CO2 photoreduction at enzyme-modified metal oxide nanoparticles

A model system for photoreduction of CO2 to CO using visible light has been extensively studied, using a catalyst for which the CO 2/CO reaction is electrochemically reversible. The hybrid system comprises metal oxide nanoparticles functionalised with the enzyme carbon monoxide dehydrogenase (CODH), and sensitised to visible light using a ruthenium bipyridyl photosensitiser. An anatase/rutile TiO2 mixture (Evonik Degussa P25) was selected as the most suitable semiconductor, and CO production rates and stability were examined as a function of each component (photosensitiser, enzyme and TiO2). Tolerance to O2 and effects of different electron donors were also investigated, together with strategies to control enzyme binding at the surface of TiO2 in order to enhance overall activity. © 2011 The Royal Society of Chemistry

Efficient and clean photoreduction of CO(2) to CO by enzyme-modified TiO(2) nanoparticles using visible light.

A hybrid enzyme-nanoparticle system is described for achieving clean reduction of CO(2) to CO using visible light as the energy source. An aqueous dispersion of TiO(2) nanoparticles modified by attachment of carbon monoxide dehydrogenase (CODH) and a Ru photosensitizer produces CO at a rate of 250 mumol of CO (g of TiO(2))(-1) h(-1) when illuminated with visible light at pH 6 and 20 degrees C

Visible light-driven CO2 reduction by enzyme coupled CdS nanocrystals.

Assemblies of carbon monoxide dehydrogenase molecules with CdS nanocrystals show fast CO(2) reduction driven by visible light. Activity is strongly influenced by size and shape of nanocrystals, and by the nature of the electron donor

How Light-Harvesting Semiconductors Can Alter the Bias of Reversible Electrocatalysts in Favor of H 2 Production and CO 2 Reduction

International audienceThe 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