One-pot synthesis of hollow AgPt alloyed nanocrystals with enhanced electrocatalytic activity for hydrogen evolution and oxygen reduction reactions.

Herein, a simple one-pot aqueous method was developed for the fabrication of uniform hollow bimetallic AgPt alloyed nanocrystals (H-AgPt NCs) by using 5-aminoorotic acid (5-amino-2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid) as a growth-directing agent, without any seed, organic solvent or template involved. The prepared H-AgPt NCs displayed enhanced electrocatalytic activity for hydrogen evolution reaction (HER) with a more positive onset overpotential ( η onset ) of −28 mV and a smaller Tafel slope of 40 mV dec −1 relative to commercial Pt black (−34 mV, 50 mV dec −1 ) and Pt/C (20 wt.%, −33 mV, 33 mV dec −1 ) in 0.5 M H 2 SO 4 . Meanwhile, the obtained catalyst exhibited improved catalytic features toward oxygen reduction reaction (ORR) with a positive η onset (0.916 V) and enhanced kinetic current density (243.23 mA mg −1 Pt ) in 0.1 M HClO 4 at 0.850 V compared with Pt black (0.876 V, 25.85 mA mg −1 Pt ). [ABSTRACT FROM AUTHOR]