Novel hexagonal Bi₂O₂CO₃ porous nanoplate/nitrogen-doped graphene nanomaterial enhanced electrochemical properties of oxygen reduction reaction in acidic medium for fuel cells

A template-free method is successfully designed to originally synthesize novel porous Bi₂O₂CO₃ hexagonal nanoplate (PBHN) and the Bi₂O₂CO₃ hexagonal nanoplate/nitrogen-doped graphene nanomaterials (PBHN/NG). Notably, PBHN-2 and PBHN/NG-2 have not yet been reported in previous literatures. For the first time, PBHN/NG-2 as the oxygen reduction reaction (ORR) catalyst has been investigated in detail for cathode of fuel cell. The measurement results show that PBHN/NG-2 has exhibited fascinating ORR performances, duo to its orthogonal-layered porous structures from porous Bi₂O₂CO₃ and NG sheets. The values of onset potential and limiting current density for PBHN/NG-2 are 1.179 V and 7.38 mA cm⁻² in 0.1 M HClO₄ respectively. The PBHN/NG-2 possess small electrochemical impedance and good methanol immunity in 0.1 M HClO₄ media. Remarkably, the relative current density of PBHN/NG-2 in acidic electrolyte can still keep 98.58% of its original density after 18000 s durable measurement. Therefore, the PBHN/NG-2 is a promising ORR catalyst to solve the problems of high costs, sluggish ORR kinetics and low durability, applied in fuel cells, metal-air batteries and other renewable energy devices.