCo and a carbon shell was used as a cocatalyst to explore and reveal the mechanism of interfacial effect for enhanced photocatalytic hydrogen evolution . It was found that the bimetallic CuCo had a heterogeneous structure with abundant Cu-Co interfaces. The desirable visible-light-driven photocatalytic hydrogen evolution rate of CuCo@C/g-C 3 N 4 was much higher than that of Cu@C/g-C 3 N 4 , Co@C/g-C 3 N 4 , and superior to that of the control group loaded with 1 wt% Pt (Pt/g-C 3 N 4 ). According to the experimental characterizations and density functional theory calculations, electrons were enriched at the Cu-Co interface, which can promote the electron-hole pairs separation and accelerate charge transfer of the g-C 3 N 4 host photocatalysts. On the other hand, the surface carbon layer and Cu-Co interface modulated the H adsorption free energy on the CuCo@C, which was favorable for hydrogen evolution. It is conceivable that further investigating and tuning different metal interfaces will facilitate the large-scale application of bimetallic cocatalysts.