Fabricating Metal@N-Doped Carbon Catalysts via a Thermal Method

Nanoparticles (NPs) encapsulated with carbon material have been proven particularly successful for improving their stability; however, this carbon-coating strategy is a compromise between activity and stability because these carbon shells also reduce, even deactivate, the activity of the catalyst by blocking active sites. Herein, we report a procedure to effectively remove the carbon layer without affecting particle morphology, which enhances the surface exposure of the nanoparticles and their catalytic activity while retaining their stability. The heat treatment, such as reduction in hydrogen atmosphere or calcination in air atmosphere, could destroy the defective carbon-surrounded Ru NPs through making the methanation or oxidation reaction occur on the carbon material surface. More importantly, the heat treatment in air atmosphere at low temperature exhibited higher power to corrode the defective carbon-surrounded Ru NPs in comparison with the heat treatment in hydrogen atmosphere. We anticipate that this defective carbon removal approach has more general applicability to encapsulated metal NPs and should lead to improvements in fields as diverse as chemicals production and environmental protection.