Understanding the Oxygen Reduction Reaction Activity and Oxidative Stability of Pt Supported on Nb-Doped TiO2.
Cheng HeShrihari SankarasubramanianIvana MatanovicPlamen AtanassovVijay K RamaniPublished in: ChemSusChem (2019)
Commercial fuel cell electrocatalyst degradation results from carbon electrocatalyst support oxidation at high operating potential transients. Guided by density functional theory (DFT) calculations, Nb-doped TiO2 (NTO) was synthesized, which exhibits a unique combination of high surface area, high electrical conductivity, and high porosity. This catalyst retained 78 % of its initial electrochemically active surface area compared with 57.6 % retained by Pt/C following the DOE/FCCJ protocol for accelerated stability test. Strong metal-support interactions, which were predicted by DFT calculations and confirmed experimentally by X-ray photoelectron spectroscopy and kinetics measurements, resulted in 21 % higher oxygen reduction reaction mass activity (at 0.9 V vs. reversible hydrogen electrode) on Pt/NTO compared with commercial Pt/C. The ex situ activity and durability of Pt/NTO translated to a fuel cell. The rise in electrode ohmic resistance and non-electrode concentration overpotential indicate that improving the conductivity of NTO and optimizing the catalyst ink formulation are critical next steps in the development of Pt/NTO-catalyzed proton exchange membrane fuel cells.
Keyphrases
- density functional theory
- visible light
- molecular dynamics
- metal organic framework
- quantum dots
- highly efficient
- high resolution
- room temperature
- single cell
- induced apoptosis
- randomized controlled trial
- stem cells
- single molecule
- electron transfer
- magnetic resonance imaging
- reduced graphene oxide
- climate change
- cell death
- pi k akt