How light-harvesting semiconductors can alter the bias of reversible electrocatalysts in favor of H2 production and CO2 reduction.
J Am Chem Soc
; 135(40): 15026-32, 2013 Oct 09.
Article
em En
| MEDLINE
| ID: mdl-24070184
ABSTRACT
The most efficient catalysts for solar fuel production should operate close to reversible potentials, yet possess a bias for the fuel-forming direction. Protein film electrochemical studies of Ni-containing carbon monoxide dehydrogenase and [NiFeSe]-hydrogenase, each a reversible electrocatalyst, show that the electronic state of the electrode strongly biases the direction of electrocatalysis of CO2/CO and H(+)/H2 interconversions. Attached to graphite electrodes, these enzymes show high activities for both oxidation and reduction, but there is a marked shift in bias, in favor of CO2 or H(+) reduction, when the respective enzymes are attached instead to n-type semiconductor electrodes constructed from CdS and TiO2 nanoparticles. This catalytic rectification effect can arise for a reversible electrocatalyst attached to a semiconductor electrode if the electrode transforms between semiconductor- and metallic-like behavior across the same narrow potential range (<0.25 V) that the electrocatalytic current switches between oxidation and reduction.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Semicondutores
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Dióxido de Carbono
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Biomimética
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Hidrogênio
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Luz
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article