2D bimetallic RuNi alloy Co-catalysts remarkably enhanced the photocatalytic H2 evolution performance of g-C3N4 nanosheets

The development of Pt-free co-catalysts matched with photocatalysts is one of the key technologies to improve the photocatalytic hydrogen production performance. Herein, the bimetallic RuNi alloys with a 2D structure are reported as a co-catalyst of g-C3N4 nanosheets for the first time. Its 2D structure can be well-matched with the 2D g-C3N4 nanosheets to form a composite photocatalyst with close contact. On the one hand, it is beneficial to reduce the transfer barrier of photogenerated electrons, and on the other hand, it can provide much more reaction sites for photocatalytic hydrogen production. Besides, the synergistic effect between Ru and Ni metals in the 2D bimetallic RuNi alloys makes it exhibit better co-catalytic performance than that of Pt. The RuNi/g-C3N4 photocatalyst with about 2.3% Ru contents shows a hydrogen production performance of up to 35,100 umol/g/h under simulated sunlight irradiation, which is more than twice that of the Pt/g-C3N4 photocatalyst with the same noble metal contents. The theoretical results by DFT calculation verify the experimental results and show that the 2D RuNi alloys have better performance of adsorbing H atoms and desorbing hydrogen. This work provides new insight for the development of efficient Pt-free metal cocatalysts and makes a significant step toward the development of co-catalyst with 2D structure for photocatalytic hydrogen evolution.