Two Carbon-Doped BN Nanosheet as Metal-Free Electrocatalysts for the Oxygen Reduction Reaction

Fuel cells can directly convert chemical energy into electric energy with both highconversion efficiency and power density. Among many factors affecting the chemical−electricalenergy conversion, oxygen reduction reaction (ORR) on the cathode is the pivot in fuel cell. Thisreaction is a kinetically slow process in comparison with the hydrogen oxidation taking place inthe anode. So almost the totality of the current research and development focuses on improvingthe cathode catalysts and electrodes [1-3]. Our calculations were performed using densityfunctional theory (DFT) as implemented in the DMol3program [4]. The Perdew−Burke−Ernzerhof (PBE) functional within generalized gradient approximation (GGA) is used to describe theelectronic exchange-correlation effects [5]. In this work, we study the performance of BNnanosheet with doped with foreign atoms. we calculate the adsorption properties of the ORRintermediatesO2, O, OOH, OH, H2O, and H2O2. Our computations revealed that twicly-doping Cinto h-BN nanosheets can cause high spin density and charge density, and reduce the energygap, resulting in the enhancement of O2 adsorption. We found that the ORR prefers to proceedthrough the OOH hydrogenation pathway with the activation barrierof 0.61 eV, which is lowerthan that of Pt-based catalyst (0.79 eV). Therefore, our computations suggested that thesubstitutionally doping C could lead to a quite promising alternative non-Pt ORR catalyst for fuelcells.

کلیدواژه ها:

BN Nanosheet ، Carbon Doping ، Oxygen Reduction Reaction ، Electrocatalyst ، DFT