TiO2-loaded boron self-doped carbon derived from nano boron carbide as a non-noble metal bifunctional electrocatalyst for oxygen reduction and evolution reactions

Abstract

TiO2-modified boron self-doped carbon/nano B4C (TiO2/B-C/B4C) was used as a non-noble metal electrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in 0.1 M KOH. Titanium oxide-modified boron carbide (TiO2/B4C) was prepared by microwave treatment of the mixture of titanyl sulfate and B4C. TiO2/B-C/B4C was obtained after heating the TiO2/B4C at 700 °C in vacuum for 3 h. The TiO2/B-C/B4C exhibited a good ORR activity with an average electron transfer number of 3.9, which was close to that obtained with 20 wt% Pt electrocatalyst. The resultant TiO2/B-C/B4C electrocatalyst showed satisfying OER performance with an overpotential of 0.31 V at 10 mA cm−2. Thus, the TiO2/B-C/B4C electrocatalyst with good ORR/OER activity can be potentially used for unitized regenerative fuel cells in new generation energy-storage systems.