Interfacial Ni–N bond in g-C3N4/CoNi2S4 for enhanced photocatalytic CO2 conversion

Cocatalyst loading has been extensively adopted in photocatalysis for enhancing photocatalytic performance. However, the sluggish interfacial charge dynamics between cocatalyst and photocatalyst has restricted the wide applications of such a strategy. Herein, we introduce the Ni–N interfacial bonds between lamellar nitrogen-vacancy-rich g-C 3 N 4 /CoNi 2 S 4 nanoparticles (CN-V N /CoNi 2 S 4 ) composite material to bridge the photogenerated charge carrier separation at their interface. Specifically, extended X-ray absorption fine structure analysis reveals that these Ni–N interfacial bonds are originated from the bonding of CoNi 2 S 4 with the nitrogen atoms adjacent to the nitrogen vacancies (V N ) in g-C 3 N 4 . Experimental evidence and theoretical calculations reveal that Ni–N interfacial bonds cannot only cause an intimate contact interface between CN-V N /CoNi 2 S 4 , but also modulate the charge distribution on the CN-V N and CoNi 2 S 4 , further boosting the photogenerated charge carrier separation. More interestingly, this tailored interfacial microenvironment significantly reduces the energy barrier for key intermediates formation while modulates the rate-determining step from *COOH generation to CO desorption, enabling efficient and controllable CO production. This work establishes a methodological framework for engineering advanced photocatalysts, enabling high-efficiency conversion of solar energy into clean fuels.