Black phosphorus coupled bismuth chloride oxide nanocomposites for efficient photocatalytic CO2 reduction

Abstract

Developing and utilizing solar to chemical energy conversion is a promising and efficient approach to green carbon-neutral energy systems. Herein, we report a facile solvothermal reaction strategy using black phosphorus (BP) nanosheets coupled with bismuth oxychloride (BiOCl) to prepare uniform BP/BiOCl composite nanocatalysts with enhanced wide-spectrum light absorption and electron-rich P modulated surface acid–base properties. BP/BiOCl possesses a typical layered structure showing the features of excellent separation of electron–hole pairs and electron transfer for efficient photocatalytic CO₂ reduction to CO. Notably, the engineered BP/BiOCl nanocomposite with substantial BP–BiOCl synergy exhibits a superior CO production rate of up to 260 μmol g⁻¹ h⁻¹, which is 130 and 13 times higher than those of BP and BiOCl counterparts, respectively. Meanwhile, the BP/BiOCl material shows excellent photostability for CO₂ transformation under visible light irradiation. The ¹³C isotope labeling experiment confirms that the carbon source of C-containing products is derived from the CO₂ substrate during the photocatalysis process. The S-scheme mechanism involving excited electron transfer and direct participation in chemical activation of inert CO₂ molecules, generation of key intermediate CO*, and final gas products for photocatalytic CO₂ reduction over the BP/BiOCl composite is thus proposed.