Cobalt and Nitrogen co-doped Carbon Composite Material Derived from Rice Husk as a cost-effective Electrocatalyst for Oxygen Reduction Reaction

Abstract

High efficiency and low cost electrocatalysts are urgently developed for the commercial application of fuel cells. Herein, rice husk, an agricultural waste, was chosen as the low-cost carbon source to synthesize a novel cobalt and nitrogen codoped carbon composite (DKCoN) electrocatalyst for oxygen reduction reaction (ORR). The as-synthesized material developed via a simple impregnation and pyrolysis process has an amorphous carbon structure with ultrahigh pyridinic nitrogen-doping level (72.08% of the total doped N) in which nanoparticles are uniformly distributed. The as-synthesized samples were characterized by high resolution TEM, XPS, XRD analysis and electrochemical measurements. According to the test results, the ORR catalyzed in acidic condition by DKCoN catalyst is dominated by a nearly four-electron process (3.5-3.8). The initial oxygen reduction potential of the DKCoN-900 eletrocatalyst during accelerated aging test (AAT) showed almost no significant decay, and the attenuation of the average polarization current density was about 0.22 mA cm-2. The DKCoN catalyst displayed comparable activity and certain corrosion resistance in acidic electrolyte, demonstrating that the rice husk derived DKCoN material obtained by the efficient approach is to be a promising, costeffective and eco-friendly electrocatalytic material for oxygen reduction in fuel cells in the future.