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[Topics in Organometallic Chemistry] || Functionalization of C(sp2)–H Bonds of Arenes and Heteroarenes Assisted by Photoredox Catalysts for the C–C Bond Formation
摘要： The formation of C–C bonds from arenes and heteroarenes through transition metal-catalyzed C–H bond functionalizations is one of the major achievements of these last decades. It is now possible to perform such transformations under mild reaction conditions with the help of visible light photocatalysis leading to eco-friendly and safer process to build organic molecules or materials. This chapter will focus on photoredox catalysis which involves a C(sp2)–H bond functionalization step for the formation of C(sp2)–C bonds [i.e., direct arylations and (per?uoro)alkylations] and will show how this hot topic contributes to the development of green chemistry.
关键词： MLTC photoredox catalysis,C(sp2)–H bond,Visible light,C–C bond formation
更新于2025-09-10 09:29:36
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Water-Dispersed Conjugated Polyelectrolyte for Visible-Light Hydrogen Production
摘要： Conjugated polymer-based photocatalysts have shown great potential in H2 production via water splitting, but an intrinsic drawback of conventional hydrophobic polymer photocatalysts is their poor wettability and relatively large particle size in aqueous media, which is favorable for charge recombination with limited interfacial reaction efficiency. Herein, a well-dispersed organic water reduction system using cationic conjugated polyelectrolyte as the photocatalyst has been reported for the first time. In comparison to a model polymer (PFBT) bearing the same conjugated backbone, the polyelectrolyte exhibits significantly enhanced photocatalytic efficiency due to the extended light absorption and improved charge separation of the polymer aggregates.
关键词： conjugated polyelectrolyte,water-dispersed,visible-light hydrogen production
更新于2025-09-10 09:29:36
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A novel poly(triazine imide) hollow tube/ZnO heterojunction for tetracycline hydrochloride degradation under visible light irradiation
摘要： A novel poly(triazine imide) hollow tube (PTI)/ZnO heterojunction was prepared by a molten salts method. The photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy, respectively. The results showed the ZnO nanoparticles were successfully coupled into the PTI hollow tube to form PTI/ZnO heterojunction. The degradation of tetracycline hydrochloride (TC) under visible light irradiation was used to evaluate the activity of photocatalyst. The PTI/ZnO-6 wt% heterojunction exhibits the highest photocatalytic activity, which can degrade almost all TC within 90 min. The kinetic constant of degradation reaction with PTI/ZnO-6 wt% heterojunction (0.034 min?1) is about 5 times as high as that of the PTI (0.0070 min?1). A possible photocatalytic mechanism for heterojunction according to the energy-band theory was proposed.
关键词： ZnO,Tetracycline hydrochloride,Visible light photocatalytic,Poly(triazine imide),Hollow tube
更新于2025-09-10 09:29:36
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[ACM Press the 17th ACM Workshop - Redmond, WA, USA (2018.11.15-2018.11.16)] Proceedings of the 17th ACM Workshop on Hot Topics in Networks - HotNets '18 - Connecting Battery-free IoT Tags Using LED Bulbs
摘要： We introduce BackVLC, a system to connect battery-free IoT tags using LED bulbs. We make use of bulbs beyond illumination. We send data to the tags with visible light communication (VLC), and retrofit the bulbs with simple circuitry to enable the uplink channel current VLC systems lack, using Radio Frequency (RF) backscatter communication from the tags. Tags process and send data, harvesting energy from light and radio. We present our system design and implementation, evaluate it in preliminary simulation studies and experiments, and discuss the research challenges to develop a complete network architecture. BackVLC is the first work that combines VLC with RF backscatter.
关键词： RF backscatter,LED bulbs,visible light communication,battery-free IoT tags,BackVLC
更新于2025-09-10 09:29:36
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Fabrication of CdS-decorated mesoporous SiC hollow nanofibers for efficient visible-light-driven photocatalytic hydrogen production
摘要： In the present work, we reported the fabrication of CdS decorated mesoporous SiC hollow nanofibers for efficient visible-light-driven photocatalytic hydrogen production. The mesoporous SiC hollow nanofibers were firstly fabricated by electrospinning, followed by hydrothermal treatment to introduce the CdS nanoparticles decorated on the preformed fiber matrix, The resultant CdS/SiC hybrid photocatalysts were systematically characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and N2 adsorption. The as-fabricated CdS/SiC hybrids exhibited a robust stability with a release rate up to ~ 124.65?μmol?h?1?g?1 for photocatalytic H2 evolution driven by visible light, which was profoundly enhanced for more than 16 times to that of pristine SiC counterparts, and comparable to the state-of-the-art one of SiC-based photocatalysts.
关键词： CdS,SiC,photocatalytic hydrogen production,visible-light-driven,hollow nanofibers
更新于2025-09-10 09:29:36
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Indoor visible light communications: performance evaluation and optimization
摘要： For indoor visible light communication (VLC), much work has been done when the noise is independent of the input signal. However, less effort is made when the VLC system suffers from the input-dependent noise. Considering the input-dependent noise, this paper focuses on the performance analysis and optimization for indoor VLC system. The Lambertian emission-based channel model and on-off keying modulation are employed. According to the system model, the bit error rate (BER) with a closed-form expression is derived. To enhance the system performance, an optimization problem that minimizes the BER by tilting the receiver plane is formulated. By solving the problem, the optimal tilting angle of the receiver is obtained. Simulation results verify the derived expression of BER. It is also shown that the BER is strongly affected by the input-dependent noise. Moreover, the optimal tilting angles for the receiver at any position are obtained, which can provide some insights for practical system design.
关键词： BER,Tilting receiver plane,Input-dependent noise,Visible light communications
更新于2025-09-10 09:29:36
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One step to prepare CNTs modified porous g-C3N4 with excellent visible-light photocatalytic performance
摘要： A kind of carbon nanotubes (CNTs) modified porous graphitic carbon nitride (CNTs/pg-C3N4) photocatalyst was successfully synthesized via one step thermal polycondensation and completely measured by some instruments, such as XRD, FTIR, TEM, BET, DRS, PL, etc. And the relevant experimental data indicated that loaded CNTs could be beneficial to the photoinduced charges transfer, facilitating photoinduced charge separation rate. Meanwhile, surface area and visible light adsorption of CNTs/pg-C3N4 photocatalyst could be increased and improved. These synergetic effects resulted in the as-synthesized CNTs/pg-C3N4 photocatalyst exhibiting better visible-light-induced photocatalytic performance for organic pollutant degradation and the product of clean energy than bulk g-C3N4, pg-C3N4 and CNTs modified bulk g-C3N4, and excellent stable photocatalytic performance was also observed after several recycling experiments. Finally, a reasonable improved photocatalytic reaction mechanism for CNTs/pg-C3N4 photocatalyst is presented.
关键词： Porous graphitic carbon nitride,Photocatalytic performance,Carbon nanotubes,Photocatalyst,Visible-light
更新于2025-09-10 09:29:36
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Enhanced visible light photoreduction of aqueous Cr(VI) by Ag/Bi4O7/g-C3N4 nanosheets ternary metal/non-metal Z-scheme heterojunction
摘要： In this paper, we successfully constructed a ternary metal/non-metal nanomaterial which can synergize Z-scheme heterojunction and plasmonic metal/semiconductor for enhancing visible light photoreduction of aqueous Cr(VI). The as-formed ternary metal/non-metal nanomaterial was composed of g-C3N4 nanosheets mutual modified by Ag nanoparticles and Bi4O7. In the ternary nanomaterial, g-C3N4 nanosheets and Bi4O7 fabricated Z-scheme heterojunction, g-C3N4 nanosheets and Ag nanoparticles formed plasmonic metal/semiconductor system, synchronously. The photodeposition experiments were designed to indirect demonstrate the Z-scheme heterojunction via photocatalytic oxidation and reduction deposition reactions, AgNO3 was used as the electron acceptor and Pb(NO3)2 as the electron donor, photocatalytic reduction product and oxidation product were selectively deposited on g-C3N4 nanosheets and Bi4O7, respectively, revealing the Z-scheme heterojunction was definite formed. In addition, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), UV–vis absorption, and Fourier-transform infrared spectroscopy (FTIR) were studied to indicate that the plasmonic metal/semiconductor system was existent in the ternary nanomaterial. The visible light photoreduction of ternary Ag/Bi4O7/g-C3N4 nanosheets was evaluated by photoreducing aqueous Cr(VI). The photoreduction results show that the ternary Ag/Bi4O7/g-C3N4 nanosheets is much higher than the pristine bulk g-C3N4 and g-C3N4 nanosheets.
关键词： Visible light,Z-scheme heterojunction,g-C3N4,Bi4O7,Cr(VI) reduction,Ag nanoparticles
更新于2025-09-10 09:29:36
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Evaluation of the reaction mechanism for photocatalytic degradation of organic pollutants with MIL-88A/BiOI structure under visible light irradiation
摘要： In this study, we synthesized novel visible light photocatalyst MIL-88A/BiOI using depositing BiOI particles on the surface of a metal–organic framework (MIL-88A). Photocatalytic application of binary composite MIL-88A/BiOI was obtained by discoloration of Methylene Blue (MB) and Acid Blue 92 (AB92) in aqueous solution under visible light source. The photodegradation experiments for treating organic dyes show that the MIL-88A/BiOI heterojunction structure possess a higher rate for decomposition of dyes due to the decreased aggregation of the BiOI nanoparticles, effective charge carrier separation and the synergistic effect between MIL-88A and BiOI samples as a heterojunction. Also, the MIL-88A/BiOI structure shows better photocatalytic degradation performance for anionic dyes (AB92) than for a cationic dye (MB). It was further found that ?OH and ?O2? radicals were the most important species responsible for the photodegradation test.
关键词： Visible light-driven,Photocatalyst,BiOI,MIL-88A metal organic framework
更新于2025-09-10 09:29:36
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Amalgamation of N-graphene quantum dots with nanocubic like TiO2: an insight study of sunlight sensitive photocatalysis
摘要： In this work, a sunlight-sensitive photocatalyst of nanocubic-like titanium dioxide (TiO2) and N-doped graphene quantum dots (N-GQDs) is developed through a simple hydrothermal and physical mixing method. The successful amalgamation composite photocatalyst characteristics were comprehensively scrutinized through various physical and chemical analyses. A complete removal of bisphenol A (BPA) is attained by a synthesized composite after 30 min of sunlight irradiation as compared to pure TiO2. This clearly proved the unique contribution of N-GQDs that enhanced the ability of light harvesting especially under visible light and near-infrared region. This superior characteristic enables it to maximize the absorbance in the entire solar spectrum. However, the increase of N-GQDs weight percentage has created massive oxygen vacancies that suppress the generation of active radicals. This resulted in a longer duration for a complete removal of BPA as compared to lower weight percentage of N-GQDs. Hence, this finding can offer a new insight in developing effective sunlight-sensitive photocatalysts for various complex organic pollutants degradation.
关键词： Visible light,Near Infrared,Nanocubic-like TiO2,Bisphenol A,N-Graphene quantum dots,Sunlight
更新于2025-09-10 09:29:36