Synthesis of biomass-derived carbon sheets decorated with metal nanoparticles and their catalytic performance in the oxygen evolution reaction

Biomass-derived carbons decorated with ultrafine metal nanoparticles were prepared by the carbonization of gelatin that had absorbed Ni and/or Fe ions. The morphology and structure of the samples were characterized by XRD, SEM, TEM, and their catalytic performance for the oxygen evolution reaction was evaluated by linear sweep voltammetry, electrochemical impedance spectroscopy and the Tafel polarization test. Results indicate that the metal nanoparticles are uniformly loaded on the carbon sheets. The FeNi alloy/carbon (FeNi/C) nanocomposite has the highest current density of 10 mA cm^-2 at the lowest overpotential of 366 mV, and features the smallest Tafel slope of 46.6 mV dec^-1 and the lowest charge transfer resistance of 13.76 ohm. Moreover, the FeNi/C nanocomposite also exhibits a long-term stability and is able to operate at 5 mA cm^-2 for 25 h. The combination of conductive carbon sheets, uniformly loaded FeNi nanoparticles and abundant pores is responsible for the increased catalytic activity and fast reaction kinetics of the FeNi/C nanocomposite for the oxygen evolution reaction.