S-Scheme-Heterojunction LaNiO₃/CdLa₂S₄ Photocatalyst for Solar-Driven CO₂-to-CO Conversion

Visible-light-driven semiconductor-catalyzed CO 2 conversion into valuable chemicals and industrial feedstocks is one of the superior pathways to address the excess carbon emissions and energy shortages. Herein, an innovative step-scheme (S-scheme) heterojunction assembled from bulk CdLa 2 S 4 and surface rare-earth perovskite-type oxide LaNiO 3 with precisely engineered suitable band alignment is employed for the selective photocatalytic conversion of CO 2 to CO. The optimized 8%-LaNiO 3 /CdLa 2 S 4 photocatalyst exhibits an outstanding CO output of up to 102.43 μmol h –1 with a selectivity of about 83.4%, rivaling all of the similar incumbent photocatalytic reaction systems for CO 2 -to-CO conversion. It highlights the effectiveness of the S-scheme heterojunction LaNiO 3 /CdLa 2 S 4 in hindering the recombination of the photogenerated electron–hole pairs. Meanwhile, a remarkable apparent quantum efficiency (AQE) of as high as 6.76% is achieved, as well as the CO output is still maintained at 99.5% of the initial value after five cycle tests, revealing the superior repeatability and reliability of the 8%-LaNiO 3 /CdLa 2 S 4 photocatalyst for solar-to-chemical conversion. In addition, an experimentally verified band alignment-boosted reaction mechanism is proposed. This study highlights the construction of structurally flexible and highly designable S-scheme heterojunctions, demonstrating potential application in carbon-negative energy conversion.