Cerium Hydroxide

Rare Earth Hydroxides

Cerium Hydroxide exists in two primary oxidation states, forming two distinct compounds: cerium(III) hydroxide (Ce(OH)₃, a weak base) and cerium(IV) hydroxide (Ce(OH)₄, also known as ceric hydroxide, a strong oxidizing agent). As key inorganic compounds in the cerium salt family, they are distinguished by their valence-dependent chemical reactivity—setting them apart from stable, valence-fixed cerium oxide (CeO₂). Unlike soluble cerium salts (e.g., cerium nitrate, cerium acetate), both Ce(OH)₃ and Ce(OH)₄ exhibit extremely low aqueous solubility, enabling controlled release of Ce³⁺/Ce⁴⁺ ions and selective reactivity in targeted processes. With base purities ranging from 98% (technical grade) to 99.999% (ultra-high purity), and strict control over valence state (≥99% single valence for most grades), they are widely used in catalysis, water treatment, material synthesis, and laboratory research.

Commercially, Cerium Hydroxide is categorized by valence state, purity, particle size, and morphology (amorphous powder or crystalline flakes) to meet diverse application needs. Technical Grade Ce(OH)₃ (purity 98.0%–99.0%, particle size 100–200 mesh, amorphous powder) prioritizes cost-efficiency for industrial uses like raw material for cerium oxide synthesis (via calcination), pH regulators in chemical processes, and precursor for cerium-based catalysts. Technical Grade Ce(OH)₄ (purity 98.0%–99.0%, particle size 150–250 mesh, crystalline powder) is used for oxidative water treatment (removal of organic pollutants) and as an oxidizing agent in organic synthesis. Reagent Grade Ce(OH)₃ (purity ≥99.5%, particle size 200–300 mesh, crystalline powder) meets laboratory standards for analytical chemistry (e.g., cerium precipitation studies) and small-scale material research (synthesis of cerium-based nanomaterials). Reagent Grade Ce(OH)₄ (purity ≥99.5%, particle size 200–300 mesh, high-purity crystals) is used for precision oxidation reactions and redox titration standards. High-Purity Grade Ce(OH)₃ (purity ≥99.99%, particle size 200–300 mesh, ultrafine powder) targets electronics and optoelectronics, including precursors for cerium-doped dielectric films and dopants for piezoelectric ceramics—where trace impurities (e.g.,<10 ppb heavy metals, <5 ppb Si/Al) must be minimized. High-Purity Grade Ce(OH)₄ (purity ≥99.99%, particle size 200–300 mesh, nanoscale powder) is used in advanced catalysis (e.g., selective oxidation of hydrocarbons) and semiconductor cleaning. Ultra-High Purity Grade (purity ≥99.999%, particle size 300–400 mesh, monodisperse powder) is a niche grade for quantum dot synthesis and biomedical imaging agents, with valence purity ≥99.9% to avoid performance interference. At standard temperature and pressure, Ce(OH)₃ appears as white to pale yellow amorphous powder, while Ce(OH)₄ is yellow to brown crystalline powder—their distinct colors simplify valence identification. Purity and valence state are verified via X-ray photoelectron spectroscopy (XPS) for valence analysis, inductively coupled plasma mass spectrometry (ICP-MS) for elemental purity, and X-ray diffraction (XRD) for crystal structure (hexagonal for Ce(OH)₃, orthorhombic for Ce(OH)₄).

Physically, Cerium Hydroxide’s traits are strongly valence-dependent. Cerium(III) hydroxide (Ce(OH)₃) has a molecular weight of 191.14 g/mol, a bulk density of ~2.23 g/cm³ (amorphous) to ~2.45 g/cm³ (crystalline), and extremely low aqueous solubility (~0.0003 g/100 mL at 20°C). It is soluble in dilute acids (e.g., HCl, HNO₃) to form Ce³⁺ salts, with solubility increasing with acid concentration. Cerium(IV) hydroxide (Ce(OH)₄) has a molecular weight of 208.15 g/mol, a higher bulk density of ~3.20 g/cm³ (crystalline), and even lower aqueous solubility (~0.0001 g/100 mL at 20°C). It dissolves in strong acids (e.g., concentrated H₂SO₄) to form ceric salts, and exhibits limited solubility in organic solvents (e.g., ethanol, acetone). Thermal stability varies significantly: Ce(OH)₃ decomposes gradually above 150°C to form cerium oxyhydroxide (CeOOH) and completely converts to Ce₂O₃ above 300°C; Ce(OH)₄ decomposes at 100–120°C (losing water) to form CeO₂·nH₂O (hydrous ceria) and fully converts to CeO₂ above 250°C. Both exhibit mild hygroscopicity (~0.3%–0.5% moisture absorption at 60% humidity) compared to highly hygroscopic cerium chloride, preventing severe caking but requiring sealed storage to maintain valence stability. Notably, Ce(OH)₄ has a high specific surface area (15–30 m²/g for nanoscale powder), enhancing its oxidizing efficiency in water treatment.

Chemically, the defining feature of Cerium Hydroxide is its valence-dependent reactivity. Ce(OH)₃ acts as a weak base: it neutralizes dilute acids to form Ce³⁺ salts (e.g., Ce(OH)₃ + 3HCl → CeCl₃ + 3H₂O) and undergoes slow oxidation in air to form Ce(OH)₄ (2Ce(OH)₃ + ½O₂ + H₂O → 2Ce(OH)₄), a reaction accelerated by light and high humidity. It forms stable complexes with chelating agents (e.g., EDTA) in acidic solutions, used in analytical chemistry for cerium separation. In contrast, Ce(OH)₄ is a strong oxidizing agent: it oxidizes reducing species (e.g., Fe²⁺ to Fe³⁺, As³⁺ to As⁵⁺) in acidic media, with the reaction Ce(OH)₄ + 4H⁺ + Fe²⁺ → Ce³⁺ + Fe³⁺ + 4H₂O widely used in water treatment and redox titrations. It is stable in neutral to alkaline environments but decomposes in strong reducing atmospheres (e.g., H₂, CO) to form Ce(OH)₃ or CeO₂. Unlike cerium oxide (inert at room temperature), both Ce(OH)₃ and Ce(OH)₄ exhibit dynamic reactivity—enabling their use in time-sensitive processes like catalytic oxidation and pollutant remediation.

The industrial production of Cerium Hydroxide is tailored to valence state, using cerium-rich raw materials and controlled precipitation. For Ce(OH)₃: Step 1, raw material purification: Cerium(III) salts (e.g., CeCl₃, Ce(NO₃)₃) or cerium oxide (Ce₂O₃) are dissolved in deionized water; solvent extraction (using P507 extractant) removes impurities (e.g., other rare earths, heavy metals) to ppb levels. Step 2, precipitation: The purified Ce³⁺ solution is slowly added to a stirred ammonium hydroxide (NH₄OH, 25% concentration) solution at 20–30°C (pH 8–9), with a molar ratio of Ce³⁺ to OH⁻ of 1:3 (reaction: Ce(NO₃)₃ + 3NH₄OH → Ce(OH)₃↓ + 3NH₄NO₃). The addition rate is controlled to avoid amorphous precipitation. Step 3, aging and washing: The slurry is aged at 40–50°C for 2–3 hours to promote crystallization; the precipitate is filtered and washed with deionized water until rinse water conductivity<10 μS/cm (removing NH₄⁺/NO₃⁻). Step 4, drying: The wet cake is dried at 60–80°C (to avoid oxidation) under inert nitrogen atmosphere, then crushed to target particle size. For Ce(OH)₄: Step 1, oxidation-precipitation: Cerium(III) salt solution is oxidized with hydrogen peroxide (H₂O₂, 30% concentration) at 40–50°C (pH 9–10, adjusted with NaOH) to convert Ce³⁺ to Ce⁴⁺, which precipitates as Ce(OH)₄ (2Ce(NO₃)₃ + H₂O₂ + 6NaOH → 2Ce(OH)₄↓ + 6NaNO₃). Step 2, purification: The precipitate is washed with dilute NaOH (0.1% concentration) to remove residual oxidants, then with deionized water. Step 3, drying: Dried at 50–70°C under air (Ce(OH)₄ is stable in air) to retain oxidizing activity. High-purity grades undergo additional ion exchange to reduce impurities, while nanoscale Ce(OH)₄ is synthesized via sol-gel methods with surfactants.

Cerium Hydroxide’s applications are driven by valence-dependent properties. In catalysis, High-Purity Grade Ce(OH)₃ is a precursor for cerium-based catalysts (e.g., CeO₂-supported Pt) used in CO oxidation: its low-temperature decomposition to CeO₂ enables uniform dispersion of active metals, enhancing catalytic efficiency. Ce(OH)₄ (Reagent Grade) is a green oxidizing agent in organic synthesis (e.g., oxidation of alcohols to ketones), avoiding toxic byproducts of traditional oxidizers (e.g., CrO₃). In water treatment, Technical Grade Ce(OH)₄ is used for advanced oxidation processes (AOPs): it generates hydroxyl radicals (•OH) in acidic conditions, degrading persistent organic pollutants (e.g., phenols, dyes) with removal efficiencies >95%. Ce(OH)₃ (Technical Grade) is used for heavy metal adsorption (e.g., Pb²⁺, Cd²⁺) via ion exchange, with adsorption capacities up to 150 mg/g. In material synthesis, High-Purity Grade Ce(OH)₃ is a precursor for cerium-doped zirconia ceramics: it improves ceramic toughness by inhibiting grain growth during sintering. Ce(OH)₄ (Ultra-High Purity Grade) is used in quantum dot synthesis (e.g., Ce-doped CdSe quantum dots) to enhance photoluminescence efficiency. In laboratory research, Reagent Grade Ce(OH)₃/Ce(OH)₄ is used as a reference for valence state studies and redox reaction calibration. Additionally, Ce(OH)₃ is used in cosmetic formulations as an anti-inflammatory agent (Ce³⁺ scavenges free radicals), while Ce(OH)₄ is a component in dental whitening products (mild oxidizing action on stains).

Safety-wise, Cerium Hydroxide requires valence-specific handling. Ce(OH)₃ has low acute toxicity: its powder may cause mild respiratory irritation if inhaled, so operators should wear N95 masks and nitrile gloves. Ce(OH)₄, as an oxidizing agent, poses higher risks: it reacts violently with strong reducing agents (e.g., Na₂SO₃, hydrazine) to release heat, potentially causing fires. Direct skin/eye contact with Ce(OH)₄ may cause chemical irritation (yellow staining from Ce⁴⁺), requiring immediate rinsing with water. Both are non-flammable, but Ce(OH)₄’s thermal decomposition (above 120°C) releases oxygen, which may intensify nearby fires. Storage: Ce(OH)₃ should be stored in cool (15–25°C), dry (<60% humidity) sealed containers under nitrogen to prevent oxidation to Ce(OH)₄; Ce(OH)₄ should be stored in airtight containers separate from reducing agents/organics, at 10–20°C to maintain oxidizing activity. Shelf life: Technical Grade Ce(OH)₃ 1–2 years, Ce(OH)₄ 6–12 months (due to gradual decomposition); High-Purity Grade 6–12 months for both. Expired products show reduced reactivity (Ce(OH)₃ oxidation to Ce(OH)₄, Ce(OH)₄ decomposition to CeO₂) and should be tested before use.

Descriptive:  WNX employs advanced automated production technology and uses high-quality raw materials to produce high-qualityCerium Hydroxide.

Key Features:

High Purity:Cerium Hydroxide contains no impurities from rare earth elements (such as iron, calcium, sodium), and the impurity content is low.

Good Solubility:Cerium Hydroxide can dissolve rapidly in water and strong acids.

Consistency: The strict batch management in the production ofCerium Hydroxide ensures stable quality for industrial large-scale production.

Chemical industrial catalyst: Cerium hydroxide (especially the tetravalent Ce(OH)₄ form) is used as an effective catalyst or catalyst precursor in the automotive exhaust purification and petroleum catalytic cracking (FCC) processes. It can significantly enhance reaction efficiency and help purify harmful gases. It is also employed in various organic synthesis reactions as a component that promotes the reaction.

Pond Phosphorus Remover: Due to its chemical properties, cerium hydroxide can effectively remove phosphate from water bodies through precipitation, which helps address the problem of water eutrophication and is applied in wastewater treatment and environmental restoration.

Batteries and energy materials: Cerium hydroxide is one of the precursors for preparing key materials used in solid oxide fuel cells (SOFCs). Its unique properties also have the potential to be applied in emerging energy storage technologies and electrochemical systems.

Chemical synthesis intermediates: As an important source of cerium, cerium hydroxide is the basic raw material for synthesizing other cerium compounds (such as cerium oxide, various cerium salts). These compounds are further utilized in the production of glass polishing powder, ceramic colorants, ultraviolet absorption materials (UV filters), and resin additives, etc.

Custom packaging available upon request