Efficient photothermal-assisted photocatalytic H2 production using carbon dots-infused g-C3N4 nanoreactors synthesized via one-step template-free thermal polymerization

Carbon-based materials present promising prospects as photocatalysts for water splitting in hydrogen (H2) production, yet the synthesis of carbon dots (CDs) is typically intricate and involves multiple steps, limiting its practical utility. In a groundbreaking approach, this study achieves the uniform and secure embedding of CDs onto the surface of porous graphitic carbon nitride vesicles (PCNVs) through one-step template-free thermal polymerization. This results in the creation of CDs/PCNVs nanoreactors designed for efficient photothermal-assisted photocatalytic H2 precipitation under simulated/real sunlight irradiation. Notably, the optimal prepared CDs/PCNVs-3 sample exhibited a H2 production rate of 25.86 mmol h−1 g−1, surpassing that of pure PCNVs by 2.2 times. The heightened photocatalytic activity primarily stems from the following reason: (i) CDs can effectively improve the separation efficiency of electron-hole pairs on the surface of the photocatalysts; (ii) the unique porous cavity structure of PCNVs can improve light absorption through the multiple reflections and scattering; (iii) the coupling of the photothermal conversion performance of CDs and the thermal insulation of PCNVs photo-thermal nanoreactors improves the photocatalytic activity from the perspective of photo-thermal assistance. Considering the simplicity and economic viability of current synthesis method for modifying CDs on the surface of photocatalysts, it offers a promising strategy for developing highly efficient CDs-based photothermal-assisted composite photocatalysts.