Catalytic Supercritical Water Gasification of Empty Palm Fruit Bunches Using ZnO-Doped Ni–CaO Catalyst for Hydrogen Production

Abstract

Supercritical water gasification (SCWG) of empty palm fruit bunches (EFBs) was investigated using ZnO-doped Ni–CaO catalysts for hydrogen-rich product gas. The catalysts were prepared via wet impregnation technique and characterized using XRD, BET, TPR–H2, and TPD–CO2. SCWG reactions were carried out 0.3 g of EFBs added to 5 wt% of the catalyst in 8 mL of deionized at 380 °C and the product gases were analyzed using gas chromatography. Incorporation of ZnO and Ni into CaO was found to be very active in promoting the water gas shift (WGS). From the various concentrations of dopants, 5 wt% ZnO with 5 wt% Ni was found to be the optimum loading on CaO, showing the highest hydrogen production (105.7 mmol mL−1). Besides, the formation of a Ni.8Zn.2O phase from the strong interaction between the dopants was found to be an active phase in promoting the WGS reaction.