Engineering Halide Perovskite‐Carbon Nitride Composites for High Performance Photocatalytic Aldehyde Synthesis

ABSTRACT

Solar light enables the selective and sustainable production of value‐added chemicals through photocatalysis. Developing catalysts to effectively harvest that energy is crucial for implementation. However, most studied materials, such as graphitic carbon nitride (GCN), still face limitations, including low surface area and fast charge carrier recombination. Forming heterojunctions with other semiconductors effectively enhances charge carrier dynamics and, consequently, improves performance. Given halide perovskites’ light‐harvesting properties (e.g., Cs ₃ Bi ₂ Br ₉ , CBB), this work investigates the synthesis and use of xGCN/CBB hybrid materials. Composites with different GCN contents (50–98 wt.%) were prepared, thoroughly characterized, and used for the visible light‐driven photocatalytic oxidation of anisyl alcohol (AA) to p ‐anisaldehyde (AAD). The 70GCN/CBB material exhibited the best performance, with 94.4% AA conversion after only 45 min of reaction. Spectroscopy results showed that CBB incorporation enhanced visible‐light absorption and decreased photoluminescence, which, combined with the electrochemical results, indicated improved energy efficiency and slower charge carrier recombination. When immobilized, the 70GCN/CBB catalyst demonstrated robust reusability. Different reaction mechanisms were identified, where the photogenerated holes and superoxide radicals consistently played a role. Overall, this work demonstrates that immobilizing xGCN/CBB catalysts is a feasible approach for efficient photocatalytic aldehyde synthesis with a lower environmental impact than traditional industrial processes.