System for Harvesting Oriented Light for Water Splitting and Carbon Dioxide Reduction

摘要

A photosynthetic system for splitting water to produce hydrogen and using the produced hydrogen for the reduction of carbon dioxide into methane is disclosed. The disclosed photosynthetic system employs photoactive materials that include oriented photocatalytic capped colloidal nanocrystals (PCCN) within their composition, in order to harvest sunlight and obtain the energy necessary for water splitting and subsequent carbon dioxide reduction processes. The photosynthetic system may also include elements necessary to transfer water produced in the carbon dioxide reduction process, for subsequent use in water splitting process. The systems may also include elements necessary to store oxygen and collect and transfer methane for subsequent transformation of methane into energy.

主权项

1. A method for water splitting and carbon dioxide reduction comprising:
forming photocatalytic capped colloidal nanocrystals, wherein each photocatalytic capped colloidal nanocrystal includes a first semiconductor nanocrystal capped with a first inorganic capping agent; depositing the formed photocatalytic capped colloidal nanocrystals onto a first substrate and a second substrate, thereby creating first and second photoactive materials; orienting the photocatalytic capped colloidal nanocrystals of the first photoactive material; orienting the photocatalytic capped colloidal nanocrystals of the second photoactive material; absorbing irradiated light with an energy equal to or greater than the band gap of the semiconductor nanocrystals by the first photoactive material to create charge carriers in a conduction band and holes in a valence band of the photocatalytic capped colloidal nanocrystals of the first photoactive material; passing water through a first reaction vessel so that the water reacts with the first photoactive material to form hydrogen and oxygen, wherein the charge carriers in the conduction band reduce hydrogen molecules from the water and the holes in the valence band oxidize oxygen molecules from the water; separating the hydrogen from the oxygen using a hydrogen permeable membrane and an oxygen permeable membrane; passing the separated hydrogen from the first reaction vessel into a second reaction vessel; passing carbon dioxide into the second reaction vessel; absorbing irradiated light with an energy equal to or greater than the band gap of the semiconductor nanocrystals by the second photoactive material to create charge carriers in a conduction band and holes in a valence band of the photocatalytic capped colloidal nanocrystals of the second photoactive material; reacting the carbon dioxide and the hydrogen with the second photoactive material in the second reaction vessel so that the charge carriers in the conduction band reduce carbon dioxide into methane and the holes in the valence band oxidize the hydrogen into water vapor; and collecting the methane using a methane permeable membrane.