Microporous Sulfur-Doped Carbon Atoms as Supports for Sintering-Resistant Platinum Nanocluster Catalysts

Carbon (C)-supported metal nanoclusters consisting of a few dozen atoms are highly attractive for a wide range of important catalytic processes with optimal reactivity and selectivity, yet they suffer from metal sintering and consequent deactivation because of the weak interaction between metals and inert C surface. Here, we report a microporous sulfur-doped carbon (S–C) as a support for sintering-resistant metal nanoclusters based on the strong interaction between metal and doped sulfur (S) atoms. The S–C support is prepared by carbonization of microporous conjugated poly(3,3′-bithiophene), which has a robust three-dimensional cross-linked network structure. The structural features of the conjugated polymer-derived S–C support, including high S contents of up to ∼26.9 wt % and large specific surface areas of 708–1019 m2 g–1, make it capable of anchoring ∼1 nm platinum (Pt) clusters even with a high Pt loading of 20 wt %. Remarkably, the S–C-supported Pt nanocluster catalysts can tolerate high-temperature treatments up to 700 °C in a reductive atmosphere or harsh hydrothermal treatments (alkaline water, 2 M bar of H2, and 200 °C for 12 h). Moreover, the S–C-supported Pt nanocluster catalysts exhibit a much enhanced catalytic performance for formic acid oxidation compared to the commercial Pt/C catalyst owing to the small-size effects.