PdZnβ catalyst with a low Pd loading on a ZnTiO3 perovskite for high-temperature methanol steam reforming

Abstract

PdZn_β alloy catalysts have attracted extensive attention in the methanol steam reforming (MSR) reaction due to their superior thermal stability compared to Cu-based catalysts, which are prone to sintering. However, conventional supported PdZn catalysts typically require a high Pd loading (e.g., Pd/ZnO, >5.0 wt%) to achieve the desired MSR performance, limiting their practical applications. In this work, we explore a ZnTiO₃ perovskite as a support and a zinc source to achieve the controlled synthesis of the PdZn_β alloy at low Pd loadings. The 0.1 wt% Pd/ZnTiO₃ catalyst achieves excellent reactivity and CO₂ selectivity (>96%) across a wide temperature range (up to 400 °C). This performance is attributed to the enhanced synergy between the small PdZn_β particles and the ZnTiO₃ support, which enhances methanol dehydrogenation and water dissociation, respectively. The catalyst also shows exceptional thermal stability over 50 hours at 350 °C with minimal loss in activity or selectivity, while pure ZnTiO₃ deactivates significantly. The advanced Pd/ZnTiO₃ catalysts with ultra-low Pd loading demonstrate superior potential over other metal oxides for efficient and stable hydrogen production in mobile applications, which typically need to operate at high reaction temperatures.