Surface facets dependent oxygen evolution reaction of single Cu_(2)O nanoparticles

摘要

Understanding and establishing the structure-activity relation of nanoparticles is a prerequisite for rational design of high-performance electrocatalysts.Cu_(2)O nanoparticles enclosed with different crystal facets,namely,o-Cu_(2)O NPs with{111}facets,c-Cu_(2)O NPs with{100}facets are prepared and their electrocatalytic properties for oxygen evolution reaction(OER)in alkaline condition are evaluated at single nanoparticle level with a combination of scanning electrochemical cell microscopy and scanning electron microscopy.It is found that the o-Cu_(2)O NPs have significantly superior OER electrocatalytic activity compared to c-Cu_(2)O,which is almost inert.The estimated turnover frequency(TOF)at 1.97 V vs.RHE on{111}facet increases from 4 s^(-1) to 115 s^(-1) with the octahedron edge length decreasing from 1.3μm to 100 nm.Deposition of carbon on c-Cu_(2)O surface barely promotes the activity,suggesting the inherent poor electric conductivity within the nanocrystal is most likely the reason for low activity.This work provides direct probing to single transition metal oxide crystals with dramatically different activity.