Synergistic effect of bimetallic active sites on Ce doped NH 2-MIL-125 for promoting photocatalytic conversion of nitrogen to NH 3

Ammonia (NH 3 ), one of the most abundant inorganic compounds in the world, is highly demanded in the international market. NH 3 is mainly synthesized using Haber -Bosch technology, which severely pollutes the environment and consumes high quantities of energy. In this study, a series of Ce doped NH 2 -MIL-125 (Ce-NH 2 -MIL-125) was prepared using a one-step solvothermal method to assess the activity of photocatalytic nitrogen fixation. The applied light energy interval of Ce-NH 2 -MIL-125 was widened, and the establishment of a Ce-O-Ti chemical bond optimized the transport path of the photogenerated carriers. This excellent photoelectric performance represents a significant improvement in the separation capacity of the photogenerated electrons and holes in Ce-NH 2 -MIL-125. Doping with Ce resulted in the generation of dual active sites, Ti 4+ /Ti 3+ and Ce 4+ / Ce 3+ , in NH 2 -MIL-125; additionally, the increase in the amount of Ti 3+ was significantly higher than that of the initial NH 2 -MIL-125. The synergistic effect of the bimetallic active sites in Ce-NH 2 -MIL-125 accelerated the photocatalytic nitrogen fixation reaction. Under full spectrum radiation, the ammonia generation rate of NH 2 -MIL-125 was 10.6 mu mol g -1 h -1 . Ce-NH 2 -MIL-125-1.0 exhibited the highest capacity for nitrogen fixation; the highest ammonia formation rate was 39.4 mu mol g -1 h -1 . The photocatalytic activity of Ce-NH 2 -MIL-125-1.0 was 3.7 times higher than that of NH 2 -MIL-125. This study provides a reference for catalytic research on modified NH 2 -MIL-125.