The unmet spectral mimicry of foliar green in camouflage materials is hampered by the lack of colorants with similar spectral properties to chlorophyll, resulting in substantial risks of exposure from hyperspectral target detection. By drawing inspiration from leaf chromogenesis, a microcapsule colorant with a chloroplast-like structure and chlorophyll-like absorption is developed, and a generic bilayer coating is designed to provide high spectral similarity to leaves with different growth stages, seasons, and species. Specifically, the microcapsule colorant preserves the monomeric absorption of the internal phthalocyanine and features the manufacturability of conventional pigments, such as amenability to painting and patterning, and compatibility to different substrates. The pigmented artificial leaves successfully deceive the hyperspectral classification algorithm in a foliar background, and outperforming the state-of-art spectral simulation materials. This coloration strategy expands the knowledge base of the spectral fine tuning of composite colorants, which are essential for their application in spectral-resolved optical materials.
To enable open environment application of artificial photosynthesis, the direct utilization of environmental CO 2 via an oxygen-tolerant reductive procedure is necessary. Herein, we introduce an in situ growth strategy for fabricating two-dimensional heterojunctions between indium porphyrin metal-organic framework (In-MOF) and single-layer graphene oxide (GO). Upon illumination, the In-MOF/GO heterostructure facilitates a tandem CO 2 capture and photocatalytic reduction on its hydroxylated In-node, prioritizing the reduction of dilute CO 2 even in the presence of air-level O 2 . The In-MOF/GO heterostructure photocatalyst is integrated with a porous polytetrafluoroethylene (PTFE) membrane to construct a floatable artificial leaf. Through a triphase photocatalytic reaction, the floatable artificial leaf can remove aqueous contaminants from real water while efficiently reducing CO 2 at low concentrations (10%, approximately the CO 2 concentration in combustion flue gases) upon air-level O 2 . This study provides a scalable approach for the construction of photocatalytic devices for CO 2 conversion in open environments.
Hydrogen and oxygen production based on photocatalytic monolithic water splitting is considered to be one of the effective ways to produce sustainable and clean energy. The key challenge in this process is to develop new photocatalysts that can simultaneously produce H 2 and O 2 at a stoichiometric ratio of 2:1 without the use of any sacrificial agents. In order to solve this problem, highly efficient and ingenious photosystems in nature have been studied intensively. Herein, we prepared printable Z-type composite photocatalysts CdS@TiO 2 /Pt/ITO/WO 3 /Co 3 O 4 mimicking biological vegetative leaves in nature and constructed an “artificial leaf” device that completely decomposes water. We use an electron solid penetrating transporter ITO, which can rapidly transfer photogenerated electrons and photogenerated holes and reduce the compound rate of photogenerated carriers. Thus, the efficiency of photocatalytic total water dissolution is enhanced. This photocatalyst was able to produce both H 2 and O 2 in water with an H 2 production rate of 75.93 μmol g −1 h −1 and an O 2 production rate of 36.49 μmol g −1 h −1 . We designed the oxygen-producing photocatalyst WO 3 /Co 3 O 4 , which produced oxygen at a rate of 159.21 μmol g −1 h −1 6 times higher than that of WO 3 alone. Furthermore, the morphology, composition, and microstructures of the photocatalyst were characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and nitrogen adsorption–desorption.