Date of Award

2014

Document Type

Thesis

First Advisor

Kuila, Debasish

Abstract

Hydrogen is a renewable, clean energy source considered to be promising for energy and environmental sustainability. Steam reforming of methanol (SRM) to produce H2 is ideal for fuel cell applications. One of the challenges of SRM at high temperature is the CO formation that poisons the Pt electrode in proton exchange membrane fuel cell (PEMFC). In order to address this issue, development of novel catalysts is necessary that can be used for PEMFC applications. In this study, a one-pot procedure containing TiO2 precursor, metal salt, and cetyltrimethylammonium bromide surfactant was used to synthesize monometallic (M: Cu, Co, Ni, Pd, Sn, and Zn) nanoparticles supported on mesoporous TiO2. The catalysts were characterized using TGA-DSC, N2 adsorption-desorption, XRD, ICP-OES, TEM, FTIR and TPR techniques. Catalysts possess high surface area in the range of 99-309 m2/g, depending on the type of metal and its loading. TEM images show highly mesoporous TiO2 with uniform dispersion of metal nanoparticles. The XRD studies confirmed the existence of catalytically active anatase phase and the nanoparticulate nature of TiO2 crystallites. Hydrogen production via SRM using these catalysts was studied to investigate their activity and CO selectivity in the reaction temperature range of 150-350 °C. Comparative SRM studies of different M-TiO2 catalysts were carried out with 10 wt% of metal loading. Results from SRM studies at 250 °C suggest that the activity of the monometallic catalysts followed the order of Pd>Ni>Co>Zn>Cu>Sn, whereas for the lower CO selectivity it was Zn>Co>Sn>Cu>Pd>Ni. The 10%Zn-TiO2 catalyst showed the best results with CO selectivity of 1.19%, H2 selectivity of 99.66%, and conversion of 82.4% at 350 °C reaction temperature. In addition, the effect of Zn loading from 5-20% was fully investigated on the activity and selectivity of the catalyst.

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