Photocatalytic reforming of ethanol to produce hydrogen: Effect of anatase doped with NiO on products and reaction pathways

Photocatalytic hydrogen production is of great significance for the transformation of energy system. To improve the hydrogen production performance, nano-photocatalysts including pure TiO2 and NiO-TiO2 were prepared by sol-gel method in this paper. To unravel reaction intermediates and pathways, the adsorption experiments and photocatalytic reaction of ethanol over the photocatalysts were carried out in combination with in situ DRIFTS technique, and the main products in the photocatalytic process were detected through gas chromatography. The results showed that 2NiO-TiO2 as the optimum photocatalyst can yield the maximum H2 rate at 20.10 mmol g−1 h−1. For the adsorption of ethanol on TiO2 and 2NiO-TiO2, the molecular form of ethanol is more dominant than the dissociated form, and CH3CH2OTi is more easily generated on 2NiO-TiO2 than pure TiO2. The hydrogen production pathway changes by doping with NiO, reducing the production of acetic acid and aldehydes and producing the important intermediate CH2CHOTi.