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•It is the first time to report visible light photodegradation of tetracycline (TC) over TiO2.•56.7% of TC was removed by TiO2 under visible (500 nm) light irradiation.•Different ...active species were found in TC degradation under different light irradiations.•UV and visible light irradiations generated different degradation products.
TiO2 is widely exploited as a photocatalyst to degrade antibiotic residues in water under UV irradiation, but it is inefficient for visible light photocatalysis due to its large band gap. Herein, it is the first time to report the photodegradation of tetracycline (TC) over TiO2 under visible light irradiation. 25.1% of removal efficiency for TC was achieved even under 700 nm light irradiation. Furthermore, it was demonstrated that O2− species, which were generated from photoexciting of a surface complex between TC molecules and TiO2, played a critical role in the visible light photocatalytic degradation of TC. In addition, it was found that the visible light photocatalytic degradation generated different active species and intermediate products from those under UV irradiation. N-doped TiO2 exhibited even better performance for visible-light photocatalytic degradation of TC with higher removal efficiency and larger mineralization rate, which followed different degradation-mechanism.
Converting intermittent energies into green and storable chemical fuels (like hydrogen) is of great importance to address the global energy crisis and environmental issues. Photoelectrochemical (PEC) ...water splitting is a promising technology designed for this purpose, but its wide application relies significantly on the exploration of both economic and efficient electrode materials. g-C3N4 is a metal-free, low-cost and visible-light responsive semiconductor that shows great potential as a photoelectrode material for PEC water splitting. However, due to the inherent disadvantages of g-C3N4 and the difficulty in fabricating homogeneous and concrete g-C3N4 films, its PEC performance has encountered a bottleneck. For further attention on and breakthroughs in the development of g-C3N4-based photoelectrodes, this review commences with the basic principle of PEC water splitting. Then, recent progress in the strategies for improving the properties of g-C3N4 and the quality of g-C3N4 film electrodes is critically discussed, following the introduction of the basic structure of g-C3N4 as well as its advantages and challenges for PEC applications. Furthermore, current challenges in and future perspectives on obtaining g-C3N4-based electrodes for highly efficient and stable PEC water splitting are presented finally.
Catalysts for CO2 reforming of CH4: a review Li, Meijia; Sun, Zhuxing; Hu, Yun Hang
Journal of materials chemistry. A, Materials for energy and sustainability,
01/2021, Letnik:
9, Številka:
21
Journal Article
Recenzirano
The increasing amount of greenhouse gases, especially CO2, in the atmosphere during the past decades has been a matter of great concern. Meanwhile, with the extensive exploration of natural gas ...resources, there is abundant CH4 waiting for valorization. CO2 or dry reforming of methane (CRM/DRM) is a promising approach to simultaneously utilize the two gases for the production of syngas. High-quality (free of sintering and carbon deposition during the reaction) and cost-effective catalysts are the key to the practical application of DRM. In this review article, the recent progress in the development of efficient and robust DRM catalysts is highlighted, after a brief introduction of the thermodynamics and general reaction mechanisms for DRM. The key factors in constructing highly efficient catalysts are addressed and the two major types of DRM catalysts, i.e., conventional supported catalysts and reduced solid solution catalysts, are clearly classified. Furthermore, with a firm belief in the great promise of DRM technology, the remaining challenges for DRM catalyst development are discussed along with our perspectives on the future research directions.
1T MoS
2
is metallic octahedral type molybdenum disulfide (MoS
2
). Compared to the most stable and widely existing triangle prismatic (2H) phase of MoS
2
, 1T MoS
2
possesses distinct ...electrochemical and electronic properties, such as a high conductivity, abundant active sites both at the edges and on the basal plane for electrochemical catalysis, and enlarged interlayer distance. Due to these merits, the last few years have witnessed a growing amount of interest in both synthesis and application of this unique material. So far, a series of methods have been developed to obtain 1T rich or 1T containing MoS
2
and the applications of 1T MoS
2
have covered a wide range of areas from electrochemical reactions, photoelectrocatalysis and photodetectors to photothermal agents, energy storage devices, and biosensors. In this article, to obtain a hint of the key reasons for the formation of 1T structured MoS
2
and instruct the exploration of more desirable new approaches, the means for fabricating 1T MoS
2
that have been reported are carefully classified and compared with a focus on the detailed procedures and the underlying mechanisms. Meanwhile, a full image of the explored applications with 1T MoS
2
is provided with an emphasis on the relationship between the properties of 1T MoS
2
and the performance and a hope to inspire the development of other potential applications for 1T MoS
2
. Additionally, the stabilization issue of 1T MoS
2
is discussed with a review of the current efforts. The content will be not only helpful for researchers currently working in the related areas but also instructive for the ones new to this field.
The current state-of-the-art of the synthesis, stabilization and applications of metallic 1T-phase MoS
2
: how it comes and where to go.
The photocatalytic degradation of antibiotics is a very promising technique to solve the pollution issues of antibiotics in water. Furthermore, catalysts play a critical role in the photocatalytic ...process. This article provides the first comprehensive review on the strategies of tuning catalysts for efficient photodegradation of antibiotics. It is shown that the doping of metals and nonmetals, coupling semiconductors, hydrogenation, ligand-to-metal charge transfer effect, and perovskite structure construction are widely exploited to improve visible light activity. Supporting catalysts on mesoporous materials, morphology (size and shape) modification of catalysts, and deposition of metals on the catalysts are demonstrated as efficient approaches for the enhancement of photodegradation efficiency. The generation pathways for reactive oxygen species overi the catalysts, the influencing factors in the photodegradation, and the assessment methods for catalyst performance are evaluated. Finally, the challenges and future research directions are discussed.
To solve the pollution issues of antibiotics in water, various strategies have been explored to develop efficient photocatalysts for the degradation of antibiotics.
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•This is the first review article specifically on single component core-shell structured TiO2.•The synthesis approaches of single component core-shell TiO2 are evaluated.•The unique ...structures and promising applications of the material are discussed.•A perspective on single component core-shell structured TiO2 is provided.
TiO2 is the most important photocatalyst for numerous processes, but effective only under UV light irradiation due to its large band gap (3.0–3.2 eV). It is a long time goal to achieve visible light photocatalytic activity by tuning the band structure of TiO2. In recent years, the core-shell structured TiO2 has emerged as a novel material with enhanced visible light absorption and photocatalytic efficiency. It is generally recognized that core-shell structured materials are composite materials, namely, the core contains a component and the shell is comprised of another component. In contrast, the core-shell structured TiO2 is a single component core-shell structured material, in which the core and shell contain the same component but with different structures. As the first review for the single component core-shell structured TiO2, this article systemically evaluates the synthesis approaches of the novel core-shell TiO2 materials, discusses their unique structures, summarizes their applications, and provides a perspective for future research.
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Capacitive deionization (CDI), which is one of up-and-coming water treatment technologies, is based on ion electrostatic adsorption on electrode surface. Herein, three-dimensional ...channel-structured graphene (CSG), which was synthesized via exothermic reaction between liquid potassium and carbon monoxide gas, was demonstrated as an efficient electrode material for CDI. Namely, the CSG electrode exhibited a specific capacity of 207.4 F/g at 0.2 A/g in 1 M NaCl aqueous solution. In a batch-mode recycling system, the electrosorption capacity of CSG can achieve 5.70 and 9.60 mg/g at 1.5 V in 50 and 295 mg/l NaCl aqueous solutions, respectively. The excellent electrosorption capacity of CSG, especially under low saline concentration, can be attributed to the synergistic effect of its large surface area (711.9 m2/g), unique channel structure, and oxygen functional groups.
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•Hydrogen treatment of TiO2 can create a novel core-shell structure.•The core-shell structured TiO2 possesses the stable Ti3+ sites inside the core.•The stable Ti3+ inside the core is ...a critical factor for visible light photocatalysis.•The visible light photocatalytic efficiency is 400% larger for the core-shell structured TiO2 than for the pristine TiO2.
TiO2 is one of the most important photocatalysts, but it is inefficient for visible light photocatalysis due to its large band gap. Herein, the unique core-shell structured TiO2 photocatalyst was synthesized by a one-step hydrogen treatment at temperature of 400–600 °C. The novel catalyst exhibited excellent performance for visible light photocatalytic dye degradation at room temperature. Even under weak visible light (40 mW cm−2) illumination, its degradation efficiency for methylene blue dye was 400% higher than that of pristine TiO2. Such a large enhancement can be attributed to the stable Ti3+ centers inside the core for visible light photocatalytic activity and the disordered shell for dye adsorption.
Hydration is a critical step that determines the performance of cement-based materials. In this paper, the effect of GO on the hydration of cement was evaluated by XRD and FTIR. It was found that GO ...can remarkably accelerate the hydration rate of cement due to its catalytic behavior. This happened because the oxygen-containing functional groups of GO provide adsorption sites for both water molecules and cement components.
•GO can remarkably accelerate the hydration of cement.•GO can play a catalytic role in cement hydration.•Water molecules on GO constitute a water reservoir and water transport channels.
Conversion of CO
2
to useful chemicals is an attractive technique for CO
2
capture and sequestration. However, it requires a high energy input to break the strong C&z.dbd;O bond of CO
2
molecules. ...Solar energy is a sustainable and green energy without environmental detriment. The utilization of solar energy especially visible light energy (which takes a large portion of solar energy) provides a promising approach to solve the energy issue for CO
2
conversion. This review provides a panorama of the latest progress in visible-light photocatalytic CO
2
conversion, including (1) photocatalytic CO
2
reduction with water, (2) photocatalytic CO
2
hydrogenation, and (3) photocatalytic reforming of CO
2
and CH
4
. The catalysts are assessed with emphasis on advanced strategies and superb materials. The current issues associated with visible-light photocatalytic conversion of CO
2
are discussed and suggestions for future developments are provided as an outlook.
Recent progress in visible light photocatalytic CO
2
conversion with H
2
O, H
2
or CH
4
was deeply evaluated with emphasis on the development of catalysts.
