Balancing Catalytic Activity and Stability in Steam Methane Reforming through Ni–Cu Synergy on Rice Husk-Derived Silica

High Resolution Image Download MS PowerPoint Slide Balancing catalytic activity and long-term stability remains a key challenge in steam methane reforming (SMR) for hydrogen production, particularly due to coke deposition on the catalysts. This study evaluated the SMR performance of Ni, Cu, and Ni–Cu catalysts supported on rice husk-derived silica (RHS), which were synthesized via the incipient wetness impregnation method. Fresh, reduced, and spent catalysts were systematically characterized to elucidate the evolution of their physicochemical properties. Rather than forming an alloy, the Ni–Cu/RHS catalyst exhibited spatially separated Ni and Cu phases, with improved metal dispersion and smaller particle sizes compared to its monometallic counterparts. The Ni/RHS catalyst exhibited high SMR activity, delivering 81% methane (CH 4 ) conversion and 71% hydrogen (H 2 ) yield, but was susceptible to coke formation. By contrast, the Cu/RHS catalyst demonstrated poor catalytic performance yet strong resistance to coke formation. Notably, the Ni–Cu/RHS catalyst exhibited comparable SMR activity to the Ni/RHS catalyst (80% CH 4 conversion and 69% H 2 yield) while substantially reducing the coke formation rate to 0.08 mmol C g cat –1 h –1 . This enhanced performance is attributed to synergistic interactions between Ni and Cu. Specifically, Cu proximity modulates the electronic and geometric environment of Ni, which suppresses coke-forming reactions while improving metal dispersion and catalyst stability. Consequently, the Ni–Cu/RHS catalyst maintains high catalytic performance while mitigating deactivation pathways. By overcoming the activity–stability trade-off in SMR using bimetallic catalysts supported on biomass-derived silica, this study provides valuable insights for the rational design of efficient, durable catalysts for sustainable hydrogen production.