Simultaneous Electrocatalytic CO₂ Reduction and Enhanced Electrochromic Effect at WO₃ Nanostructured Electrodes in Acetonitrile

Abstract

Serious concerns about the climate change make particularly attractive the reutilization of CO 2 , being one option the electroreduction of CO in acetonitrile solutions on a range of electrode materials. Among them, transition metal oxides stand out as cost effective alternatives. In this context, the electrocatalytic activity of nanostructured WO 3 electrodes for carbon dioxide reduction in both humid and dry acetonitrile media has been addressed by using electrochemical and spectroelectrochemical measurements. Importantly the cathodic faradaic process starts at potentials as high as-0.16 V vs SHE. Gas chromatography measurements show CO as being the main product in both dry and humid acetonitrile, together with formate in the presence of humidity. Interestingly, purging with CO 2 not only causes the appearance of cathodic faradaic currents, but also an increase in capacitive currents, which are directly associated with an enhanced electrochromic effect. The ICP-MS determination of tungsten upon electrolysis confirms a minor electrodissolution of WO 3 electrode. On the basis of these observations, a mechanism is proposed in which WO 3 is not only the electrode material, but also a mediator in the CO 2 reduction process

Spectroelectrochemical Study of CO2 Reduction on TiO2 Electrodes in Acetonitrile

“…An analogous model was previously proposed for WO 3 electrodes in acetonitrile solutions, providing an explanation for the direct relationship existing between an enhanced electrochromic effect and CO 2 reduction. 31 In this section, after some electrochemical considerations, a model for CO reduction on TiO 2 electrodes is first presented, offering an explanation for both the catalytic behavior for CO 2 reduction and the concomitant enhanced electrochromic effect observed. Next, the UV-vis absorbance decay at open circuit potential is analyzed in detail and shown to include kinetic information for CO 2 reduction on TiO 2 electrodes.…”

Solvents and Supporting Electrolytes in the Electrocatalytic Reduction of CO2

“…Acetonitrile (Aylmer-Kelly et al, 1973;Kaiser and Heitz, 1973;Fischer et al, 1981;Eggins and McNeill, 1983;Ikeda et al, 1987;Desilvestro and Pons, 1989;Christensen et al, 1990;Higgins and Christensen, 1995;Gennaro et al, 1996aGennaro et al, , 1996bTomita et al, 2000;Lv et al, 2013;Oh et al, 2014;Sun et al, 2014;Berto et al, 2015;Matsubara et al, 2015;Díaz-Duque et al, 2015;Rudnev et al, 2016;Zhu et al, 2016aZhu et al, , 2016bFigueiredo et al, 2016;Mendieta-Reyes et al, 2018) 314 G 6 0.341 35.9 59.0 Problematic Dimethylformamide (Gambino and Silvestri, 1973;Lamy et al, 1977;Amatore and Savé ant, 1981;Fischer et al, 1981;Goodridge and Presland, 1984;Gennaro et al, 1996aGennaro et al, , 1996bOh et al, 2014;Berto et al, 2015;Kai et al, 2017;Shi et al, 2017) 194 G 14 0.802 36.7…”

Review on the Versatility of Tungsten Oxide Coatings

“…Furthermore, by an elevated temperature photothermal coupling, reaction of CH 4 with O 2 may be promoted leading to the generation of CH 3 OH as hydrocarbon fuel. An interesting approach has been pursued by Mendieta‐Reyes et al consisting of fabrication of nanostructured WO 3 electrodes and the study of CO 2 reduction in both humid and dry acetonitrile solution. This study revealed that the presence of water traces was critical to the formation of formate along with the CO production.…”