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

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. [ABSTRACT FROM AUTHOR]