Optimization for hydrogen production from methanol partial oxidation over Ni–Cu/Al2O3 catalyst under sprays

Abstract

In this work, a novel Ni–Cu/Al2O3 catalyst is used to trigger the partial oxidation of methanol (POM) for hydrogen production. This reaction system also employed ultrasonic sprays to aid in dispersing methanol fuel. The prepared catalyst is analyzed by scanning electron microscope (SEM), energy-dispersive X-ray (EDX) spectroscopy, and X-ray diffraction (XRD) to explore the catalyst's surface structure, elemental composition, and physical structure, respectively. The Box-Behnken design (BBD) of response surface methodology (RSM) is utilized for experimental design to achieve process optimization. The operating parameters comprise the O2/C molar ratio (0.5–0.7), preheating temperature (150–250 °C), and weight percent (wt%) of Ni (10–30%) in the catalyst. The results show that methanol conversion is 100% in all the operating conditions, while the reaction temperature for H2 production ranges from 160 to 750 °C, stemming from heat released by POM. The significance and suitability of operating conditions are also analyzed by analysis of variance (ANOVA). It indicates that the highest H2 yield is 2 mol (mol CH3OH)−1, occurring at O2/C = 0.5, preheating temperature = 150 °C, and Ni wt% = 10. Compared with the commercial h-BN-Pt/Al2O3 catalyst, the prepared Ni–Cu/Al2O3 catalysts have higher activity for H2 production. The O2/C ratio is the most influential factor in the H2 yield. Moreover, the interaction of the O2/C ratio and Ni content is sound, reflecting that changing Ni content in the catalyst will affect the trend of H2 yield under each O2/C.