Reduction of nitrophenols to aminophenols under concerted catalysis by Au/g-C3N4 contact system

•Au/g-C3N4 contact system exhibits both catalytic and photocatalytic activity.•Reduction of nitrophenol can be achieved under concerted catalysis by Au/g-C3N4.•Effectively concerted catalysis is attributed to the negative shift in Fermi level of Au.

We report a facile one-step strategy to fabricate an Au/g-C3N4 contact system with different Au contents. Morphology observation shows that Au nanoparticles with an average diameter of 2.6 nm are firmly anchored on the surface of two-dimensional g-C3N4 sheets. It is found that the Au/g-C3N4 contact system exhibits an unusual bi-functionality of catalytic and visible-light-driven photocatalytic activities, thus the hydrogenation reduction of nitrophenol to aminophenol can be rapidly achieved under concerted catalysis by the system. Among the Au/g-C3N4 contact systems studied, the Au/g-C3N4-6 exhibits the highest rate constant of 5.9362 × 10−3 s−1 in the dark and 7.9895 × 10−3 s−1 under visible light irradiation for the reduction of p-nitrophenol to p-aminophenol, which is impressively higher than that pure Au nanoparticles or recently reported Au-based nanocatalysts. Such a concerted catalysis can be attributed to the negative shift in Fermi level of Au caused by the induced charge-transfer effect as a result of the strong interaction between Au nanoparticles and g-C3N4.

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