Up-conversion fluorescent carbon quantum dots decorated covalent triazine frameworks as efficient metal-free photocatalyst for hydrogen evolution

Abstract

Photocatalytic hydrogen production holds great promise for alleviating the energy shortage through effective photo-to-chemical conversion, and the development of visible-light responsive, low-cost and sustainable photocatalysts remains key priority. In this study, carbon quantum dots/covalent triazine-based framework (CQDs/CTF) non-metallic photocatalyst was constructed through a simple impregnation method for photocatalytic H 2 evolution. Upon 0.24% CQDs loading, a three-fold enhanced H 2 production activity of 102 μmol∙g −1 ∙h −1 was achieved compared with pristine CTF-1 (34.5 μmol∙g −1 ∙h −1 ). Photoluminescence and photoelectrochemical study revealed carbon quantum dots served as the electron libraries, which was conducive to facilitate electron capture and promote the separation of photoinduced electron-hole pairs in CTF-1. Notably, the excitation-independent up-conversion fluorescent characteristics of CQDs endowed the catalysts broadened visible-light response range and higher solar energy utilization efficiency. This study deepens insights into the mechanism of CQDs modification and paves a trustworthy strategy for harvesting visible-light-driven metal-free photocatalyst with highly-active and robust performance. • A highly active and stable metal-free photocatalyst based on CTFs was constructed. • The fluorescent behavior of CQDs under different wavelength ranges were studied. • The lights emitted by CQDs could be efficiently utilized to stimulate CTFs. • The photocatalytic process and mechanism were systematically studied.