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 -28mV and a smaller Tafel slope of 40mVdec ^-1 relative to commercial Pt black (-34mV, 50mVdec ^-1 ) and Pt/C (20wt.%, -33mV, 33mVdec ^-1 ) in 0.5M H ₂ SO ₄ . Meanwhile, the obtained catalyst exhibited improved catalytic features toward oxygen reduction reaction (ORR) with a positive η _onset (0.916V) and enhanced kinetic current density (243.23mAmg ^-1 _Pt ) in 0.1M HClO ₄ at 0.850V compared with Pt black (0.876V, 25.85mAmg ^-1 _Pt ).
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