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The influence of flow step ratio (FSR) on the startup characteristics of instant heat pump water heaters (IHPWHs) with natural mixture M (R744/R290 (12/88)) under nominal conditions was studied experimentally to verify the feasibility of a new quick startup method. The results show that the FSR had a marked effect on the startup time of system performance parameters. Under the optimal FSR of 0.6, the shortest system startup time and available hot water supply time were 700 s and 250 s, respectively, which were markedly shorter than those in the conventional startup. Therefore, rapid startup of the system and rapid production of usable domestic hot water can be realized by controlling the flow step. The influence of flow step on the variation trend of system performance parameters was obviously different, and there was no slow warming section for the heat sink outlet temperature (HSOT) under three FSRs. The HSOT, heating capacity, and high pressure side pressures had the maximum values in the quick startup, and the maximum values were obviously affected by the FSR. The FSR had no marked effect on the minimum suction pressure. The refrigerant pressures and refrigerant temperatures fluctuated markedly in both rapid and conventional starts. [ABSTRACT FROM AUTHOR]

Highly polar C N functional groups on polyacrylonitrile (PAN) facilitate strong hydrogen bonding and dipole-dipole interactions with hydroxyl groups on the surfaces of active materials and current collectors. Here we report that the strong interaction between PAN and carbon black (CB) particles facilitates a uniform distribution of CB particles within the electrode and forms a well-connected conductive network on the surface of active material particles. This significantly enhances electron transport within the electrode, offering superior rate performance and cycling stability beyond traditional binders like polyvinylidene fluoride (PVDF). Activated carbon (AC) electrodes containing 7.70 wt.% PAN binder (AC-7.7PAN) deliver areal capacitances over 0.60 F cm⁻2 at a scan rate of 500 mV s⁻1, and exhibits a high gravimetric energy density (E g) of 26.20 Wh kg⁻1 and high areal energy density (E a) of 0.33 mWh cm⁻2 at a current density of 1 A g⁻1. An AC-7.7PAN coin-cell supercapacitor maintains up to 62 % of its initial capacitance at a scan rate of 200 mV s⁻1, while a controlled AC-7.7PVDF coin-cell keeps only 37 % under the same conditions. The AC-7.7PAN coin-cell retains 91 % of its capacity even after 50,000 charge/discharge cycles at a constant current of 5 A g⁻1. The ability of PAN to evenly distribute conductive agents might be attractive for other power-type electrochemical electrodes, for which effective electron transport are extremely required. [ABSTRACT FROM AUTHOR]

The development of high-performance non-noble metal-based oxygen electrocatalysts is crucial for the practical application of zinc–air batteries. Most of them suffer from low intrinsic activity and poor stability, failing to meet the needs of practical applications. Here, we report an efficient and durable bifunctional oxygen electrocatalyst of Fe@Fe-SAC composite (SAC stands for single atoms on carbon). A facile and ease-to-scale-up process synthesizes it. Fe single-atom and Fe nanoparticles are anchored on nitrogen-doped porous carbon, with the latter encapsulated by the graphitic shell. It exhibits appealing activity and durability in a basic electrolyte, requiring a half-wave potential of 0.805 V for oxygen reduction reaction (ORR) and an overpotential of only 348 mV to deliver a current density of 10 mA cm−2 for oxygen evolution reaction (OER). Both activities are comparable to the corresponding benchmarking electrocatalyst of Pt/C for ORR and IrO2 for OER. The superior activities are attributed to the strong electronic interaction between metal single-atom and nanoparticles. The favorable stability is ascribed to the physical encapsulation of carbon coatings on nanoparticles. This work presents a feasible scheme for designing and large-scale preparation of high-performance non-noble metal-based bifunctional oxygen electrocatalysts. [ABSTRACT FROM AUTHOR]

A novel naphthalimides‐based fluorescent probe (NPHD) selectively detected Cu2+ and PPi through "strong yellow‐weak green‐strong yellow" photonic response in a sequential manner. The formation of NPHD‐Cu2+ resulted in obvious fluorescence decreased and wavelength shift from 595 nm to 525 nm by adding Cu2+ to NPHD solution. The mechanism could be attributed to d→π* electron transfer (ET) from Cu2+ to NPHD. Furthermore, the NPHD‐Cu2+ complex exhibited high selectivity toward PPi through via emission recovery of chemosensor NPHD. The detection limits of NPHD to Cu2+ and NPHD‐Cu2+ to PPi were estimated to be 5.72×108M and 2.39×108M. In addition, NPHD could be employed to detect exogenous Cu2+ and PPi in Hep G2 cells. [ABSTRACT FROM AUTHOR]

Conventional methods for the general and efficient synthesis of 4‐hydroxybenzo‐ phenones are extremely underdeveloped and limited. We herein report a challenging metal‐free protocol to rapidly construct 4‐hydroxybenzophenones from para‐quinone methides (p‐QMs) in DMSO in the presence of KOH using the inexpensive and readily available elemental sulfur as redox reagent. As an unprecedented method, this simple but efficient approach has excellent site specificity, green sustainability, excellent atomic economy, and broad functional group compatibilities. Mechanistic studies show that the novel reaction proceeds through a radical pathway. [ABSTRACT FROM AUTHOR]

[Display omitted] • Preparation of low-cost, eco-friendly, efficient porous hard carbons (PHC) electrodes and sodium-ion batteries (SIBs). • A comparative study between conventional activation and one-step sonochemical activation. • Physiochemical adsorption of Na+ ions on surface sites/functional groups, and intercalation into graphitic layers. • PHC-1 exhibited the highest specific capacity, excellent rate capability, and superior cycle stability with good retention. • Dependence of the low-voltage plateau region's capacity on graphitization and that of the high-voltage slope on porosity. A facile one-step sonochemical activation method is utilized to fabricate biomass-derived 3D porous hard carbon (PHC-1) with tuned-surface and is compared with the conventional two-step activation method. As raw biomass offers good KOH impregnation, ultrasonication power diffuses both K+ and OH– ions deep into its interior, creating various nanopores and attaching copious functional groups. In contrast, conventional activation lacks these features under the same carbonization/activation parameters. The high porosity (1599 m2/g), rich functional groups (O = 8.10%, N = 0.95%), and well-connected nanoporous network resulting from sonochemical activation, remarkably increased specific capacity, surface wettability, and electrode stability, consequently improved electrochemical performance. Benefiting from its suitable microstructure, PHC-1 possesses superior specific capacity (330 mAh/g at 20 mA/g), good capacity retention (89.5%), and excellent structural stability over 500 sodiation/desodiation cycles at high current density (1000 mA/g). Apart from modus operandi comparison, the two activation methods also provide mechanistic insights as the low-voltage plateau region and graphitic layers decrease simultaneously. This work suggests a scalable and economical approach for synthesizing large-scale activated porous carbons that are used in various applications, be it energy storage, water purification, or gas storage, to name a few. [ABSTRACT FROM AUTHOR]

Abstract: A newly designed N-doped porous carbon with magnetic nanoparticles formed in situ (RHC-mag-CN) was fabricated through simple impregnation then polymerization and calcination. The doped nitrogen in RHC-mag-CN was in the form of graphite-type layers with the composition of CN. The resultant nanocomposite maintained a high surface area of 1136 m2 g−1 with 18.5 wt% magnetic nanoparticles (Fe3O4 and Fe) inside, which showed a saturation magnetization (Ms) of 22 emu/g. When used as an adsorbent, the RHC-mag-CN demonstrated a very quick adsorption property for the removal of Cr(VI), during which 92% of Cr(VI) could be removed within 10 min for dilute solutions at 2 g L−1 adsorbent dose. The high adsorption capacity (16 mg g−1) is related to the synergetic effects of physical adsorption from the surface area and chemical adsorption from complexation reactions between Cr(VI) and Fe3O4. Importantly, the basic CNs in RHC-mag-CN increase its negative charge density and simultaneously increase the adsorption of metallic cations, such as Cr3+ formed in the acid solution from the reduction of Cr(VI). The formation of magnetic nanoparticles inside not only supplies complexing sites for the adsorption of Cr(VI), but also shows perfect magnetic separation performance from aqueous solution. [Copyright &y& Elsevier]

Developing interfacial connections is one of the breakthrough strategies to improve the photocatalytic activity. Herein, ZnBi 2 O 4 nanoparticles-ZnO nanorods heterojunction was successfully synthesized and used, as a dual-function photocatalyst, for photocatalytic degradation of Bisphenol A and hydrogen production with improved photocatalytic activity under simulated sunlight irradiation. The highest H 2 production (3.44 mmol g−1 h−1) was obtained for ZnO-20 wt% ZnBi 2 O 4 sample, which is around 12.7 times higher than pure ZnO. According to the HRTEM result, the intimate interfacial connections are formed between ZnO and ZnBi 2 O 4 which could act as trapping centers for charge carriers and results in the boosted photocatalytic activity. Further, a high aspect ratio of 1D ZnO nanorods and small size of 0D ZnBi 2 O 4 nanoparticles (~10 nm) increases the number of interfacial contacts and thus the charge carriers' recombination was suppressed more efficiently. Based on the trapping experiments, ESR and Mott-Schottky analysis, ZnBi 2 O 4 –ZnO hybrid photocatalyst followed the S -scheme charge transfer mechanism. • Novel 0D/1D ZnBi 2 O 4 /ZnO p-n heterojunction was successfully prepared. • The prepared hybrid system revealed improved H 2 production and BPA decomposition. • The highest hydrogen evolution (3.44 mmol.g−1.h−1) was achieved on ZnO–20%ZnBi 2 O 4. • S -scheme mechanism was suggested for boosted photocatalytic activity. • The defects formed at the interfacial contacts decreased the recombination rate. [ABSTRACT FROM AUTHOR]

• Alloying and Iridium surface segregation influence surface strain and achieve dissociative adsorption of hydrogen on all the catalysts. • Iridium segregation on the surface of IrRu 3 core-shell catalyst downshift the d-band and improve the hydrogen oxidation due to surface charge redistribution. • Core-shell type catalyst with higher Ru content notably enhances HOR performance. • Iridium surface segregation should take into account in Ir-Ru catalyst. The catalysis of hydrogen oxidation reaction (HOR) at the anode is one of the most important topics in achieving high-performance proton exchange membrane fuel cells, especially in the presence of hydrogen fuel impurities and during the start-up/shutdown cycling and cell reversal. To improve catalytic HOR performance, Iridium-Ruthenium alloy (IrRu) catalysts have been explored to address the issues. For fundamental understanding of the catalytic HOR activities, this paper employs density functional theory (DFT) calculations to elucidate and interpret the surface modifications and Ru content effect on hydrogen adsorption energy of the IrRu alloys. The catalytic HOR activity trend of the alloyed IrRu catalysts is calculated to be Ir 3 Ru > IrRu > IrRu 3 , which is opposite to that experimentally observed. However, if the surface enrichment of Ir atoms on the IrRu surfaces to form core-shell type catalysts, the calculated trend becomes to IrRu 3 > IrRu > Ir 3 Ru, which is in agreement with the experiment result. In spite of higher surface energy on IrRu 3 core-shell surface, the compelling d-band downshift can attribute to the surface charge depletion, decreasing hydrogen adsorption energy, and resulting in the highest catalytic activity. For Ir 3 Ru core-shell catalyst, a relatively higher charge accumulation on the surface Ir is observed, which can up-shift the d-band and increase hydrogen adsorption, resulting the lowest catalytic activity. The IrRu catalyst has intermediate d-band downshift and hydrogen adsorption energy so that its catalytic activity remains between IrRu 3 and Ir 3 Ru for both alloyed and core-shell structures. [ABSTRACT FROM AUTHOR]

Carbon-based aerogels have demonstrated to have a great promise as advanced microwave absorption materials due to their ultralow volumetric density, unique pore structure, and high electrical conductivity. However, the comparatively complex fabrication process, weak machinability and difficulty in regulation of electromagnetic properties still hinder their large-scale application. Here, we reported a facile and scalable fabrication of novel carbon hybrid aerogels with adjustable electromagnetic properties from naturally abundant bacterial cellulose. Composed of robust network of ultrahigh-aspect-ratio metal/carbon nanofibers, the carbon hybrid aerogels exhibited combined characteristics of highly porous structure, ultralow density, physical flexibility and electromagnetic properties. As fillers of microwave absorption materials, the fabricated hybrid aerogels delivered strong microwave-absorbing ability with the minimum reflection loss of −70.1 dB even at the filler loading as low as 0.8 wt%, superior to previously reported carbon-based aerogels. Especially, the naturally unique surface chemistry and physical properties of bacterial cellulose provided the possibility of manipulating the microstructure and morphology of carbon hybrid aerogels in easy ways as demonstrated in this work, which can be utilized to optimize microwave absorption property and absorption band. Thus, biocarbon materials exhibit promising potential for meeting the increasing demand for scalable, high-efficiency and requirement-guided microwave absorption materials. Image 1 [ABSTRACT FROM AUTHOR]

Two-dimensional material Ti 3 C 2 T x (T = OH, O, F) attracts great attention due to its excellent performance in energy storage. The functional groups on the surface have tremendous influence on its electrochemical performance. Herein, Ti 3 C 2 T x powders with different surface chemistry were obtained via the etching with sodium hydroxide and hydrofluoric acid and used as anode materials for Li-ion batteries. Alkali etched Ti 3 C 2 T x (mass loading: 1.24 mg cm−2) possesses a larger c -lattice parameter and functional groups without fluorine terminated, showing nearly twice capacities higher than that of Ti 3 C 2 T x etched by hydrofluoric acid (mass loading: 1.06 mg cm−2) at current density of 0.5 A g−1. It is suggested that fluorine-free Ti 3 C 2 T x etched via alkali is more promising for lithium-ion batteries than its fluorine-containing counterpart. Unlabelled Image • Fluorine-free Ti 3 C 2 T x via alkali treatment owns larger spacing between 2D layers. • Alkali etched Ti 3 C 2 T x shows nearly twice capacities higher than that of acid etched Ti 3 C 2 T x. • Fluorine-free Ti 3 C 2 T x is more promising for lithium-ion batteries than its fluorine-containing counterpart. [ABSTRACT FROM AUTHOR]

• A novel benzothiazole derivative BP was prepared for the relay quantification of Fe3+ and PPi. • Chemosensor BP displayed highly selective fluorescence "ON-OFF-ON" response to Fe3+ and PPi. • This chemosensor BP was applied to living cells imaging. A novel on-off-on fluorescence chemosensor BP based on benzothiazole for the relay recognition of Fe3+ and PPi was designed and synthesized. The chemosensor BP exhibited a high affinity to Fe3+ in the presence of other competing cations. The resultant BP -Fe3+ showed excellent recognition ability for PPi via Fe3+ displacement approach. The detection limits of BP for Fe3+ and BP -Fe3+ for PPi were estimated to be 2.59 × 10−8 M and 8.47 × 10−8 M, respectively. The low cytotoxicity and good cell-membrane permeability of BP and BP -Fe3+ complex makes them capable of Fe3+ and PPi imaging in living Hep G2 cells. [ABSTRACT FROM AUTHOR]

Herein TiO 2 coated on glass fiber cloth (TiO 2 /glass fiber cloth, TGFC) was synthesised by sol-gel method. We demonstrated the property about TGFC of photocatalytic decomposition of organic pollutants under ultraviolet-visible (UV–vis) light and sunlight. Glass fiber cloth (GFC) was chosen as the support of TiO 2 in order to improve the practical applications for water purification. TGFC-1–6 were characterized by ERSEM, XRD and XPS. Photocatalytic decomposition of crystal violet (CV) was carried out to investigate the photocatalytic activity of TGFC. The efficiency of TGFC-3 was the best. And its photocatalytic decomposition rate of the second to fifth cycle was higher than the first cycle. The photocatalytic decomposition rate of TGFC-3 was 85% under sunlight from 8:00–14:00. We could design and regulate the shape of TGFC and estimate the area, weight and thickness of TiO 2 , more easily than glass fibers. TGFC is suitable for photocatalytic decomposition of organic pollutants in the water, especially to be fixed in sewage treatment pool and reused. [ABSTRACT FROM AUTHOR]

The slow photon effect in a photonic crystal (PC) can lead to delay and storage of light in the PC and has an immense potential for improving solar-to-energy efficiency. A series of biomorphic TiO 2 photonic crystal (TiO 2 -BMPC) structures are fabricated through a sol–gel method by using butterfly wings as templates, and subsequently gold nanoparticles (Au NPs) with an average size of about 9 nm are deposited in situ into the TiO 2 -BMPC. Varying structural characteristics of the PCs by choosing different butterfly wings, the slow photon region of the photonic band gap could be purposely tuned to overlap with strong localized surface plasmon resonance (SPR) region of the Au NPs. The matching slow photon of the TiO 2 -BMPC templated from the butterfly wings of Euploea mulciber intensifies the SPR responses (central at 550 nm) of the Au NPs. Consequently, the visible-light harvesting capability of the Au/TiO 2 -BMPC is significantly improved due to this unique biomorphic architecture. As a result, the designed photocatalyst exhibits a photocatalytic activity that is several time higher than conventional Au/TiO 2 -P25 material, as illustrated by the example of the photocatalytic decomposition of methyl orange (MO) under visible-light illumination. [ABSTRACT FROM AUTHOR]

Porous hard carbons (PHC) are promising anode materials in sodium-ion batteries; however, the availability of large surface area creates numerous irreversible active sites that cause rapid initial cycle capacity fading and electrode degradation, resulting in lower specific capacity and poor cycle stability. PHC surface modification via 2D transition metal dichalcogenides is a synergistic approach to combine excellent electrochemical properties of both materials and resolve these issues. Therefore, we designed 1T MoS 2 nanopatterned PHC skeleton using carbonization and hydrothermal treatment of biomass (chickpea husk). As a result, HC@MoS 2 -II electrode with extended d 002 spacing of MoS 2 nanolayers (0.650 nm) exhibited an excellent specific capacity of 470 mAh/g at 50 mA/g with high initial coulombic efficiency (63%) and ultra-long cycle stability (190 mAh/g) at 1000 mA/g over 3500 cycles. The extraordinary electrochemical performance can be attributed to the synergistic assembly, where the high surface area PHC skeleton effectively buffered large volume expansion during charging/discharging, and 1T MoS 2 nanoflowers added fast ionic diffusion kinetics and PHC surface protection. [Display omitted] [ABSTRACT FROM AUTHOR]

Through billions of years of evolution, nature has created biological materials with remarkable properties. Studying these biological materials can guide the design and fabrication of bio-inspired materials. Many of the complex natural architectures, such as shells, bones, and honeycombs, have been studied to imitate the design and fabrication of materials with improved hardness and stiffness. Recently, an increasing number of researchers have investigated the wings of lepidopterans (butterflies and moths) because these structures may exhibit dazzling colors. Based on previous studies, these iridescent colors are attributable to periodic structures on the scales that constitute the wing surfaces. These complex and diverse structures have recently become a focus of multidisciplinary research due to their promising applications in the display of structural colors, advanced sensors, and solar cells. This review provides a broad overview of the research into these wings, particularly the microstructures in the wing scales. This review investigates the following three fields: structural characterization and optical property analysis of lepidopteran wings, modeling and simulation of the optical properties and microstructure, and the fabrication of artificial structures inspired by these wings. [ABSTRACT FROM AUTHOR]

• Seaweed carbon has a high surface area and interconnected mesoporous framework. • Seaweed carbon substrate solves the agglomeration of RuO 2 nanoparticles. • Seaweed carbon provides abundant active sites for ions adsorption/desorption. • The mesopores in seaweed carbon facilitate the fast transportation of ions. • Partially graphitized seaweed carbon ensures the rapid transfer of the electrons. Supercapacitors (SCs) have attracted widespread attention due to the fast development of electronics and electrical vehicles. As a potential pseudocapacitive electrode material for SCs, RuO 2 is promising for fast energy storage, but its performance is severely restricted by the spontaneous agglomeration and high cost. Here, we prepared seaweed-derived porous carbon (SDC) as a conductive substrate of hydrous RuO 2 nanoparticles for electrochemical SCs, and the as-prepared hybrid exhibits high specific capacitance of 807 F g−1 at 2 mV s−1, excellent high-rate (988.1 F g−1 at 0.1 A g−1 and 635.9 F g−1 at 5 A g−1) and cycling performances (93.8% retention after 1000 cycles at 1 A g−1) in 1 M H 2 SO 4. The outstanding performance of the hybrid can be attributed to the interconnected three-dimensional mesoporous structure of the SDC and the uniform dispersion of hydrous RuO 2 nanoparticles. This work demonstrates that the hierarchical porous SDC can be used as an excellent conductive substrate to further enhance the electrochemical performance of other easily agglomerated nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: A sonochemical method was introduced to synthesize SnO2 nanoparticles in the pores of mesoporous carbon without any other agents. The nitrogen adsorption measurement and transmission electron microscopy results revealed that the SnO2 nanoparticles with the average particle size of around 10nm were homogeneous distribution in the matrix. The aggregation of SnO2 was hindered by the three-dimensioned porous frameworks, resulting in a relatively large surface area of 362m2 g−1, which is beneficial for lithium-ion storage in batteries. The resultant composites with 43% SnO2 exhibited a high reversible capacity of 200mAhg−1 even after 300 cycles, which is 186% higher than that of the initial mesoporous carbon matrix. This strategy is expected to incorporate other functional nanoparticles inside mesoporous carbon for many applications. [Copyright &y& Elsevier]

Abstract: Using ultrasonication we succeed in a controlled incorporation of TiO2 nanoparticles on the graphene layers homogeneously in a few hours. The average size of the TiO2 nanoparticles was controlled at around 4–5nm on the sheets without using any surfactant, which is attributed to the pyrolysis and condensation of the dissolved TiCl4 into TiO2 by ultrasonic waves. The photocatalytic activity of the resultant graphene–TiO2 composites containing 25wt.% TiO2 is better than that of commercial pure TiO2. This is partly due to the extremely small size of the TiO2 nanoparticles and partly due to the graphene–TiO2 composite structure consisting of homogeneous dispersion of crystalline TiO2 nanoparticles on the graphene sheets. As the graphene in the composites has a very good contact with the TiO2 nanoparticles it enhances the photo-electron conversion of TiO2 by reducing the recombination of photo-generated electron–hole pairs. [Copyright &y& Elsevier]

Ag doped Sn 3 O 4 Nanostructure and immobilized on hyperbranched polypyrrole is investigated in this project. The product was synthesized by the hydrothermal synthesis method. The surface and structural characteristics of the product was studied by different instrumental analysis. The fabricated nanocomposites was utilized as a nano photocatalyst in the removal of methylene blue dye. The crystallography results depicts the triclinic phase of Sn 3 O 4 with the crystallite size 36.3 nm. The band gap of the Ag-Sn 3 O 4 /hyperbranched polypyrrole was found 1.50 eV from kubelka-munk measurements. The specific surface area was increased in the presence of the hyperbranched polypyrrole as compared to Ag-Sn 3 O 4 samples. The photo-catalytic activity of composites was found 100.0% degradation of CR in 30 min under visible light irradiation. The catalytic kinetic was followed from the first kinetic model. Moreover, the Ag/Sn 3 O 4 /hyperbranched polypyrrole was applied as a bactericidal agent against Streptococcus pneumoniae , and Pseudomonas aeruginosa bacteria. Determination of Streptococcus pyogenes as a pathogenic bacteria was investigated by using aptamer/Ag/Sn 3 O 4 /hyperbranched polypyrrole in peroxidase activity. The detection limit of S. pyogenes was 71.0 CFU/mL by using the nano-aptamer. • Ag/Sn 3 O 4 /HPPy prepared by chemical method. • The Ag/Sn 3 O 4 /HPPy was studied for degradation of CR dye under visible light. • The Ag/Sn 3 O 4 /HPPy showed excellent anti-bacterial activity. • The bacterial detection was conducted by using the aptamer-Ag/Sn 3 O 4 /HPPy. [ABSTRACT FROM AUTHOR]

[Display omitted] • We designed and developed a porous layered graphene like carbon material based on biomass resources (chitosan), and prepared a new ruthenium nanoparticle HER catalyst with it as the carrier (CNF@Ru-x). • Under alkaline conditions (1.0 M KOH), it showed good HER catalytic activity with low HER overpotential of CNF@Ru-2 is 50.2 mV and 186 mV at 10 and 100 mA cm−2, respectively. • The interaction between Ru metal and support was deeply explored through structural characterization and surface analysis. The development of cheap and efficient nonplatinum catalysts under alkaline conditions is of great significance for hydrogen evolution. Here, a N-doped porous layered graphene-like carbon material was designed. When J = 10 mA cm−2, it showed good HER catalytic activity, the overpotential was 50.2 mV, and 186.0 mV at 100 mA cm−2. And its outstanding catalytic ability is confirmed by Tafel slope, EIS, C dl , ECSA and electrochemical stability. Its excellent performance provides a reasonable way to explore and develop catalysts in the field of environment and energy. [ABSTRACT FROM AUTHOR]

• The 1T'-MoS 2 nanoflakes were anchored on holey graphene (hG) sheets through a facile and scalable assembly approach. • Energetically more favorable metallic 1T'-MoS 2 was first used for LIBs anode, improving the overall conductivity. • Abundant oxygenous groups on holey graphene facilitate the 2D/2D assembly with 1T'-MoS 2 nanoflakes. • Outstanding high-rate performance is obtained, with a capacity retention of 94.5% after 2000 cycles at 5 A g−1. Rapid charging is of high demand in lithium-ion batteries (LIBs). Molybdenum sulfide (MoS 2) has attracted great interest as a potential anode for LIBs due to its high theoretical capacity. However, low electronic conductivity and severe volume change upon lithiation/delithiation hinder its applications, especially in high-rate applications. Herein, we develop a facile assembly process to fabricate a highly conductive 1T'-MoS 2 /rhGO composite where rhGO is referred as reduced holey graphene oxide. The abundant oxygen-containing groups on holey graphene make it possible for realizing 2D/2D assembly of 1T'-MoS 2 with graphene oxide. When used in LIBs, the 1T'-MoS 2 /rhGO anode delivered a high specific capacity of 1084 mAh g−1 at 0.2 A g−1 and outstanding high-rate performance, 635 mAh g−1 at a large current density of 5 A g−1 for 2000 cycles with capacity retention reaching 94.5%. The excellent high-rate performance is attributed to the synergic effects of the metallic 1T'-MoS 2 and the holey graphene matrix. The former increases the overall conductivity while the latter anchors 1T'-MoS 2 nanoflakes tightly through chemical bonding, thus preventing volume changes during cycling. This facile approach for achieving 2D and 2D assembly paves a new way of developing high-rate performance anodes for LIBs which can better fulfill the demand for fast-charging technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel visible driven WO 3 -CeO 2 heterojunction was successfully synthesized. • The prepared photocatalyst was applied for degradation of Sulfamerazine from an aqueous solution. • Incorporation of CeO 2 on WO 3 significantly enhanced the photodegradation percentage. • S-scheme mechanism was suggested for the boosted photocatalytic activity. • Photodegradation pathways of Sulfamerazine antibiotic were investigated. In this work, hierarchical WO 3 -CeO 2 hollow sphere heterojunctions were fabricated via a two-step hydrothermal method and applied for degradation of sulfamerazine antibiotic under visible light irradiation. The incorporation of CeO 2 into the WO 3 microspheres was confirmed by XRD, BET, HRTEM, and XPS analysis. The results revealed that the photocatalytic activity of WO 3 -CeO 2 heterojunction was greatly enhanced compared to pure CeO 2 and WO 3 samples, and the highest degradation percentage of sulfamerazine was achieved on the WO 3 -CeO 2 heterojunction with 30 mol. % CeO 2 content. This could be ascribed to the efficient separation of charge carriers which was facilitated by oxygen vacancies formed at the interfaces of two coupled semiconductors. EIS analysis verified that the charge transfer resistance of WO 3 -30CeO 2 heterojunction was decreased, which is due to the heterojunction effect. Moreover, based on the Mott-Schottky calculations, radical trapping experiments and ESR analysis, hydroxide radicals were identified as the main active species, and an S-scheme charge transfer mechanism was suggested to explain the enhanced photocatalytic activity. The possible degradation pathway of sulfamerazine was suggested through the detection of degradation intermediates by mass spectroscopy. [ABSTRACT FROM AUTHOR]

• Novel Bi 2 WO 6 -ZnBi 2 O 4 heterojunction was prepared by sonochemical assisted hydrothermal method. • Sonochemical pretreatment caused spherical to flake-like morphology evolution. • The optimal Bi 2 WO 6 -20ZnBi 2 O 4 revealed good stability (4% loss) after 5 cycling runs. • Direct Z-scheme mechanism was proposed for the enhanced photodegradation of MG. • Bi 2 WO 6 -ZnBi 2 O 4 can efficiently remove both MG dye and colorless 2,4-DCP contaminants. In this work, novel Bi 2 WO 6 -ZnBi 2 O 4 p-n heterojunction was successfully synthesized through combination of sonochemical and hydrothermal procedures. The results revealed that the sonochemically prepared nanocomposites had spherical shape with amorphous structure which became crystalline particles with flak-like morphology after hydrothermal treatment. Bi 2 WO 6 -ZnBi 2 O 4 nanocomposite with 20 wt% ZnBi 2 O 4 content demonstrated the highest photocatalytic performance compared to the pure Bi 2 WO 6 and ZnBi 2 O 4 samples toward the degradation of Malachite Green (MG). This finding is associated with the efficient separation of photo-generated electron/hole pairs due to the formation of interfacial charge transfer between Bi 2 WO 6 and ZnBi 2 O 4. However, further ZnBi 2 O 4 loading had no significant effect on the enhancement of photocatalytic activity of nanocomposite samples owing to the shielding effect of ZnBi 2 O 4 against incident light. The obtained results were further verified by optical and photocurrent density measurements. Based on the obtained results from active species trapping experiments, electron spin resonance and Mott-Schottky calculations, the Z-scheme charge transfer pathway was proposed as the predominant mechanism for the photocatalytic reactions. Also, the photocatalytic degradation of 2,4-dichlorophenol, as a colorless model pollutant, was conducted on optimal composite sample to study the possible contribution of MG dye sensitization mechanism in the enhancement of photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • We designed and developed a novel HER catalyst of ruthenium nanoparticles supported on oxide carbon nanotubes (Ru@OCNT-700). • For HER performance in alkaline media (1 M KOH), the as-formed Ru@OCNT-700 reaches 10 mA cm−2 at an overpotential of 13.2 mV with a Tafel slope of 45.4 mV dec−1. • Through the characterization of the surface and structure of the catalyst sample, the interaction between ruthenium metal and carrier was analyzed. "Cracking" water is of great significance to develop (HER) catalysts with high catalytic performance for non-platinum hydrogen evolution under alkaline conditions. In this paper, we prepared a ruthenium nanoparticle catalyst on oxidized carbon nanotubes (Ru@OCNT) support. Electrochemical tests showed that Ru@OCNT-700 exhibited excellent catalytic performance and good stability under alkaline conditions (1 M KOH). When the current density reached 10 mA cm−2, it only needed an overpotential of 13.2 mV. The Tafel slope was 45.4 mV/dec−1. Due to its excellent HER performance, Ru@OCNT electrocatalyst could have broad applicability in large-scale hydrogen production. [ABSTRACT FROM AUTHOR]

Vanadium nitride (VN) is a promising electrode material for sodium-ion storage due to its multivalent states and high electrical conductivity. However, its electrochemical performance has not been fully explored and the storage mechanism remains to be clarified up to date. Here, the possibility of VN/carbon hybrid nanorods synthesized from a metal-organic framework for ultrafast and durable sodium-ion storage is demonstrated. The VN/carbon electrode delivers a high specific capacity (352 mA h g -1 ), fast-charging capability (within 47.5 s), and ultralong cycling stability (10 000 cycles) for sodium-ion storage. In situ XRD characterization and density functional theory (DFT) calculations reveal that surface-redox reactions at vanadium sites are the dominant sodium-ion storage mechanism. An energy-power balanced hybrid capacitor device is verified by assembling the VN/carbon anode and active carbon cathode, and it shows a maximum energy density of 103 Wh kg -1 at a power density of 113 W kg -1 ., (© 2024 Wiley‐VCH GmbH.)

The use of porous hard carbons (PHCs) as electrode materials in sodium-ion batteries has great potential; however, the exposure of large surface areas to electrolyte flow results in irregular and irreversible solid electrolyte interfaces (SEIs), leading to deteriorated ionic and electronic mobility and inferior initial Coulombic efficiency (ICE). These issues can be addressed through suitable structural modifications of PHC materials. Herein, the integration of high-surface-area PHCs with carbon nanofibers (CNFs) was accomplished by a simple electrospinning technique, which resulted in a uniform and reversible SEI layer. In the meantime, the CNFs' mesh provided connectivity and conductivity in the as-integrated electrodes, whereas PHCs offered fast diffusion kinetics and high Na + ion storage capacity. Additionally, PHC integration with CNFs demonstrated an excellent ICE of 77% and a specific capacity of 505 mAh/g at 25 mA/g. Furthermore, the conjugated microstructure also provided flexibility and stability to the electrode (260 mAh/g after 500 cycles). This remarkable synergy may promote the development of free-standing, flexible, and highly porous properties in a single material for advanced energy storage applications.

Pt single-atom materials possess an ideal atom economy but suffer from limited intrinsic activity and side reaction of producing H 2 O 2 in catalyzing the oxygen reduction reaction (ORR); platinum alloys have higher intrinsic activity but weak stability. Here, we demonstrate that anchoring platinum alloys on single-atom Pt-decorated carbon (Pt-SAC) surmounts their inherent deficiencies, thereby enabling a complete four-electron ORR pathway catalysis with high efficiency and durability. Pt 3 Co@Pt-SAC demonstrates an exceptional mass and specific activities 1 order of magnitude higher than those of commercial Pt/C. They are durable throughout 50000 cycles, showing only a 10 mV decay in half-wave potential. An in situ Raman analysis and theoretical calculations reveal that Pt 3 Co core nanocrystals modulate electron structures of the adjacent Pt single atoms to facilitate the intermediate absorption for fast kinetics. The superior durability is attributed to the shielding effect of the Pt-SAC coating, which significantly mitigates the dissolution of Pt 3 Co cores. The hybridizing strategy might promote the development of highly active and durable ORR catalysts.

Electrocatalysts for the oxygen reduction reaction (ORR) play a central role in fuel cells and zinc-air batteries. Bimetal single atoms and nanoparticle hybrids are emerging ORR electrocatalysts, superior to the most exploited unary metal single-atom catalysts (SACs). Here, we report bimetal SAC-based nanofiber networks of Co 3 Fe 7 @Co/Fe-SAC for efficient ORR electrocatalysis and zinc-air batteries. A facile and easy-to-scale-up process is developed, and the versatility is validated in three hybrids. Strong electronic interaction is revealed between bimetal single atoms and alloy nanoparticles, leading to improved catalytic performances for ORR. Specifically, the Co 3 Fe 7 @Co/Fe-SAC hybrids exhibit a half-wave potential of 0.841 V in a basic electrolyte, comparable to the Pt/C electrocatalyst. Assembled in a zinc-air battery, a Co 3 Fe 7 @Co/Fe-SAC hybrid-based cell demonstrates a power density 1.8 times higher than the benchmark Pt/C-IrO 2 -based one, and it is stable for 150 cycles galvanostatic charge/discharge. The superior device performance is attributed to the appealing intrinsic activity, the carbon shielding effect for anti-leaching, and the hierarchical porous networks for large accessibility of active sites and favorable mass transport. Theoretical calculations suggest that alloy nanoparticles significantly improved the intrinsic catalytic activity of Fe single-atom sites at the expense of slightly lowering the activity of Co single-atom sites. This work presents a versatile process for the mass production of efficient composite electrocatalysts and highlights the power of bimetal single-atom-based hybrids and hierarchically porous structures for ORR device performances.

2D transition metal carbides and/or nitrides, so-called MXenes, are noted as ideal fast-charging cation-intercalation electrode materials, which nevertheless suffer from limited specific capacities. Herein, it is reported that constructing redox-active phosphorus-oxygen terminals can be an attractive strategy for Nb 4 C 3 MXenes to remarkably boost their specific capacities for ultrafast Na + storage. As revealed, redox-active terminals with a stoichiometric formula of PO 2 - display a metaphosphate-like configuration with each P atom sustaining three PO bonds and one PO dangling bond. Compared with conventional O-terminals, metaphosphate-like terminals empower Nb 4 C 3 (denoted PO 2 -Nb 4 C 3 ) with considerably enriched carrier density (fourfold), improved conductivity (12.3-fold at 300 K), additional redox-active sites, boosted Nb redox depth, nondeclined Na + -diffusion capability, and buffered internal stress during Na + intercalation/de-intercalation. Consequently, compared with O-terminated Nb 4 C 3 , PO 2 -Nb 4 C 3 exhibits a doubled Na + -storage capacity (221.0 mAh g -1 ), well-retained fast-charging capability (4.9 min at 80% capacity retention), significantly promoted cycle life (nondegraded capacity over 2000 cycles), and justified feasibility for assembling energy-power-balanced Na-ion capacitors. This study unveils that the molecular-level design of MXene terminals provides opportunities for developing simultaneously high-capacity and fast-charging electrodes, alleviating the energy-power tradeoff typical for energy-storage devices., (© 2022 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Lithium-ion capacitors (LICs) have attracted intense attention due to their high energy/power densities and good stability. However, their performance is severely limited by the imbalance in reaction kinetics and electrochemical capacity between the faradaic battery-like anodes and non-faradic capacitive cathodes. Here, we propose an all alginate-derived LIC assembled with a three-dimensional porous orthorhombic phase Nb 2 O 5 /C hybrid as the anode, seaweed-derived carbon as the cathode and sodium alginate (SA) as the electrode binder. The increase in the rate performance of the anode and the capacity of the cathode efficiently mitigates the mismatch between the counter electrodes, and the SA binder provides facilitated access for Li ions to the surfaces of electrode materials. The all alginate-derived LIC exhibits high energy (143.9 W h kg -1 at 87.6 W kg -1 ) and power (17.5 kW kg -1 at 75.1 W h kg -1 ) densities with a superior cyclability (84.6% capacity retention after 3000 charge-discharge cycles), surpassing those of previous Nb 2 O 5 -based LICs. This work provides a novel design strategy for the electrodes of next-generation high-performance LICs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Dense, thick, but fast-ion-conductive electrodes are critical yet challenging components of ultrafast electrochemical capacitors with high volumetric power/energy densities 1-4 . Here we report an exfoliation-fragmentation-restacking strategy towards thickness-adjustable (1.5‒24.0 μm) dense electrode films of restacked two-dimensional 1T-MoS 2 quantum sheets. These films bear the unique architecture of an exceptionally high density of narrow (sub-1.2 nm) and ultrashort (~6.1 nm) hydrophobic nanochannels for confinement ion transport. Among them, 14-μm-thick films tested at 2,000 mV s -1 can deliver not only a high areal capacitance of 0.63 F cm -2 but also a volumetric capacitance of 437 F cm -3 that is one order of magnitude higher than that of other electrodes. Density functional theory and ab initio molecular dynamics simulations suggest that both hydration and nanoscale channels play crucial roles in enabling ultrafast ion transport and enhanced charge storage. This work provides a versatile strategy for generating rapid ion transport channels in thick but dense films for energy storage and filtration applications., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Graphitic carbon nitride (g-C 3 N 4 ) is a promising photocatalyst for CO 2 reduction to alleviate the greenhouse effect. However, the low light absorption, small specific surface area, and rapid charge recombination limit the photocatalytic efficiency of g-C 3 N 4 . Herein, we demonstrate a bioinspired nanoarchitecturing strategy to significantly improve the light harvesting and charge separation of the g-C 3 N 4 /Au composite, as proven by the remarkable photocatalytic CO 2 reduction. Specifically, a biotemplating approach is employed to transfer the sophisticated hierarchical structures and the related light-harvesting functionality of Troides helena butterfly wings to the g-C 3 N 4 /Au composite. The resulting g-C 3 N 4 /Au composite shows high photocatalytic efficiency under UV-visible excitation with triethanolamine as the sacrificial agent. The yields of CO and CH 4 are 331.57 and 39.71 μmol/g/h, respectively, which are ∼36 times and ∼88 times that of pure g-C 3 N 4 under the same conditions. Detailed experiments and the finite-difference time-domain method suggest that the superb photocatalytic activity should be ascribed to the unique periodic hierarchical structure which assists the light absorption and the localized surface plasmon resonance for promoted charge separation in addition to the more effective CO 2 diffusion and larger specific surface area. Our work provides a new path for the design and optimization of photocatalysts based on biological structures that are usually unattainable artificially.

The performance and cost of electrocatalysts play an important role in the development and application prospects of energy conversion technology. Single-atom catalysts (SACs) have constituted a new frontier in the field of catalytic science in recent years. As a non-precious metal, iron (Fe)-SACs show great potential in the field of electrocatalysis, which is comparable to or even better than the performance of precious metal catalysts. However, a robust, generic synthetic strategy toward atomically dispersed Fe catalysts is still lacking, which is still a formidable challenge to maintain the dispersion of Fe atoms at high temperatures and to obtain high catalytic activity. In this review, the latest progress in the synthesis of Fe-SACs is introduced and summarized, and the electrochemical applications of Fe-SACs are further summarized and discussed. Herein, the relationship between the structural characteristics and performance of Fe-SACs is further introduced and discussed. Finally, the existing problems and development prospects of Fe-SACs are discussed., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

As attractive materials for photoeletrochemical hydrogen evolution reaction (PEC HER), conjugated polymers (e.g., conjugated acetylenic polymers [CAPs]) still show poor PEC HER performance due to the associated serious recombination of photogenerated electrons and holes. Herein, taking advantage of the in situ conversion of nanocopper into Cu 2 O on copper cellulose paper during catalyzing of the Glaser coupling reaction, a general strategy for the construction of a CAPs/Cu 2 O Z-scheme heterojunction for PEC water reduction is demonstrated. The as-fabricated poly(2,5-diethynylthieno[3,2-b]thiophene) (pDET)/Cu 2 O Z-scheme heterojunction exhibits a carrier separation efficiency of 16.1% at 0.3 V versus reversible hydrogen electrode (RHE), which is 6.7 and 1.4-times higher respectively than those for pDET and Cu 2 O under AM 1.5G irradiation (100 mW cm -2 ) in the 0.1 m Na 2 SO 4 aqueous solution. Consequently, the photocurrent of the pDET/Cu 2 O Z-scheme heterojunction reaches ≈520 µA cm -2 at 0.3 V versus RHE, which is much higher than pDET (≈80 µA cm -2 ), Cu 2 O (≈100 µA cm -2 ), and the state-of-the-art cocatalyst-free organic or organic-semiconductor-based heterojunctions/homojunctions photocathodes (1-370 µA cm -2 ). This work advances the design of polymer-based Z-scheme heterojunctions and high-performance organic photoelectrodes., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

Due to the potential application in the future energy conversion system, there is an increasing demand for efficient, stable and cheap platinum-free catalysts for hydrogen evolution. However, it is still a great challenge to develop electrocatalysts with high activity similar to platinum or even higher, especially those that can work under alkaline conditions. Ruthenium (Ru), as a cheap substitute for platinum, has been studied as a feasible substitute for (HER) catalyst for hydrogen evolution reaction. In this paper, we designed and developed a novel Ru catalyst (Ru@CNT) supported on nitrogen-doped carbon nanotubes. Electrochemical tests show that even under alkaline conditions (1 M KOH), Ru@CNT still shows excellent catalytic performance and good durability. It only needs 36.69 mV overpotential to reach a current density of 10 mA cm -2 , and its Tafel slope is 28.82 mV dec -1 . The catalytic performance of the catalyst is comparable to that of 20% Pt/C. The significant activity is mainly attributed to the chelation of highly dispersed ruthenium atoms on nitrogen-doped carbon nanotubes. Secondly, the one-dimensional pore structures supported by nitrogen heterocarbon nanotubes can provide more opportunities for active centers. Excellent HER performance makes Ru@CNT electrocatalyst have a broad application prospect in practical hydrogen production., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Natural biological systems are constantly developing efficient mechanisms to counter adverse effects of increasing human population and depleting energy resources. Their intelligent mechanisms are characterized by the ability to detect changes in the environment, store and evaluate information, and respond to external stimuli. Bio-inspired replication into man-made functional materials guarantees enhancement of characteristics and performance. Specifically, butterfly architectures have inspired the fabrication of sensor and energy materials by replicating their unique micro/nanostructures, light-trapping mechanisms and selective responses to external stimuli. These bio-inspired sensor and energy materials have shown improved performance in harnessing renewable energy, environmental remediation and health monitoring. Therefore, this review highlights recent progress reported on the classification of butterfly wing scale architectures and explores several bio-inspired sensor and energy applications., (© The Author(s) 2020. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd.)

Sophisticated metastructures are usually required to broaden the inherently narrowband plasmonic absorption of light for applications such as solar desalination, photodetection, and thermoelectrics. Here, nonresonant nickel nanoparticles (diameters < 20 nm) are embedded into cellulose microfibers via a nanoconfinement effect, producing an intrinsically broadband metamaterial with 97.1% solar-weighted absorption. Interband transitions rather than plasmonic resonance dominate the optical absorption throughout the solar spectrum due to a high density of electronic states near the Fermi level of nickel. Field solar purification of sewage and seawater based on the metamaterial demonstrates high solar-to-water efficiencies of 47.9-65.8%. More importantly, the solution-processed metamaterial is mass-producible (1.8 × 0.3 m 2 ), low-cost, flexible, and durable (even effective after 7 h boiling in water), which are critical to the commercialization of portable solar-desalination and domestic-water-purification devices. This work also broadens material choices beyond plasmonic metals for the light absorption in photothermal and photocatalytic applications., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new ternary composite of 1T-molybdenum disulfide, hexagonal tungsten trioxide, and reduced graphene oxide (M-W-rGO) is synthesized by using a one-pot hydrothermal process. The synergetic effect of 1T-MoS 2 and hexa-WO 3 nanoflowers improves the electrochemical performance for supercapacitors by inducing additional active sites and hexagonal tunnels, respectively, which lead to high storage capacity and easy transfer of electrolyte ions. The ternary M-W-rGO composite has a high specific capacitance of 836 F g -1 at 1 A g -1 , which is nearly twice that of binary composites of M-rGO and W-rGO with high capacitance retention of 86.35 % after 3000 cycles at a high current density of 5 A g -1 . This study provides a new ternary composite that can be used as an electrode material for high-performance supercapacitors., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Surface modification for templated synthesis is crucial to achieving three-dimensional (3D) architectured materials for catalysis, photonics, energy storage, etc. However, the existing facile and versatile modification methods (e.g. with dopamine and catechol) generate modification layers that are unstable in harsh environments. These methods are thus unsuitable for electrical applications. Here we report that Ce4+ can act as an effective surface modification reagent for a broad range of substrates (chitinous butterfly wings, carbon paper, nickel foam, and polyethylene terephthalate planks) with various structural features owing to its strong oxidizing ability and Lewis acid nature. The modification yields discrete CeO2 seed layers on substrate surfaces in ca. 0.25-2 h, important for the subsequent conformal growth of CeO2 nanoparticles, Ni(OH)2 nanowires, FeOOH nanosheets, and WO3 nanosheets into 3D architectured materials. The conformally synthesized FeOOH on nickel foam (NF) yields an overpotential of 241 mV at 10 mA cm-1 for an oxygen evolution reaction. This value is comparable to a typical catalyst Ni(Fe)OOH-NF for which the Ni/Fe ratio must be well-optimized. This facile and versatile strategy might have broad applications in the conformal fabrication and application of 3D architectured materials, especially when applied in electrical applications of architectured materials (e.g. Li-ion battery).

Hard carbon attracts wide attentions as the anode for high-energy rechargeable batteries due to its low cost and high theoretical capacities. However, the intrinsically disordered microstructure gives it poor electrical conductivity and unsatisfactory rate performance. Here we report a facile synthesis of N-doped graphitized hard carbon via a simple carbonization and activation of a urea-soaked self-crosslinked Co-alginate for the high-performance anode of lithium/sodium-ion batteries. Owing to the catalytic graphitization of Co and the introduction of nitrogen-functional groups, the hard carbon shows structural merits of ordered expanded graphitic layers, hierarchical porous channels, and large surface area. Applying in the anode of lithium/sodium-ion batteries, the large surface area and the existence of nitrogen functional groups can improve the specific capacity by surface adsorption and faradic reaction, while the hierarchical porous channels and expanded graphitic layers can provide facilitate pathways for electrolyte and improve the rate performance. In this way, our hard carbon provides its feasibility to serve as an advanced anode material for high-energy rechargeable lithium/sodium-ion batteries.

MXenes, 2D compounds generated from layered bulk materials, have attracted significant attention in energy-related fields. However, most syntheses involve HF, which is highly corrosive and harmful to lithium-ion battery and supercapacitor performance. Here an alkali-assisted hydrothermal method is used to prepare a MXene Ti 3 C 2 T x (T=OH, O). This route is inspired from a Bayer process used in bauxite refining. The process is free of fluorine and yields multilayer Ti 3 C 2 T x with ca. 92 wt % in purity (using 27.5 m NaOH, 270 °C). Without the F terminations, the resulting Ti 3 C 2 T x film electrode (ca. 52 μm in thickness, ca. 1.63 g cm -3 in density) is 314 F g -1 via gravimetric capacitance at 2 mV s -1 in 1 m H 2 SO 4 . This surpasses (by ca. 214 %) that of the multilayer Ti 3 C 2 T x prepared via HF treatments. This fluorine-free method also provides an alkali-etching strategy for exploring new MXenes for which the interlayer amphoteric/acidic atoms from the pristine MAX phase must be removed., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We prepare group VI transitional metal dichalcogenides (TMDs, or MX 2 ) from the 1T phase with quantum-sized and monolayer features via a quasi-full electrochemical process. The resulting two-dimensional (2D) MX 2 (M = W, Mo; X = S, Se) quantum dots (QDs) are ca. 3.0-5.4 nm in size with a high 1T phase fraction of ca. 92%-97%. We attribute this to the high Li content intercalated in the 1T-MX 2 lattice (mole ratio of Li:M is over 2:1), which is achieved by an increased lithiation driving force and a reduced electrochemical lithiation rate (0.001 A/g). The high Li content not only promotes the 2H → 1T phase transition but also generates significant inner stress that facilitates lattice breaking for MX 2 crystals. Because of their high proportion of metallic 1T phase and sufficient active sites induced by the small lateral size, the 2D 1T-MoS 2 QDs show excellent hydrogen evolution reactivity (with a typical η 10 of 92 mV, Tafel slope of 44 mV/dec, and J 0 of 4.16 × 10 -4 A/cm 2 ). This electrochemical route toward 2D QDs might help boost the development of 2D materials in energy-related areas.

Designing materials with a negative feedback function is beneficial for achieving temperature regulation inside a greenhouse. VO 2 has been studied extensively because of its low insulator-to-metal transition temperature (IMT). In this study, reflection changes during a VO 2 phase transition were investigated. Glass fiber cloth was used as a substrate, as it is stable and soft. A VO 2 thin film on a glass fiber cloth whose surface contained 96% V 4+ and 4% V 5+ was prepared using an inorganic sol-gels method. The insulator-to-metal transition temperature was decreased by 38 °C, which was observed from the reflection curve detected using an angle-resolved spectrometer. This decrease in IMT occurred mainly because of the presence of V 5+ , which causes destabilization of the monoclinic phase of VO 2 . When the greenhouse temperature was increased from 30 °C to 40 °C, the reflected intensity of VO 2 on glass fiber cloth decreased by 22% for the wavelength range of 400 nm to 800 nm. In addition, the angle-independent property of the VO 2 thin film was observed using an angle-resolved spectrometer. Owing to its thermo-reflective properties, the thin film can serve as a soft-smart-mirror (SSM) inside a greenhouse to stabilize the temperature, playing a negative feedback role.

Diatomite combined with certain metal-organic frameworks (MOFs) is shown to be an effective CO2 absorbent, although diatomite alone is regarded as inert with respect to CO2 absorption. This finding opens the prospect of reactivating millions of tons of diatomite for CO2 absorption. It also shows for the first time that diatom frustules can act as CO2 buffers, an important link in a successive biological CO2 concentration mechanism chain that impacts on global warming., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)