Two-dimensional oxygen-deficient TiO2 nanosheets-supported Pt nanoparticles as durable catalyst for oxygen reduction reaction in proton exchange membrane fuel cells

Abstract

The activity and stability for oxygen reduction reaction (ORR) of the cathode catalyst of proton exchange membrane fuel cells (PEMFCs) are important issues that should even be considered for practical application. Modifying the catalyst electronic structure and finding durable supports are good approaches for improving these properties. Carbon-free multifunctional oxygen-deficient titanium oxide nanosheets (TiO2-x NSs) are established as a catalyst support for fuel cell application. The TiO2-x NSs support shows improved electronic conduction compared to TiO2 NSs. Pt nanoparticle-loaded TiO2-x NSs (Pt–TiO2-x NSs) catalyst prepared in this study shows excellent activity towards the ORR. This is ascribed to a strong metal-support interaction (SMSI) between the Pt nanoparticles (NPs) and the TiO2-x NSs support. In addition, the Pt–TiO2-x NSs catalyst shows outstanding durability in repeating square-wave potential cycling tests at 80 °C over 10000 cycles. The fuel cell using the Pt–TiO2-x NSs catalyst shows high power density (958 mWcm−2), which exceeds that of the commercial Pt-loaded carbon catalyst. Also, the projected catalyst showed an excellent stability (more than 100 h) in fuel cell performance. Thus, the proposed TiO2-x NSs will be a promising carbon-free support to be loaded in the future PEMFCs technology.