Photocatalytic CO2 Reduction System

摘要

A system employing sunlight energy for reducing CO2 into methane and water is disclosed. The system may include the use of a photoactive material including plasmonic nanoparticles and photocatalytic capped colloidal nanocrystals (PCCN). A method for producing the PCCN may include a semiconductor nanocrystal synthesis and an exchange of organic capping agents with inorganic capping agents. Additionally, the PCCN may be deposited between the plasmonic nanoparticles, and may act as photocatalysts for redox reactions. The CO2 reduction system may use inorganic capping agents that cap the surface of semiconductor nanocrystals to form PCCN, which may be deposited on a substrate and treated to form a photoactive material. The photoactive material may be employed in the system to harvest sunlight and produce energy necessary for carbon dioxide reduction. The system may also include elements necessary to collect and transfer methane, for subsequent transformation into electrical energy.

主权项

1. A method for reducing carbon dioxide comprising:
forming photocatalytic capped colloidal nanocrystals, wherein each photocatalytic capped colloidal nanocrystal includes a first semiconductor nanocrystal capped with a first inorganic capping agent; forming plasmonic nanoparticles, wherein the plasmonic nanoparticles include noble metal nanoparticles; depositing the formed plasmonic nanoparticles onto a substrate; depositing the formed photocatalytic capped colloidal nanocrystals on the substrate between the plasmonic nanoparticles, wherein each photocatalytic capped colloidal nanocrystal is deposited between at least two plasmonic nanoparticles; thermally treating the substrate, the photocatalytic capped colloidal nanocrystals, and the plasmonic nanoparticles; absorbing light with a frequency equal to or greater than a frequency of electrons oscillating against the restoring force of positive nuclei within the plasmonic nanoparticles to cause localized surface plasmon resonance, whereby the localized surface plasmon resonance creates an electric field between two adjacent plasmonic nanoparticles; absorbing irradiated light with an energy equal to or greater than the band gap of the photocatalytic capped colloidal nanocrystals that causes electrons of the photocatalytic capped colloidal nanocrystals to migrate from the valance band of the photocatalytic capped colloidal nanocrystals into the conduction band of the photocatalytic capped colloidal nanocrystals for use in a reduction reaction, wherein the electric field prevents the electrons from recombining into the valence band of the plasmonic nanoparticles; reacting carbon dioxide and hydrogen with the photocatalytic capped colloidal nanocrystals so that the charge carriers in the conduction band reduce carbon dioxide into methane and holes in the valence band of the photocatalytic capped colloidal nanocrystals oxidize the hydrogen into water vapor; and collecting the methane and water using a methane permeable membrane and a water vapor-permeable membrane.