Metal–organic framework-derived hierarchical porous N/Co-doped carbon-supported sponge-like Pd–SnO2 nanostructures for low-temperature CO oxidation

Abstract

Metal–organic framework-derived porous N/Co-doped carbon (MOF-PNC) nanostructures-supported metal nanoparticles (NPs) are of great importance in multidisciplinary catalytic reactions; however, their catalytic performance toward low-temperature CO oxidation (CO_Oxid) is rarely reported. Herein, a MOF-PNC-supported Pd–SnO₂ (Pd–SnO₂/MOF-PNC) was synthesized via a microwave-irradiation (MW-I), annealing, and chemical etching approach for thermal CO_Oxid. The as-prepared Pd–SnO₂/MOF-PNC had hierarchical porous sponge-like nanostructures composed of porous two-dimensional ultrathin nanosheets (NSs), co-doped with N/Co, with a high specific surface area (185.40 m² g⁻¹) and pore volume (0.045 cm³ g⁻¹), and ornamented with Pd–SnO₂ NPs (7.79 ± 1.42 nm). These merits endowed the Pd–SnO₂/MOF-PNC with excellent thermal catalytic CO_Oxid activity at a low complete CO conversion temperature (T₁₀₀ = 65.6 °C) compared to those of Pd(1%)–SnO₂/MOF-PNC (165.2 °C), Pd–SnO₂ (199.1 °C), Pd/MOF-PNC (107.9 °C) and commercial Pd/C catalysts (201.2 °C), due to the augmented electronic interaction and synergy of Pd NPs with oxygen-rich SnO₂ supports and Co–N_x active sites in MOF-PNC. Thus, coupling two supports (i.e., SnO₂/MOF-PNC) is more crucial for promoting the low-temperature CO_Oxid activity of Pd NPs.