Effect of heat treatment on the activity and stability of PtCo/C catalyst and application of in-situ X-ray absorption near edge structure for proton exchange membrane fuel cell

• Published in: Journal of power sources 2015-10, Vol.293, p.274-282
• Main Authors: Lin, Rui, Zhao, Tiantian, Shang, Mingfeng, Wang, Jianqiang, Tang, Wenchao, Guterman, Vladimir E., Ma, Jianxin
• Format: Article
• Language: English
• Subjects: Catalyst; Heat treatment; In-situ XANES; Stability
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2015.05.067

For the purpose of reducing the cost and improving the performance of the proton exchange membrane fuel cell (PEMFC), some low-Pt or non-Pt catalysts have been studied in recent years. PtCo/C electrocatalysts are synthesized by a two-step reduction approach followed by the heat treatment. PtCo metal particles are uniformly dispersed on the surface of XC-72 carbon support, with a uniform particle size distribution. The PtCo/C catalyst after 400 °C heat treatment has the best electrochemical performance among the as-prepared catalysts, even superior to the commercial Pt/C catalyst. In the durability test, PtCo/C-400 also shows excellent stability with only 6.9% decline of electrochemical surface area (ECSA) after 1000 cyclic voltammetry (CV) cycles. In-situ X-ray absorption near edge structure (XANES) technique is conducted to explore the nanostructure change of Pt during the PEMFC operation. For PtCo/C catalyst, with the fuel cell operation potential decreasing from open circuit voltage (OCV) to 0.3 V, the Pt L3 white line intensity decreases continuously, indicating the decline of Pt 5d-vacancy due to the adsorption of oxygenated species. •Highly and homogeneously dispersed PtCo/C catalysts were synthesized.•Heat treatment of different temperatures was performed.•Potential-dependence of Pt L3 white line intensity was found by in-situ XANES.