Ultrathin Ag Nanowires Electrode for Electrochemical Syngas Production from Carbon Dioxide

The mass production of silver nanowires (Ag NWs) with ultrathin diameter (∼35 nm) and a high aspect ratio (>1000) is prepared from an optimized polyol solution. The Ag NWs possess several promising advantages, including good conductivity and excellent film formability, and have already been used to fabricate a large area flexible Ag NWs-based electrode through a simple drop-casting method. The Ag NWs electrode displayed good activity to convert carbon dioxide (CO2) to carbon monoxide (CO) in high Faradaic efficiency (FE) of ∼80% under low working potential (−0.9 V vs reversible hydrogen electrode (RHE)), and at the same time, the fraction of CO/H2 can be tuned from 1/1 to 4/1. A small amount of HCOOH (FE: 2.6–5.6%) was also measured as a byproduct in liquid phase. The constant working current density and CO FE recovered superstability of the Ag NWs electrode. The high-resolution transmission electron microscopy (TEM) recovered the {111} facet exposed to the surface contribuing to the effective performance. Ag NWs with larger diameter (70 nm) and Ag plate electrode were also evaluated under the same condition, where formic acid (HCOOH) was also detected besides CO as another main product. Combined with easy fabrication, low cost, high selectivity, and excellent stability, Ag NWs based electrode is promising for further application in larger scale for syngas production and other electrocatalysis.