Efficient photothermocatalytic hydrogen production performance over a graphene-titanium dioxide hybrid nanomaterial

• Published in: International journal of hydrogen energy 2021-01, Vol.46 (3), p.2871-2877
• Main Authors: Ma, Lijing, Luo, Bing, Geng, Jiafeng, Huang, Zhesong, Guo, Liejin
• Format: Article
• Language: English
• Subjects: Graphene; Hydrogen production; Photo-thermal; TiO2
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.04.178

Here, Graphene@TiO2 nanomaterials were prepared for photothermocatalytic H2 production to make full-use of solar spectrum. The H2 evolution rate (HER) was 17.6 μmol/h and 89.8 μmol/h at room temperature and 90 °C, respectively. Interestingly, it could sharply increase to 436.5 μmol/h when the temperature reached 110 °C, which was about 24.8 times that of under room temperature. The introduction of graphene effectively promoted the specific surface area and pore volume of the composite, thus, contributing to the quick diffusion of reactants. Meanwhile, graphene absorbed and converted the energy of long wavelength photons into heat via photothermal effect, thus, enhancing the temperature of reaction system. The enhanced HER might be attributed to the existence of gas-liquid two-phase flow in micro-boiling state, the strengthened migration/diffusion rate of sacrificial reagent molecules, and as well as the excitation of adsorbed reactant molecules stemming from the elevated temperature. Our work should be valuable for the design of novel and efficient photothermocatalytic hydrogen production system driven by full-spectrum of sun light. [Display omitted] •Photothermocatalytic H2 production of Graphene@TiO2 nanomaterial was studied.•Graphene acted as the photothermal material to promote reaction temperature.•Photothermocatalysis outperformed photocatalysis or thermocatalysis.•The H2 production rate of Graphene@TiO2 at 110 °C was 24.8 times that of at 35 °C.