Direct methanol fuel cells (DMFC) are electrochemical conversion device that can produce electricity at high fuel efficiencies, and Pt the excellent and major catalyst in them, is too expensive to be developed for applications widely. Before large-scale consumer use, three technological problems should be solved. 1. The activity of electrodes should be improved to increase efficiency, and then the amount (i.e. cost) of platinum catalyst in electrodes. 2. Poisoning effects of CO on Pt catalyst should be removed. 3. The conductivity of catalyst should be enhanced to reduce the energy waste in system.

Nano-sized platinum (Pt) particles were successfully reduced on tin phosphate (SnP) precipitated carbon black (C) to form Pt/SnP/C catalysts. In methanol oxidation reaction (MOR), these catalysts revealed the more electrochemical mass activity and less obvious CO poisoning effects than Pt/C to become potential for bi-functional catalysts. However, the serious agglomeration of Pt is observed. In this study, Poly (vinyl pyrrolidone) (PVP) was firstly added dispersed carbon black supports, assigned to C (PAD), to avoid the further agglomeration after SnP precipitation on them for increasing the specific surface area of SnP on which platinum was reduced, and hence enhancing the electrochemical performance as well as detoxifying function.

By using the characterization of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), and inductively coupled plasma-mass spectrometry (ICP-MS), the characterization of catalyst Pt/SnO₂-SnP/C (PAD) was carried out.

The particle size of platinum is 4.431 nm by XRD analyses and 3.61~3.97 nm observed by TEM. In hydrogen oxidation reaction (HOR) tests, electrochemical surface area (ECSA) of Pt/SnP/C was 765 (cm²/mg), and that of Pt/SnP/C (PAD) increased to 1268 (cm²/mg). In methanol oxidation reaction (MOR), catalyst Pt/SnP/C (PAD) illustrates the higher mass activity 80.67 (A/g_Pt, at 0.4 V) and the lower on-set potential 0.2 V (vs. Ag/AgCl). No forward current peaks was observed, indicating the deletion of CO poison effect on Pt than Pt/SnP/C. In membrane electrode assembly (MEA) tests, Pt/SnP/C (PAD) also reveals the greater power density and open circuit voltage than Pt/C (Alfa). TEM observations show that SnP is the nucleation site of Pt which is more dispersed than Pt/SnP/C in catalyst, leading to the better electrochemical performance.