3. Photochemical Solid-Phase Synthesis of Platinum Single Atoms on Nitrogen-Doped Carbon with High Loading as Bifunctional Catalysts for Hydrogen Evolution and Oxygen Reduction Reactions
ACS Catal. 2018, 8, 8450−8458
Tuanfeng Li, Jingjun Liu,* Ye Song, and Feng Wang*
Abstract: Currently, Pt single atoms as promising electrocatalysts have been applied to electrocatalysis aiming to significantly improve performance and remarkably lower usage of the noble metal. Herein, we propose a photochemical solid-phase reduction method to fabricate well-defined isolated Pt atoms on a nitrogen-doped porous carbon (Pt1/ NPC). Using this simple and fast synthesis strategy, the formed Pt atoms are well-dispersed on the carbon without clusters or nanoparticles. The loading of the Pt is up to 3.8 wt % relative to the carbon. The Pt1/NPC catalyst displays an ultrahigh electrocatalytic activity for hydrogen evolution reaction with an overpotential of 25 mV at the current density of 10 mA cm-2 and mass activity of 2.86 A mg-1 Pt (24-times higher than a commercial Pt/C). Moreover, the catalyst also presents efficient catalytic activity for the oxygen reduction reaction. Its mass activity is 4.3-times that obtained by a commercial Pt (20 wt %). The improved electrocatalytic activities of the Pt1/NPC catalyst are ascribed to the favorable chemical and electronic structure of the Pt-N4 coordination raised by strong electron transfer from the isolated Pt atoms to the coordinated N atoms in this catalyst. The Pt1/NPC can be employed as a bifunctional catalyst for fuel cells and hydrogen production.
