Photocatalytic CO reduction of 2D/0D CoAl-LDH@CuO catalyst with p-n heterojunction.

Layered double hydroxides (LDHs) are widely used in catalytic field, especially in photocatalysis, benefiting from the ultrathin 2D structure and luxuriant surface functional groups. However, the wide band gap and low utilization rate of solar spectrum affect their photocatalytic performance. Herein, we integrated n-type CoAl-LDH with p-type CuO nanoparticles to construct a p-n heterojunction with a strong built-in electric field, which can prevent photoinduced electron-hole pairs from recombination as well as facilitate charge transfer. With the X-ray photoelectron spectroscope and Fourier transform infrared spectroscopy, we confirmed the charge transfer under light illumination complying with the type II-scheme mechanism and analyzed the intermediates during photocatalytic CO reduction reaction (CORR). The highest yields reached 320.9 μmol h g for CoAl-LDH@CuO-60 (LC-60) under 1 h light irradiation, which was about 1.6 times than the pristine CoAl-LDH. The sample also exhibited excellent stability which maintained 84.1% of initial performance after 4 circulations.