Photo-catalytic Systems for Production of Hydrogen

摘要

A system for splitting water and producing hydrogen for later use as an energy source may include the use of a photoactive material including PCCN and plasmonic nanoparticles. A method for producing the PCCN may include a semiconductor nanocrystal synthesis and an exchange of organic capping agents with inorganic capping agents. The PCCN may be deposited between the plasmonic nanoparticles and may act as photocatalysts for redox reactions. The photoactive material may be used in presence of water and sunlight to split water into hydrogen and oxygen. Production of charge carriers may be triggered by photo-excitation and enhanced by the rapid electron resonance from localized surface plasmon resonance of plasmonic nanoparticles. By combining different semiconductor materials for PCCN and plasmonic nanoparticles and by changing their shapes and sizes, band gaps may be tuned to expand the range of wavelengths of sunlight usable by the photoactive material. The system may include elements for collecting, transferring, and storing hydrogen and oxygen, for subsequent transformation into electrical energy.

主权项

1. A method for water splitting 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 nanocrystal that causes electrons of the plasmonic nanoparticles to migrate from the valance band of the photocatalytic capped colloidal nanocrystallinto 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 photocatalytic capped colloidal nanocrystal; passing water through the reaction vessel so that the water reacts with the photocatalytic capped colloidal nanocrystals and forms hydrogen gas and oxygen gas, wherein the charge carriers in the conduction band reduce hydrogen molecules from the water and holes in the valence band of the photocatalytic capped colloidal nanocrystal oxidize oxygen molecules from the water; and collecting the hydrogen gas and the oxygen gas in a reservoir that includes a hydrogen permeable membrane and an oxygen permeable membrane.