Alloying Ni–Cu Nanoparticles Encapsulated in SiO₂ Nanospheres for Synergistic Catalysts in CO₂ Reforming with Methane Reaction

In this work, we studied CO2 reforming with the methane (CRM) reaction over Ni–Cu alloy nanoparticles encapsulated in SiO2 nanospheres, for which combinational functions of alloy effect, size effect, metal-support interaction, and confinement effect exhibited high performance, good sintering resistance, and trace carbon deposition in CRM. The appropriate Cu-addition catalysts 0.2Cu–Ni@SiO2 and 0.5Cu–Ni@SiO2 had smaller NiCu alloy nanoparticles and a stronger metal-support interaction, exhibiting a better performance than the excessive Cu-addition catalysts 1.5Cu–Ni@SiO2 and 3Cu–Ni@SiO2 having Cu clusters and a weaker metal-support interaction. The best synergy of alloy effect, size effect, confinement effect, and metal-support interaction in the 0.5Cu–Ni@SiO2 catalyst contributed to the highest rates of CH4 and CO2 in CRM reported so far. This work demonstrates the importance of appropriate Cu addition in Ni–Cu@SiO2 catalysts, and the synergy for perfectly resolving sintering and carbon deposition in CRM.