Mesoporous LaMnO3+δ perovskite from spray−pyrolysis with superior performance for oxygen reduction reaction and Zn−air battery

Oxygen reduction reaction (ORR) is the key reaction in various electrochemical energy devices. This work reports an inexpensive mesoporous LaMnO 3+δ perovskite for ORR with remarkable activity, synthesized by a facile aerosol-spray assisted approach. The mesoporous LaMnO 3+δ material shows a factor of 3.1 higher activity (at 0.9   V vs. RHE) than LaMnO 3 obtained from co-precipitation method (LMO-CP). Based on results of x-ray absorption near-edge spectroscopy (XANES), x-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis, we conclude that the chemical state of surface Mn and the high surface area are the sources to the notably enhanced activity. The study of Zn-air batteries device further confirmed a Pt/C comparable performance in the practical devices with the novel mesoporous LaMnO 3+δ catalyst, where the power density at 200   mA/cm 2 is only 2.1% lower than in the battery with same-loaded Pt/C catalyst. Therefore, the high mass activity and low-cost of Mn/La may make LaMnO 3+δ further approach to the application of electrochemical devices .