Supported gold (Au) nanocatalysts have attracted extensive interests in the past decades because of their unique catalytic properties for a number of key chemical reactions, especially in (selective) oxidations. The activation of O₂ on Au nanocatalysts is crucial and remains a challenge because only small Au nanoparticles (NPs) can effectively activate O₂. This severely limits their practical application because Au NPs inevitably sinter into larger ones during reaction due to their low Taman temperature. Here we construct a Au-SiO₂ interface by depositing thin SiO₂ layer onto Au/TiO₂ and calcination at high temperatures and demonstrate that the interface can be not only highly sintering resistant but also extremely active for O₂ activation. This work provides insights into the catalysis of Au nanocatalysts and paves a way for the design and development of highly active supported Au catalysts with excellent thermal stability.

Cobalt-based electrocatalysts have been well exploited in oxygen reduction reactions (ORR) for potential applications in alkaline-based fuel cells. In this study, we report a one-pot protocol to prepare facile Co/CoN_x–C electrocatalysts, which are comprised of metallic Co⁰ clusters simultaneously integrated with Co^IIN_x species on N-doped carbon matrixes. The optimized Co/CoN_x–C exhibits high ORR activity in terms of E_onset (0.926 V vs. RHE) and E_1/2 (0.853 V) and shows good stability and methanol tolerance compared with the benchmark Pt/C in an alkaline electrolyte. The enhanced ORR performance arises from the unique integration and synergetic effect of Co clusters with adjacent single-atomic CoN_x sites in the resultant Co/CoN_x–C electrocatalysts, which is further substantiated by density functional theory simulations. This scalable synthesis strategy provides a perspective for design of highly efficient non-noble metal electrocatalysts, encouraging extensive utilization for electrochemical energy conversion.