Aqueous phase reforming of sorbitol over Calcium doped Nickel based catalysts supported on Gadolinium

Aqueous phase reforming (APR) is the most promising technology to produce hydrogen and value-added chemicals. The use of different supports of the catalysts has produced different products during APR reaction. Gd2O3, support has gained interest due to its ability to improve the catalyst surface reactivity and reduce coke formation during the reaction. In this research, Ni based catalysts supported on Gd2O3 and doped with different percentage of Ca (0, 3, 5 and 7 wt.%) were synthesised by a wet impregnation method. The catalysts were subjected to several characterisation technique such TGA, XRD, FESEM and BET analysis. Then, the performance of the catalysts was studied for APR of sorbitol. The TGA results showed that the calcination temperature of the catalysts was at 500°C. The XRD results show that all the three compound, NiO, CaO and Gd2O3 were present in the catalysts and the peak shows decreased in Gd2O3 peak intensity with increasing Ca compositions. The FESEM images of the catalysts show the agglomeration of the metal catalyst which was increasing with Ca addition. The BET analysis indicated that Ca percentage below 5% provides positive impact on Ni surface area and dispersion, which indicated better performance of the catalysts during the reaction. The liquid products obtained from the APR reaction were analysed using HPLC analysis. The results show the presence of pentanediol, 1,4-butanediol, 1-propanol and ethylene glycol in the liquid products. It was also observed that low Ca percentage prefers formation of C5-C4 products through decarbonylation whereas high Ca percentage favours the formation of C3-C2 carbon through retro-aldol condensation reactions.