Nanostructured Cu2O Synthesized via Bipolar Electrochemistry

Abstract

Cuprous oxide (Cu2O) was synthesized for the first time via an open bipolar electrochemistry (BPE) approach and characterized in parallel with the commercially available material. As compared to the reference, Cu2O formed through a BPE reaction demonstrated a decrease in particle size; an increase in photocurrent; more efficient light scavenging; and structure-correlated changes in the flat band potential and charge carrier concentration. More importantly, as-synthesized oxides were all phase-pure, defect-free, and had an average crystallite size of 20 nm. Ultimately, this study demonstrates the impact of reaction conditions (e.g., applied potential, reaction time) on structure, morphology, surface chemistry, and photo-electrochemical activity of semiconducting oxides, and at the same time, the ability to maintain a green synthetic protocol and potentially create a scalable product. In the proposed BPE synthesis, we introduced a common food supplement (potassium gluconate) as a reducing and complexing agent, and as an electrolyte, allowing us to replace the more harmful reactants that are conventionally used in Cu2O production. In addition, in the BPE process very corrosive reactants, such as hydroxides and metal precursors (required for synthesis of oxides), are generated in situ in stoichiometric quantity, providing an alternative methodology to generate various nanostructured materials in high yields under mild conditions.

Evolution of Structural and Optical Properties of Cuprous Oxide Particles for Visible Light Absorption

“…The band gap is in the range of 2:04 ≤ Eg ≤ 2:09 eV and increases slightly with the rise of glucose content. This difference is explained by the effect of the particle size due to quantum confinement, i.e., the generation of discrete energy levels in the valence and the conduction bands [21,40,64]. The reduction in particle size leads to an increase in the band gap of the material, which shows a blue shift similar to what is reported in the literature [12,21].…”

“…Cuprous oxide is used in electrodes for lithium-ion batteries, photochemical cells, hydrogen production, sensors, photocatalysts, supercapacitors, magnetic storage, and water splitting [15][16][17][18][19][20][21], as well as a bactericide, colorant, and additive for corrosion-proof coatings [22][23][24]. Various methods have been developed to obtain Cu 2 O, such as the water bath method, the SILAR (Successive Ionic Layer Absorption and Reaction) method, the polyol method, chemical reduction, and sol-gel [4,10,17,[25][26][27][28][29][30][31][32]; however, some of these methods require special equipment [17,27,28], catalysts, organic additives, or expensive surfactants [25,31,32].…”

TiO2/Cu2O/CuO Multi-Nanolayers as Sensors for H2 and Volatile Organic Compounds: An Experimental and Theoretical Investigation

“…From the nanotechnology point of view, metallic copper (Cu) and its oxides have received much attention due to their variety of real applications, particularly in the field of new nanotechnology components for microelectronics. ,, Copper oxides are p -type semiconducting oxides and can be obtained in forms such as cuprite (Cu 2 O) and cupric oxide (CuO) depending on the oxygen availability. The cuprous oxide cuprite (Cu 2 O) is among the earliest semiconducting oxides used in solid-state electronics. ,, Although cuprite has been the focus of numerous experimental and theoretical studies ,,− aimed at understanding its vibrational and optical properties, the electronic properties of Cu 2 O continue to puzzle the scientific community.…”

“…From the nanotechnology point of view, metallic copper (Cu) and its oxides have received much attention due to their variety of real applications, particularly in the field of new nanotechnology components for microelectronics. 4,8,9 Copper oxides are p-type semiconducting oxides and can be obtained in forms such as cuprite (Cu 2 O) and cupric oxide (CuO) depending on the oxygen availability. The cuprous oxide cuprite (Cu 2 O) is among the earliest semiconducting oxides used in solid-state electronics.…”

“…6,10,11 Although cuprite has been the focus of numerous experimental and theoretical studies 1,7,12−14 aimed at understanding its vibrational and optical properties, the electronic properties of Cu 2 O continue to puzzle the scientific community. As applications of Cu 2 O in nanoelectronics, photovoltaics, solid-state electronics, biosensing, and spintronics emerge, 4,9,15 including the light-driven purification of wastewater, 8 understanding the electronic structure of Cu 2 O at the atomic level is important for the control of its properties and the identification of future applications in devices or nanodevices.…”