ZnO–ZnCr2O4 composite prepared by a glycine nitrate process method and applied for hydrogen production by steam reforming of methanol

Abstract

To address climate change, the energy crisis, and global warming, hydrogen (H₂) can be used as a potential energy carrier because it is clean, non-toxic and efficient. Today, the mainstream industrial method of H₂ generation is steam reforming of methanol (SRM). In this process, a zinc-based commercial catalyst is usually used. In this work, a ZnO–ZnCr₂O₄ catalyst was successfully synthesised by the glycine nitrate process (GNP) and developed for use in H₂ production by SRM. The specific surface area, porous structure and reaction sites of the zinc-based catalyst were effectively increased by the preparation method. The as-combusted ZnO–ZnCr₂O₄ composite catalyst had a highly porous structure due to the gas released during the GNP reaction process. Moreover, according to the ZnO distribution and different G/N ratios, the specific surface area (S_BET) of the as-combusted ZnO–ZnCr₂O₄ catalyst varied from 29 m² g⁻¹ to 46 m² g⁻¹. The ZnO–ZnCr₂O₄ composite catalyst (G/N 1.7) exhibited the highest hydrogen production, 4814 ml STP min⁻¹ g-cat⁻¹, at a reaction temperature of 450 °C without activation treatment. After activation, the ZnO–ZnCr₂O₄ composite catalyst achieved hydrogen production of 6299 ml STP min⁻¹ g-cat⁻¹ at a reaction temperature of 500 °C. The hydrogen production performance of the ZnO–ZnCr₂O₄ composite powder was improved by the uniform addition of ZnO to ZnCr₂O₄. Based on the performance, this ZnO–ZnCr₂O₄ composite catalyst has great potential to have industrial and economic impact due to its high efficiency in hydrogen production.