Syngas production by electrocatalytic reduction of CO2 using Ag-decorated TiO2 nanotubes

Abstract

Huge efforts have been done in the last years on electrochemical and photoelectrochemical reduction of CO 2 to offer a sustainable route to recycle CO 2. A promising route is to electrochemically reduce CO 2 into CO which, by combination with hydrogen, can be used as a feedstock to different added-value products or fuels. Herein, perpendicular oriented TiO 2 nanotubes (NTs) on the electrode plate were grown by anodic oxidation of titanium substrate and then decorated by a low loading of silver nanoparticles deposited by sputtering (i.e. Ag/TiO 2 NTs). Due to their quasi one-dimensional arrangement, TiO 2 NTs are able to provide higher surface area for Ag adhesion and superior electron transport properties than other Ti substrates (e.g. Ti foil and TiO 2 nanoparticles), as confirmed by electrochemical (CV, EIS, electrochemical active surface area) and chemical/morphological analysis (FESEM, TEM, EDS). These characteristics together with the role of the TiO 2 NTs to enhance the stability of CO 2 •intermediate formed due to titania redox couple (Ti IV /Ti III) lead to an improvement of the CO production in the Ag/TiO 2 NTs electrodes. Particular attention has been devoted to reduce the loading of noble metal in the electrode(14.5 %w/%w) and to increase the catalysts active surface area in order to decrease the required overpotential.

Facile synthesis of cubic cuprous oxide for electrochemical reduction of carbon dioxide

“…It is worth noting that the three electrodes containing Cu 2 O cubes achieve higher production rates of syngas at relatively lower overpotentials with respect to other similar studies [44,45] and they also obtain comparable current densities with respect to the Cu-based gas diffusion electrodes (GDEs) in a flow reactor at the same potentials reported by Lan et al [46]. Figure 10a, b summarizes the CO selectivity and H 2 /CO ratios of the produced syngas, respectively.…”

Microwave‐Assisted Synthesis of Copper‐Based Electrocatalysts for Converting Carbon Dioxide to Tunable Syngas

“…Other electrodes display a similar behavior (Figure S5‐S7). It is worth noting that the production rates of syngas at our electrodes are higher, as compared to other similar studies . To further investigate the stability behavior, 6 hours of electrolysis has been performed on the Cu‐5 electrode at −0.7 V. As shown in Figure e, the Cu‐5 electrode maintains a quasi‐steady current density.…”

“…It is worth noting that the production rates of syngas at our electrodes are higher, as compared to other similar studies. [26,27] To further investigate the stability behavior, 6 hours of electrolysis has been performed on the Cu-5 electrode at À 0.7 V. As shown in Figure 6e, the Cu-5 electrode maintains a quasi-steady current density. However, the selectivity for the CO formation drops down from 45 % to 32 %, while the FE for H 2 yield increases to 57 % at the end of the test.…”

Electrochemical conversion of pressurized CO2 at simple silver-based cathodes in undivided cells: study of the effect of pressure and other operative parameters

“…Several works have shown that the implementation of electrodes with high active surface allows operating at higher current intensities than that achieved at simple plate electrodes improving the performances of the process [21][22][23][24][25][26][27]. For example, Lu [23] and Ma [22] and co-workers have synthesized, respectively, a nanoporous (np-Ag) and an oxide-derived nanostructured (OD-Ag) silver catalyst (i.e.…”