PdNi nanoparticles decorated on defective mesoporous carbon: An efficient bifunctional electrocatalysts in alkaline direct methanol fuel cells

Abstract

Defective CMK-3 carbon (CMK-3-D) supported Pd–Ni nanoparticles with different molar ratio and metal loadings have been synthesized. It is found that the PdNi nanoparticles (Pd/Ni molar ratio of 1:1, Pd loading ≤ 10 wt%) are homogeneously distributed on CMK-3-D with particle size of ac. 50 nm, due to the defective carbon support with increased surface areas could provide numerous nucleation active sites for PdNi alloys. Combined the advanced catalytic performance of PdNi with that of defective carbon, the PdNi/CMK-3-D(10) catalyst exhibits remarkable high performance on oxygen reduction reaction. The half-wave potential of PdNi/CMK-3-D(10) catalyst is −0.218 V vs. Ag/AgCl, only 30 mV lower than that of Pt/C catalyst. The more positive onset potential and high limiting current density is comparable to that of Pt/C catalyst. The PdNi/CMK-3-D(10) catalyst also shows an excellent activity on methanol oxidation reaction with a more negative onset potential, higher methanol oxidation current and larger If/Ib ratio. Moreover, due to the defective carbon support provides abundant anchoring sites for PdNi particles, the PdNi/CMK-3-D(10) catalyst has an enhanced catalytic durability on ORR and MOR. This novel combination of PdNi alloy catalyst with defective carbon support would be an efficient bifunctional electrocatalysts in alkaline direct methanol fuel cells.