Photocatalytic hydrogen production from water with nonfood hydrocarbons as oxidizing sacrifice agents



To enhance photocatalytic water splitting, various oxidizing sacrifice agents (OSA) have been added to the system in order to scavenge the coproduced O2, and, thus, to hinder the reverse reactions. In the aim of achieving carbon-neutral photocatalytic water splitting, nonfood hydrocarbons of castor- and jojoba-oils were evaluated as OSA. Moreover, various surfactants were tested as emulsifiers for W/O binary solution for promoting photocatalytic water splitting rate. Among the OSA used, the castor-oil was found to be more suitable candidate compared to jojoba-oil, which was attributed to its smaller carbon chain numbers of mainly 18. Without surfactants, around 20 vol %-castor-oil aqueous binary solution with TiO2/Pt(0.10 wt %) provided the highest water splitting rate of about 30 mL-H2/(m2·h). Among tested surfactants, liquid-detergent was the best due to its optical transparency. 40 vol %- or 60 vol %-castor-oil emulsion with a drop of liquid-detergent resulted in a water splitting rate of 125 mL-H2/(m2·h), which was four times greater that the aforementioned highest value. © 2010 American Institute of Chemical Engineers AIChE J, 2011