During the research period, the electrodes with thin film catalyst nanostructures from PtNi nanowire arrays (PtNi NW) were developed. Both ethylene glycol method and formic acid reduction method were explored. The effects of post acid washing and annealing on the surface properties of PtNi NW gas diffusion electrodes (GDEs) were investigated. The optimal PtNi NW GDEs showed a slightly improved power performance compared to the GDEs from the commercial Pt/C (TKK) nanoparticle electrocatalysts. Serval different types of hydrophobic ILs were synthesized, and well-tuned in physicochemical properties and functionalities and used to modify PtNi NW, Pt NW and Pt/C nanoparticle electrodes. The modification process was carefully studied. The power performance and durability of the as-prepared electrodes were then evaluated in single PEMFCs and compared. The final results showed that the IL modification effectively improved the power performance of PtNW and Pt/C electrodes, but the enhancement in the stability is limited. Regarding the PtNi NW electrodes, the modification by ILs showed only a very small enhancement in its power performance, which can be ascribed to the . The mechanisms behind were explored.
In addition to the work originally proposed, an alternative more promising work was conducted on using ILs to modify platinum group metal (PGM) free ZnCo-N-C electrocatalysts. The half-cell electrochemical measurement and in-situ test in fuel cells showed that the IL modification could effectively protect ZnCo-N-C electrocatalysts from corrosion in the acidic environment, showing 140% higher power density in fuel cell operation.
A few presentations have been gave at international conferences and workshops. Two papers have been published on related results (Front. Chem. Sci. Eng. 2019, doi:10.1007/s11705-019-1838-8; ACS Energy Lett., 2019, 4(9), 2104-2110, doi: 10.1021/acsenergylett.9b01407) and two others are still under preparation.
