Ultra-Small Pt–Ni Bimetallic Nanoparticles Confined in Dendritic Mesoporous Silica with Remarkable CO Catalytic Oxidation Performance

A high-surface area (572 m2 g–1) dendritic mesoporous silica (KCC-1) was synthesized successfully and used as a support to confine Pt–Ni bimetallic nanoparticles (NPs). It is revealed that the Pt–Ni NPs are highly dispersed with an ultra-small size of 1.0 nm, and the large specific surface area as well as the abundant mesoporous structure of dendritic KCC-1 can effectively promote the dispersion and the thermal stability of Pt–Ni nanoparticles, thus significantly improving the CO oxidation activity. Compared with monometallic 1% Pt/KCC-1 and 1% Ni/KCC-1 catalysts, the combination of Pt and Ni together with a suitable ratio can further enhance the activity of the catalyst due to the synergetic effect between Pt and Ni. Over the 1% Pt7Ni3/KCC-1, the optimal catalyst in this study, 100% CO conversion was achieved at 100 °C. The incorporation of Ni into Pt leads to a reduction in the amount of noble metal required while simultaneously enhancing catalytic activity. This study offers a pathway for designing CO oxidation catalysts with low precious metal loading, yet exhibiting superior catalytic activity.