Morphology Effect of Ir/La2O2CO3 Nanorods with Selectively Exposed {110} Facets in Catalytic Steam Reforming of Glycerol

Tuning the morphology of nanocatalysts has been regarded as a powerful approach to high-performance heterogeneous catalysts, since the highly active facets might be selectively exposed to reactants. Herein, we report how the shape effect significantly improves the performance of Ir/La2O2CO3 catalyst in the steam reforming of glycerol at high temperatures up to 650 °C toward a sustainable hydrogen production. La2O2CO3 nanorods (NRs) with different sizes and aspect ratios were synthesized for supporting Ir nanoparticles. Compared with conventional Ir/La2O2CO3, the NR catalysts considerably improved the activity, selectivity, and stability, allowing for a stable hydrogen production for 100 h without obvious deactivation. The role of the NRs was rationalized by XRD, XPS, TPR, TPD, and HRTEM analysis. The high performance of the NR catalyst is elucidated by the formation of hexagonal La2O2CO3 NRs with selectively exposed {110} facets under reaction conditions, which strongly interact with Ir catalysts, thereby preventing the tiny catalyst particles from sintering at 650 °C. A mechanistic insight is presented to understand the interaction based on the structure of the La2O2CO3 supports.