Black phosphorus coupled black titania nanocomposites with enhanced sunlight absorption properties for efficient photocatalytic CO2 reduction

• Published in: Applied catalysis. B, Environmental Vol. 295; p. 120211
• Main Authors: Bi, Qingyuan, Hu, Keyan, Chen, Jiacheng, Zhang, Yaru, Riaz, Muhammad Sohail, Xu, Jing, Han, Yifan, Huang, Fuqiang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.10.2021; Elsevier BV
• Subjects: Absorption; Black phosphorus; Black titania; Carbon dioxide; CO2− species; Dosage; Fourier analysis; Fourier transforms; Infrared analysis; Irradiation; Lattice vacancies; Light irradiation; Methane; Nanocomposites; Phosphorus; Photocatalysis; Photocatalytic CO2 reduction; Reduction; Route selection; Selectivity; Single electrons; Solar-to-chemical conversions; Sunlight; Surface chemistry; Titanium dioxide; Solar-to-chemical conversions; Black titania; Photocatalytic CO2 reduction; CO2− species; Black phosphorus
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2021.120211

[Display omitted] •Black phosphorus coupled black titania composites give wide spectrum absorption.•The optimized catalyst shows the best performance for photocatalytic CO2 reduction.•Kinetic isotope effects and in situ infrared detect the crucial reaction processes.•A four-step reaction mechanism involved CO2− intermediate is proposed. Herein, we report a facile direct solid-state reaction strategy using black phosphorus coupled black titania to prepare uniform BP-BT materials with enhanced wide-spectrum sunlight absorption properties. BP-BT possesses a typical crystalline core-amorphous shell (TiO2@TiO2−x) structure with numerous oxygen vacancies and electron-rich P dosage in the layer and exhibits excellent solar-to-chemical conversion for efficient photocatalytic CO2 reduction to CH4. Notably, the optimized BP-BT shows superior activity of CH4 formation of 16.8 μmol g−1 h−1, a selectivity of 80.1 %, and excellent stability for CO2 transformation under solar light irradiation. The kinetic isotope effects and in situ diffuse reflectance infrared Fourier transform spectroscopy analysis reveal that the adsorption and chemical activation of inert CO2 molecule over the surface-defective and surface basic-site-modulated BP-BT are kinetically-relevant steps. The existence of crucial intermediate of CO2− species from single-electron CO2 reduction route and the rate-determining step of CO bond cleavage in photocatalytic CH4 generation were also confirmed.