Engineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications

In photoreactors, non-uniform light distribution leads to regions either with an overabundance of light or insufficient light irradiation. The integration of light-guiding elements such as waveguides into photocatalytic reactors has been an emerging approach to improve light delivery. However, tradi...

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Autores principales:	Xiangkun Elvis Cao, Tao Hong, Spencer Hong, David Erickson
Formato:	article
Lenguaje:	EN
Publicado:	Elsevier 2021
Materias:	Gradient etching Uniform scattering Glass waveguide Optofluidics Photoreactor Chemical engineering TP155-156
Acceso en línea:	https://doaj.org/article/07e8272eb3854eff87b8cc939bc675a0
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id	oai:doaj.org-article:07e8272eb3854eff87b8cc939bc675a0
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spelling	oai:doaj.org-article:07e8272eb3854eff87b8cc939bc675a02021-11-18T04:53:31ZEngineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications2666-821110.1016/j.ceja.2021.100192https://doaj.org/article/07e8272eb3854eff87b8cc939bc675a02021-11-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S2666821121001071https://doaj.org/toc/2666-8211In photoreactors, non-uniform light distribution leads to regions either with an overabundance of light or insufficient light irradiation. The integration of light-guiding elements such as waveguides into photocatalytic reactors has been an emerging approach to improve light delivery. However, traditional waveguides with constant surface properties experience an exponential decay in scattering light intensity under side irradiation. This reduces the light propagation length and hinders the scale-up potential. In this work, we derive the relationship between attenuation coefficients with etching time, determine the correlation between etching time and waveguide location for uniform scattering, and experimentally validate different light scattering profiles by engineering the surface roughness distribution of waveguides. We apply a dimensionless number, the coefficient of variation, to characterize the relative light distribution uniformity for gradient-etched, uniform-etched, and unmodified waveguides. Scattering light uniformity via gradient etching is more than 13 times higher than that for uniform-etching. In addition, the light distribution for gradient etching exhibits improved uniformity than other approaches, such as tip coating, physical carving, and engineered pillars. We then evaluate the effect of different light scattering profiles on photocatalytic activities in a photodegradation test for methylene blue, with non-etched, uniform-etched, and gradient-etched waveguides serving as internal light-guiding elements. Gradient-etched waveguides show ∼4 times improvement in photodegradation activity over uniform-etched designs and ∼8 times over non-etched configurations. This result underscores gradient etching for waveguides as a viable approach for precision light delivery to increase the light distribution uniformity, thus enhancing reaction rates for photocatalytic reactors.Xiangkun Elvis CaoTao HongSpencer HongDavid EricksonElsevierarticleGradient etchingUniform scatteringGlass waveguideOptofluidicsPhotoreactorChemical engineeringTP155-156ENChemical Engineering Journal Advances, Vol 8, Iss , Pp 100192- (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Gradient etching Uniform scattering Glass waveguide Optofluidics Photoreactor Chemical engineering TP155-156
spellingShingle	Gradient etching Uniform scattering Glass waveguide Optofluidics Photoreactor Chemical engineering TP155-156 Xiangkun Elvis Cao Tao Hong Spencer Hong David Erickson Engineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications
description	In photoreactors, non-uniform light distribution leads to regions either with an overabundance of light or insufficient light irradiation. The integration of light-guiding elements such as waveguides into photocatalytic reactors has been an emerging approach to improve light delivery. However, traditional waveguides with constant surface properties experience an exponential decay in scattering light intensity under side irradiation. This reduces the light propagation length and hinders the scale-up potential. In this work, we derive the relationship between attenuation coefficients with etching time, determine the correlation between etching time and waveguide location for uniform scattering, and experimentally validate different light scattering profiles by engineering the surface roughness distribution of waveguides. We apply a dimensionless number, the coefficient of variation, to characterize the relative light distribution uniformity for gradient-etched, uniform-etched, and unmodified waveguides. Scattering light uniformity via gradient etching is more than 13 times higher than that for uniform-etching. In addition, the light distribution for gradient etching exhibits improved uniformity than other approaches, such as tip coating, physical carving, and engineered pillars. We then evaluate the effect of different light scattering profiles on photocatalytic activities in a photodegradation test for methylene blue, with non-etched, uniform-etched, and gradient-etched waveguides serving as internal light-guiding elements. Gradient-etched waveguides show ∼4 times improvement in photodegradation activity over uniform-etched designs and ∼8 times over non-etched configurations. This result underscores gradient etching for waveguides as a viable approach for precision light delivery to increase the light distribution uniformity, thus enhancing reaction rates for photocatalytic reactors.
format	article
author	Xiangkun Elvis Cao Tao Hong Spencer Hong David Erickson
author_facet	Xiangkun Elvis Cao Tao Hong Spencer Hong David Erickson
author_sort	Xiangkun Elvis Cao
title	Engineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications
title_short	Engineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications
title_full	Engineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications
title_fullStr	Engineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications
title_full_unstemmed	Engineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications
title_sort	engineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications
publisher	Elsevier
publishDate	2021
url	https://doaj.org/article/07e8272eb3854eff87b8cc939bc675a0
work_keys_str_mv	AT xiangkunelviscao engineeringwaveguidesurfacebygradientetchingforuniformlightscatteringinphotocatalyticapplications AT taohong engineeringwaveguidesurfacebygradientetchingforuniformlightscatteringinphotocatalyticapplications AT spencerhong engineeringwaveguidesurfacebygradientetchingforuniformlightscatteringinphotocatalyticapplications AT daviderickson engineeringwaveguidesurfacebygradientetchingforuniformlightscatteringinphotocatalyticapplications
_version_	1718424892764848128

Engineering waveguide surface by gradient etching for uniform light scattering in photocatalytic applications

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