UV LED Sources for Heterogeneous Photocatalysis

Abstract

This review article presents an overview of the application of ultraviolet light-emitting diode (UV LED) sources in heterogeneous photocatalysis within the context of artificial UV sources. The feasibility of UV LEDs as a source of UV irradiation in heterogeneous photocatalysis was first demonstrated almost a decade ago; however, for the most part, photocatalytic experimental set-ups utilise artificial light sources in the form of conventional UV lamps to initiate the desired photocatalytic transformations. A look at all sources of UV irradiation used in heterogeneous photocatalysis is taken with a focus on the growing importance of solid-state lighting devices such as UV LEDs. UV LEDs have higher external quantum efficiency and a lifetime of over 100,000 h; they are small in size and produce directional UV light which can be of the desired wavelength. In recent times, these UV LED sources have become widely applied in heterogeneous photocatalysis studies in the research literature and are fast becoming a viable alternative to conventional UV lamps.

Photocatalytic degradation of saccharin under UV‐LED and blacklight irradiation

“…The energy efficiency, extended lifetime and less toxic nature (i.e. mercury and lead‐free) of LEDs can lower the cost and improve process sustainability while their small footprint, directional light output and narrow band emission spectra allow for flexible design and development of compact water treatment units …”

“…The energy efficiency, extended lifetime and less toxic nature (i.e. mercury and lead-free) of LEDs can lower the cost and improve process sustainability 17,18 while their small footprint, directional light output and narrow band emission spectra allow for flexible design and development of compact water treatment units. 19 UV-LEDs were first employed by Chen et al for the photocatalytic treatment of perchloroethylene 20 and since then LED-photocatalysis has been proved feasible for the treatment of a wide range of contaminants.…”

Controlled periodic illumination in semiconductor photocatalysis

“…The claim that no advantage accrued from the use of CPI over continuous illumination was further investigated by Chen et al [56] who first studied CPI using UV LED sources [57] which were more suitable for the series of light and dark times required by CPI ( fig. 4).…”

Hierarchical TiO2 nanonetwork–porous Ti 3D hybrid photocatalysts for continuous-flow photoelectrodegradation of organic pollutants

“…However, these materials and devices usually suffer from certain shortcomings, such as their difficulty to scale up for large-scale production, a relatively low membrane strength, inability to resist erosion, and so on. Recently, environmentally friendly lost cost LEDs have been developed, and LEDs have been shown to be a suitable alternative to traditional UV irradiation as an energy-efficient light source for continuous flow photocatalysis [24][25][26][27][28][29][30]. They can be realized in continuous flow photocatalysis, but they are hard affix, have less effective photocatalysts content, and result in a lower photocatalytic efficiency [3,13,[15][16][17][18][19][20][21].…”