Steering Catalytic Activity and Selectivity of CO<sub>2</sub> Photoreduction to Syngas with Hydroxy‐Rich Cu<sub>2</sub>S@<i>R</i><sub>OH</sub>‐NiCo<sub>2</sub>O<sub>3</sub> Double‐Shelled Nanoboxes
Lei Li, Xinyan Dai, De‐Li Chen, Yinxiang Zeng, Yong Hu, Xiong Wen Lou
Abstract
Abstract Simultaneous transformation of CO 2 and H 2 O into syngas (CO and H 2 ) using solar power is desirable for industrial applications. Herein, an efficient photocatalyst based on double‐shelled nanoboxes, with an outer shell of hydroxy‐rich nickel cobaltite nanosheets and an inner shell of Cu 2 S (Cu 2 S@ R OH ‐NiCo 2 O 3 ), is prepared via a multistep templating strategy. The high performance of Cu 2 S@ R OH ‐NiCo 2 O 3 (7.1 mmol g −1 h −1 for CO; 2.8 mmol g −1 h −1 for H 2 ) is attributed to the hierarchical hollow geometry and p–n heterojunction to promote light absorption and charge separation. Spectroscopic and theoretical analyses elucidate that the R OH ‐NiCo 2 O 3 surface enhances *CO 2 adsorption and lowers energy barriers for CO 2 ‐to‐CO. Therefore, modulating the hydroxy contents of R OH ‐NiCo 2 O 3 can achieve broad CO/H 2 ratios from 0.51 to 1.24. This work offers in‐depth insights into adjustable syngas photosynthesis and generalized concepts of selective heterogeneous CO 2 photoreduction beyond cobalt‐based oxides.