Controllable fabrication of a N and B co-doped carbon shell on the surface of TiO2 as a support for boosting the electrochemical performances

Abstract

A valid pathway has been exploited to create a B,N co-doped carbon shell on the surface of TiO₂ nanoparticles (TiO₂@CNB) as a support of Pt nanoparticles. The shell thickness of TiO₂@CNB can be easily controlled by pyrolysis of TiO₂@polymer networks. The as-prepared Pt/TiO₂@CNB catalyst with a thicker CNB layer of 5.0 ± 0.5 nm shows improved performance for the oxygen reduction reaction (ORR) with high onset (0.65 V) and half-wave potentials (0.56 V), which are significantly higher than those of commercial Pt/C (20 wt%) catalysts. For the methanol oxidation reaction (MOR), the Pt/TiO₂@CNB catalyst with a moderate CNB layer of 3.3 ± 0.3 nm thickness demonstrates the highest activity and stability compared with that with a CNB thickness of 2.1 ± 0.3, or 5.0 ± 0.5 nm, even Pt/C. Our findings indicate that the synergy between Pt nanoparticles and the B,N co-doped carbon shell, as well as the shell thickness plays a key role in improving the electrochemical performances of the Pt/TiO₂@CNB composite materials.