Electrochemical Reduction of Carbon Dioxide over CNT‐Supported Nanoscale Copper Electrocatalysts

Abstract

This paper presents the experimental investigation of copper loaded carbon nanotubes (CNTs) electrocatalysts for the electrochemical reduction of carbon dioxide. The electrocatalysts were synthesized by homogeneous deposition precipitation method (HDP) using urea as precipitating agent. The prepared catalysts were characterized by TEM, SEM, XRD, XPS, BET, and FTIR for their morphology and structure. Characterization results confirm the deposition of Cu nanoparticles (3–60 nm) on CNTs. Linear sweep voltammetry (LSV) and chronoamperometry (CA) were used to investigate the activity of the as-prepared catalysts for the electrochemical reduction of carbon dioxide. The electrocatalysts reduced CO2with high current density in the potential range 0~−3 V versus SCE (standard calomel electrode). Among all catalysts tested, 20 wt. % copper loaded CNTs showed maximum activity. Gas chromatograph with TCD was used to analyze liquid phase composition. The faradaic efficiency for methanol formation was estimated to be 38.5%.

Electrochemical Reduction of CO 2

“…Under N 2 saturation current density was 0.0044 A-cm -2 at -1.4 V while under CO 2 saturation current density was 0.00628 A-cm -2 at -1.4V. Such trends of results were also reported in the literature [17], [95], [96].…”

“…Both of these reactions competes each other"s [17], [93], [94]. Hydrogen evolution consumes electrons and lowers the CO 2 reduction.…”

“…It increases the selectivity of alcohols with high chances of C-C chain due to microspores in CNTs. [17].…”

Carbon Solving Carbon's Problems: Recent Progress of Nanostructured Carbon‐Based Catalysts for the Electrochemical Reduction of CO2

“…[72][73][74] Recently, CNTs have been used to support nanoparticles of Pd and Cu and have reduced CO 2 to acetic acid and methanol, respectively. [73,74] With an average particle size of 5.7 nm, Pd NPs supported on MWCNTs (Pd-MWCNTs) were able to produce formic and acetic acid with at maximum FE of 34.5% and 52.3%, respectively. However, these maximum efficiencies occurred at relatively high cell potentials (-4 V), did not occur concurrently and were dependent on electrolyte concentration.…”

“…[74] Again, this required potential is relatively high and reminds us of the direct consequence of multi-step, multi-intermediate reaction pathways in the formation of more complex end products. [76] The optimum Cu loading was found to be 20 wt% as catalytic current density was maximised and loss in catalytic activity was observed for higher loadings.…”