H2 Generation On Low Content Pt Supported Over Nano Size Mesoporous TiO2

Production of hydrogen from renewable resources (e.g., biomass) is considered an effective approach to mitigating the environmental problems caused by pollutant emissions from fossil fuels. There is a great deal of interest in Pt/TiO2 because of its promising catalytic prospects in applications of hydrogen production from biomass. However, one important problem should be overcome is that CO as a by-product that will significantly impair the catalytic performance even the presence of carbon monoxide (CO) is as low as only 5-10 ppm. In the present paper, we aimed to fabricate CO poisoning resistant Pt/TiO2 catalyst by doping Pt onto nano-size mesoporous TiO2 and investigate its H2 generation performance in steam reforming reactions.

Nano-size mesoporous TiO2 and 0.5, 1.0, and 2.0% wt Pt-doped, nano-size mesoporous TiO2 were synthesized by a hydrolyzing followed by sintering process. Adsorption isotherms of carbon monoxide (CO) on the synthesized mesoporous TiO2 and on Pt/TiO2 were measured at temperatures 308K, 323K, 348K, 373K, 398K, and 423K and pressures up to 700 mmHg. The 0.5% wt Pt/TiO2 catalyst resulted in better CO adsorption than those which were tested on the nano-size mesoporous TiO2 support. The amounts of CO adsorbed with 1.0% wt and 2.0% wt Pt/TiO2 catalysts were found to be larger than those on nano-size mesoporous TiO2. All measured adsorption isotherms of CO were correlated to fit adsorption models Sips, Toth, and UNILAN in the experimental temperature/pressure range. Sips and Toth models were found to be more accurate for presenting CO adsorption on Pt/TiO2. It suggests that the 0.5% wt Pt/TiO2 catalyst have potentially good CO poisoning resistivity within a wide temperature range. Steam reforming of glucose and methanol under different experimental condition were utilized to generate H2 on the synthesized Pt/TiO2. And for comparison purposes, 5% Pt/Al2O3 was applied as well. It is found that the synthesized low content Pt/TiO2 is more cost-effective.