Diphenoquinone-Based Covalent Organic Frameworks for Efficient H2O2 Production via Photothermal Synergistic Catalysis.

Abstract

Covalent organic frameworks (COFs) have recently attracted tremendous attention as advanced photocatalytic platforms for H2O2 production from oxygen and water. However, their intrinsic catalytic activity and solar-to-chemical energy conversion efficiency are unsatisfactory for practical applications. In this work, a photothermal synergistic catalysis strategy for improving H2O2 production of photocatalysts was proposed. As a proof of concept, two novel diphenoquinone-based frameworks (COF-JLU240 and COF-JLU241) with donor-acceptor character were constructed for the first time. These frameworks feature broad light harvesting, inherent photoelectric properties, and superior photothermal conversion efficiency. Under the illumination of a 660 nm laser with 100 mW cm-2, the temperature of COF-JLU241 drastically increased from 26.5°C to 184.6°C within 1 min. Importantly, COF-JLU241 exhibits an impressive H2O2 production rate of 4894.9 µmol h- 1 g- 1 in pure water under simulated sunlight, which is 3.86-fold higher than that obtained at the conventional temperature (23°C). Experimental and theoretical studies revealed that increasing the reaction temperature via photothermal effect can effectively promote the separation and transport of photogenerated charges and reduce the energy barrier for surface reactions. This finding contributes a fascinating photothermal synergy strategy for increasing the conversion of solar into chemical energy and broadens the scope of COF-based photocatalysts.