H2O2 is one of the fastest growing industrial chemicals in the world in recent ten years, and has been widely used as a multi-purpose environmental friendly oxidant in biological process, water purification and chemical industry since it only emits water as a final byproduct. Currently, industrial production of H2O2 is through anthraquinone oxidation, which is limited by high energy input and tedious steps for multiple hydrogenation and oxidation reactions. Therefore, it is still challengeable but highly demanding to produce H2O2 in a facile, clean, and safe way. Photocatalytic production of hydrogen peroxide (H2O2) using water and molecular oxygen as the sole material source is a promising and sustainable solar fuel approach. However, the efficiency using TiO2 as the photocatalyst is limited by: (1) adsorbed hydrogen peroxide in the form of complexes can be oxidized into oxygen; (2) the predominant one-electron reduction of O2 on TiO2 surface results in the inherent low efficiency of oxygen reduction reaction (ORR) and H2O2 production. Target on these shortcomings, we firstly developed an efficient photocatalyst (SN-GQD/TiO2) for H2O2 syntheses by tuning TiO2 with sulfur and nitrogen co-doped graphene quantum dots (SN-GQDs), which displayed a high selectivity for two-electron ORR. The H2O2 production efficiency on SN-GQD/TiO2 improved to 2.4 times of that on TiO2 suspension. Furthermore, Nafion modification of SN-GQD/TiO2 (Nf-SNG/TiO2) was developed to modulate proton coupled electron transfer rates for ORR, and to simultaneously inhibit H2O2 decomposition. The H2O2 production rate enhanced to 373μM/h, which was 5.5 times of that on TiO2. The H2O2 production could be further improved by optimizing proton donor, extending light absorption ranges and so on.

Rational design and synthesis of TiO2-based photocatalysts for H2O2 production

2019 Spring National Meeting

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