Constructing Donor-Acceptor Covalent Organic Frameworks for Highly Efficient H2O2 Photosynthesis Coupled with Oxidative Organic Transformations

Abstract

The development of photocatalytic systems that enable the simultaneous production of H₂O₂ and value-added organic chemicals presents a dual advantage: generating valuable products while maximizing the utilization of solar energy. Despite the potential, there are relatively few reports on photocatalysts capable of such dual functions. In this study, we synthesized a series of donor-acceptor covalent organic frameworks (COFs), designated as JUC-675 to JUC-677, to explore their photocatalytic efficiency in the co-production of H₂O₂ and N-benzylbenzaldimine (BBAD). Among them, JUC-675 exhibited exceptional performance, achieving a H₂O₂ production rate of 22.8 mmol g^-1 h^-1 with an apparent quantum yield of 15.7 %, and its solar-to-chemical conversion efficiency was calculated to be 1.09 %, marking it as the most effective COF-based photocatalyst reported to date. Additionally, JUC-675 demonstrated a high selectivity (99.9 %) and yield (96 %) for BBAD in the oxidative coupling of benzylamine. The underlying reaction mechanism was thoroughly investigated through validation experiments and density functional theory (DFT) calculations. This work represents a significant advancement in the design of COF-based photocatalysts and the development of efficient dual-function photocatalytic platforms, offering new insights and methodologies for enhanced solar energy utilization and the synthesis of value-added products.

Keywords: H2O2 production; co-production systems; covalent organic frameworks; oxidative organic transformations; photocatalytic.