Low-Temperature Catalytic Dry Reforming of Methane over Pd Promoted Ni–CaO–Ca₁₂Al₁₄O₃₃ Multifunctional Catalyst

The dry reforming of methane (DRM) suffers from high energy consumption and catalyst deactivation over time on stream at high operating temperatures (>800 °C). Here, we demonstrate that DRM is effectively catalyzed at 600 °C by Pd promoted Ni–CaO–Ca12Al14O33 multifunctional adsorbent/catalyst materials with 67% CO2 conversion, 68% CH4 conversion, and a H2/CO ratio close to unity. Notably, the catalyst shows no sign of deactivation at 600 °C for a 50 h continuous on-stream DRM reaction. The high performance is ascribed to the enhanced CH4 dissociation activity with the presence of Pd. CH4 reformed with CaCO3 achieved the transformation between bulk CaCO3 and nanoparticles of CaO. The dynamic transformation may allow for reversible encapsulation and release of Ni particles, thereby suppressing Ni sintering. Furthermore, the coke formed on the catalyst is mainly the active carbon species which is easily removed by CO2 and CaCO3, thus ensuring the long-term stability. The results demonstrated herein shed light on a new paradigm to design low-temperature DRM reaction catalysts

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