Titanium dioxide, also known as titanium(IV) oxide or titania, is the inorganic compound derived from titanium with the chemical formula TiO
2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. It is a white solid that is insoluble in water, although mineral forms can appear black. As a pigment, it has a wide range of applications, including paint, sunscreen, and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million tonnes. It has been estimated that titanium dioxide is used in two-thirds of all pigments, and pigments based on the oxide have been valued at a price of $13.2 billion.
Methyl violet is a family of organic compounds that are mainly used as dyes. Depending on the number of attached methyl groups, the color of the dye can be altered. Its main use is as a purple dye for textiles and to give deep violet colors in paint and ink. It is also used as a hydration indicator for silica gel. Methyl violet 10B is also known as crystal violet and has medical uses.
Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder which is insoluble in water. ZnO is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, ceramics, glass, cement, lubricants, paints, sunscreens, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, semi conductors, and first-aid tapes. Although it occurs naturally as the mineral zincite, most zinc oxide is produced synthetically.
A nanoparticle or ultrafine particle is a particle of matter 1 to 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At the lowest range, metal particles smaller than 1 nm are usually called atom clusters instead.
In chemistry, photocatalysis is the acceleration of a photoreaction in the presence of a photocatalyst, the excited state of which "repeatedly interacts with the reaction partners forming reaction intermediates and regenerates itself after each cycle of such interactions." In many cases, the catalyst is a solid that upon irradiation with UV- or visible light generates electron–hole pairs that generate free radicals. Photocatalysts belong to three main groups; heterogeneous, homogeneous, and plasmonic antenna-reactor catalysts. The use of each catalysts depends on the preferred application and required catalysis reaction.
Cerium(IV) oxide, also known as ceric oxide, ceric dioxide, ceria, cerium oxide or cerium dioxide, is an oxide of the rare-earth metal cerium. It is a pale yellow-white powder with the chemical formula CeO2. It is an important commercial product and an intermediate in the purification of the element from the ores. The distinctive property of this material is its reversible conversion to a non-stoichiometric oxide.
Silver molybdate (Ag2MoO4), a chemical compound, is a yellow, cubic crystalline substance often used in glass. Its crystals present two types of electronic structure, depending on the pressure conditions to which the crystal is subjected. At room temperature, Ag2MoO4 exhibits a spinel-type cubic structure, known as β-Ag2MoO4, which is more stable in nature. However, when exposed to high hydrostatic pressure, the tetragonal α-Ag2MoO4 forms as a metastable phase.
Platinum nanoparticles are usually in the form of a suspension or colloid of nanoparticles of platinum in a fluid, usually water. A colloid is technically defined as a stable dispersion of particles in a fluid medium.
Photocatalytic water splitting is a process that uses photocatalysis for the dissociation of water (H2O) into hydrogen (H
2) and oxygen (O
2). The inputs are light energy (photons), water, and a catalyst(s). The process is inspired by Photosynthesis, which converts water and carbon dioxide into oxygen and carbohydrates. Water splitting using solar radiation has not been commercialized. Photocatalytic water splitting is done by dispersing photocatalyst particles in water or depositing them on a substrate, unlike Photoelectrochemical cell, which are assembled into a cell with a photoelectrode. Hydrogen fuel production using water and light (photocatalytic water splitting), instead of petroleum, is an important renewable energy strategy.
Silver nanoparticles are nanoparticles of silver of between 1 nm and 100 nm in size. While frequently described as being 'silver' some are composed of a large percentage of silver oxide due to their large ratio of surface to bulk silver atoms. Numerous shapes of nanoparticles can be constructed depending on the application at hand. Commonly used silver nanoparticles are spherical, but diamond, octagonal, and thin sheets are also common.
Calliandra haematocephala, the red powder puff, is a species of flowering plants of the genus Calliandra in the family Fabaceae.
An antimicrobial surface is coated by an antimicrobial agent that inhibits the ability of microorganisms to grow on the surface of a material. Such surfaces are becoming more widely investigated for possible use in various settings including clinics, industry, and even the home. The most common and most important use of antimicrobial coatings has been in the healthcare setting for sterilization of medical devices to prevent hospital-associated infections, which have accounted for almost 100,000 deaths in the United States. In addition to medical devices, linens and clothing can provide a suitable environment for many bacteria, fungi, and viruses to grow when in contact with the human body which allows for the transmission of infectious disease.
Graphitic carbon nitride (g-C3N4) is a family of carbon nitride compounds with a general formula near to C3N4 (albeit typically with non-zero amounts of hydrogen) and two major substructures based on heptazine and poly(triazine imide) units which, depending on reaction conditions, exhibit different degrees of condensation, properties and reactivities.
Photocatalyst activity indicator ink (paii) is a substance used to identify the presence of an underlying heterogeneous photocatalyst and to measure its activity. Such inks render visible the activity of photocatalytic coatings applied to various "self-cleaning" products. The inks contain a dyestuff that reacts to ultraviolet radiation in the presence of the photocatalytic agent in the coating. They are applied to the coated product and show a color change or disappearance when exposed to ultraviolet radiation. The use of a paii based on the dye resazurin forms the basis of an ISO standard test for photocatalytic activity.
In materials and electric battery research, cobalt oxide nanoparticles usually refers to particles of cobalt(II,III) oxide Co
3O
4 of nanometer size, with various shapes and crystal structures.
Photogeochemistry merges photochemistry and geochemistry into the study of light-induced chemical reactions that occur or may occur among natural components of Earth's surface. The first comprehensive review on the subject was published in 2017 by the chemist and soil scientist Timothy A Doane, but the term photogeochemistry appeared a few years earlier as a keyword in studies that described the role of light-induced mineral transformations in shaping the biogeochemistry of Earth; this indeed describes the core of photogeochemical study, although other facets may be admitted into the definition.
A copper nanoparticle is a copper based particle 1 to 100 nm in size. Like many other forms of nanoparticles, a copper nanoparticle can be prepared by natural processes or through chemical synthesis. These nanoparticles are of particular interest due to their historical application as coloring agents and the biomedical as well as the antimicrobial ones.
Zinc oxide nanoparticles are nanoparticles of zinc oxide (ZnO) that have diameters less than 100 nanometers. They have a large surface area relative to their size and high catalytic activity. The exact physical and chemical properties of zinc oxide nanoparticles depend on the different ways they are synthesized. Some possible ways to produce ZnO nano-particles are laser ablation, hydrothermal methods, electrochemical depositions, sol–gel method, chemical vapor deposition, thermal decomposition, combustion methods, ultrasound, microwave-assisted combustion method, two-step mechanochemical–thermal synthesis, anodization, co-precipitation, electrophoretic deposition, and precipitation processes using solution concentration, pH, and washing medium. ZnO is a wide-bandgap semiconductor with an energy gap of 3.37 eV at room temperature.
Chuanyi Wang is a Chinese American, environmental chemistry scientist, academic, and an author. He is a Distinguished Professor and Academic Dean at the School of Environmental Science and Engineering at the Shaanxi University of Science & Technology. He is recognized for his research in environmental photocatalysis, environmental materials, surface/interface chemistry, nanomaterials, and pollution controlling.
Solar reforming is the sunlight-driven conversion of diverse carbon waste resources into sustainable fuels and value-added chemicals. It encompasses a set of technologies operating under ambient and aqueous conditions, utilizing solar spectrum to generate maximum value. Solar reforming offers an attractive and unifying solution to address the contemporary challenges of climate change and environmental pollution by creating a sustainable circular network of waste upcycling, clean fuel generation and the consequent mitigation of greenhouse emissions.
