Achieving a high rate of electrochemical conversion at a high efficiency in an electrochemical reactor requires the use of flow-through porous electrodes with a high surface area per unit volume, a high conductivity, and large mass-transfer rates. Several types of porous electrodes are commercially available, including carbon paper, graphite felt, reticulated vitreous carbon (RVC), metal mesh, and metal foam. However, these electrodes were all developed in the 1970’s, and there has been little innovation in this field for ~40 years. This presentation will describe the synthesis, fabrication, and properties of flow-through electrodes made from Cu nanowires. Cu Nanowires were synthesized in a basic solution by reducing Cu(NO3)2 by glucose in the presence of ethylenediamine. Filtration and annealing of Cu nanowires resulted in an electrode porosity of 94%. Compared to carbon paper, which has the highest surface area of any commercially available flow-through electrode, the Cu nanowire electrode had 15 times more surface area and was 32 times more conductive. A disadvantage of the Cu nanowire electrode was its hydraulic permeability was 10 times lower than carbon paper. The Cu nanowire electrode could reduce Cu ions at a single-pass conversion of 70% at a flow rate 611 times greater than for carbon paper under mass-transport limited conditions (i.e. low concentrations of Cu ions). Under kinetically limited conditions (i.e. high concentrations of Cu ions) the Cu nanowire electrode could achieve a flow rate 10 times greater than carbon paper at a single pass conversion of 70%. The Cu nanowire electrode was also compared to carbon paper for the intramolecular cyclization of 2,2′-bis(bromomethyl)-1,1′-biphenyl to produce 9,10-dihydrophenanthrene via electrochemical reductive dehalogenation. The maximum productivity of the Cu nanowire electrode was 4 times higher than that of carbon paper, demonstrating the ability of Cu nanowire electrodes to improve the productivity of organic electrosynthesis.

Properties of three-dimensional flow-through electrodes made from solution-synthesized metal nanowires

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.