Microchemical environmental regulation of POMs@MIL-101(Cr) promote photocatalytic nitrogen to ammonia.

The polyoxometalates (POMs) have been shown to be highly effective as reactive sites for photocatalytic nitrogen fixation reactions. However, the effect of POMs regulation on catalytic performance has not been reported yet. Herein, a series of composites (SiWM@MIL-101(Cr) (M = Fe, Co, V, Mo) and D-SiWMo@MIL-101(Cr), D, Disordered) were obtained by regulating transition metal compositions and arrangement in the POMs. The ammonia production rate of SiWMo@MIL-101(Cr) is much higher than that of other composites, reaching 185.67 μmol·h·g in N without sacrificial agents. The structural characterization of composites reveals that the increase of the electron cloud density of W atom in composites is the key to improve the photocatalytic performance. In this paper, the microchemical environment of POMs was regulated by transition metal doping method, thereby promoting the efficiency of photocatalytic ammonia synthesis for the composites, which provides new insights into the design of POM-based photocatalysts with high catalytic activity.