Graphene-based porous carbon-Pd/SnO2 nanocomposites with enhanced electrocatalytic activity and durability for methanol oxidation
Noble metal Pd is usually regarded as a promising electrode material for fuel cells due to its high electrocatalytic activity, abundance and greater resistance to CO poisoning. Moreover, the electrocatalytic performance of Pd can be further improved by using novel carbon materials as supports or metal oxides as catalyst promoters. In this work, Pd nanoparticles with a trace of SnO2 are synthesized and anchored on a novel graphene-based porous carbon (G-mC) support by using a modified electroless plating technique. The two-dimensional (2D) porous carbon film on the graphene can separate Pd nanoparticles and limit their growth (<3 nm), while the graphene substrate can enhance the electronic conductivity of the composite. In addition, SnO2 nanoparticles around Pd catalysts may prevent CO poisoning at the catalytic sites, which is beneficial to improving the electrocatalytic performance of Pd catalysts. Therefore, compared to porous carbon (CMK-3) supported Pd catalysts with SnO2 or G-mC supported Pd catalysts without SnO2, G-mC supported Pd catalysts with SnO2 show enhanced electrocatalytic activity and durability for methanol oxidation. In particular, the electrocatalytic activity retention of the composite is maintained at ∼85% after 500 cycles. This novel 2D carbon support is expected to be applied in batteries, supercapacitors or fuel cells.