Atomically precise metal nanocluster sandwich heterojunction for robust and efficient photocatalytic CO2 reduction to methanol

Developing heterogeneous nanocatalyst with well-defined structure and excellent reactivity and stability is vital for understanding catalytic mechanism and practical industrial application. Herein, we report the construction of atomically precise metal nanocluster sandwich heterojunction (MIL-125-NH2-Au25(L-Cys)18/g-C3N4, M-A/C for short). Compared with the binary counterparts, the M-A/C efficiently and selectively photocatalyzes CO2 reduction to methanol under visible light irradiation with remarkably enhanced activity and stability, due to the protective shell. Moreover, the ternary M-A/C heterojunction not only broadens light absorption region, strengthens CO2 adsorption, but also expands interface charge transfer channel, benefiting for photocatalytic performance. Additionally, the integrating of precise structure and in situ spectrometry unveils the evolution from CO2 to CH3OH. This work opens a promising avenue to design highly-efficient and robust atomically precise metal cluster-based heterojunction catalyst.