posted on 2017-12-21, 00:00authored byXiong Peng, Stavros G. Karakalos, William E. Mustain
Selective electrochemical
reduction of CO2 is one of the most important processes
to study because of its promise to convert this greenhouse gas to
value-added chemicals at low cost. In this work, a simple anodization
treatment was devised that first oxidizes Ag to Ag2CO3, then uses rapid electrochemical reduction to create preferentially
oriented nanoparticles (PONs) of metallic Ag (PON-Ag) with high surface
area as well as high activity and very high selectivity for the reduction
of CO2 to CO. The PON-Ag catalyst was dominated by (110)
and (100) orientation, which allowed PON-Ag to achieve a CO Faradaic
efficiency of 96.7% at an operating potential of −0.69 V vs
RHE. This performance is not only significantly higher than that of
polycrystalline Ag (60% at −0.87 V vs RHE) but also represents
one of the best combinations of activity and selectivity achieved
to date - all with a very simple, scalable approach to electrode
fabrication.