Abstract
Achieving CO
2
reduction with H
2
O on metal photocatalysts and understanding the corresponding mechanisms at the molecular level are challenging. Herein, we report that quantum-sized Au ...nanoparticles can photocatalytically reduce CO
2
to CO with the help of H
2
O by electron-hole pairs mainly originating from interband transitions. Notably, the Au photocatalyst shows a CO production rate of 4.73 mmol g
−1
h
−1
(~100% selectivity), ~2.5 times the rate during CO
2
reduction with H
2
under the same experimental conditions, under low-intensity irradiation at 420 nm. Theoretical and experimental studies reveal that the increased activity is induced by surface Au–O species formed from H
2
O decomposition, which synchronously optimizes the rate-determining steps in the CO
2
reduction and H
2
O oxidation reactions, lowers the energy barriers for the *CO desorption and *OOH formation, and facilitates CO and O
2
production. Our findings provide an in-depth mechanistic understanding for designing active metal photocatalysts for efficient CO
2
reduction with H
2
O.
Controlling the compositions and morphologies of the electrocatalysts were conventionally used for improving the catalytic activities. Here, visible-light-enhanced electrocatalytic water reduction ...reactions on semimetal bismuth (Bi) nanorods were achieved. The Bi catalyst not only exhibited an ideal Faradaic efficiency of 98% for electrocatalytic hydrogen production, but also acted as a light absorber for improving the activity even under light irradiation up to 740 nm. As a result, the solar-to‑hydrogen conversion efficiency under simulated AM 1.5G illumination was reached to 0.82%, which is 2.7 times higher than that induced by plasmon Au nanoparticles. This conversion efficiency is attributed to the excellent solar light absorption property of Bi and the enhanced electron-transfer at the interface of Bi/electrolyte under irradiation. The low-cost Bi catalyst with the dual function could open a venue toward designing more-energy-efficient electrocatalysts for hydrogen production assisted by sunlight.
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•The bismuth nanorods exhibited an ideal Faradaic efficiency of 98% for electrocatalytic H2 production.•The electrocatalytic H2 production can be significantly enhanced under light irradiation up to 740 nm.•The solar-to‑hydrogen conversion efficiency under simulated AM 1.5G illumination reached to 0.82%.
In order to improve the hydro- and oleo-phobic properties of anti-fingerprint coating, novel oligosiloxane intermediate bearing perfluorodecyl/octyl and triethoxy silylethylene groups were ...synthesized; then, a series of nano-hybrid perfluoroalkyl oligosiloxane resins (FSi@SiO2) were synthesized using the hydrolysis and condensation of FVPS with tetraethylorthosilicate. The chemical structure, morphology, and performance of FSi@SiO2 were investigated. The results indicate that the FSi@SiO2 is a nano hybrid fluorinated polysiloxane resin with mean particle sizes of 200–400 nm. And under nanoparticles and perfluoroalkyl groups bonded in the resin, FSi@SiO2 not only showed a micro rough morphology in atomic force microscopy observation but also could provide the treated substrates with excellent hydro- and oleo-phobicity. As a result, the water and oil contact angles reached 120.3° and 87.5° on the treated glass, respectively; meanwhile, fingerprints were easily cleaned without any stains.
Utilizing recycled crushed clay brick (RCB) from C&D waste in road engineering construction as the substitute for natural aggregates has attracted a lot of attention, which would be a promising step ...forward towards sustainable development and green construction. The objective of this study is to assess the feasibility of cement-stabilized macadam (CSM), incorporating various RCB fine aggregate substitution ratios. For this purpose, the physical and chemical properties of RCB fine aggregate was tested, and RCB exhibited a porous surface micro-morphology, high water absorption and pozzolanic activity. Subsequently, a comprehensive experimental investigation of modified CSM with RCB has been carried out based on laboratory tests concerning the mechanical and shrinkage properties. Results showed that higher RCB fine aggregate substitution ratio resulted in lower unconfined compressive strength, and the negative influence of RCB on unconfined compressive strength would decrease gradually, varying curing time; however, the higher the RCB substitution ratio was, the larger the indirect tensile strength at 90 d curing time of the late curing period was. CSM containing RCB had an overall increasing accumulative water loss rate, accumulative strain of dry shrinkage and average coefficient of dry shrinkage, except that 20% RCB resulted in an excellent dry shrinkage property. Moreover, RCB with pozzolanic activity reacted very slowly mainly at later ages, enhancing the interfacial transition zone.
Terahertz technology is of great significance for the development of science. The research on THz optical devices will enable us to further understand THz technology. In this paper, a High refractive ...index sensitivity adjustable six band absorber based on dual regulation of embedded Dirac semi metal and active graphene is proposed, which can be divided into three layers, the top layer of bulk Dirac semi metal (DBS) layer, the middle layer of graphene and the bottom layer of gold substrate. The absorber has six absorption modes, which mode I-V is located in the THz band and mode VI is located at the edge of the THz band and in the infrared band. The absorptivity of four absorption modes of the absorber is higher than 0.99, and the relative impedance of the absorber in the working area is indirectly close to the impedance value in free space, which is consistent with the classical theory. After analysis, the absorption of electromagnetic wave by the absorber mainly came from the local surface plasmon resonance caused by the light wave excitation of the plasma on the material surface and the resonance coupling between the BDS layer and the graphene layer. By tuning the physical parameters, the Fermi energy of BDS layer and graphene layer, the absorber shows strong tunability. In the sensor performance test, the absorber has high refractive index sensitivity in most modes. The superior properties of the absorber make it have high application potential in communication, biomedicine and other fields.
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•The absorber has six absorption modes.•The working band of the absorber is 0.5-10.5THz.•The absorber can realize the tuning of absorption characteristics by changing the Fermi energy of graphene and Dirac semi-metal.•The absorber has high refractive index sensitivity and good sensing performance.
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