Tuning the Interfaces of ZnO/ZnCr2O4 Derived from Layered-Double-Hydroxide Precursors to Advance Nitrogen Photofixation

Graphical Advanced ZnO/ZnCr 2 O 4 photocatalysts derived from ZnCr-layered double hydroxide (ZnCr-LDH) precursors are successfully synthetized by a simple thermal process. The optimized ZnO/ZnCr 2 O 4 exhibit a considerable ammonia photosynthesis rate of 31.7 μmol g −1 h −1 in pure water, with the origin of the high activity being derived from the high-efficiency carrier separation due to the abundant interfaces. Drawing inspiration from the enzyme nitrogenase in nature, researchers are increasingly delving into semiconductor photocatalytic nitrogen fixation due to its similar surface catalytic processes. Herein, we reported a facile and efficient approach to achieving the regulation of ZnO/ZnCr 2 O 4 photocatalysts with ZnCr-layered double hydroxide (ZnCr-LDH) as precursors. By optimizing the composition ratio of Zn/Cr in ZnCr-LDH to tune interfaces, we can achieve an enhanced nitrogen photofixation performance (an ammonia evolution rate of 31.7 μmol g −1 h −1 using pure water as a proton source) under ambient conditions. Further, photo-electrochemical measurements and transient surface photovoltage spectroscopy revealed that the enhanced photocatalytic activity can be ascribed to the effective carrier separation efficiency, originating from the abundant composite interfaces. This work further demonstrated a promising and viable strategy for the synthesis of nanocomposite photocatalysts for nitrogen photofixation and other challenging photocatalytic reactions.