NOVELTY - A photoactive material (602) comprises substrate including primary set of parallel wires, piezoelectric actuator (a) coupled to primary set of wires at end of primary set, piezoelectric actuator (b) coupled to primary set at other end of primary set of wires, secondary set of parallel wires, piezoelectric actuator (c) coupled to secondary set of wires at end of secondary set, piezoelectric actuator (d) coupled to secondary set of wires at other end of secondary set of wires, and plasmonic nanoparticles and photocatalytic capped colloidal nanocrystals deposited on substrate.    USE - Photoactive material is used in carbon dioxide reduction system and water splitting system (all claimed).    ADVANTAGE - The photoactive material has high-surface-area grid, and excellent light harvesting efficiency and energy conversion efficiency, and is efficient.    DETAILED DESCRIPTION - A photoactive material comprises substrate. The substrate contains primary set of parallel wires extending in a primary direction, piezoelectric actuator (a) coupled to the primary set of wires at end of the primary set of wires, piezoelectric actuator (b) coupled to the primary set of wires at another end of the primary set of wires, secondary set of parallel wires extending in a secondary direction is perpendicular to the primary direction, piezoelectric actuator (c) coupled to the secondary set of wires at a end of secondary set of wires, piezoelectric actuator (d) coupled to the secondary set of wires at another end of the secondary set of wires, and plasmonic nanoparticles and photocatalytic capped colloidal nanocrystals deposited on the substrate. The plasmonic nanoparticles create electric field between two adjacent plasmonic nanoparticles when absorbing light. Each photocatalytic capped colloidal nanocrystal is deposited between at least two plasmonic nanoparticles. INDEPENDENT CLAIMS are included for the following:    (1) carbon dioxide reduction system, which contains reaction vessel (704) housing the photoactive material and configured to receive carbon dioxide from a primary inlet, receive hydrogen from secondary inlet, and facilitate carbon dioxide reduction reaction and hydrogen oxidization reaction which produces methane and water vapor, and collector comprising methane-permeable membrane and water-vapor-permeable membrane, and configured to receive the produced methane and water vapor from the reaction vessel through an outlet line and separate and collect methane and water vapor using the methane-permeable membrane and the water-vapor-permeable membrane. The reaction occurs when the plasmonic nanoparticles absorb irradiated light which causes electrons in the valence band of the plasmonic nanoparticles to migrate into the conduction band of the photocatalytic capped colloidal nanocrystals. The photocatalytic capped colloidal nanocrystals include semiconductor nanocrystals (A) capped with inorganic capping agent (A-1); and    (2) water splitting system, which contains reaction vessel housing photoactive material and configured to receive water through a nozzle and facilitate a water splitting reaction when water reacts with the photocatalytic capped colloidal nanocrystals and plasmonic nanoparticles. The reaction occurs when the plasmonic nanoparticles absorb irradiated light which causes electrons in the valence band of plasmonic nanoparticles to migrate into the conduction band of the photocatalytic capped colloidal nanocrystals, and the electrons in the conduction band of the photocatalytic capped colloidal nanocrystals are used to reduce water into hydrogen gas and oxygen gas, collector connected to the reaction vessel and comprising hydrogen-permeable membrane configured to separate the hydrogen from the oxygen in the collector, in which the hydrogen passes through the hydrogen-permeable membrane into a hydrogen storage, and oxygen-permeable membrane configured to separate oxygen from hydrogen in the collector, in which oxygen passes through the oxygen-permeable membrane into an oxygen storage, and fuel cell configured to mix the hydrogen gas received from the hydrogen storage and oxygen gas received from the oxygen storage to produce water and electricity.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the photoactive material.    Photoactive material (602)    Water (702)    Reaction vessel (704)    Light intensifier (904)    Carbon dioxide (1404)