Electrocatalytic and Photoelectrochemical Reduction of Carbon Dioxide at Hierarchical Hybrid Films of Copper(I) Oxide Decorated with Tungsten(VI) Oxide Nanowires

Abstract

Unique hybrid systems for electroreduction of CO 2 under both conventional and visible-light-induced conditions are proposed and designed here by over-coating copper(I) oxide with tungsten(VI) oxide nanowires. When Cu 2 O and WO 3 nanostructures are sequentially deposited on glassy carbon substrate, the resulting system has exhibited high electrocatalytic activity toward reduction of CO 2 in phosphate buffer of pH = 6.1. By introducing WO 3 , the Cu-based system becomes more selective against the competitive hydrogen evolution and exhibits higher CO 2 -reduction currents relative to the performance of single components. During electroreduction, highly catalytic Cu sites are generated or intercalated within WO 3 nanowires partially reduced to mixed-valence hydrogen-absorbing tungsten(VI,V) oxide bronzes, H x WO 3 , co-existing with sub-stoichiometric tungsten(VI,IV) oxides, WO 3-y . Strong adsorption and activation of CO 2 molecule has been demonstrated at the WO 3 -decorated Cu 2 O interface. Under photoelectrochemical conditions involving illumination with sun-light, the proposed hierarchical system of Cu 2 O semiconductor deposited onto the transparent fluorine-doped conducting glass electrode and decorated with WO 3 nanowires is well-behaved and active toward CO 2 -reduction in the Na 2 SO 4 neutral medium. In addition to the Cu 2 O stabilization effect, the heterojunction formed by p-type Cu 2 O and n-type WO 3 semiconductors seems to facilitate charge distribution and separation at the photoelectrochemical interface.

Photoelectrochemical Reduction of CO2 at Poly(4‐Vinylpyridine)‐Stabilized Copper(I) Oxide Semiconductor: Feasibility of Interfacial Decoration with Palladium Cocatalyst

“…Representative systems cover various electrocatalytic materials, starting from diverse metallic, bimetallic, and carbon structures, often in a form of distinct nanomaterials that include nanoparticles, nanowires, or nanotubes, nanoporous films, core–shell structures, metal complexes, organometallic networks, porphyrins with metal active sides, conducting polymers, biological catalysts, and multifunctional/multicomponent hybrid systems. [ 1,5,10,11,15–24 ] Obviously, the CO 2 RR efficiency strongly depends on the geometry, morphology, porosity, roughness, or particle size of catalytic materials. For example, the efficiency for carbon monoxide production during CO 2 reduction over Pd nanoparticles was reported to increase with their decreasing size from ≈10 to 2 nm.…”

Aminopolysiloxane as Cu2O Photocathode Overlayer: Photocorrosion Inhibitor and Low Overpotential CO2‐to‐formate Selectivity Promoter

“…The origin of both photoactivity/photoinstability of cuprous oxide, as well as, strategies for stabilization can be found in the literature [6] and includes the association with different semiconductors [7,8] or the deposition of protective layers [9] . These strategies provide higher photocurrent and extend the lifetime of Cu 2 O electrodes when submitted to cathodic polarization and visible light irradiation.…”

Electrochemical reduction of CO2to ethylene on Cu/CuxO-GO composites in aqueous solution

“…In this regard, the electrochemical reduction of CO 2 (ERC) has attracted considerable attention to address the problem of global climate change. [1][2][3][4] In particular, conversion of CO 2 to hydrocarbons like methane, [5][6][7] ethane, ethylene, etc. which are energy dense fuels and chemicals, would be an added advantage.…”