Copper-Oxide-Coated Silver Nanodendrites for Photoelectrocatalytic CO₂ Reduction to Acetate at Low Overpotential

Abstract

The photoelectrocatalytic reduction of CO 2 uses sunlight to reduce the external energy needed to convert this greenhouse gas into value-added products. We report the deposition of a thin film of copper oxide onto a large-surface-area plasmonic silver structure, which generates an efficient photoelectrocatalyst for CO 2 reduction. Using incoherent visible light illumination and applying −0.4 V versus Ag/AgCl(KCl 1M), CO 2 was reduced to acetate with a faradaic efficiency of 54%. Rather than adding plasmonic nanoparticles as sensitizers onto semiconductors, here we electrodeposit a thin uniform layer of Cu 2 O/CuO over a plasmonic silver structure. The formation of acetate at this low potential has not been reported before and appears to arise from synergistic effects in this hybrid plasmonic-semiconductor material. In this work, we investigate changes in the photophysics under different preparation conditions. Varying the deposition time of Cu 2 O/CuO deposited onto the Ag to form the Ag/ Cu 2 O/CuO electrodes alters electron−hole recombination. The Ag/Cu 2 O/CuO electrodes show the highest photocurrent density when a minimal Cu 2 O/CuO film covers the Ag structure. Synergistic effects between the localized surface plasmon resonance of silver and semiconductor properties of Cu 2 O/CuO decrease the necessary overpotential required for CO 2 reduction, reduce charge recombination processes, and stabilize the Cu 2 O/ CuO semiconductor on the photoelectrode. The stabilization of Cu 2 O/CuO in the presence of energetic charge carriers is believed to be key to producing acetate with high efficiency. These properties suggest an interesting approach to photoelectrocatalytic materials.

Hybrid Plasmonic Nanomaterials for Hydrogen Generation and Carbon Dioxide Reduction

“…This was probed by Landaeta et al with a plasmonic–metal semiconductor system, consisting of Ag and Cu 2 O/CuO (Ag/Cu x O). 91 The illuminated hybrid system allowed the production of acetate with a FE of 54% at a potential of −0.4 V Ag/AgCl . The formation of acetate at such a low potential had not been reported before.…”

Unexpected high selectivity for acetate formation from CO2 reduction with copper based 2D hybrid catalysts at ultralow potentials

“…3,4 In recent years, various Cu-based electrocatalysts have been developed including metallic Cu and Cu alloys, as well as Cu compounds, 5,6 and their catalytic performance has been continuously improved by surface faceting, nanostructuring, doping, etc. [7][8][9][10][11][12][13][14][15] It is now widely accepted that the oxidation states of Cu have significant effects on the products of CO 2 RR. For instance, metallic Cu is found to produce CO and HCOOH as the main products at low overpotentials but CH 4 or C 2 H 4 at higher overpotentials.…”

Catalytic hydrodeoxygenation of biomass-derived pyrolysis oil over alloyed bimetallic Ni3Fe nanocatalyst for high-grade biofuel production

“…The Nyquist plots of Au/α-Fe2O3 and Au/α-Fe2O3/RGO are shown in Figure 4b and fitted with the Randles equivalent circuit. 6,14 The Au/α-Fe2O3/RGO electrode showed a charge transfer resistance Rct of ≈167 Ω, which is lower than that of Au/α-Fe2O3 (≈230 Ω), indicating higher Faradaic reaction rates and lower ohmic resistance on the Au/α-Fe2O3/RGO electrode surface. 51 The reduced impedance confirmed that the 2D RGO in the nanohybrids provided abundant electron transfer pathways, which further facilitated electron transfer.…”

“…The PECs, which connect a metallic anode for water oxidation (2H2O → O2 + 4H + ) to produce O2 along with protons (H + ), and a p-type photocathode could produce sufficient photogenerated electrons over a wide range of solar light wavelengths; thus, the produced H + and ecan effectively participate in the reduction of CO2 at the cathode surface. 5 Usually, various nanostructured p-type semiconductors and their composites, including Cu NP/f-RGO/CF, 6 CuFe2O4@PANI, 7 Au NP-modified glass carbon electrodes, 8 porphyrin-modified cobalt sulfide, 9 CuBi2O4/TiO2-NTs, 10 Pt-modified TiO2 nanotubes, 11 CuO/g-C3N4, 12 GO−CuFe2O4, 13 Ag/Cu2O/CuO electrodes, 14 S-TiO2@GS, 15 CuBi2O4/TiO2-NTs, 10 worm-like FeS2/TiO2 nanotubes, 16 Cu@porphyrin-COFs nanorods, 17 TiO2NT@PDA electrodes, 18 Pd-Cu cathodes, 19 ZnO:rGO-Cu:Cu2O, 20 Cu/Cu2O-Cu(BDC-NH2), 21 and FTO/Cu/Bi2Se3-Se/Cu2O electrodes 22 , were successfully used as the photocathode or photoanode for PEC CO2 reduction for fuel production.…”