Fabricating Amorphous g-C3N4/ZrO2 Photocatalysts by One-Step Pyrolysis for Solar-Driven Ambient Ammonia Synthesis

Solar-driven nitrogen fixation remains a significant challenge. Graphitic carbon nitride (g-C3N4) is considered as a promising visible light photocatalyst. However, the photocatalytic performance of g-C3N4 is unsatisfactory because of the random transfer of charge carriers in the plane and the low activation efficiency of the reactants. Herein, amorphous ZrO2 was used as a robust cocatalyst of g-C3N4 to increase the NH3 production activity. The g-C3N4/ZrO2 lamellar composites were constructed by a simple one-step pyrolysis of the deep eutectic solvent ZrOCl2·8H2O/urea. The optimum NH4+ yield could reach as high as 1446 μmol·L-1·h-1 at 30 wt % ZrO2 in the g-C3N4/ZrO2 composites, with an apparent quantum efficiency over 2.14% at 400 nm. It is 7.9 times that of pristine g-C3N4 and 27.5 times that of ZrO2. The introduction of amorphous ZrO2 restrained the hydrogen generation, and the amorphous ZrO2 and g-C3N4 together contribute to the rapid photoproduced electron transfer of less electron-hole pair recombination.