Ni-Co-N doped honeycomb carbon nano-composites as cathodic catalysts of membrane-less direct alcohol fuel cell

Ni-Co-N doped honeycomb carbon (HC) nano-composites Ni 3 Co 1 -N/HC (Ni 3 Co 1 -N/HC-20, Ni 3 Co 1 -N/HC-30 and Ni 3 Co 1 -N/HC-40 with respective metal mass percentage of 20%, 30% and 40%) with a regular hexagonal structure have been fabricated by using the simple polymethylmethacrylate (PMMA) emulsion template method . The side length of the carbon hexagon is ca. 100 nm for the honeycomb carbon (HC). For the Ni 3 Co 1 -N/HC catalysts, the NiCo nanoparticles and the nanocarbon tubes derived from dicyandiamide are uniformly dispersed on HCs. The as-synthesized Ni 3 Co 1 -N/HC catalysts exhibit efficient electroactivity for oxygen reduction reaction (ORR) in alkaline medium and possess excellent tolerance to the alcohols (ethanol, n -propanol and iso -propanol). Based on these results, a membrane-less direct alcohol fuel cell has been assembled with the Ni 3 Co 1 -N/HC as the cathodic catalyst, the ternary Pd 7 Ag 2 Sn 2 /CNT as the anodic catalyst and alcohol (ethanol, n -propanol or iso -propanol) as the fuel. The fuel cell with the Ni 3 Co 1 -N/HC-40 as the cathodic catalyst displays the open circuit voltage of 0.79 V and maximum power density of 42.2 mW cm −2 for the ethanol fuel , 0.60 V and 33.3 mW cm −2 for the n -propanol fuel, and 0.43 V and 14.4 mW cm −2 for the iso -propanol fuel. The membrane-less fuel cell also presents stable discharge performance at different discharging current densities.