Methanol steam reforming over highly efficient CuO–Al2O3 nanocatalysts synthesized by the solid-state mechanochemical method

CH3OH steam reforming is an attractive way to produce hydrogen with high efficiency. In this study, CuO.xAl2O3 (x = 1, 2, 3, and 4) were fabricated based on the solid-state route, and the calcined samples were employed in methanol steam reforming at atmospheric pressure and in the temperature range of 200–450 °C. The results revealed that all samples have a high BET area (173–275 m2 g−1), and their crystallinity was reduced by increasing the alumina content in the catalyst formulation. The catalytic activity tests showed that the CH3OH conversion and H2 selectivity decreased by rising the Al2O3·CuO molar ratio. The methanol conversion enhanced from 13% to 85% by increasing the reaction temperature from 200 °C to 450 °C over the CuO·Al2O3 catalyst, due to the higher reducibility of this catalyst at lower temperatures compared to other prepared samples. The influence of calcination temperature (300–500 °C), GHSV (28,000–48000 ml h−1. g−1cat), feed ratio (C:W = 1:1 to 1:9), and reduction temperature (250–450 °C) was also determined on the yield of the chosen sample. The results revealed that the maximum methanol conversion decreased from 90 to 79% by raising the calcination temperature from 300 to 500 °C due to the reduction of surface area and sintering of species at high calcination temperatures.