In situ synthesis of PtPd bimetallic nanocatalysts supported on graphene nanosheets for methanol oxidation using triblock copolymer as reducer and stabilizer

A facile hydrothermal co-reduction strategy has been demonstrated to in situ synthesize PtPd bimetallic nanocatalysts supported on graphene nanosheets (PtPd/GNs) with triblock pluronic copolymer P123 as both reducer and stabilizer. The nucleation mode and morphology of the PtPd bimetallic nanoparticles were tuned simply by changing the molar ratio of Pt and Pd precursor. Defect investigation upon graphene nanosheets predicts that the synergetic role between P123 and PtPd may have great influence on generating defects in graphene, which inducing the in situ loading of PtPd bimetallic nanocatalysts at the defect sites. Compared with the common process to assemble nanocatalysts in pre-synthesized graphene substrate, the one-pot in situ assembly is more facile, cost-effective, and ensuring the effective control of the location and distribution of PtPd nanocatalysts. Both of the PtPd/GNs showed enhanced electrocatalytic performances towards methanol oxidation reaction (MOR) in acidic media, among which Pt1Pd1/GN (Pt/Pd molar ratio 1/1) exhibited the highest specific activity, mass activity, stability and best CO tolerance for MOR. The synthetic process without any seeds, templates, or toxic organic solvent and extra reducer, turns out a promising method to construct the Pt-based nanocatalysts for direct methanol fuel cells (DMFCs).

PtPd/GNs anode nanocatalysts with different composition and morphology were fabricated by the in situ synthesis strategy with triblock copolymer P123 as reducer and stabilizer. Electrochemical test demonstrating that Pt1Pd1/GN exhibits the best anti-CO poisoning property and outstanding electrocatalytic performance for MOR.145