Boosting the photogenerated charge separation of g-C3N4 by constructing a Ni@Ni2P cocatalyst with a core–shell structure

Abstract

Constructing a high-efficiency and low-cost cocatalyst on g-C₃N₄ is of great significance for realizing efficient photocatalytic hydrogen production. However, balancing the active center and mass transport is still a great challenge in the design of a cocatalyst. Herein, a Ni@Ni₂P cocatalyst with a core–shell structure was rationally fabricated on g-C₃N₄ such that photogenerated electrons could transfer to Ni₂P through Ni directionally and orderly, as their amount can strongly influence photocatalytic H₂ evolution performance. The optimal H₂ evolution rate of 50P-Ni reaches 2.9 mmol h⁻¹ g⁻¹, which is about 3.5-fold and 137-fold higher than that of g-C₃N₄ and Ni/g-C₃N₄, respectively. Systematic investigations reveal that the Ni@Ni₂P cocatalyst with a unique core–shell structure not only endows Ni metal with stability from corrosion but also prolongs the recombination time of photoinduced electrons and holes, which results in better separation efficiency. This work provides useful inspiration for rationally designing a robust and efficient core–shell cocatalyst for photocatalytic H₂ evolution.