In-situ topology synthesis of defective MoN nanosheets/g-C3N4 2D/2D heterojunction photocatalyst for efficient H2 production

Solar-driven water splitting in the powder system is considered as one alternative way to obtain H2 fuel. Recently, graphitic carbon nitride (g-C3N4) has received intensive interest owing to the unique characteristics such as excellent stability, ease of synthesis, and so forth. However, the performance is restricted by the serious recombination of photoinduced electrons and holes and insufficient active sites. In this context, we have developed an in-situ topology strategy to synthesize defective MoN nanosheets with abundant active sites for H2 evolution reaction (HER). Moreover, by virtue of this in-situ topology synthesis strategy, MoN nanosheets/g-C3N4 2D/2D heterojunction was constructed with an intimate interface connected via Mo-C bond, speeding up electrons transfer and inhibiting the recombination of photogenerated carriers. Besides retarding the return of photogenerated electrons, defective MoN nanosheets can also provide considerable active sites, decreasing the active energy of photocatalytic HER. Thus, compared with bare g-C3N4, a 120-times improvement of H2 production rate is achieved. It is expected that this in-situ topology synthesis strategy can be applied to other nitrides and the construction of advanced composite system.