Silver Nanowire/Carbon Sheet Composites for Electrochemical Syngas Generation with Tunable H₂/CO Ratios

Abstract

Generating syngas (H 2 and CO mixture) from electrochemically reduced CO 2 in an aqueous solution is one of the sustainable strategies utilizing atmospheric CO 2 in value-added products. However, a conventional single-component metal catalyst, such as Ag, Au, or Zn, exhibits potential-dependent CO 2 reduction selectivity, which could result in temporal variation of syngas composition and limit its use in large-scale electrochemical syngas production. Herein, we demonstrate the use of Ag nanowire (NW)/porous carbon sheet composite catalysts in the generation of syngas with tunable H 2 /CO ratios having a large potential window to resist power fluctuation. These Ag NW/carbon sheet composite catalysts have a potential window increased by 10 times for generating syngas with the proper H 2 /CO ratio (1.7–2.15) for the Fischer–Tropsch process and an increased syngas production rate of about 19 times compared to that of a Ag foil. Additionally, we tuned the H 2 /CO ratio from ∼2 to ∼10 by adjusting only the quantity of the Ag NWs under the given electrode potential. We believe that our Ag NW/carbon sheet composite provides new possibilities for designing electrode structures with a large potential window and controlled CO 2 reduction products in aqueous solutions.

Tunable Syngas Formation from Electrochemical CO2 Reduction on Copper Nanowire Arrays

“…Recently, a number of catalysts, including cadmium sulfoselenide nanorods, 16 Cu-enriched Au, 15 silver nanowire/ carbon sheet composites, 19 and silver diphosphide nanocrystals, 20 have been demonstrated as active catalysts for ECR syngas formation. However, ECR technologies are still far from being economically completive.…”

Tailoring Copper Foam with Silver Dendrite Catalysts for Highly Selective Carbon Dioxide Conversion into Carbon Monoxide

“…A commonly employed 0.5 M KHCO 3 aqueous electrolyte solution saturated with CO 2 (pH = 7.5) was used as catholyte. 21,24,26,29 The fluidic characteristics of the employed cell design allowed to recirculate the catholyte solution (flow rate of 20 ml/min), while the CO 2 gas was directly injected through the macroporous 3D Cu-Ag…”

“…In this regard, dendritic structures are of particular interest and were targeted in this study. Besides numerous examples of Ag based materials for CO 2 RR to CO, such as nanoplates, 20 nanoporous material and nanoparticles, [21][22][23][24][25] nanowires, 26,27 nanoclusters 28 and porous foams, 29 , dendritic structures offer large active surface areas paired with facile and non-expensive synthetization. [30][31][32] In this regard, we selected the electrodeposition method to deposit the Ag catalyst.…”

Interrogation of the Selectivity and Electrokinetics of CO2 Reduction by AgSn Films in the Presence of Protic Organic [DBU–H]+ Cations as judged by Impedance Spectroscopy and Distribution of Relaxation Times Analysis

“…25 A number of researchers have demonstrated that Ag promotes CO evolution in both aqueous and non-aqueous systems with varying electrokinetics that are largely influenced by the surface morphology and nature of electrolyte adsorption at the electrode-electrolyte interface. 25,26,27 It has also been shown that oxide derived nanostructured Ag materials exhibit excellent ability to convert CO2 to CO with selectivities exceeding 80%.…”