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-C 3 N 4 ) is considered as a promising visible light photocatalyst. However, the photocatalytic performance of g-C 3 N 4 is unsatisfactory because of the random transfer of charge carriers in the plane and the low activation efficiency of the reactants. Herein, amorphous ZrO 2 was used as a robust cocatalyst of g-C 3 N 4 to increase the NH 3 production activity. The g-C 3 N 4 /ZrO 2 lamellar composites were constructed by a simple one-step pyrolysis of the deep eutectic solvent ZrOCl 2 ·8H 2 O/urea. The optimum NH 4 + yield could reach as high as 1446 μmol·L –1 ·h –1 at 30 wt % ZrO 2 in the g-C 3 N 4 /ZrO 2 composites, with an apparent quantum efficiency over 2.14% at 400 nm. It is 7.9 times that of pristine g-C 3 N 4 and 27.5 times that of ZrO 2 . The introduction of amorphous ZrO 2 restrained the hydrogen generation, and the amorphous ZrO 2 and g-C 3 N 4 together contribute to the rapid photoproduced electron transfer of less electron–hole pair recombination.