Fan Wu,Chuan Pu,Minxian Zhang,Bin Liu,Jingling Yang
Solar photocatalysis is a clean and sustainable approach for removing atmospheric NO, but suffers from unsatisfactory removal efficiency. Efficient charge separation and surface reaction are critical factors ensuring the efficiency of solar energy conversion by photocatalysts. To achieve efficient charge steering and an enhanced surface reaction, we synthesized a bicomponent photocatalyst consisting of multivalent Ag species embedded in defect-rich twin-brush ZnO (Ag/TB-ZnO) with strong metal-support interaction (SMSI). The optimum Ag/TB-ZnO with silver loading of 2.0 wt.% achieved NO oxidation efficiency of 71.0% under a GHSV of 1,200,000 mL h −1 g −1 , and NO 3 − selectivity of 94.8%. Outstanding stability of up to 4 h was demonstrated. This superior performance was attributed to the enhanced efficacy of charge separation and surface reaction by the SMSI effect, surface plasmon resonance effect of metallic Ag and the efficient activation of oxygen species through vacancy-rich TB-ZnO.
Using ammonium chloride (NH 4 Cl) as a gas template, we conveniently fabricated ultrathin two-dimensional layered silver-embedded graphitic carbon nitride nanosheets (AgCNS) by melamine blowing method with triazine groups of pristine graphite carbon nitride. Compared with bulk g-C 3 N 4 (BCN) and g-C 3 N 4 nanosheets (CNS), the antibacterial activity of the optimized AgCNS-5 at a minimum inhibitory concentration (MIC) of 40 ppm against Escherichia coli ( E. coli ) was significantly enhanced. Under visible-light irradiation, E. coli could be completely killed by 100 µg·mL −1 of AgCNS-5 within 30 min. The mechanism of enhanced antibacterial activity was systematically investigated by ultraviolet-visible diffuse reflectance spectra (UV-vis DRS), photoluminescence spectra (PL), electrochemical impedance spectroscopy (EIS), and photogenerated current densities. Surface plasmonic resonance (SPR) of Ag nanoparticles (NPs) with g-C 3 N 4 was found to lead to an enhancement of visible light absorption and an acceleration of photo-induced electron-hole migration/separation, which is responsible for the enhanced photocatalytic bactericidal performance. Through trapping experiments and electron spin resonance spectroscopy (ESR) techniques, the bactericidal mechanism was revealed that the species of •O 2 − and •OH play important roles in antibacterial process. Considering the facile preparation and excellent performance, AgCNS-5 may be a promising and competitive visible-light-driven candidate toward sterilizing agent.
Youkang Shen,Zhiqiang Lin,Xuebin Liu,Tao Zhao,Pengli Zhu,Xierong Zeng,Yougen Hu,Rong Sun,Ching-Ping Wong
Designing robust, flexible, and low metal consuming hybrid foams for high-performance electromagnetic interference (EMI) shielding is crucial yet challenging. A new metallization strategy of foam type materials is presented to fabricate the robust and flexible silver embedded poly (styrene-block-butadiene-block-styrene)/carbon black hybrid foam (Ag@SBS/CB) with ultra-low silver consumption. The synergistic effect between the embedded isolate Ag nanoparticles and carbon black endows the Ag@SBS/CB foam with high mechanical and electrical stability as well as outstanding EMI shielding performance. The Ag@SBS/CB foam can endure over 1500 cycles of the compression-release test without detectable decay in the relative conductivity. A significant influence of the pore size and the silver fraction on the EMI shielding performance is revealed, providing an intriguing microstructure design strategy. The EMI shielding effectiveness (SE) of the foam reaches 81.3 dB with the silver fraction of 0.63 vol% and a CB fraction of 15 wt% at a thickness of about 5 mm. In particular, the Ag@SBS/CB foam with a thinner thickness of 2 mm shows a much better near-field EMI shielding than Al plate.
We report a facile approach to fabricate an Ag-embedded fullerene (C60) catalyst by the chemical reduction of the AgNO3 complex encapsulated fullerene microcrystal, which showed an enhanced catalytic reduction of 4-nitrophenol because of the strong absorption and propagation of H2 along the fullerene surface. With the aid of visible-light radiation, photodegradation of orange G dye is achieved through the formation of an electron donor–acceptor dyad between plasmon Ag nanostructures and fullerene molecules, which effectively offsets the “electron–hole” recombination. Neither Ag nanoparticle nor fullerene crystal used in isolation could perform this chemical conversion, implying that the metal–fullerene hybrid structure is imperative for performing the catalytic reaction. The obtained Ag-embedded fullerene crystal is characterized by scanning electron microscopy (SEM), associated energy-dispersive X-ray spectroscopy (EDX) imaging, and X-ray photoelectron spectroscopy (XPS) and demonstrates that the present hybrid materials would add a supplemental member to a family of photocatalysts toward the organic synthesis and wastewater remediation.
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