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

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 H2 evolution. Upon 0.24% CQDs loading, a three-fold enhanced H2 production activity of 102 mmol center dot g-1 center dot h-1 was achieved compared with pristine CTF-1 (34.5 mmol center dot g-1 center dot 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 excitationindependent 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.

Automated summary

This study successfully enhanced the activity of photocatalytic hydrogen production by constructing carbon quantum dots/covalent triazine-based framework (CQDs/CTF) non-metallic photocatalyst. Carbon quantum dots played an important role in electron capture and the separation of photoinduced electron-hole pairs. Additionally, the up-conversion fluorescent characteristics of CQDs broadened the visible-light response range and improved solar energy utilization efficiency.