Hydrogen production via steam reforming of methanol over nano-structured gold catalysts for fuel cell applications

Abstract

Gold supported on ceria (CeO2) and zine oxide (ZnO) was utilized as the catalysts for steam reforming of methanol to produce hydrogen. In the case of Au/CeOc, the preparation technique strongly affected the catalyst characteristics and activities. It was observed that co-precipitation (CP) and deposition-precipitation (DPS) methods gave a satisfactory catalytic activity; however, the incipient wetness impregnation (IWI) method gave a relative low activity. The catalyst preparation method of small gold particle (nanometre range) was required because the high methanol conversion obtained by small gold particle. The Au (220) of the prepared catalysts were 28.98, 13.77, and 4.12 nm which belonging to IWI, CP, and DPS catalyst, respectively. The measurements were accomplished in the temperature range of 200 - 450C and good methanol conversion and low CO levels were observed in the temperature range of 300 - 400C. A comparative study of the steam reforming of methanol (SRM) and decomposition of methanol (DM) was carried out. The results showed that CO and CO2 were mainly produced through DM and SRM, respectively In addition, the effects of gold loading and steam/carbon ratio on the catalytic activity were also investigated. For the effect of support, Au/ZnO showed better activity than Au/CeO2 in terms of the hydrogen production rate and methanol conversion. Au (220) crystallite size of Au/ZnO is 5.11 nm so Au (220) is the crucial factor for SRM. The critical Au (220) crystallite size is about 5 nm with the proper of catalyst preparation is required.