Overview of cuprous oxide
Cuprous oxide, the chemical formula is Cu2O, is monovalent copper oxide, a bright red powder solid, almost insoluble in water, in acidic solution disproportionation into copper and copper elemental, in the wet air gradually oxidized into black copper oxide. Cuprous oxide is mainly used in the manufacture of ship bottom antifouling paint (used to kill lower Marine animals), insecticides, and various copper salts, analytical reagents, red glass, but also used in the preparation of copper plating and copper plating alloy solution.
It is disproportionated to copper in an acidic solution, indicating that the stability of copper ions in the solution is greater than that of copper ions. For example, cuprous oxide reacts with sulfuric acid to produce copper sulfate and copper.
Cu2O + H2SO4 → CuSO4 + Cu + H2O
Cuprous oxide reacts with nitric acid to form copper nitrate, nitric oxide and water
3Cu2O + 14HNO3(dilute)→ 6Cu(NO3)2 + 2NO↑ + 7H2O
Cuprous oxide reacts with ammonia water and hydrogen halide acid to form complex and does not disproportionate into divalent copper and copper
Soluble in concentrated ammonia solution to form the colorless complex [Cu(NH3)2]+ (copper (I) ammonia ion), which is oxidized in the air to the blue [Cu(NH3)4(H2O)2]2+ (copper (II) hydrate ammonia ion)
Curious oxide soluble in hydrochloric acid to form HCUCL ₂ (cuprous chloride complex), also soluble in sulfuric acid and nitric acid respectively form copper sulfate and copper nitrate.
Cuprous Oxide (Cu₂O)
Cuprous oxide is used as a pigment in ceramics to produce blue, red and green, and sometimes grey, pink or black glazes.
It was also mistakenly used as a dietary supplement in animal feed.
Due to low biological activity, the absorbable copper is negligible. It is also used for welding with copper alloys. Cuprous oxide is also used to make ship bottom antifouling paint (to kill lower Marine animals).
Used as bactericide, ceramic and enamel coloring agent, red glass dyeing agent, also used in the manufacture of various copper salts, analytical reagents and used in the electrical industry in the rectification electroplating, crop fungicide and rectifier materials. Cuprous oxide is also commonly used as a catalyst for organic synthesis.
In the electronics industry, cuprous oxide is used as a p-type semiconductor material for the manufacture of photocells, light meters, and rectifiers. Its direct bandgap of approximately 2.1 eV makes it suitable for photovoltaic applications, including solar cells. The use of Cu₂O in gas sensors takes advantage of its electrical resistance changes upon exposure to gases such as carbon monoxide and nitrogen dioxide. In catalysis, Cu₂O is used for various chemical reactions, including the synthesis of organic compounds and the degradation of pollutants. The use of Cu₂O in water treatment is based on its ability to adsorb heavy metals and organic contaminants. In the construction industry, Cu₂O is used as a pigment and preservative in paints and coatings. The development of new Cu₂O-based materials for energy storage, sensing, and environmental remediation continues to expand its application range. The versatility of cuprous oxide in these diverse applications reflects its unique combination of properties and its importance in modern industry.
Chemical Behavior of Cu₂O
Toxic when swallowed. Skin can be harmful if absorbed through the skin. May cause skin irritation. Eye irritation may occur.
Acute toxicity: LD50:470mg /kg in mice; The abdominal meridian of mice was LD50:380 mg/kg; When the dust content of this product in the air reaches 0.22 ~ 14mg/m3, it will cause acute poisoning after working for 1 ~ 2h, which is manifested as headache, weakness, pharynx and conjunctiva redness, nausea, muscle pain, sometimes vomiting and diarrhea, fatigue, and elevated body temperature. After a day, the body temperature may return to normal, but weakness, headache, dizziness, rapid pulse count, and lymphocytosis remain. The gastric lavage with a certain concentration of K4[Fe(CN)6] solution and the taking of milk and other measures were taken for the acutely infected patients. The maximum allowable concentration in the air is 0.1mg/m³. You can wear a mask, dustproof glasses, wear protective work clothes, and take a shower after work.
Chronic poisoning is: the local skin, hair and conjunctiva of the workers who contact copper compounds sometimes become light yellow or black green, and there is dark red or magenta edge on the gingival. Irritating to the skin, dust irritates the eyes and causes corneal ulcers.
The health hazards of cuprous oxide are primarily related to excessive exposure to copper dust or fumes. The nervous system, liver, and kidneys are the primary target organs for copper toxicity. Acute poisoning from inhalation of high concentrations of copper dust can cause metal fume fever, characterized by headache, nausea, chills, fever, and sweating. Chronic exposure can lead to skin and eye irritation, discoloration of skin and hair, and gum changes. The use of appropriate engineering controls, including local exhaust ventilation and dust collection systems, is essential for minimizing exposure. Personal protective equipment, including respirators, protective clothing, and safety goggles, should be used where exposure cannot be eliminated. Regular monitoring of airborne copper levels and medical surveillance of exposed workers are important for early detection of adverse health effects. The occupational exposure limit for copper dust is typically 0.1 mg/m³ in many jurisdictions. The continued research on the health effects of copper compounds is expected to lead to better understanding and improved safety practices.
What's the difference between CuO and Cu2O?
Cu2O is obtained by oxidizing the copper metal or by reducing a solution of copper (II) with sulfur oxide, while CuO is obtained by pyrometallurgical methods used to extract copper from ore. Many wood preservatives are made from copper. It is also used as a pigment to make different glazes.
The key differences between CuO and Cu₂O are summarized in the following table. CuO contains copper in the +2 oxidation state and is black, while Cu₂O contains copper in the +1 oxidation state and is red. CuO is produced by pyrometallurgical methods, while Cu₂O is produced by oxidation of copper metal or reduction of copper(II) solutions. CuO is used in wood preservatives, pigments, and catalysts, while Cu₂O is used in antifouling paints, fungicides, and semiconductors. Both compounds have important industrial applications, and the choice between them depends on the specific requirements of the application.
Cu₂O vs CuO
Usually, the direct oxidation method of metal copper: the metal copper is suspended in the vertical tubular electric furnace with platinum wire, in the nitrogen atmosphere containing 1%(volume fraction) oxygen, heated at 1000℃ for 24h to get cuprous oxide. Or the chemical calculation of metal copper and copper oxide mixture is closed in a vacuum tube, heated at 1000℃ for 5h to make its reaction to getting cuprous oxide. The order of forming oxide phase from copper through thermal oxidation is as follows: Cu→Cu + Cu2O→Cu2O→Cu2O + CuO→CuO. In addition, the formation of pure Cu2O occurs at about 200°C, while the formation of CuO begins at 300°C to 1000°C.
Cuprous oxide can also be produced by the dry process.
Dry method: The copper powder is mixed with copper oxide after impurity removal, and then sent into the calcining furnace to be heated to 800~900°C to be calcined into cuprous oxide. After taking it out, use a magnet to remove mechanical impurities, and then pulverize to 325 mesh. If copper sulfate is used as the raw material, first use an iron to reduce the copper in the copper sulfate. The subsequent reaction steps are the same as the method using copper powder as the raw material.
Preparation of Cu₂O
Red copper is a reduced form of ordinary black copper oxide (CuO).In normal oxidizing roasting, it will be converted to the copper oxide form (CuO), which produces the normal green color in the glaze and glass. If reduced and sintered, it will retain its Cu2O structure to produce the typical copper-red color.
The red color of Cu₂O is due to its electronic structure, which absorbs light in the visible spectrum and reflects red wavelengths. The color is sensitive to the oxidation state of copper and the firing conditions. In oxidizing atmospheres, Cu₂O converts to CuO, which produces green or blue colors in glazes and glass. In reducing atmospheres, CuO is reduced to Cu₂O, producing the characteristic copper-red color. The ability to control the oxidation state of copper through firing conditions makes it possible to produce a wide range of colors in ceramics and glass. The red color of Cu₂O is also exploited in the production of red glass, ruby glass, and copper-red glazes. The stability of the red color depends on the composition of the glaze and the firing conditions. The development of new copper-red glaze formulations continues to expand the range of colors and effects achievable with Cu₂O.
Aminopolysiloxane as Cu2O Photocathode Overlayer: Photocorrosion Inhibitor and Low Overpotential CO2‐to‐formate Selectivity Promoter
Photo-active P-type semiconductor based on Earth-rich elements represents photoactive P-type semiconductor of photoelectrochemical CO2 reduction reaction (PEC CO2RR). However, although light absorption and appropriate conduction edge energy, rapidly performs photo corrosion under PEC CO 2RR conditions. Here, the amine-functionalized polysiloxane (AF-PSI) is evaluated by the amine-CO2 adduct, and the amine-functionalized polysiloxane (AF-PSI) is evaluated as a protective layer and a PEC CE2RR promoter. Electrochemical experiments and X-ray diffraction indicate that light stability is significantly improved by AF-PSI cover. Electrolysis experiments under visible light illumination showed that the feed efficiency of the feed was 61% of the preferred production of 61%. Detailed in situ FTIR studies have shown that the amine group is combined with CO2 to form a urethane substance, and the method is to confirm the double effect of the AF-PSI layer by the favored cathode polarization.
The use of aminopolysiloxane as a photocathode overlayer represents a significant advancement in the development of stable and efficient photocathodes for CO₂ reduction. The AF-PSI layer protects the Cu₂O photocathode from photocorrosion while promoting CO₂ reduction through the formation of amine-CO₂ adducts. The amine groups in the AF-PSI layer react with CO₂ to form carbamate species, which are key intermediates in the reduction process. The AF-PSI layer also promotes the selectivity of the reaction toward formate production. The development of new photocathode materials with improved stability and selectivity is an area of active research, driven by the need for sustainable CO₂ conversion technologies. The combination of Cu₂O with AF-PSI represents a promising approach for photoelectrochemical CO₂ reduction.
Cu₂O Photocathode for CO₂ Reduction
Cuprous Oxide, Cu₂O, Copper Oxide, Antifouling Paint, Fungicide, p-Type Semiconductor, Catalyst, Pigment, Marine Coatings
