Insights into the greatly improved catalytic performance of N-doped BiOBr for CO2 photoreduction

Abstract

Photocatalytic carbon dioxide (CO₂) reduction represents a hopeful approach to addressing global energy and environmental issues. The quest for catalysts that demonstrate both high activity and selectivity for CO₂ conversion has attracted significant attention. In this study, ultrathin N-doped BiOBr was synthesized using a simple straightforward method. Systematic experimental results indicated that N-doping reduced the thickness of the BiOBr nanosheets and increased their specific surface area. Moreover, the efficiency of photogenerated charge carrier migration and the CO₂ adsorption capacity were significantly enhanced, contributing to improved CO₂ photoreduction performance. Experimental results showed that the 2N-BiOBr exhibited the best catalytic performance, with a CO evolution rate of 18.28 ​μmol·g⁻¹·h⁻¹ and nearly 100% CO selectivity in water, which was three times higher than that of pure BiOBr. The potential photocatalytic mechanism was investigated using in situ FTIR analysis and DFT simulations. Mechanistic studies revealed that N atoms replaced O atoms as adsorption centers, enhancing the strong adsorption selectivity towards CO₂ over O–H in BiOBr and facilitating the formation of key reaction intermediates. This study provides new perspectives on the creation and developmen of effective photocatalytic materials, offering theoretical support for the application of photocatalytic technology in energy and environmental science.