Improving steam-reforming performance by nanopowdering CuCrO₂

In this study, the delafossite type CuCrO₂ nanopowder was used as a precursor for preparing Cu-based catalyst for steam reforming of methanol (SRM). The efficiency of hydrogen generation was greatly improved by reducing the size of CuCrO₂ to nanoscale. The reduction temperature of Cu metal particles from CuCrO₂ decreased from 600 °C to 200 °C due to this size effect. Additionally, because of lowered activation energy, CuCrO₂ nanopowder could be reduced by methanol vapor. Thus the CuCrO₂ nanopowder, prepared by GNP method, had much higher SRM efficiency than bulk CuCrO₂ and the commercial SRM catalyst, even without H₂ activation process. The SEM images revealed that the powder retained a cotton candy-like porous structure after reduction treatment. The TEM images showed that the Cu particles were about 5 nm in diameter and well dispersed on Cr₂O₃ after the reduction of CuCrO ₂ nanopowder at 500 °C. The catalyst was evaluated by the generation rate with steam reforming of methanol, and the peak hydrogen generation rate read as high as 2550 ml/min g-cat at 360 °C with hydrogen activation. CuCrO₂ nanopowder showed high catalytic activity even without reduction treatment, and hydrogen generation rate read as high as 1740 ml/min g-cat at 360 °C.