Partially oxidized niobium carbonitride as a non-platinum catalyst for the reduction of oxygen in acidic medium

摘要

Partially oxidized NbC_(0.5)N_(0.5) has been evaluated as a non-platinum catalyst for the reduction of oxygen in acidic medium. NbC_(0.5)N_(0.5) powder was partially oxidized in N_2 gas containing O_2 of 10~(-4) atm at the temperature range of 700-1000 °C. Partially oxidized NbC_(0.5)N_(0.5) had a definite oxygen reduction reaction (ORR) activity, while as-prepared NbC_(0.5)N_(0.5) and completely oxidized Nb_2O_5 had a poor catalytic activity for ORR. The onset potential of the partially oxidized NbC_(0.5)N_(0.5) for the ORR achieved 0.92 V vs. RHE in 0.1 M H_2SO_4 at 30°C. The results of X-ray absorption spectroscopy and ionization potential measurements suggested that oxygen-vacancy defects might be responsible for the oxygen reduction capability by creating electronically favorable oxygen adsorption sites.