CEN/TC 386 - Photocatalysis

The glossary lists a consistent set of definitions to be used in standards on photocatalysis for their consistency and connection with the scientific literature.

This document specifies a method for assessing the performance of photocatalytic inorganic materials contained in cement mortars and/or limes or ceramic-based matrices, paints or materials deposited as thin films or coatings on a variety of substrates for the photocatalytic abatement of nitric oxide in the gas phase. This method does not apply to the assessment of samples to be applied with flow perpendicular to the surface or flow permeating the surface itself as polymeric and paper filters, honeycomb structures and suchlike.
The performance for the photocatalytic sample under test is evaluated by measuring the degradation rate of nitric oxide (NO) using the method specified herein. The photocatalytic abatement rate is calculated from the observed rate by eliminating the effects of mass transfer. The intrinsic photocatalytic abatement rate is an intrinsic property of the material tested and makes it possible to distinguish the photocatalytic activities of various products with an absolute scale defined with physical and engineering meaning.
For the measurements and calculations described in this document the concentration of nitrogen oxides (NOx) is defined as the stoichiometric sum of nitric oxide (NO) and nitrogen dioxide (NO2).

This document describes a test method to evaluate the performance of photocatalytic materials in water purification by measuring phenol degradation. This test method is applicable to photocatalytic materials in form of powders (suspensions in water, slurries) under UV irradiation. The photocatalytic performance of the tested material is assessed by the observed rate of phenol degradation at specified experimental conditions as determined by HPLC.

This European Standard describes the methodologies to be used in a laboratory air tight chamber to test prototype or commercial air cleaner systems with a maximum flow rate of 1,000 m3/h used for photocatalytic indoor air remediation.
It is applicable to the treatment of atmospheres that are representative of the air inside buildings and workplaces.
This protocol is applicable solely to photocatalytic systems alone or to combined systems that include a photocatalytic function. The photocatalytic function is demonstrated by verifying the mineralization of model VOCs to form CO2.

This European Standard specifies a test method for the evaluation of the photocatalytic self-cleaning performance of materials showing photocatalytic activity, usually based on semiconducting metal oxides such as titanium dioxide, by the measurement under solid/solid conditions of the decolouring ability under irradiation with ultraviolet light (UV-A) of a test sample on which a dye solution is sprayed and dried.
This European Standard is intended for use with opaque and rough surfaces of different kinds, such as construction materials in flat sheet, board or plate shape, that are the basic forms of materials for various applications.
This European Standard also applies to fabric, plastic or composites containing photocatalytic materials that are not soluble in acetone. This European Standard does not apply to photocatalytic glass, granular materials (unless they are deposited in compact films or layers over flat solid surface) and flat non porous materials.
The method evaluates only the self-cleaning ability of the material under ultraviolet light irradiation. It cannot be applicable to evaluate other performance attributes of photocatalytic materials, i.e. decomposition of water contaminants in liquid or gas phases contacting the material, and antifogging and antibacterial actions.

This Technical Specification prescribes the conditions for irradiating photocatalytic surfaces in order to perform photocatalytic efficiency tests. In addition, the measurement and documentation of these irradiation conditions with respect to the spectral distribution, irradiance and homogeneity are given.

A common language for standards, disclosed to a wide audience and referring only to the operational protocols and to their outcomes, is needed both for a consistent set of standards and the connection with the scientific literature. This glossary will take into account existing glossary of terms used in photocatalysis and photochemistry. Because in photocatalysis numerous properties are difficult to be evaluated, it is strongly recommended in standard norms to avoid reporting properties depending on number of actives sites, the mechanisms of adsorption or kinetic mechanisms of photocatalytic reactions. For the same reason instead of the quantum yield and related quantities it is easier to report the photonic efficiency.
Most of the definitions reported in this Technical Specification are a sub-set of the IUPAC definitions in photocatalysis and radiocatalysis [1]. Some other definitions, in particular for the photocatalytic rate and reactors are taken from a dedicated work [2]. The use and many technical specifications on the physical values suggested for irradiation conditions in the standards are reported in a separate Technical Specification [3].
The arrangement of entries is alphabetical, and the criterion adopted by the IUPAC has been followed for the typeface used: italicized words in a definition or following it indicate a cross-reference in the Glossary.

This standard describes a method for assessing the performance of photocatalytic inorganic materials contained in cement mortars and/or limes or ceramic-based matrices, paints or materials deposited as thin films or coatings on a variety of substrates for the photocatalytic abatement of nitric oxide in the gas phase. This method is not suitable for the assessment of samples to be applied with flow perpendicular to the surface or flow permeating the surface itself as polymeric and paper filters, honeycomb structures and suchlike.
The performance for the photocatalytic sample under test is evaluated by measuring the degradation rate of nitric oxide (NO) using the method described herein. The photocatalytic abatement rate is calculated from the observed rate by eliminating the effects of mass transfer. The intrinsic photocatalytic abatement rate is an intrinsic property of the material tested and makes it possible to distinguish the photocatalytic activities of various products with an absolute scale defined with physical and engineering meaning.
For the measurements and calculations described in this standard the concentration of nitrogen oxides (NOx) is defined as the stoichiometric sum of nitric oxide (NO) and nitrogen dioxide (NO2).
Safety statement
Persons using this document should be familiar with the normal laboratory practice, if applicable. This document cannot address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any regulatory conditions.
Environmental statement
It is understood that some of the material permitted in this standard may have negative environmental impact. As technological advantages lead to better alternatives for these materials, they will be eliminated from this standard to the extent possible.
At the end of the test, the user of the standard will take care to carry out an appropriate disposal of the wastes, according to local regulation.