In the upcoming decades, connected vehicles will join regular vehicles to appear on roads, and the characteristics of traffic flow will be changed accordingly. To model the heterogeneous traffic ...mixing regular and connected vehicles, a generic car-following framework is first proposed in this paper. A linear stability condition is theoretically derived, which indicates that the stability of the heterogeneous traffic is closely related to the penetration rate and the spatial distribution of connected vehicles. The generic car-following framework is applied by taking the Intelligent Driver Model as an example, and it is shown that connected vehicles can obviously enhance the stability of traffic flow and improve traffic efficiency in particular when traffic is in congestion. Moreover, a driver assistance strategy based on distributed feedback control is developed for connected vehicles, and the simulation results show that the proposed driver assistance strategy performs satisfactorily in stabilizing traffic as well as improving traffic efficiency.
A facile and controllable in situ reduction strategy is used to create surface oxygen vacancies (OVs) on Aurivillius‐phase Sr2Bi2Nb2TiO12 nanosheets, which were prepared by a mineralizer‐assisted ...soft‐chemical method. Introduction of OVs on the surface of Sr2Bi2Nb2TiO12 extends photoresponse to cover the whole visible region and also tremendously promotes separation of photoinduced charge carriers. Adsorption and activation of CO2 molecules on the surface of the catalyst are greatly enhanced. In the gas‐solid reaction system without co‐catalysts or sacrificial agents, OVs‐abundant Sr2Bi2Nb2TiO12 nanosheets show outstanding CO2 photoreduction activity, producing CO with a rate of 17.11 μmol g−1 h−1, about 58 times higher than that of the bulk counterpart, surpassing most previously reported state‐of‐the‐art photocatalysts. Our study provides a three‐in‐one integrated solution to advance the performance of photocatalysts for solar‐energy conversion and generation of renewable energy.
Surface oxygen vacancies introduced on Sr2Bi2Nb2TiO12 nanosheets provide a three‐in‐one integrated solution to simultaneously promote photoabsorption, separation of photoinduced carrier carriers, and the adsorption and activation of CO2 molecules. This results in a prominent CO2 photoreduction activity.
Graphitic carbon nitride (g-C
3
N
4
), as an intriguing earth-abundant visible light photocatalyst, possesses a unique two-dimensional structure, excellent chemical stability and tunable electronic ...structure. Pure g-C
3
N
4
suffers from rapid recombination of photo-generated electron-hole pairs resulting in low photocatalytic activity. Because of the unique electronic structure, the g-C
3
N
4
could act as an eminent candidate for coupling with various functional materials to enhance the performance. According to the discrepancies in the photocatalytic mechanism and process, six primary systems of g-C
3
N
4
-based nanocomposites can be classified and summarized: namely, the g-C
3
N
4
based metal-free heterojunction, the g-C
3
N
4
/single metal oxide (metal sulfide) heterojunction, g-C
3
N
4
/composite oxide, the g-C
3
N
4
/halide heterojunction, g-C
3
N
4
/noble metal heterostructures, and the g-C
3
N
4
based complex system. Apart from the depiction of the fabrication methods, heterojunction structure and multifunctional application of the g-C
3
N
4
-based nanocomposites, we emphasize and elaborate on the underlying mechanisms in the photocatalytic activity enhancement of g-C
3
N
4
-based nanocomposites. The unique functions of the p-n junction (semiconductor/semiconductor heterostructures), the Schottky junction (metal/semiconductor heterostructures), the surface plasmon resonance (SPR) effect, photosensitization, superconductivity,
etc
. are utilized in the photocatalytic processes. Furthermore, the enhanced performance of g-C
3
N
4
-based nanocomposites has been widely employed in environmental and energetic applications such as photocatalytic degradation of pollutants, photocatalytic hydrogen generation, carbon dioxide reduction, disinfection, and supercapacitors. This critical review ends with a summary and some perspectives on the challenges and new directions in exploring g-C
3
N
4
-based advanced nanomaterials.
This review summarizes recent advances in the design, synthesis, mechanistic understanding and multifunctional applications of g-C
3
N
4
based heterojunctions/heterostructures.
Graphitic carbon nitride (g-C3N4) has been widely investigated and applied in photocatalysis and catalysis, but its performance is still unsatisfactory. Here, we demonstrated that K-doped g-C3N4 with ...a unique electronic structure possessed highly enhanced visible-light photocatalytic performance for NO removal, which was superior to Na-doped g-C3N4. DFT calculations revealed that K or Na doping can narrow the bandgap of g-C3N4. K atoms, intercalated into the g-C3N4 interlayer via bridging the layers, could decrease the electronic localization and extend the π conjugated system, whereas Na atoms tended to be doped into the CN planes and increased the in-planar electron density. On the basis of theoretical calculation results, we synthesized K-doped g-C3N4 and Na-doped g-C3N4 by a facile thermal polymerization method. Consistent with the theoretical prediction, it was found that K was intercalated into the space between the g-C3N4 layers. The K-intercalated g-C3N4 sample showed increased visible-light absorption, efficient separation of charge carriers, and strong oxidation capability, benefiting from the narrowed band gap, extended π conjugated systems, and positive-shifted valence band position, respectively. Despite that the Na-doped g-C3N4 exhibited narrowed bandgap, the high recombination rate of carriers resulted in the reduced photocatalytic performance. Our discovery provides a promising route to manipulate the photocatalytic activity simply by introducing K atoms in the interlayer and gains a deep understanding of doping chemistry with congeners. The present work could provide new insights into the mechanistic understanding and the design of electronically optimized layered photocatalysts for enhanced solar energy conversion.
The ring-opening process is the rate-determining step for photocatalytic decomposition of aromatic volatile organic compounds (VOCs). However, the ring-opening pathway has not been fully revealed, ...which enables efficient photocatalytic VOC degradation. Taking the photocatalytic toluene degradation as a typical case, the ring-opening pathway and regulation strategy were systematically investigated and proposed with an aim to regulate the rate-determining step and accelerate the reaction rates. Herein, BiOCl with tailored facets was designed as a model photocatalyst to clarify the mechanism of photocatalytic toluene degradation. Theoretical calculations and
in situ
DRIFTS technology were closely combined to dynamically predict and monitor the photocatalytic toluene degradation reactions. It is revealed that the lowest energy barrier was precisely located at the ring-opening of benzoic acid which was generated from toluene oxidation. This result implied that the benzyl must be fully oxidized to benzoic acid to elevate the ring-opening reaction rates. Moreover, the alternative charge arrangement on the {010} facet of BiOCl facilitated the benzyl oxidation and selectivity for benzoic acid ring-opening reactions, subsequently resulting in remarkably enhanced photocatalytic efficiency, exceeding that of the {001} facet by 100% towards toluene decomposition. This work demonstrates that probing and tailoring the ring-opening pathway are vital to increase the overall toluene decomposition efficiency and could provide new insights into the understanding of the photocatalytic reactions in VOC degradation.
The synergy between metal alloy nanoparticles (NPs) and single atoms (SAs) should maximize the catalytic activity. However, there are no relevant reports on photocatalytic CO2 reduction via utilizing ...the synergy between SAs and alloy NPs. Herein, we developed a facile photodeposition method to coload the Cu SAs and Au–Cu alloy NPs on TiO2 for the photocatalytic synthesis of solar fuels with CO2 and H2O. The optimized photocatalyst achieved record-high performance with formation rates of 3578.9 for CH4 and 369.8 μmol g–1 h–1 for C2H4, making it significantly more realistic to implement sunlight-driven synthesis of value-added solar fuels. The combined in situ FT-IR spectra and DFT calculations revealed the molecular mechanisms of photocatalytic CO2 reduction and C–C coupling to form C2H4. We proposed that the synergistic function of Cu SAs and Au–Cu alloy NPs could enhance the adsorption activation of CO2 and H2O and lower the overall activation energy barrier (including the rate-determining step) for the CH4 and C2H4 formation. These factors all enable highly efficient and stable production of solar fuels of CH4 and C2H4. The concept of synergistic SAs and metal alloys cocatalysts can be extended to other systems, thus contributing to the development of more effective cocatalysts.
Methanol conversion to olefins, as an important reaction in C1 chemistry, provides an alternative platform for producing basic chemicals from nonpetroleum resources such as natural gas and coal. ...Methanol‐to‐olefin (MTO) catalysis is one of the critical constraints for the process development, determining the reactor design, and the profitability of the process. After the construction and commissioning of the world's first MTO plant by Dalian Institute of Chemical Physics, based on high‐efficiency catalyst and fluidization technology in 2010, more attention has been attracted for a deep understanding of the reaction mechanism and catalysis principle, which has led to the continuous development of catalysts and processes. Herein, the recent progress in MTO catalyst development is summarized, focusing on the advances in the optimization of SAPO‐34 catalysts, together with the development efforts on catalysts with preferential ethylene or propylene selectivity.
The past decades have witnessed remarkable development in the commercialization of the methanol‐to‐olefin (MTO) processes, the fundamental understanding of catalyst structure–property relationships, and the synthesis control of molecular sieve catalysts. Recent advances relating to MTO catalysts are highlighted, aiming to promote their rational design and preparation, and enhance the efficiency of this reaction process.
The nitrogen oxides (NOx) formed by photochemical reaction of surface nitrates raise significant concerns. However, little is known about the effect of visible light (>380 nm) on nitrate ...decomposition and the reaction mechanism. Herein, the decomposition of surface nitrates is investigated under visible light. The results indicate that visible light photocatalysis contributes significantly to nitrate decomposition. Monodentate nitrate (m‐NO3−) can be decomposed into NOx by photogenerated electrons starting from the weakly coordinated N−O bond. Water vapor promotes NOx generation because more stable bidentate nitrate (b‐NO3−) will be converted into m‐NO3− by surface hydroxyl groups through hydrogen bonding interactions. Alternatively, b‐NO3− can be directly decomposed to NO2− by NO attack, but this process is subject to photocatalytic oxidation. This work brings a new focus on the atmospheric NOx sources and provides a more nuanced understanding of nitrates decomposition processes.
Visible light photocatalysis contributes significantly to the decomposition of surface nitrates. Monodentate nitrate (m‐NO3−) can be gradually decomposed to NOx by photogenerated electrons starting from the weakly coordinated N−O bond. The presence of water vapor promotes the generation of gas‐phase products because more stable bidentate nitrate (b‐NO3−) will be converted into m‐NO3− by the abundant surface hydroxyl groups through hydrogen bonding interactions.
Tissue inhibitor of metalloproteinase 3 (TIMP3) is unique among the four TIMPs due to its extracellular matrix (ECM)-binding property and broad range of inhibitory substrates that includes matrix ...metalloproteinases (MMPs), a disintegrin and metalloproteinases (ADAMs), and ADAM with thrombospondin motifs (ADAMTSs). In addition to its metalloproteinase-inhibitory function, TIMP3 can interact with proteins in the extracellular space resulting in its multifarious functions. TIMP3 mRNA has a long 3’ untranslated region (UTR) which is a target for numerous microRNAs. TIMP3 levels are reduced in various cardiovascular diseases, and studies have shown that TIMP3 replenishment ameliorates the disease, suggesting a therapeutic potential for TIMP3 in cardiovascular diseases. While significant efforts have been made in identifying the effector targets of TIMP3, the regulatory mechanism for the expression of this multi-functional TIMP has been less explored. Here, we provide an overview of TIMP3 gene structure, transcriptional and post-transcriptional regulators (transcription factors and microRNAs), protein structure and partners, its role in cardiovascular pathology and its application as therapy, while also drawing reference from TIMP3 function in other diseases.
Simulating photosynthesis has long been one of the ideas for realizing the conversion of solar energy into industrial chemicals. Heterogeneous N2 photofixation in water is a promising way for ...sustainable production of ammonia. However, a mechanistic understanding of the complex aqueous photocatalytic N2 reduction is still lacking. In this study, a light‐dependent surface hydrogenation mechanism and light‐independent protection of catalyst surface for N2 reduction are revealed on ultrathin Bi4O5Br2 (BOB) nanosheets, in which the creation and annihilation of surface bromine vacancies can be controlled via a surface bromine cycle. Our rapid scan in situ FT‐IR spectra verify that photocatalytic N2 reduction proceeds through an associative alternating mechanism on BOB surface with bromine vacancies (BrV‐BOB). This work provides a new strategy to combine light‐dependent facilitated reaction with light‐independent regeneration of catalyst for advancing sustainable ammonia production.
Photocatalytic N2 reduction on ultrathin Bi4O5Br2 nanosheets reveals a light‐dependent surface hydrogenation mechanism and light‐independent protection of the catalyst surface. Creation and annihilation of surface bromine vacancies can be controlled via a surface bromine cycle.
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