Isoparaffin production by aqueous phase processing of sorbitol over the Ni/HZSM-5 catalysts: Effect of the calcination temperature of the catalyst

Ni/HZSM-5 catalysts calcined at different temperatures were used in the isoparaffin production by aqueous phase processing of sorbitol and characterized by N2 physical adsorption, temperature-programmed reduction (H2-TPR), temperature-programmed desorption of ammonia (NH3-TPD) and Raman techniques. The effect of calcination temperature of the catalysts on the catalytic performance for the reaction was investigated. The activity test results indicated that the maximal i-C6H14 selectivity of 45.4% and the total i-C6H14 and i-C5H12 yield of 32.3% were obtained over the catalyst calcined at 500 °C, which exhibited the optimum surface area and pore structure with 100% of the reducibility of Ni species on the surface of HZSM-5. In addition, the amount and the strength distribution of acidic surface sites of the catalyst decreased with the increase of calcination temperature at 500 °C above. All these factors result in an increase in the formation of isoparaffin.