Highly dispersed platinum nanoparticles on graphitic carbon nitride: A highly active and durable electrocatalyst for oxidation of methanol, formic acid and formaldehyde

摘要

Finding efficient electrocatalyst for oxidation of small organic molecules such as methanol (CH3OH), formic acid (HCOOH), formaldehyde (HCHO) etc. is essential for the development of their respective direct fuel cells. We report here highly dispersed platinum nanoparticles (PtNPs) on carbon nitride (CNx) were successfully synthesized by the ultrasound mediated sodium borohydride reduction of H2PtCl6 in presence of CNx nanosheets. This platinum-carbon nitride (Pt/CNx) composite exhibited superior electrocatalytic activity towards oxidation of CH3OH, HCOOH and HCHO in acid media. The mass activity, onset potential, tolerance to carbon monoxide (CO) poisoning and long term durability for the catalytic oxidation of CH3OH, HCOOH, HCHO on Pt/CNx catalyst in acid media is much higher than that of commercial Pt/C catalyst. The mass activity of Pt/CNx catalyst at similar to 0.64 V (forward scan) is 310 mA/mgpt which is 2.7 time higher than that of commercial Pt/C for methanol oxidation. The electrooxidation of HCOOH on Pt/CNx occurs via dual mechanism with greatly enhanced oxidation through dehydrogenation pathway in comparison with commercial Pt/C. The mass activity on Pt/CNx at 0.3 V (vs. NHE) is 25 times higher than that of Pt/C for oxidation of HCOOH. The superior catalytic activity and durability of this Pt/CNx catalyst can be attributed to high dispersion of PtNPs and strong catalyst support interaction. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.