Experimental investigation of a catalyst under various solar light conditions for hydrogen production.
Date
2013-09-01
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The light absorption characteristics of the photocatalyst {[Ru(bpy)2(dpp)]2RhBr2}5+ and
the photochemical Ru(bpy)2(dpp)2+ is investigated. Extinction coefficient versus
wavelength is determined for both a low intensity broad spectrum LED light source and
one sun intensity simulated sunlight. Variation in the absorption characteristics from
both the previously published monochromatic values and from each other is observed.
absorption characteristics are dependent upon the type of light used and that specific
testing for the design wavelength range should be conducted so that the actual absorption
characteristics are then used to establish an optimum light absorbing configuration for
photocatalyst use. This technique is used to create a simulation model that is analyses the
distribution of hydrogen production rates in the existing test cell and demonstrates that
most of the hydrogen production occurs in a relatively small volume within the existing
test configuration. The absorption spectroscopy of the photocatalyst is found to change
after extended exposure to light. Two possibilities exist, transformation of the
photocatalyst to a different configuration and breakdown of the photocatalyst into
component parts. Degradation would explain observed changes in photocatalyst quantum
efficiency with time. A chemical model for water photocatalysis is proposed. In addition
to identifying several of the isomers that occur and explaining the changes in absorption
spectroscopy; it also addresses the impact of changing solution solvent on quantum
efficiency. It also addresses the apparent contradiction between photon supply rate and
molecular excited state lifetimes on photocatalytic ability.
Description
Keywords
Solar, Hydrogen, Photocatalyst, Absorption spectroscopy, Extinction coeffiecient