Alumina based doped templated carbons: A comparative study with zeolite and silica gel templates

Abstract

Alumina based templates were used for preparation of nitrogen and platinum doped templated carbons and compared with silica gel and zeolite templated carbons. For alumina based templated carbons, 5–6 times higher surface area was obtained compared to corresponding templates while that for zeolite and silica gel templates, it was only 1–2 times higher. The surface area of surfactant modified alumina templated carbon was comparable with that of microporous zeolite templated carbon but pore size and volume was comparable to that of mesoporous silica templated carbon. Higher dispersion of the Pt metal was observed within the matrix of mesoporous templates with highest for surfactant modified alumina templated carbon. The morphology of surfactant modified alumina templated carbon was similar to that of silica gel templated carbon and co-doping with platinum resulted in noddle like structure. At 25 bar and −196 °C the hydrogen uptake was in the range of 4–3.4 wt% and decreased linearly with decrease in surface area. Both surface area and pore volume dropped for all Pt co–doped samples. However uptake capacity varied; for co–doped silica gel and zeolite templated carbons it was reduced, while that of co–doped alumina based templated carbons it increased. The highest hydrogen uptake of 4.1 wt% for surfactant modified alumina templated co–doped carbon was attributed to synergistic effect of significant surface area, highest pore volume and highly dispersed platinum. The study concludes that alumina based templates are equally good or better for synthesis of the templated carbons.