Indexed on: 25 Jul '18Published on: 12 Jul '18Published in: ACS Sustainable Chemistry & Engineering
A metal-free carbon-doped hexagonal boron nitride activates oxygen for its electroreduction.A rational design of electrocatalyst for oxygen reduction reaction (ORR) with activity 2–3 times higher than platinum has been of great demand for low temperature fuel cell applications. Particularly, metal-free ORR electrocatalysis has recently been explored rigorously because of limitations such as high price and scarcity of the state-of-the-art platinum catalyst. Here, we present a simple one-step method for the synthesis of carbon-doped hexagonal boron nitride (BNC) by a chemical vapor deposition method. An inert and insulating h-BN has been made active by carbon doping. From the structural analysis using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), we confirmed the formation of novel BNC nanostructures. BNC nanostructures exhibit rice grain-like shape having length ∼ 50 nm with interlayer distance of 0.34 nm, indicating hexagonal stacking of BN layers. As-synthesized BNC nanostructures obtained after annealing at 850 °C (BNC2-850) show interesting catalytic activity toward ORR with onset potential of 0.83 V versus RHE and a current density of 4.6 mA/cm2 in alkaline condition. More interestingly, the BNC2-850 nanostructures also reveal better stability even up to 10,000 potential cycles with concomitant negligible poisoning effect during methanol crossover process. Such a systematic and controlled study of carbon doping in h-BN nanostructures could certainly support the promising candidature of BNC as a metal-free electrocatalyst toward ORR.