Borophene, a monolayer of boron, has risen as a new exciting two-dimensional (2D) material having extraordinary properties, including anisotropic metallic behavior and flexible ...(orientation-dependent) mechanical and optical properties. This review summarizes the current progress in the synthesis of borophene on various metal substrates, including Ag(110), Ag(100), Au(111), Ir(111), Al(111), and Cu(111), as well as heterostructuring of borophene. In addition, it discusses the mechanical, thermal, magnetic, electronic, optical, and superconducting properties of borophene and the effects of elemental doping, defects, and applied mechanical strains on these properties. Furthermore, the promising potential applications of borophene for gas sensing, energy storage and conversion, gas capture and storage applications, and possible tuning of the material performance in these applications through doping, formation of defects, and heterostructures are illustrated based on available theoretical studies. Finally, research and application challenges and the outlook of the whole borophene’s field are given.
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•NaTi2(PO4)3 decorated carbon nanofiber network (eCNF/NTP) was synthesized.•eCNF/NTP was used as the electrode for rocking-chair capacitive deionization (RCDI).•The RCDI displays high ...desalination capacity/rate and outstanding cycling stability.
Faradic-based capacitive deionization (CDI), as an important derivative of conventional CDI, has received wide attention in the desalination community. Yet, oriented from its intrinsic ion storage mechanism, faradic-based CDI has been plagued by several serious issues (e.g., imbalanced ion storage capacity, low desalination rate, and poor cycling stability), which greatly constrained its further development. Herein, we put forward an innovative strategy by using carbon nanofiber-reinforced NaTi2(PO4)3 (eCNF/NTP) as the core material (for Na+-capturing) and further coupling it with rational rocking-chair capacitive deionization (RCDI) cell architecture. Of note, owing to the unique 3D network structure of eCNF/NTP that not only provides sufficient redox-activate sites but also offers a rigid network structure to prevent the potential aggregation during cycling, as well as the rational RCDI symmetric cell architecture to avoid the imbalanced cation and anion storage capacity, the RCDI system equipping with eCNF/NTP electrode displays an excellent desalination performance (desalination capacity: 168.2 mg g−1; desalination rate: 0.46 mg g−1 s−1) with outstanding cycling stability (only 6 % desalination capacity degradation after 80 cycles). This work is interesting because it showcases the critical importance of both delicate material design and rationalized cell architecture in addressing the bottleneck issue of CDI, which could shed light on the future development of other high-performance desalination systems.
Alternative water resources (seawater, brackish water, atmospheric water, sewage, etc.) can be converted into clean freshwater via high-efficiency, energy-saving, and cost-effective methods to cope ...with the global water crisis. Herein, we provide a comprehensive and systematic overview of various solar-powered technologies for alternative water utilization (i.e., “sunlight–energy–water nexus”), including solar-thermal interface desalination (STID), solar-thermal membrane desalination (STMD), solar-driven electrochemical desalination (SED), and solar-thermal atmospheric water harvesting (ST-AWH). Three strategies have been proposed for improving the evaporation rate of STID systems above the theoretical limit and designing all-weather or all-day operating STID systems by analyzing the energy transfer of the evaporation and condensation processes caused by solar-thermal conversion. This review also introduces the fundamental principles and current research hotspots of two other solar-driven seawater or brackish water desalination technologies (STMD and SED) in detail. In addition, we also cover ST-AWH and other solar-powered technologies in terms of technology design, materials evolution, device assembly, etc. Finally, we summarize the content of this comprehensive review and discuss the challenges and future outlook of different types of solar-powered alternative water utilization technologies.
Electrocatalytic reduction of carbon dioxide to valuable chemicals is a sustainable technology that can achieve a carbon‐neutral energy cycle in the environment. Electrochemical CO2 reduction ...reaction (CO2RR) processes using metal–organic frameworks (MOFs), featuring atomically dispersed active sites, large surface area, high porosity, controllable morphology, and remarkable tunability, have attracted considerable research attention. Well‐defined MOFs can be constructed to improve conductivity, introduce active centers, and form carbon‐based single‐atom catalysts (SACs) with enhanced active sites that are accessible for the development of CO2 conversion. In this review, the progress on pristine MOFs, MOF hybrids, and MOF‐derived carbon‐based SACs is summarized for the electrocatalytic reduction of CO2. Finally, the limitations and potential improvement directions with respect to the advancement of MOF‐related materials for the field of research are discussed. These summaries are expected to provide inspiration on reasonable design to develop stable and high‐efficiency MOFs‐based electrocatalysts for CO2RR.
With many advantages including atomically dispersed active sites and controllable structures, metal–organic frameworks (MOFs)‐related single‐atom catalysts have been identified as promising catalysts for the electrochemical CO2 reduction. The progress on MOF‐related single‐atom catalysts for CO2 reduction is highlighted. The challenges and potential improvement directions concerning the advancement of MOF‐related materials for CO2 reduction are proposed.
Currently, hybrid capacitive deionization (HCDI) with faradaic material cathode and active carbon (AC) anode has attracted much attention due to its very excellent desalination performance even in ...highly-concentrated saline water. However, the carbon oxidation reaction occurring at a potential of 0.7–0.9 V in a CDI system still exists at the carbon anode in a HCDI system, which causes the performance degradation during long-term operation. Introducing costly ion exchange membranes has been reported to solve this issue. In this work, we report a more simple and cost-saving approach to improve the desalination performance of membrane-free HCDI cell by using nickel hexacyanoferrate/reduced graphene oxide (NiHCF/rGO) cathode which possesses high theoretic capacity and low Na+ intercalation/extraction potential at a low voltage operation (0.6 V). A high desalination capacity of 22.8 mg g−1 is achieved for this membrane-free HCDI cell, higher than those for the conventional AC//AC CDI cell. More importantly, the AC//NiHCF/rGO cell shows a stable cycling performance with a capacity retention of 78% at 0.6 V over 100 desalination-regeneration cycles, significantly improved compared with that at 1.2 V. The strategy should provide a helpful guidance for practical CDI operation.
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•Nickel hexacyanoferrate/reduced graphene oxide (NiHCF/rGO) electrode is prepared.•Hybrid capacitive deionization (HCDI) consists of NiHCF/rGO cathode with AC anode.•Low voltage operation is used to suppress the oxidation reaction on AC anode.•HCDI exhibits both high desalination capacity and stable cycling performance.
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•Chloride pre-intercalated CoFe-layered double hydroxide (CoFeCl-LDH) was prepared.•CoFeCl-LDH was used as Cl--capturing electrode for rocking-chair CDI system.•The system exhibits an ...ultrahigh desalination capacity and fast desalination rate.
Faradic electrochemical deionization (EDI), as the next generation of capacitive deionization (CDI), was considered one of the most promising solutions to address the global fresh-water shortage, while rationalizing its cell architecture and developing suitable electrode material are of equal importance to the desalination performance of EDI. In this work, chloride pre-intercalated CoFe-layered double hydroxides (LDH) (CoFeCl-LDHs) were fabricated through coprecipitation and further used as Cl- capturing electrodes for rocking-chair CDI (RCDI) system. By coupling the advantages of both rational cell architecture (symmetric RCDI system with balanced ion storage) and suitable electrode material (reversible Cl- intercalation and fast charge transfer), the CoFeCl-LDH-based RCDI system exhibits an ultrahigh desalination capacity (100.2 mg g−1) and fast desalination rate (0.38 mg g−1 s−1), which outpperform those of the other LDH-based CDI systems. The outstanding desalination performance of the CoFeCl-LDH-based RCDI further demonstrates the critical importance of both electrode material and cell architecture to the EDI system, which could shed light on the future design of highly efficient EDI systems.
Under the double pressures of both the energy crisis and environmental pollution, the exploitation and utilization of hydrogen, a clean and renewable power resource, has become an important trend in ...the development of sustainable energy‐production and energy‐consumption systems. In this regard, the electrocatalytic hydrogen evolution reaction (HER) provides an efficient and clean pathway for the mass production of hydrogen fuel and has motivated the design and construction of highly active HER electrocatalysts of an acceptable cost. In particular, graphene‐based electrocatalysts commonly exhibit an enhanced HER performance owing to their distinctive structural merits, including a large surface area, high electrical conductivity, and good chemical stability. Considering the rapidly growing research enthusiasm for this topic over the last several years, herein, a panoramic review of recent advances in graphene‐based electrocatalysts is presented, covering various advanced synthetic strategies, microstructural characterizations, and the applications of such materials in HER electrocatalysis. Lastly, future perspectives on the challenges and opportunities awaiting this emerging field are proposed and discussed.
Electrode catalysts for the hydrogen evolution reaction are at the heart of electrochemical water splitting technology. Recent advances in the controllable synthesis, microstructural analysis, and electrocatalytic properties of graphene‐based hydrogen evolution electrocatalysts are presented, together with a discussion of the major challenges and opportunities in this emerging field.
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•The immobilized MIL-88A(Fe) onto cotton fibers (MC) was prepared.•MC was used to achieve efficient and long-term elimination of tetracyclines matrix.•A fixed bed reactor is ...constructed from MC in a home-made annular setup.•MC displayed boosted long-term stability in both batch and fixed bed tests.
This work demonstrates the successful immobilization of MIL-88A(Fe) MOF on cotton fibers to fabricate MIL-88A(Fe)/cotton fibers (MC) by an eco-friendly method. The prepared MC is used to activate peroxydisulfate for eliminating multiple tetracycline antibiotics, such as oxytetracycline (OTC), tetracycline (TTC), and chlortetracycline (CTC) in simulated wastewater under UV-light irradiation. The photoactivated sulfate radical-advanced oxidation processes (SR-AOPs) towards the removal of tetracycline antibiotics matrix (initial concentration of 10.0 mg/L) using MC were initially investigated using a batch method. The results reveal that 97.5% OTC, 95.2% TTC, and 100.0% CTC can be degraded in the MC/UV/PDS system in the presence of 2 g/L of MC and 1 mM of PDS. The degradation pathways of OTC, TTC, and CTC were clarified via liquid chromatography-mass spectrometry analysis and DFT calculations. The quantitative structure–activity relationship analysis shows that the tetracycline antibiotics are transformed into their corresponding intermediates with lower toxicity within 8.0 min. A self-designed fixed bed reactor, in which the MC was packed into the annular channel, was adopted to test the long-term operation possibility of the MC in the continuous photoactivated SR-AOP system. The findings demonstrate that the whole antibiotics matrix can be removed completely within 22 h. This work is the first to demonstrate the use of MOFs as catalysts for SR-AOP to achieve continuous purification of simulated wastewater. The findings highlight a new possibility for the use of MOFs in large-scale wastewater treatment over.
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•Ti3C2Tx MXene acts as cocatalyst for tetracycline hydrochloride degradation and Cr (VI) reduction.•High charge separation efficiency is achieved by introducing the Ti3C2Tx.•Enhanced ...visible light harvesting and Schottky junction result in enhanced photocatalytic performance.•The photogenerated h+, ·O2− and e− dominate the degradation and reduction process.
The low charge transfer efficiency of isolated semiconductors is an urgent challenge in the photocatalytic degradation of hazardous contaminants. In this work, CaIn2S4/MXene Ti3C2Tx Schottky heterojunctions are synthesized via a simple hydrothermal method and applied for tetracycline hydrochloride degradation and Cr(VI) reduction. Results show that Ti3C2Tx as a cocatalyst can limit the charge recombination and boost the absorption of visible light, thus promoting the photocatalytic efficiency of pure CaIn2S4. An optimized CaIn2S4-Ti3C2Tx hybrid has the highest catalytic rate in the degradation of tetracycline hydrochloride (96%) and reduction of Cr(VI) (98%). Studies probing the mechanism indicate that the photogenerated superoxide radicals and holes play a key role in the tetracycline hydrochloride degradation process, while electrons are core to the Cr(VI) reduction reaction. Besides the high photocatalytic efficiency, the CaIn2S4-Ti3C2Tx hybrids also exhibit outstanding photo-stability in the present conditions, suggesting the potential for practical use.
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