Spinels with the formula of AB2O4 (where A and B are metal ions) and the properties of magnetism, optics, electricity, and catalysis have taken significant roles in applications of data storage, ...biotechnology, electronics, laser, sensor, conversion reaction, and energy storage/conversion, which largely depend on their precise structures and compositions. In this review, various spinels with controlled preparations and their applications in oxygen reduction/evolution reaction (ORR/OER) and beyond are summarized. First, the composition and structure of spinels are introduced. Then, recent advances in the preparation of spinels with solid-, solution-, and vapor-phase methods are summarized, and new methods are particularly highlighted. The physicochemical characteristics of spinels such as their compositions, structures, morphologies, defects, and substrates have been rationally regulated through various approaches. This regulation can yield spinels with improved ORR/OER catalytic activities, which can further accelerate the speed, prolong the life, and narrow the polarization of fuel cells, metal–air batteries, and water splitting devices. Finally, the magnetic, optical, electrical, and catalytic applications beyond the OER/ORR are also discussed. The future applications of spinels are considered to be closely related to environmental and energy issues, which will be aided by the development of new species with precise preparations and advanced characterizations.
Electrochemical water splitting is a promising technology for sustainable conversion, storage, and transport of hydrogen energy. Searching for earth‐abundant hydrogen/oxygen evolution reaction ...(HER/OER) electrocatalysts with high activity and durability to replace noble‐metal‐based catalysts plays paramount importance in the scalable application of water electrolysis. A freestanding electrode architecture is highly attractive as compared to the conventional coated powdery form because of enhanced kinetics and stability. Herein, recent progress in developing transition‐metal‐based HER/OER electrocatalytic materials is reviewed with selected examples of chalcogenides, phosphides, carbides, nitrides, alloys, phosphates, oxides, hydroxides, and oxyhydroxides. Focusing on self‐supported electrodes, the latest advances in their structural design, controllable synthesis, mechanistic understanding, and strategies for performance enhancement are presented. Remaining challenges and future perspectives for the further development of self‐supported electrocatalysts are also discussed.
Self‐supported transition‐metal hydrogen and oxygen evolution electrocatalysts combining advantages of low cost, high mechanical strength, abundant exposed active sites, and facile charge transfer are attractive for water electrolysis. An overview of recent progress is presented by highlighting the materials selection, electrode structure design, electrocatalytic property investigation, and performance enhancement strategies of example self‐supported electrodes.
The electrochemical carbon dioxide reduction reaction (CO2RR) provides an attractive approach to convert renewable electricity into fuels and feedstocks in the form of chemical bonds. Among the ...different CO2RR pathways, the conversion of CO2 into CO is considered one of the most promising candidate reactions because of its high technological and economic feasibility. Integrating catalyst and electrolyte design with an understanding of the catalytic mechanism will yield scientific insights and promote this technology towards industrial implementation. Herein, we give an overview of recent advances and challenges for the selective conversion of CO2 into CO. Multidimensional catalyst and electrolyte engineering for the CO2RR are also summarized. Furthermore, recent studies on the large‐scale production of CO are highlighted to facilitate industrialization of the electrochemical reduction of CO2. To conclude, the remaining technological challenges and future directions for the industrial application of the CO2RR to generate CO are highlighted.
The selective electrochemical reduction of CO2 to CO provides a promising approach to realize a sustainable, carbon‐neutral economy. This Review gives a comprehensive overview focusing on catalyst and electrolyte design, and their integration with electrolyzer technology towards industrial implementation. The current challenges in the commercial use of CO2 electrolysis to generate CO are also presented to enable future developments.
Bisphenol analogues (BPs) have been widely applied to industry as the substitutes for bisphenol A (BPA), which have been detected frequently in surface water, sediment, sewage and sludge. The ...presence of BPs in natural environment could pose risks to the aquatic ecosystem and human health. This study outlined the occurrence, toxicity of BPs in aquatic environment and manifested their potential ecological risk to the aquatic ecosystem throughout the world. As for occurrence, BPA was losing its dominance, while BPs were occupying a large part, especially for bisphenol S (BPS), bisphenol F (BPF) and bisphenol AF (BPAF). In some heavily polluted areas, BPs concentration reached µg/L in aquatic environment, which in the effluent of sewage plants was higher than that in the surface water. BPs content in sludge and sediment was more than that in the aqueous phase. All BPs other than BPS and Bisphenol P (BPP) had moderate toxicity. The current data supports that exposure to BPs may have adverse effects on dysfunction of endocrine system such as thyroid hormone concentration, enzyme activity, and even cell dysfunction, gene damage and chromosomal abnormalities. According to the risk quotient (RQ), BPF shows the highest ecological risk in China, Japan and South Korea, followed by BPA and BPS. The occurrence of bisphenols and their neurotoxicity on aquatic organisms merit further investigation.
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•Bisphenol analogues (BPs) are widespread in aquatic environment.•The pollution level of BPF, BPS and BPAF increases year by year.•BPs other than BPA has adverse effects on endocrine system, especially BPP.•BPF causes the higher ecological risk in many parts of the world.
Covalent organic frameworks with designable periodic skeletons and ordered nanopores have attracted increasing attention as promising cathode materials for rechargeable batteries. However, the ...reported cathodes are plagued by limited capacity and unsatisfying rate performance. Here we report a honeycomb-like nitrogen-rich covalent organic framework with multiple carbonyls. The sodium storage ability of pyrazines and carbonyls and the up-to twelve sodium-ion redox chemistry mechanism for each repetitive unit have been demonstrated by in/ex-situ Fourier transform infrared spectra and density functional theory calculations. The insoluble electrode exhibits a remarkably high specific capacity of 452.0 mAh g
, excellent cycling stability (~96% capacity retention after 1000 cycles) and high rate performance (134.3 mAh g
at 10.0 A g
). Furthermore, a pouch-type battery is assembled, displaying the gravimetric and volumetric energy density of 101.1 Wh kg
and 78.5 Wh L
, respectively, indicating potentially practical applications of conjugated polymers in rechargeable batteries.
Nanomaterials are widely used in daily life owing to their superior characteristics. The release and transport of nanoparticles (NPs) in the environment is inevitable during their entire life cycle, ...posing a risk to the aquatic environment. Thus, considerable attention has been focused on the fate and behavior of NPs in porous media, as well as the co-transport of NPs with other pollutants. In this review, current knowledge about the retention and transport behavior of NPs in porous media is summarized. NP transport in porous media is dominated by various internal and external factors, including the characteristics of NPs, porous media, and water flow. Generally, NPs with high density, small particle size, and surface coating are easily transported in porous media with the characteristics of large size, smooth surface, and low water saturation. Meanwhile, high pH and velocity, low temperature, and natural organic matter-containing fluids are also conducive to NP transport. Aggregation, adsorption, straining, and blocking are the primary mechanisms by which NPs affect the transport of co-existing pollutants in porous media. Current research on NP transport has been performed predominantly using modal porous media (e.g., sand and glass beads); however, there is a large gap between simulated and natural porous media. Further studies should focus on the transport, fate, and interaction of NPs and coexistent pollutants in natural porous media, as well as the coupling mechanisms under actual environmental conditions.
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•The transport of NPs is affected by the properties of NPs, porous media and fluid.•Aggregation, adsorption, straining and blocking are the main mechanisms involved.•NPs can change the diffusion of co-existing pollutants and co-transport with them.•Interaction of NPs and pollutants in natural media requires further investigation.
Electrochemical deposition is a facile strategy to prepare functional materials but suffers from limitation in thin films and uncontrollable interface engineering. Here we report a universal ...electrosynthesis of metal hydroxides/oxides on varied substrates via reduction of oxyacid anions. On graphitic substrates, we find that the insertion of nitrate ion in graphene layers significantly enhances the electrodeposit-support interface, resulting in high mass loading and super hydrophilic/aerophobic properties. For the electrocatalytic oxygen evolution reaction, the nanocrystalline cerium dioxide and amorphous nickel hydroxide co-electrodeposited on graphite exhibits low overpotential (177 mV@10 mA cm
) and sustains long-term durability (over 300 h) at a large current density of 1000 mA cm
. In situ Raman and operando X-ray diffraction unravel that the integration of cerium promotes the formation of electrocatalytically active gamma-phase nickel oxyhydroxide with exposed (003) facets. Therefore, combining anion intercalation with cathodic electrodeposition allows building robust electrodes with high electrochemical performance.
There is a rising concern about the pollution of microplastics (plastic particles < 5 mm) in water due to their physicochemical properties, especially their interaction with organic contaminants; ...however, such knowledge is still limited. The mass production and consumption of medication for the treatment of infectious diseases in human and animals have led to the ubiquity of antibiotics in the environment. We studied the single and joint effects of microplastics (1-μm and 10-μm polystyrene particles, PS) and roxithromycin (ROX) on
Daphnia magna
through the acute and sublethal toxicity tests. The 48-h median effective concentration (EC
50
) of 1-μm and 10-μm PS to
D. magna
was 66.97 mg/L and 199.94 mg/L, respectively, while the value of ROX was 20.28 mg/L. Malondialdehyde (MDA) levels and the activities of four enzymatic biomarkers, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione S-transferase (GST), were further detected to assess the oxidative stress caused in
D. magna
caused. The results showed that 48-h exposure to PS (0.1 mg/L) or ROX (0.01 mg/L) alone activated the activities of CAT and GST and MDA levels. When compared with the ROX alone, the responses of GPx and MDA in
D. magna
co-exposed to 1-μm PS were significantly decreased, while co-exposure to 10-μm PS significantly decreased the responses of GST and MDA. Furthermore, the integrated biomarker response version 2 (IBRv2) analysis revealed that co-exposure to 1-μm PS and ROX led to the strongest biological responses in
D. magna
. Our findings underlined that microplastics should be a concern when they interact with the co-existence of pollutants in the aquatic environment.
Electrochemical water splitting is a promising technology for hydrogen production and sustainable energy conversion, but the electrolyzers that are currently available do not have anodic electrodes ...that are robust enough and highly active for the oxygen evolution reaction (OER). Electrodeposition provides a feasible route for preparing freestanding OER electrodes with high active site utilization, fast mass transport and a simple fabrication process, which is highly attractive from both academic and commercial points of view. This minireview focuses on the recent electrodeposition strategies for metal (hydro)oxide design and water oxidation applications. First, the intrinsic advantages of electrodeposition in comparison with traditional technologies are introduced. Then, the unique properties and underlying principles of electrodeposited metal (hydro)oxides in the OER are unveiled. In parallel, illustrative examples of the latest advances in materials structural design, controllable synthesis, and mechanism understanding through the electrochemical synthesis of (hydro)oxides are presented. Finally, the latest representative OER mechanism and electrodeposition routes for OER catalysts are briefly overviewed. Such observations provide new insights into freestanding (hydro)oxides electrodes prepared
via
electrodeposition, which show significant practical application potential in water splitting devices. We hope that this review will provide inspiration for researchers and stimulate the development of water splitting technology.
This minireview looks at recent electrodeposition strategies for metal (hydro)oxide design and water oxidation applications, unveiling the unique properties and underlying principles of electrodeposited metal (hydro)oxides in the OER.
Sodium metal is a promising anode, but uneven Na deposition with a dendrite growth seriously impedes its application. Herein, a fibrous hydroxylated MXene/carbon nanotubes (h‐Ti3C2/CNTs) composite is ...designed as a scaffold for dendrite‐free Na metal electrodes. This composite displays fast Na+/electron transport kinetics and good thermal conductivity and mechanical properties. The h‐Ti3C2 contains abundant sodiophilic functional groups, which play a significant role in inducing homogeneous nucleation of Na. Meanwhile, CNTs provide high tensile strength and ease of film‐forming. As a result, h‐Ti3C2/CNTs exhibit a high average Coulombic efficiency of 99.2 % and no dendrite after 1000 cycles. The h‐Ti3C2/CNTs/Na based symmetric cells show a long lifespan over 4000 h at 1.0 mA cm−2 with a capacity of 1.0 mAh cm−2. Furthermore, Na‐O2 batteries with a h‐Ti3C2/CNTs/Na anode exhibit a low potential gap of 0.11 V after an initial 70 cycles.
A friend to sodium: A fibrous hydroxylated h‐Ti3C2/carbon nanotubes composite is designed as a scaffold for dendrite‐free Na metal electrodes. It displays fast Na+/electron transport kinetics, high sodiophilicity, and satisfactory thermal conductivity and mechanical properties.
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