Fluorine-based multi-halogen atom doped vinasse carbon quantum dots on vertical graphene: A bifunctional catalytic electrode for water splitting

The development of a low-cost and high-performance electrode for water electrolysis is important for green energy development. In this paper, fluorine-based multi-halogen atom doped carbon quantum dot loaded vertical graphene electrodes are prepared using biomass waste vinasse as a carbon source. F and Cl co-doping has the best electrochemical properties among multi-halogen atom doping. The HER overpotentials of FCl-CQDs/VG at a current density of 10 mA cm-2 are 171 mV and 161 mV at 1 M KOH and 0.5 M H2SO4, and the OER overpotentials are 393 mV and 556 mV at 1 M KOH and 0.5 M H2SO4, respectively. The Faraday efficiencies of FClCQDs/VG are 89 % (HER) and 86.5 % (OER), respectively. Cl atom doping can increase the content of ionic and semi-ionic bonds C-F, accelerate charge transfer, and improve electrochemical performance. This study improves the basis and ideas for the development of low-cost and high-performance self-supported all-carbon electrodes.