Nitrogen doping of materials with melamine for proton exchange membrane fuel cells: Pre-treatment of carbon support or post treatment of the electrocatalyst

In this study, two different routes were followed for nitrogen doping and compared with each other. In the first route, carbon support was nitrogen doped (Method 1). In the second route, firstly, carbon supported Pt catalysts were synthesized, and then these electrocatalysts were nitrogen doped (Method 2). Physical characterizations including elemental analysis, inductively coupled plasma mass spectrometer (ICP-MS), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, Brunauer–Emmett–Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), contact angle measurement, and PEM fuel cell performance tests were performed. In Method 1, Pt/C:M-4:1/Pre catalyst showed the current density of 235.5 mA/cm2 @0.6 V and a max. power density of 160.5 mW/cm2. In Method 2, Pt/C:M-1:1/Post electrocatalyst had the current density of 626.0 mA/cm2 @0.6 V and a max. power density of 374.3 mW/cm2. Maximum power density obtained for Method 2 was 2.3 times higher than the electrocatalyst prepared with Method 1. Overall, it was observed that nitrogen doping of the electrocatalyst gave better result than nitrogen doping of the support material.