Oxygen Defects Induce Strongly Coupled Pt/Metal Oxides/rGO Nanocomposites for Methanol Oxidation Reaction

For Pt/metal oxides/rGO ternary electrocatalysts used for the methanol oxidation reaction (MOR), the interaction between Pt and metal oxides as well as that between metal oxides and rGO both play a critical role in dominating the catalytic performance. In this work, nonstoichiometric metal oxides (TiOx or SnOx, x < 2) with abundant surface oxygen defects are produced by the pulsed-laser ablation in liquids (PLAL) method. On the surface of TiOx or SnOx, the unsaturated metal atoms provide free electrons to reduce in situ PtCl42– ions and GO to zerovalent Pt and rGO, respectively. Therefore, such nonstoichiometric metal oxides act as a perfect linker to strongly couple with Pt nanoparticles (NPs) and rGO. Characterization data indicate that the formed Pt NPs with an average size of 1.7 ± 0.6 (or 2.1 ± 0.7) nm are uniformly anchored on TiO2 (or SnO2) in Pt/TiO2/rGO (or Pt/SnO2/rGO) nanocomposites (NCs). The obtained ternary NCs both present a higher value of mass activity toward MOR than those of Pt/rGO and commercial Pt/C catalysts. Importantly, these ternary catalysts further exhibit excellent long-term cyclic stability, which is attributed to the improved tolerance toward CO poisoning and resistance to Pt agglomeration which resulted from the strong interaction between Pt and metal oxides.