PtAg Alloy Nanoparticles Embedded in Polyaniline as Electrocatalysts for Formate Oxidation and Hydrogen Evolution
Meng Huang, Hanyu Zhang, Yin Song, Xiaoxue Zhang, Jun Wang
Abstract
We successfully synthesized partly crystalline polyaniline (c-PANI) induced by PtAg alloy nanoparticles (c-PANI@PtAg). The liquid phase reduction PtAg nanoparticles were directly embedded in the c-PANI on a Pt sheet (c-PANI@PtAg/Pt) by in situ polymerization. c-PANI@PtAg/Pt demonstrated excellent electrocatalysis for formate oxidation reaction (FOR) and hydrogen evolution reaction (HER). The ordered structure of c-PANI showed a peak-separation effect and therefore significantly enhanced the catalytic path selectivity of c-PANI@PtAg/Pt for FOR. Meanwhile the current holding ratio after 1000 circles of voltamogram scanning reaches 91.4%. Research on the electrocatalysis of [email protected]/Pt for HER indicated the overpotentials at 1.0 mA cm–2 in both acid and alkaline solutions were more positive than that of pure Pt. Moreover, c-PANI@PtAg/Pt exhibits a much lower overpotential of 68 mV than that of 115 mV of Pt and a smaller Tafel slope of 27 mV dec–1 than that of 46 mV dec–1 of Pt.