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How does a PCO photocatalytic air purifier work? In a nutshell, ultraviolet light shines onto a catalyst, which converts water in the air into a form that turns molecules of pollution into more harmless substances.
Photocatalytic oxidation is a process that differs qualitatively and quantitatively from traditional photocatalytic oxidation with oxygen or ozonation without a photocatalyst, involving the use of ozone for oxidation in the presence of a catalyst.
In chemistry, photocatalysis is the acceleration of a photoreaction in the presence of a photo catalyst, the excited state of which "repeatedly interacts with the reaction partners forming reaction intermediates and regenerates itself after each cycle of such interactions." [1] .
Photons are absorbed by the pigments in these photosystems, where the energy is used to excite electrons. Collectively, these two photosystems harvest enough energy to power the reactions of H 2 O oxidation (on the site of PSII) and the synthesis of NADPH (on PSI).
The semiconducting metal oxide’s photocatalytic activity is based on two broad features : (i) the oxidation of OH − anions to produce hydroxyl radicals, and (ii) the reduction of O 2 to produce superoxide radicals. These radical reactive species can disinfect or mineralize organic contaminants into harmless byproducts.
Catalysts are materials used to increase reaction rates by introducing new reaction pathways with lower activation energies.
Photocatalysis as one of the advanced oxidation processes (AOPs) has progressed rapidly since the discovery of photoelectrochemical water splitting reaction using semiconductor by Fujishima and Honda in 1972. It has been known as an environmental friendly, sustainable, and energy-saving technology.
Photocatalytic oxidation is one of the most recent and promising technologies, and it has been the subject of numerous studies over the past two decades. Hence, the photocatalyst is the most reassuring aspirant due to its adequate bandgap and exquisite stability.
Photocatalysis is a unique process for rectifying energy and environmental issues. This chapter aims at semiconductor-based photocatalysis, that is, processes occurring on semiconductor–fluid interfaces while illuminated with the light of suitable energies.
The main purpose of our photocatalytic flat-plate reactor is to generate intrinsic oxidation rates for selected gaseous species of importance to indoor air quality. Design features include uniform irradiation of the photocatalyst surface, radiation of appropriate range of wavelength, and elimination of mass-transport influence (on the reactants ...