Sb-Substituted Cs₂AgBiBr₆/g-C₃N₄ Composite for Photocatalytic C(sp³)–H Bond Activation in Toluene

Abstract

The visible-light-driven photocatalytic selective aromatic C­(sp3)–H bond activation utilizing all-inorganic halide perovskites as photocatalysts is a sustainable and green approach to obtain value-added oxygenates. These catalysts, however, are restricted by low activity due to undesirable charge recombination and inefficient light absorption. In this research, we developed a Sb-substituted Cs2AgBiBr6/g-C3N4 composite to enhance the photocatalytic performance for toluene oxidation. The introduction of the Sb dopant extended the visible light absorbance to 650 nm, and the formation of the heterointerface and the staggered band structure between the two components substantially suppressed the charge recombination. This composite features a 2.3-fold and 72.5-fold higher visible light photocatalytic toluene oxidation rate toward benzaldehyde than that of either Sb-substituted Cs2AgBiBr6 or g-C3N4 alone, respectively, with a high selectivity of over 96%. The development of all-inorganic lead-free halide perovskite-based heterostructures for visible light photocatalytic organic transformations is expected to have wide-reaching application.

Photocatalysis Based on Metal Halide Perovskites for Organic Chemical Transformations

“…Moreover, introducing Sb 3+ in Bi-based perovskites prolongs the charge carrier lifetimes. To have strong light absorption, along with excellent carrier separation, Li et al used Sb-substituted Cs 2 AgBiBr 6 /g-C 3 N 4 (CASBB/CN) composite for photocatalytic C-H bond activation [165]. The CASBB/CN composite was made by mechanical grinding powders of ASBB and using different ratios of g-C 3 N 4 .…”

Preparation of a Nanosheeted Uranyl–Organic Framework for Enhanced Photocatalytic Oxidation of Toluene

“…In general, it is accepted that the easy recombination and low migration between electrons and holes are main reasons for the low efficiency of photocatalytic conversion . To address the issues, many strategies such as constructing defects or heterojunctions have been employed, but they are still far from meeting the needs of practical production. − Consequently, it is necessary to develop effective ways to improve the separation and migration rates between photogenerated electrons and holes and further raise the conversion rate of photocatalytic reaction.…”

Fe Species Supported on Blue-TiO2/WO3 Nanocomposite as Catalyst for the Decomposition of Toluene Vapor under White Light-Emitting Diode Lighting

“…However, several challenges exist in applying this technology: low photon utilization efficiency, difficulty scaling up, and the deactivation of nanomaterials during prolonged photoreaction. , Its activity, especially, decreases significantly under visible light irradiation, as the redox power of excited electrons and holes in visible light photocatalysts is lower than that of UV-active photocatalysts. Moreover, targeting aromatic compounds such as toluene, xylene, and benzene poses a high challenge due to their stable resonance structure, which requires much higher energy to break the aromatic rings. − The fundamentals of photocatalytic removal of VOCs are based on a radical chain reaction. , The improvement in photodriven reactive oxygen species (ROS) evolution capability is directly related to the VOC removal efficiency.…”