Search

We report an efficient ORR electrocatalyst containing cobalt single atom and cobalt nanoparticle active sites embedded in a porous nitrogen-doped graphitic carbon network. The robust electrocatalyst exhibits superior electrochemical ORR activity with onset and half-wave potentials of 0.96 V and 0.87 V (vs. reversible hydrogen electrode), respectively, and has excellent durability and methanol tolerance further enhancing the potential of this system for practical applications. [ABSTRACT FROM AUTHOR]

The underutilization of active sites limits the performance enhancement of functional carbon nanomaterials in electrocatalytic oxygen reduction reactions (ORR). Here, we propose a molten salt-regulated synthesis of indole-based hypercrosslinked polymers to create a series of nitrogen-doped porous carbon materials (NPC) with controllable quantities of active sites and specific surface areas (SSA). A deep investigation of the structure–property relationship indicates that the environment of the active sites, particularly the electrochemical active surface area (ECSA), plays a pivotal supporting role. Furthermore, the ECSA per active site (EPA) correlates directly with ORR performance. The NPC–Zn catalyst, which possesses the highest EPA, demonstrates the highest half-wave potential (0.859 V) and kinetic current density (102.64 mA cm−2), and excellent performance in the rechargeable zinc–air battery (ZAB). Furthermore, the NPC–Zn-based capacitive deionization (CDI) device, powered by NPC–Zn-based ZAB, exhibits a stable adsorption capacity of 27.8 mg g−1 for 6 hours, which is consistent with that driven by a direct-current supply. This work provides new insights into the utilization efficiency of active sites in carbocatalysts for ORR, serving as a prime example for designing high-performance ORR electrocatalysts with broad application prospects in the field of environmental energy. [ABSTRACT FROM AUTHOR]

The development of high-performance electrocatalysts that rival Pt catalysts is crucial for efficiently driving the hydrogen evolution reaction (HER) to produce H2. Herein, we engineer sophisticated interfacial modulation of the Ru catalysts by constructing B, N co-doped porous carbon confined ultra-small MoC quantum dots (MoC@BNC) as an advanced catalyst carrier and stimulator. Combined experimental and theoretical calculations prove enhanced electron interaction between the Ru catalysts and the MoC quantum dots. Additionally, the B, N co-doped carbon substrate further refines the electronic structure of MoC, reinforcing the modulation of Ru catalysts. The Ru/MoC@BNC catalyst embodies a boosted H2O dissociation ability with a lowered H bonding strength, which promises an outstanding HER performance with an overpotential of 14 mV at 10 mA cm−2 in an alkaline solvent. Furthermore, robust catalytic stability is achieved with almost zero deterioration after the cycling test. This result exemplifies the importance of interfacial manipulation of the Ru catalysts to promote HER catalytic performance. [ABSTRACT FROM AUTHOR]

The exponential expansion of the lithium battery market has led to challenges in acquiring lithium resources. Extracting lithium from seawater has been explored as a potential solution to address the shortage of lithium supply. However, seawater lithium extraction presents significant challenges due to its low lithium-ion concentration and complex marine environment. Capacitive deionization (CDI) technology has demonstrated a remarkable ability to selectively separate metal ions from seawater, in which electrode materials play a crucial role. Traditional methods of discovering electrode materials have relied on the trial-and-error principle, and the experimental process of material design and synthesis requires substantial manpower and material resources. The emergence of materials informatics has revolutionized the design and development of electrode materials, substantially reducing the application cost of CDI. Combining our research experience, we explored the application prospects of theoretical calculations in CDI lithium extraction and introduced the development progress of electrode materials that are not limited to CDI lithium extraction in recent years. The key points of using density functional theory (DFT), molecular dynamics (MD), and finite element simulation (FES) to study the mechanism of lithium extraction process, using high-throughput computing and machine learning (ML) to screen new electrode materials are emphasized. The research emphasizes the synergistic utilization of DFT, MD, ML, and FES methodologies to provide instructive insights, aimed at advancing the design of effective CDI electrode materials tailored for lithium extraction from seawater. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 reduction reaction (CO2RR) for high value-added multi-carbon product (C2+) production over copper oxide-based catalysts is an important way to realize the carbon cycle. However, developing effective reaction interfaces and microenvironments to improve the Faraday efficiency (FE) and current density of C2+ remains a major challenge. Herein, we construct Cu0–Cu+–NH2 composite interfaces with the assistance of SiO2. Using Cu2O nanoparticles as a model catalyst, a layer of porous SiO2 is first coated on the surface of the particles, and then, a silane coupling agent containing –NH2 is bonded on the surface of SiO2. The strong interaction between SiO2 and Cu2O at the interface induces the oxidation effect of low valent Cu, and even under the CO2RR, part of Cu+ is reduced to Cu0 and part of Cu+ still maintains positive valence, forming the interface of Cu0–Cu+. SiO2 also acts as a bridge between copper species and –NH2 to create a Cu catalyst–NH2 group interface. With the help of the synergistic effect of the composite interfaces, the optimized Cu2O@SiO2–NH2 catalyst achieves a FE of 81.2% for C2+ products with a current density of 292 mA cm−2 at −1.7 V versus a reversible hydrogen electrode. In situ Raman and attenuate total reflectance-infrared absorption spectroscopy spectra show that the interaction between surface –NH2 and CO2 molecules enhances the adsorption and activation process of CO2 and promotes the formation of CO intermediates (*CO). On the Cu0–Cu+ interface, the C–C coupling process between *CO is accelerated, and the two interfaces synergistically promote the generation of C2+ products. This work provides a new strategy for constructing composite interfaces to improve the CO2RR to C2+ products. [ABSTRACT FROM AUTHOR]

Extensive chloride ions present in seawater can undergo a competitive reaction with water oxidation on the anode during seawater electrocatalysis. The use of alkaline electrolytes enhances the selectivity of seawater oxidation towards the oxygen evolution reaction rather than the chlorine evolution reaction by increasing the potential gap between the two reactions. Layered double hydroxides (LDHs), also known as hydrotalcites, which can withstand alkaline environments, are suitable for seawater oxidation due to their stability and selectivity. Recent years have witnessed a growing number of publications on LDH-catalyzed seawater splitting. To gain a comprehensive understanding of the current state and challenges of LDH-related electrocatalysts in seawater electrocatalysis, this review conducts a thorough assessment of recent advances in the synthesis, characterization, and electrocatalytic performance of LDH-related materials. First, the review introduces the reaction mechanisms of seawater electrocatalysis over LDH-related materials. The second part presents the common synthetic methods of LDHs, along with the advantages and limitations of each method, as well as various characterization techniques for investigating the structure–activity relationship. Subsequently, the principles for designing LDH-based electrocatalysts and modulating their electrocatalytic activities for seawater splitting are summarized. Furthermore, this review concludes with an analysis of the electrocatalytic performances of LDH derivatives (metal(oxy)hydroxides and phosphides) obtained from LDH precursors. Finally, the challenges and prospects of LDH-related electrocatalysts for seawater electrolysis are discussed. [ABSTRACT FROM AUTHOR]

In this study, nanosheet-like sorghum biomass is obtained by a mild alkaline treatment and high-energy ball milling. N, S co-doped hard carbon (NSSC) with the nanosheet morphology is subsequently synthesized by a direct-carbonization of the nanosheet-like sorghum biomass mixed with thiourea. NSSCs obtained at various annealing temperatures demonstrate that the optimal annealing temperature is necessary to balance the efficient heteroatom-doping and the level of carbonization. NSSC-600 obtained at the optimized annealing temperature of 600 °C presents a great K-ion storage performance as an anode material with a high reversible specific capacity of 268 mA h g−1 at 100 mA g−1 and outstanding stability over 2400 cycles. The effect of N and S heteroatom-doping on K-ion adsorption capacity is also verified by density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Herein we report the rational syntheses of three conjugated microporous polymers (CMPs) through one-pot polycondensation coupling of a boronated triphenylpyridine (TPP-3Bor) with 4,7-bis(5-bromothien-2-yl)benzo[c][1,2,5]thiadiazole (ThZ-2Br), 2,5-dibromothiophene (Th-2Br), and 1,4-dibromobenzene (Bz-2Br), yielding the TPP-ThZ, TPP-Th, and TPP-Bz CMPs, respectively, featuring different thiophene contents, topologies, and molecular structures. Various characterization techniques are used to investigate the structural properties of these TPP-based CMPs, revealing their spherical morphologies, tunable pore volumes, and high thermal and chemical stabilities. We test the TPP-based CMPs for their use in the dynamic adsorptive reduction of toxic Cr(VI) ions. Among them, the TPP-ThZ CMP possesses the highest adsorption capacity for Cr(VI) (209 mg g−1); this performance is also higher than those of other recently reported adsorbents. Furthermore, our TPP-based CMPs exhibit good reusability for the reduction and adsorption of Cr(VI) ions. Accordingly, these novel thiophene-based CMPs not only function as dynamic materials for the reduction–adsorption of Cr(VI) but also reveal the potential of thiophene linkers in the future design of such Cr(VI) adsorbents. [ABSTRACT FROM AUTHOR]

The upgrading of bio-oil often leads to significant carbon losses due to excessive decarboxylation and decarbonylation. However, this may be alleviated by deploying an innovative multi-functional catalyst that promotes C–C coupling while catalyzing deoxygenation/hydrodeoxygenation reactions. In this work, we develop trifunctional catalysts by consecutive post-synthesis treatments of commercial ZSM-5 catalyst (ZSM-comm). These treatments include impregnation of alkaline metal (magnesium) followed by temporary pore blocking with CTAB prior to the growth of SBA-15 using P123 as a template and transition/noble metal salts (nickel nitrate and platinum chloride). The prepared trifunctional catalysts exhibit three active sites, namely acidity, basicity, and reducibility as confirmed by NH3-TPD, CO2-TPD, and TPR measurements. The integration of the three active sites results in a remarkable increase in oil yield from 4.9% over ZSM-comm to 17.1 and 13.5% over Mg–Ni/meso-ZSM and Mg–Pt/meso-ZSM catalysts, respectively. These trifunctional catalysts also exhibit enhanced selectivity toward alkenes and alkanes in oil, which increases from 7.6% over ZSM-comm to 26.3 and 19.6% over Mg–Ni/meso-ZSM and Mg–Pt/meso-ZSM, respectively. The oxygenates (phenols, furans, acids, and ketones) also show an apparent shift in the carbon number toward the fuel range (C5–C13), suggesting the occurrence of C–C coupling. Additionally, the trifunctional catalysts help in increasing the selectivity toward monocyclic aromatic hydrocarbons (MAHs) from 75.2 to 93.7%. [ABSTRACT FROM AUTHOR]

Engineering MXene-based 2D heterostructures is a hot research topic for capacitive deionization (CDI) materials. Herein, MXene nanosheets were ingeniously integrated with metal–organic framework (MOF)-derived carbons to generate the N, P-doped graphitic carbon/Ti3C2Tx MXene heterostructures (N, P-GC/MXene). The ZIF-67/MXene precursors were synthesized through in situ nucleation of ZIF-67 dodecahedra onto the MXene nanosheets, followed by thermal carbonization and phosphatization to prepare N, P-GC/MXene, which was composed of homogeneously distributed heteroatoms (N and P) in the carbon frameworks. By virtue of structural characteristics, high electrochemical conductivity, and pseudocapacitive contributions, the N, P-GC/MXene electrodes exhibited a superior salt adsorption capacity of 55.3 mg g−1, rapid removal rate, and excellent cycling stability. This work demonstrates the potential of MXene-based heterostructures for CDI materials and propels the development of the CDI technique. [ABSTRACT FROM AUTHOR]

In this work, hierarchically porous bimetallic zeolitic imidazolate framework (ZIF) particles (etched Zn33Co67-ZIF) exhibiting both micropores and mesopores have been designed and prepared through an ethylene glycol-assisted aqueous etching method. The etching process effectively increases the pore size, surface area, and pore volume of the bimetallic ZIF particles. After the thermal treatment, the etched Zn33Co67-ZIF particles are transformed into cobalt and nitrogen co-doped hierarchically porous carbon (i.e., etched Zn33Co67–C). Etched Zn33Co67–C has an increased mesoporosity, leading to an approximately 45% increase in its specific capacitance compared to the unetched one. In addition, etched Zn33Co67–C displays a higher capacitance retention (67%) than unetched Zn33Co67–C (41%) over a range of scan rates from 1 to 100 mV s−1. The presented ethylene glycol-assisted aqueous etching process provides a facile template-free strategy to enlarge the porosity of MOFs and their corresponding porous carbons for improving their energy storage performance. [ABSTRACT FROM AUTHOR]

Hexacyanometallates, known as Prussian blue (PB) and its analogues (PBAs), are a class of coordination compounds with a regular and porous open structure. The PBAs are formed by the self-assembly of metallic species and cyanide groups. A uniform distribution of each element makes the PBAs robust templates to prepare hollow and highly porous (hetero)nanostructures of metal oxides, sulfides, carbides, nitrides, phosphides, and (N-doped) carbon, among other compositions. In this review, we examine methods to derive materials from PBAs focusing on the correlation between synthesis steps and derivative morphologies and composition. Insights into catalytic and electrochemical properties resulting from different derivatization strategies are also presented. We discuss challenges in manipulating the derivatives' properties, give perspectives of synthetic approaches for the target applications and present an outlook on less investigated grounds in Prussian blue derivatives. [ABSTRACT FROM AUTHOR]

The upcycling of waste polymers into novel materials with high added value is a vital task for modern chemical engineering. Here, we propose diversifying waste polyethylene terephthalate (PET) upcycling to materials with enhanced photothermal properties by laser-assisted carbonization of surface-grown UiO-66. The UiO-66 homogenous layer was formed using a solvo-thermal procedure on the surface of recycled PET sheets. The treatment by a 405 nm laser system allowed the formation of a carbonaceous layer with enhanced electrical conductivity and photothermal properties due to the presence of zirconium carbide and graphene. The developed approach opens new perspectives in the application of upcycled PET-based materials. [ABSTRACT FROM AUTHOR]

Conjugated microporous polymers (CMPs) are a prospective class of porous materials that are promising in a wide variety of applications due to their outstanding physical and chemical properties. Here, we introduce a strategy to synthesize two novel phenazine-based CMPs, namely, TPT-QP and Py-QP CMPs through the Suzuki coupling condensation reaction of 3,6,14,17-tetrabromodibenzo[a,c]dibenzo[5,6:7,8]quinoxalino[2,3-i]phenazine (QP-4Br) with boronic acid pinacol ester of triphenyltriazine (TPT-3Bpin) and pyrene (Py-4Bpin), respectively. These two CMPs are fully characterized and exhibit high surfaces areas, and good thermal stabilities. Interestingly, the obtained TPT-QP CMP has a considerable number of hydrogen-bonding sites, which are able to detect sub-ppm of vaporized acidic hydrocarbons with high sensitivity and selectivity. In this study, a phenazine-based CMP-based quartz crystal microbalance (QCM) sensor is fabricated for the first time, and it demonstrates an excellent capacity to detect trace amounts of volatile formaldehyde (HCHO). The density functional theory (DFT) calculations reveal that interaction between HCHO and the TPT-QP CMP is dominated by hydrogen-bonding interaction. The active sites of the TPT-QP CMP act as antennae for the selective detection of HCHO vapors over other interfering gaseous chemical-vapor analytes. The sensitivity of the TPT-QP-based QCM sensor towards HCHO is found to be among the highest (2.4 Hz ppm−1) of the substances examined, with a limit of detection (LOD) down to the sub-ppm level. On the other hand, the Py-QP CMP having lower content of hydrogen-bonding sites exhibited lower sensitivity towards HCHO, but more sensitive to benzene which could be attributed to the stronger π–π stacking interaction between the π-rich electron pyrene units and benzene. This sensing technique based on the TPT-QP CMP creates a simple, low-cost method for enhancing QCM sensors' functionality in detecting HCHO vapors with the use of smart electronic noses. [ABSTRACT FROM AUTHOR]

In this study, we successfully demonstrate the synthesis of a novel necklace-like Co, Fe, and N co-doped one-dimensional (1D)-assembly of hollow carbon nanoboxes (1D-HCNB-x) and its potential for a supercapacitor application. The unique hybrid nanoarchitecture of 1D-HCNB-x consisting of hollow zero-dimensional (0D) carbons arrayed along the 1D carbon nanofiber is highly desirable for supercapacitors because it presents improved rate capability and high axial electron conductivity. The presence of Fe, Co and N dopants in the carbon matrix also generates pseudocapacitance to further improve specific capacitance. The optimized 1D-HCNB-900 generates a specific capacitance of 370.0 F g−1 at a current density of 2 A g−1, high rate capability and tolerance, and great cyclability. [ABSTRACT FROM AUTHOR]

The energy crisis and depletion of non-renewable energy resources have been aggravated due to the drastic rise in world pollution and the energy demand. Facile hydrogen production through water splitting has become a popular alternative source of energy owing to the numerous environmentally friendly and economic benefits it provides. Additionally, it is preferred due to the depletion of non-renewable energy resources, pollution caused by the burning of non-renewable energy resources, and climate change. Hydrogen is generated from water and acts as a clean energy without contributing to carbon emissions. Various water-splitting methods such as electrolysis, thermochemical, mechanocatalysis, plasmolysis, photocatalysis, and photoelectrocatalysis can be applied to obtain hydrogen and oxygen. This review highlights the multifunctional materials used in photo-electrochemical water splitting and their superior properties for producing carbon-free energy from water. Multifunctional materials help reduce aqueous protons to hydrogen and oxidize water to oxygen during the splitting of water. This paper discusses a wide class of materials such as carbon materials, metal–organic frameworks, perovskites, and semiconducting oxides for efficient hydrogen production. Different types of water-splitting methods and multifunctional materials with varying properties can lead to improved results. The review sheds light upon the hydrogen economy and future prospects, elucidating the selection of multifunctional materials for efficient hydrogen production. [ABSTRACT FROM AUTHOR]

Supported amorphous alloy catalysts have received wide attention due to their unique structural and electronic properties, high catalytic activity, and thermal stability. In this work, a carbon nanotube (CNT)-supported amorphous Ni–P alloy nanoparticles (NPs) catalyst, referred to as Ni–P/CNTs-MA, is synthesized using a simple one-pot microwave-assisted approach. The prepared Ni–P/CNTs-MA catalyst displays smaller Ni–P NPs, higher metal dispersion and stronger metal–support interactions than the reference catalyst prepared by the traditional water bath heating method (Ni–P/CNTs-WB). The resulting Ni–P/CNTs-MA catalyst exhibits enhanced catalytic activity for the hydrogenation of nitroarenes compared to the Ni–P/CNTs-WB catalyst. The Ni–P/CNTs-MA catalyst also exhibits improved thermal stability and catalytic durability, probably due to the strong interaction between the Ni–P NPs and CNTs. [ABSTRACT FROM AUTHOR]

Diabetes is a dangerous disease caused by the inability of the body to produce and use insulin properly, resulting in an increase in the blood glucose level. The most advanced technology for glucose detection is the surface plasmon resonance (SPR)-based sensor. However, this technology has a slight drawback due to the small size of glucose. As a porous material, Zr-based UiO-66 MOF has good adsorption with glucose via hydrogen bonding, so it can be utilized as a receptor and active layer for the SPR glucose sensor, without the need for other receptors, such as glucose oxidase, concanavalin A, or boronic acid-based compounds. This study investigates the morphology effect, immobilization techniques, and signal amplification strategies for optimizing the utilization of UiO-66 in the SPR glucose sensor. By optimizing these parameters, a high-performance SPR glucose sensor with a detection limit of 0.0693 mM (S/N = 3) in the concentration range of 0.01–10 mM is successfully developed. In addition, a selectivity test reveals that the UiO-66/Au-based SPR sensor exhibits a high selectivity toward glucose. Furthermore, the developed SPR sensor showed a good ability in detecting glucose in human blood serum, suggesting its promising potential for practical applications. [ABSTRACT FROM AUTHOR]

Due to its low atomic weight, two-dimensional structure, and unique physical and chemical properties, borophene has attracted strong interest from researchers across different fields. Currently, the experimentally realized polymorphs of single-atomic-layered borophene are all grown on substrates and free-standing forms are yet to be obtained, thus restricting the applications. Functionalizing borophene and boron nanosheets, such as attachment of surface functional groups, heteroatom doping, and formation of composites, not only improves structural stability but also generates new physical and chemical properties. Therefore, functionalized borophene/boron nanosheets with new features have more versatile applications than pristine ones. This review summarizes the recent advances in both theoretical prediction and experimental work of functionalized borophene/boron nanosheets. Various functionalization techniques are systematically reviewed with in-depth discussion of their effects on the properties and performance when utilized in various devices. The advantages and limitations of the functionalization methods are discussed with the aim to stimulate thoughts for future research on boron nanosheets, which are believed to possess a plethora of applications in fields such as electronics, energy, biochemistry, and optics, just to name a few. [ABSTRACT FROM AUTHOR]

A gas barrier film with moderate permeance due to capillary flow and high adhesion was made from only water and layered aluminosilicates. The surface adsorbed water acts as a polar binder between the layers of aluminosilicates which enhances gas barrier efficiency, especially toward less polar gases. Oxygen permeability was 4.91 × 10−16 mol m m−2 s−1 Pa−1 (23 °C, 60% relative humidity (RH), permeance: 4.31 × 10−12 mol m−2 s−1 Pa−1), which is 1/26th that of Kraft paper (at 25 °C, 65% RH) and 146 times that of polyvinylidene chloride films. This film with moderate gas permeability is suitable for the preservation of fresh produce requiring low level respiration after harvest. The film applied to the surface of apples preserved their freshness, presumably by blocking oxygen transfer and microorganisms. Furthermore, the high adhesion of this film is more expedient for blocking gases generated from produce because the film excludes gaps between the film and the produce, which is difficult for usual cling wraps. This film can also be used for cultivating produce instead of conventional pesticides because it reduces the emission of aromatic volatiles that attract pests. This sustainable film whose component is the same as the main component of soil has the potential to reduce food loss. In addition, the film from another smectite with larger lateral size was revealed to have lower gas permeability due to diffusion and not capillary flow. [ABSTRACT FROM AUTHOR]

In electrochemical water splitting, the balance between water dissociation step and the hydrogen adsorption on the catalysts is an ongoing challenge. Herein, Bi2O3, an inactive catalyst for the hydrogen evolution reaction (HER) caused by its unfavourable hydrogen adsorption Gibbs free energy (ΔGH*), is activated by an in situ phase engineering strategy for efficient HER electrocatalysis in alkaline media. Through this strategy, two-dimensional (2D) dual active Bi2O3 nanosheets with both BixNi alloy phases and α-Bi2O3 were fabricated to simultaneously catalyse the water dissociation step and the hydrogen formation step during an alkaline HER. In combination with the advantages of 2D nanomaterials and dual active catalytic sites, this phase engineered Bi2O3-based catalyst exhibited much improved alkaline HER performance. The modulated catalyst demonstrated an overpotential of 127 mV (at j = 10 mA cm−2) and a Tafel slope of 92 mV dec−1 in 1 M KOH, and is exceptional compared with other Bi2O3-based HER electrocatalysts. This work not only provides an innovative way to activate HER-inferior bismuth-based catalysts, but also offers new insights into the design of dual active catalysts for sluggish alkaline HER catalysis. [ABSTRACT FROM AUTHOR]

As a conventional modification approach, nitrogen doping in carbon can greatly improve the electrochemical performance for potassium (K)-ion storage. However, we realized that the improvement of electrochemical performance by simple nitrogen doping alone in carbon was not as good as we expected. In this work, we develop a new approach to design active nitrogen-rich carbon nanosheets (PANC) by phytic acid induction, which present a remarkable improvement specific capacity of 317 mA h g−1 after 100 cycles at 50 mA g−1 and 202 mA h g−1 at 500 mA g−1, even after 3200 cycles. Density functional theory (DFT) calculations confirm the increased pyridinic-N as active sites contributes towards the enhancement of K-ion adsorption ability. In addition, our calculations illustrate that pyridinic-N exhibits a lower energy barrier of 0.16 eV compared to that of 1.12 eV for pyrrolic-N, indicating that pyridinic-N in carbon is the critical factor to improving the K-ion storage performance for our PANCs. This result was also confirmed by electrochemical impedance spectroscopy and pseudocapacitance analysis. We believe that our work describes the development of an effective approach to realize active N adjustment, which will inspire the design of high-performance anode materials for K-ion storage. [ABSTRACT FROM AUTHOR]

The urgent desire for high-energy lithium-ion batteries (LIBs) has motivated scientists to develop large-capacity electrode materials with innovative compositions and/or architectures. Herein, we report a three-dimensional (3D) hierarchical MoO2/MoS2/C heterostructure composed of tiny crumpled nanosheets arrayed on a larger lamellar substrate through a facile hydrothermal polymerization–carbonization route. Benefiting from the intrinsically high capacity contribution from Mo-based components, expedited charge transfer from the intimately integrated carbon matrix, sufficient electrolyte penetration, rapid lithium transportation and volume change tolerance from the 3D hierarchical heteroconfiguration, our MoO2/MoS2/C demonstrates an appreciable reversible capacity (787.5 mA h g−1 at 0.1 A g−1), outstanding rate performance (80% capacity retention even as the current density increases tenfold), and superior long-term cyclability with a slow fading of 0.02% per cycle over 2000 cycles, holding great promise for the fabrication of desirable LIBs with high energy density and long lifetimes. [ABSTRACT FROM AUTHOR]

Carbon-based electrodes play important roles in constructing efficient capacitive deionization (CDI) devices. Therefore, the rational design of carbon materials with optimized structure, composition, and morphology is crucial for further improving the CDI performance. Herein, a novel N, P co-doped eave-like hierarchical porous carbon (NP-EHPC) for CDI is reported. To prepare the NP-EHPC, the core–shell ZIF-8@AF particles are first prepared through the kinetically-controlled growth of zeolitic imidazolate framework-8 (ZIF-8) and polymerization of p-aminophenol and formaldehyde (AF), followed by subsequent pyrolysis and post-doping with phosphorus. Owing to the unique eave-like morphology, presence of abundant mesopores, and co-doping of P and N, the NP-EHPC exhibits a high desalination capacity of 24.14 mg g−1 in 500 mg L−1 NaCl solution at 1.2 V and long cycling stability of over 150 cycles. Moreover, the density functional theory (DFT) calculation results reveal that the co-doping of N and P atoms can greatly enhance the binding energies for Na and Cl atoms and lead to superior electrosorption capacity. This work provides a new insight into the design of high-performance carbon materials for the desalination of brackish water. [ABSTRACT FROM AUTHOR]

We have developed a simple soft template-mediated coupling construction approach to achieve an unexplored sandwiched mesoporous polypyrrole nanocoating/single-crystal Ag nanoplate hybrid by a one-step inorganic/organic redox reaction at the liquid interface, and the hybrid possesses an adjustable meso-structure and architecture, strong near-infrared absorption and Raman enhancement effect, and outstanding chemical sensing performance. [ABSTRACT FROM AUTHOR]

Environmental pollution has been a known threat to our world due to the rapid urbanization, changing lifestyle of people, and modern industrialization. Therefore, there is an urgent need to develop novel sensing approaches having promising performance with high reliability and sensitivity for the precise monitoring of various pollutants. Metal–organic frameworks (MOFs) have been intensively investigated by many researchers as electrode modifiers for electrochemical sensing due to their excellent properties and efficiency. Diverse MOF-based electrochemical sensing systems are applied for environmental analysis for the sensitive, rapid and cost-effective determination of various analytes because of their unique structures, and properties, including the tunable pore size, high surface area, high catalytic activity, and high density of active sites. The aim of this review article is to evaluate the application of MOFs in the electrochemical sensing of environmental pollutants including heavy metal ions, pesticides, phenolic compounds, nitroaromatic compounds, antibiotics, nitrite, and hydrazine. Current limitations and future directions for the application of MOF-based electrochemical sensors for the detection of environmental pollutants are discussed. [ABSTRACT FROM AUTHOR]

Synthesizing mesoporous alloys composed of metals with divergent reactivities and standard redox potentials (E0) is challenging because the kinetics of metal deposition is totally different. Herein, we report the first method to generate mesoporous RhNi alloy films via electrochemical co-deposition using self-assembled micelle templates. The concentration of Rh precursor (Rh3+) is crucial to control reaction kinetics and morphology because Rh deposition is the trigger of Ni co-deposition. The ratio of Rh3+ : Ni2+ (in the precursor) can be altered to generate different alloy compositions, and the impact of pH and deposition potentials is also investigated. We examine the mesoporous RhNi films as electrocatalytic electrodes for the hydrogen evolution reaction (HER). Ni-doping serves to enhance the HER performance of the mesoporous films, and the 1 : 1 alloy (mesoporous Rh49Ni51 film) shows the best performance with the overpotential of 59 mV @ 10 mA cm−2 and Tafel slope of 67 mV dec−1. The insight gained here will enable researchers to experiment with different noble-transition metal alloys to generate better porous electrodes for electrocatalysis. [ABSTRACT FROM AUTHOR]

In this study we performed one-pot polycondensations of BFTB-4CHO with PyTA-4NH2, BFTB-4NH2, and BCTA-4NH2 to prepare the bifluorenylidene-based covalent organic frameworks (COFs) BFTB–PyTA, BFTB–BFTB, and BFTB–BCTA, respectively. These three COFs possessed extremely high thermal stabilities, excellent crystallinities, and high specific surface areas. The BFTB–PyTA COF featured pores of a single size, whereas the BFTB–BFTB and BFTB–BCTA COFs had dual porosities. The COFs were exceptional adsorbers of the small dye molecule rhodamine B (RhB) in water; the maximum adsorption capacities reached as high as 2127 mg g−1, outpacing those of all previously reported COFs, conjugated polymers, activated carbons, and other common nanoporous adsorbents. In addition, our COFs reached up to 99.2% of their maximum adsorption capabilities very rapidly (within 5 min). Furthermore, these COFs displayed good performance when used in electrodes for supercapacitors, with high stability after 2000 cycles. The superior adsorption efficiencies, ultrafast kinetics, and excellent reusability endow such COFs with tremendous potential for use as materials for removing RhB—and, presumably, other organic pollutants—from wastewater. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical method that uses localized surface plasmon resonances (LSPRs) to enhance the Raman cross-section of adsorbed molecules. Nanostructured copper (Cu) has been investigated as a SERS substrate in recent years because it is also a plasmon-supporting metal like gold (Au) and silver (Ag), but Cu is orders of magnitude more abundant in the Earth's crust. Although Cu is more prone to oxidation and tends to generate weaker LSPRs than Au or Ag, the sheer affordability of Cu metal drives the demand for SERS applications where the highest levels of sensitivity are not necessary. In addition, simplifying the fabrication methods for SERS substrates and avoiding costly lithographical techniques are problems to be overcome. In this report, we describe a method to fabricate mesoporous Cu films (MCuFs) using self-assembled block copolymer micelles as pore-directing agents in an electrochemical deposition method. The pores generated by the micelles are relatively large (>20 nm), which enables strong electromagnetic field enhancements via the LSPR. Different electrodeposition conditions such as potentials, times, and micelles molecular weights were tested to study MCuF formation and their effect on the pore size, porous structure, and SERS activity. We found that the samples created with small micelles generated the most robust SERS response. Electromagnetic simulations indicate that small pores are important for generating strong fields and that the presence of interconnected grooves assists in the collection of light into these small pores. The optimal MCuF substrate generated an enhancement factor (EF) and limit of detection (LoD) of 3.8 × 105 and 10−6 M, respectively. The results confirm that MCuFs are efficient for practical SERS applications due to their simple synthesis, high performance, and low cost. [ABSTRACT FROM AUTHOR]

Nanoporous ruthenium (np-Ru) comprising reaction active facets is synthesized from a ruthenium–cerium (Ru2Ce) alloy precursor. Spontaneous nanophase separation of Ru2Ce in an oxidative atmosphere results in a lamellar nanocomposite consisting of Ru metal and cerium oxide (CeO2). Selective leaching of the Ru–CeO2 nanocomposite in sulfuric acid yields np-Ru with a high surface area of 48 m2 g−1, predominantly surrounded by reaction active {101¯0} facets. Active-faceted np-Ru efficiently catalyzed the hydrogen evolution reaction (HER) in acidic media at an overpotential of +74 mV vs. the reversible hydrogen electrode, which is 20 mV lower than that for carbon-supported Ru (Ru/C) and rather close to +58 mV for state-of-the-art Pt/C. Np–Ru has great potential in broad applications such as hydrogen battery electrodes because of its low HER overpotential and scalable synthetic protocol. [ABSTRACT FROM AUTHOR]

A variety of carbon materials such as carbon nanotubes and graphene have been widely investigated as conductive substrates to immobilize metal complex-based catalysts for electrocatalytic CO2 reduction. However, highly ordered mesoporous carbons have received scant attention as substrates for CO2 reduction electrocatalysts. The unique porous structure of such carbon provides the opportunity to not only house catalytically active materials but also facilitate reactant transport. In this work, we propose a simple approach for immobilization of the highly active and cost-efficient molecular catalyst iron porphyrin, into a highly ordered mesoporous carbon, CMK-3 having a large surface area of 1345 m2 g−1via a simple vacuum infiltration method. The resulting heterogeneous electrocatalyst (CMK-FeTPP) is utilized for the conversion of aqueous CO2 into CO with 92.1% faradaic efficiency and a high effective turnover frequency of 3.9 s−1 at an overpotential of 680 mV. We believe that this new approach has the potential to be widely used to fabricate efficient electrocatalysts for not only CO2 conversion but also other electrochemical gas conversion systems. [ABSTRACT FROM AUTHOR]

Energy conversion and storage materials have received wide attention as fossil fuels are gradually running out and climate change is looming. Hexagonal boron nitride (h-BN) is not usually considered as a promising material for these applications because of its chemical inertness and poor electronic conductivity. However, through physical and chemical modification, h-BN shows tuneable properties that make it interesting for energy conversion and storage. The excellent stability and environmentally benign nature make h-BN derived materials particularly attractive for green energy applications. In this review, we survey the studies on structural and chemical properties of functionalised h-BN materials as well as their energy-related applications. Research progress in energy conversion and utilisation such as electrochemical catalysis, photocatalysis, and selective oxidative dehydrogenation is reviewed. Energy storage applications including rechargeable batteries, supercapacitors, and hydrogen storage are also presented. Finally, we discuss the future and challenge for functionalised h-BN in energy conversion and storage. [ABSTRACT FROM AUTHOR]

There is growing interest in developing mesoporous metallic alloys for electrochemical applications such as catalysts in fuel cells and batteries. As is well known, the chemical compositions of alloys can significantly affect their electrochemical properties. Although tuning the chemical compositions of mesoporous metallic alloys for enhancing the electrochemical activity has been reported, they have mostly been limited to binary components partly because experimental exploration over possible multi-compositional spaces is a time-consuming process. Here, we describe, for the first time, the application of the active learning scheme using Bayesian optimization for the exploratory search of the chemical compositions of mesoporous trimetallic PtPdAu alloys with optimum catalytic activity in the electrocatalytic oxidation of methanol. Unexpectedly, it was found that the PtPdAu alloys yielding the highest catalytic activity contain only a small percentage of Au. These compositions were discovered by performing only 47 experiments, less than 1% of all possible compositions in our experimental design. Our current approach is highly efficient and would be applicable to any system to accelerate the discovery of novel materials. [ABSTRACT FROM AUTHOR]

The use of certain small molecule aromatic carbonyl compounds (ACCs) as positive electrode materials in lithium ion batteries is a dilemma because of their good electrochemical properties (a high capacity density and good reversibility of the electrochemical reaction) and their fatal problems (a low electron conductivity and high solubility in organic electrolytes). To promote commercial application of ACCs, the synthesis and electrochemical behavior of an organic combination of carbon fiber felt and 2,6-diaminoanthraquinone (DAAP) were explored. The surface of carbon fiber felt after acidification (C) was rich with carboxyl groups, which reacted with the amine groups in DAAP molecules to form stable chemical bonds via amide bonds (–CO–NH–). The organic combination of carbon fiber felt and DAAP (DAAP@C) not only effectively enhanced the electronic conductivity and insolubility of the composites but also significantly improved their electrochemical performance (rate performance, cycle life, etc.). Compared with DAAP, the electronic conductivity, charge transfer resistance, lithium ion diffusion coefficient, initial capacity density (0.5C), and capacity retention rate (5C after 400 cycles) of DAAP@C were 111.1 S cm−1 (8.339 S cm−1), 103 Ω (418 Ω), 1.37 × 10−12 cm−2 s−1 (2.87 × 10−13 cm−2 s−1), 285 mA h g−1 (209 mA h g−1), and 80% (0%), respectively. This method, to graft soluble organic molecules onto tangible materials with high electronic conductivity, is an effective approach to simultaneously solve the problems of solubility and electronic conductivity inherent to most of small organic molecules with electrochemical activity, and with its use, the spring of organic electrode materials will come. [ABSTRACT FROM AUTHOR]

The understanding of the influence of hierarchically nanostructured architectures as support materials for catalysts loading, is critical towards development of efficient electrocatalytic interfaces. The knowledge on mass transport limitation of reactants within such catalyst-support structures remains elusive. Herein, we performed systematic investigation through a novel hierarchical 1D–3D structure by loading mesoporous Pd with an average pore size of ∼10 nm and wall thickness of ∼4 nm onto highly ordered TiO2 nanotube arrays via pulse electrodeposition. Electrochemical CO2 reductions achieved a CO2-to-formate faradaic conversion efficiency of 88 ± 2% under optimal conditions. Importantly, the product selectivity is found to depend significantly on the tube length, highlighting the influence of mass transport limitations of CO2. This work offers vital insight into practical consideration in designing efficient catalyst-support interfaces with an optimal hierarchically geometry, that must optimise mass transport as well as electrochemical kinetics. [ABSTRACT FROM AUTHOR]

This study demonstrates the tailorable self-weaving of bimetallic nickel–cobalt (Ni–Co) hydrogen phosphate nanotubes into one-dimensional (1D) microspindles or two-dimensional (2D) sheet-like structures by utilizing monodispersed Ni–Co glycerate spheres as sacrificial templates. The conversion process is achieved through a two-step solvothermal method in the presence of phosphoric acid (H3PO4) as a phosphorus source and promoter of the self-weaving process. The formation of such nanotube-assembled architectures is promoted by the "peeling-self-weaving" mechanism, in which the bimetallic Ni–Co hydrogen phosphate nanotubes initially grow on the surface of the Ni–Co glycerate spheres due to the reactions between Ni and Co metals bonded to the glycerate anions with hydrogen phosphate anions present in the solution. This is followed by the peeling of the overgrown nanotubes from the etched glycerate spheres and their self-weaving into 1D or 2D architectures depending on the Ni/Co molar ratio. The electrocatalytic test results reveal the superior activity of the Ni-rich Ni–Co hydrogen phosphate electrode for oxygen evolution reaction (OER) compared to its Co-rich and equimolar counterparts, leading to smaller overpotential of 320 mV and lower Tafel slope of 84 mV dec−1. Post-OER analysis of this sample reveals that the high OER activity is derived from the formation of active Ni–Co oxyhydroxide phase on its surface. [ABSTRACT FROM AUTHOR]

Noble-metal–metalloid binary palladium–boron (Pd–B) nanoalloys are interesting because the smaller boron atoms enlarge the Pd–Pd interlattice spacings and modify the binding energy barriers of catalytic intermediates. Binary Pd–B nanoalloys with nanostructured morphologies are an emerging class of (electro)catalysts that leverage these properties to enhance their performance in various chemical reactions. We describe here the first synthesis of Pd–B alloy mesoporous nanospheres (MNSs) and evaluate their electrocatalytic performance in the ethanol oxidation reaction (EOR). This method uses dimethylamine borane and boric acid as both the reducing agents and boron sources and amphiphilic dioctadecyldimethylammonium chloride (DODAC) as the surfactant template. The cylindrical mesophase of DODAC inhibits the mobility of the Pd metal precursor and confines the crystalline growth to form binary Pd–B MNSs with three-dimensional dendritic center-radial mesochannels. We demonstrate that the synthetic protocol can be adopted to rationally tune the diameters of the Pd–B MNSs from 30 nm to 120 nm without destroying the mesoporous structure and elemental composition. The Pd–B MNSs combine high surface area with favorable electrocatalytic surface properties to generate exceptional electrocatalytic performance for the EOR under alkaline conditions, illustrating the potential of this method as a platform to yield a new type of highly efficient electrocatalyst. [ABSTRACT FROM AUTHOR]

Constructing metal nanocrystal (NC)–polymer heteronanostructures (HNSs) with excellent properties in terms of ethanol adsorption and activation will lead to catalysts with a significantly enhanced electrochemical ethanol oxidation reaction (EOR). Herein, we present a facile and effective synthesis method for shape-controlled Pd NC–polyaniline (PANI) HNSs with various PANI thicknesses, which are achieved by using cubic and octahedral Pd NCs as metal NC seeds. By investigating the electrocatalytic properties of various Pd NC–PANI HNSs and their counterparts, we found that the electrocatalytic properties of the Pd NC–PANI HNSs highly depend on both the exposed facets of Pd NCs and thickness of the PANI coating. The cubic Pd NC–PANI (Pdcube-PANI) HNSs with cubic Pd NCs and a 0.7 nm PANI coating significantly improved the electrocatalytic performance for the EOR compared to the Pdcube-PANI HNSs with different PANI coating thicknesses, octahedral Pd NC–PANI (Pdocta-PANI) HNSs with octahedral Pd NCs, cubic Pd NCs, and commercial Pd/C because of synergistic advantages of the favorable exposed facet and optimal PANI coating thickness. [ABSTRACT FROM AUTHOR]

Correction for 'Prussian blue and its analogues as functional template materials: control of derived structure compositions and morphologies' by Behnoosh Bornamehr et al., J. Mater. Chem. A, 2023, 11, 10473–10492, https://doi.org/10.1039/D2TA09501G. [ABSTRACT FROM AUTHOR]

Metallic molybdenum disulfide (MoS2) has attracted wide attention owing to its high electrical conductivity and promising application in the electrocatalytic hydrogen evolution reaction (HER). However, it is difficult to realize the scale-up production of thermodynamically metastable metallic MoS2via conventional approaches. Although some research efforts have been devoted to producing metallic MoS2, it is still a challenging task to simultaneously realize metallic phase control and morphological regulation in MoS2. Here, metallic MoS2 with a controllable hierarchical spherical structure has been achieved via a hydrothermal strategy by using carbon nitride (C3N4) nanospheres as a self-sacrificial template. In the crystal growth, C3N4 played an important role in controlling the morphology of MoS2 by serving as the nucleation and growth site. Meanwhile, the decomposed C3N4 acted as an intercalated material which could further stabilize the metallic phase MoS2. Owing to good electroconductibility and unique structure design, metallic phase MoS2 with a hierarchical flower-like architecture exhibits enhanced electrolytic properties for the HER in an acidic medium. [ABSTRACT FROM AUTHOR]

Carbon materials, especially N-doped carbon materials with a one-dimensional (1D) hollow structure, have attracted great attention as one of the most efficient and eco-friendly catalysts for advanced oxidation processes (AOPs). The complex synthesis process of 1D hollow carbon however remains a major challenge in meeting the growing demand for it as a superior carbon-based catalyst. Herein, we demonstrate a facile strategy to synthesize 1D hollow carbon nanofibers (HCNFs) in a scalable manner. In this study, zeolitic imidazolate framework-8 (ZIF-8)/polyacrylonitrile (PAN) fibers were fabricated via electrospinning, and subsequent pyrolysis of the as-prepared ZIF-8/PAN composite nanofibers produced HCNFs. With excellent structural advantages and N-doped composition, HCNFs exhibited a remarkable level of catalytic degradation of tetracycline (TC) in the peroxymonosulfate (PMS) activation system. Furthermore, the HCNFs also showed good mechanical flexibility. A catalytic device was then constructed to explore the potential applications of HCNFs. [ABSTRACT FROM AUTHOR]

This work reports the fabrication of a three-dimensional (3D) zinc oxide/zinc cobaltite (ZnO/ZnCo2O4) hybrid with a hierarchical macroporous honeycomb-like structure using highly uniform cobalt glycerate spheres as a self-sacrificial template. In the proposed method, the conversion of the template cobalt glycerate nanospheres into a 3D hierarchical macroporous honeycomb-like ZnO/ZnCo2O4 hybrid is achieved via a facile room-temperature reaction with aqueous zinc nitrate solution, followed by calcination in air at 350 °C. The proposed method offers several benefits including (i) the attainment of the ZnO/ZnCo2O4 hybrid in one step without additional or separate coating steps, (ii) the achievement of a unique 3D hierarchical macroporous honeycomb-like structure with interconnecting nanosheets and macropores which are assembled from smaller mesopores, leading to higher surface area and good interparticle separation, (iii) the relatively low calcination temperature required to obtain the ZnO/ZnCo2O4 hybrid (350 °C) and (iv) potential generalization for the creation of other macroporous honeycomb-like cobalt-based oxide nanostructures (including Al–Co and Cu–Co systems). When evaluated as a sensing material for carbon monoxide (CO), the hierarchical honeycomb-like ZnO/ZnCo2O4 hybrid sensor displays a higher sensing response with enhanced selectivity and stability towards CO gas at 300 °C compared to both ZnO hierarchical spheres and ZnCo2O4 nanospheres. The enhanced sensing performance of the hierarchical honeycomb-like ZnO/ZnCo2O4 hybrid is derived from the synergistic cooperation of the formed p–n heterojunction, large surface area and hierarchical macroporous nature of the as-synthesized ZnO/ZnCo2O4 hybrid. It is expected that the proposed general method may open a new path for creating other hierarchical macroporous honeycomb-like oxide nanostructures with enhanced surface areas and improved functional performance. [ABSTRACT FROM AUTHOR]

Polymer electrolyte membrane fuel cells (PEMFCs) are one of the most sustainable energy conversion systems because of their high energy conversion efficiency and low/zero emissions. Unfortunately, the utilization of highly active but costly platinum (Pt)-based electrocatalysts is necessary to accelerate the sluggish kinetics of cathodic oxygen reduction in PEMFCs for practical applications. Under such circumstance, enormous efforts have been devoted to the exploration of inexpensive and earth-abundant non-noble metal-based electrocatalysts to replace or reduce the usage of Pt-based electrocatalysts in the past decades. Heteroatom-doped carbon materials are among some of the most promising non-noble metal-based electrocatalysts, especially transition metal- and nitrogen-doped carbon materials. According to previous findings, iron- and nitrogen-doped carbon (Fe-N/C) materials derived using various methodologies showed outstanding electrocatalytic activity and impressive durability. Therefore, tremendous progress has been achieved in the synthesis of Fe-N/C and the identification of active sites for oxygen reduction reaction (ORR). Creating ORR active sites, such as Fe-Nx, N/C, and Fe3C@C moieties, increasing the density of active sites and improving the utilization efficiency of ORR active sites are considered as the most effective steps for enhancing the ORR performance of Fe-N/C electrocatalysts. The creation of nanoporous structure of Fe-N/C electrocatalysts plays critical roles in increasing the number of ORR active sites and exposing abundant accessible ORR active sites to electrolytes. In addition, the interconnected nanopores facilitate the mass transfer of reactants and products inside the carbon matrix during the ORR reactions. Therefore, this review pays specific attention to the design and synthetic strategies of Fe-N/C materials with porous structures and their merits toward ORR. Finally, based on the construction of nanoporous structures, the challenges and perspectives with respect to future development of highly active nanoporous Fe-N/C electrocatalysts are discussed. [ABSTRACT FROM AUTHOR]

Hexagonally ordered covalent organic frameworks (COFs) are interesting new crystalline porous materials that have massive potential for application in gas storage. Herein, we report the synthesis of two series of two-dimensional hexagonally ordered COFs―TPA-COFs and TPT-COFs―through one-pot polycondensations of tris(4-aminophenyl)amine (TPA-3NH2) and 2,4,6-tris(4-aminophenyl)triazine (TPT-3NH2), respectively, with triarylaldehydes featuring different degrees of planarity, symmetry, and nitrogen content. All the synthesized COFs exhibited high crystallinity, large BET surface areas (up to 1747 m2 g−1), excellent thermal stability, and pore size distributions from 1.80 to 2.55 nm. The symmetry and planarity of the monomers strongly affected the degrees of crystallinity and the BET surface areas of the resultant COFs. In addition, these COFs displayed excellent CO2 uptake efficiencies of up to 65.65 and 92.38 mg g−1 at 298 and 273 K, respectively. The incorporation of the more planar and higher-nitrogen-content triaryltriazine unit into the backbones of the TPA-COFs and TPT-COFs enhanced the interactions with CO2, leading to higher CO2 uptakes. Moreover, the synthesized COFs exhibited electrochemical properties because of their conjugated structures containing redox-active triphenylamine groups. This study exposes the importance of considering the symmetry and planarity of the monomers when designing highly crystalline COFs; indeed, the structures of COFs can be tailored to vary their functionalities for specific applications. [ABSTRACT FROM AUTHOR]

The fabrication of continuous mesoporous Pt-based alloy films is very important for electrochemical energy conversion. Herein, we propose an extremely simple soaking method for achieving in situ fabrication of a continuous mesoporous PtRu film on macroporous Ni foam (mPtRu–NF). Owing to its continuous mesoporous structure and bi-metallic compositions, the mPtRu–NF exhibits high activity and durability for both the oxygen reduction reaction and oxygen evolution reaction. Furthermore, when the mPtRu–NF was used as a binder-free air electrode for rechargeable Zn–air batteries (ZABs), it shows superior electrochemical performance. Being very different from previous complex de-alloying or template-based approaches, this method provides a truly simple way for achieving direct fabrication of mesoporous metallic films on metallic substrates. The proposed one-step method is readily available for scale-up fabrication of continuous mesoporous Pt-based films on metallic substrates with designed compositions and desired performances. [ABSTRACT FROM AUTHOR]

Stabilizing the reactive metal anode is a critical challenge for the development of next-generation alkali metal batteries. This work demonstrates that sodium-difluoro(oxalato)borate (NaDFOB)-based carbonate-ester electrolytes have excellent compatibility with the anode in sodium metal batteries, enabling high rate performance and long cycle life. The NaDFOB-based electrolytes possess favourable electrochemical stability and effectively passivate the Na metal anode by forming a compact, robust and conductive solid-electrolyte interphase (SEI) layer. Quantitative nuclear magnetic resonance (NMR) measurements of electrolyte solvents indicated that the SEI layer forms mainly in the initial cycles, and it prevents further solvent degradation. Solid-state NMR and X-ray photoelectron spectroscopy studies revealed the chemical composition of the NaDFOB-derived SEI film, which includes a mixed phase consisting primarily of sodium diborate, tetrafluoroborate and carbonate. The formation of such a composite SEI rich in borate and tetrafluoroborate provides robust structural and chemical stability, and facilitates fast ion transport for uniform Na stripping/plating. [ABSTRACT FROM AUTHOR]

A great challenge in the application of carbon-based materials to Li–O2 batteries is to prevent the formation of carbonate-based side products, thereby extending the cycle life of Li–O2 batteries. Herein, for the first time, CNT@Ni@NiCo silicate core–shell nanocomposite is designed and used as a cathode catalyst in Li–O2 batteries. This nanocomposite shows a promising electrochemical performance with a discharge capacity of 10 046 mA h gcat−1 and a low overpotential of 1.44 V at a current density of 200 mA gcat−1, and it can sustain for more than 50 cycles within the voltage range of 2–4.7 V. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations prove that the formation of Li2CO3 and other side products are prevented, likely due to the encapsulation of CNTs by NiCo silicates and Ni nanoparticles, which may help decompose the side products. Finally, the synergistic effects, which are contributed by the high electrical conductivity of CNTs, high surface area, the high oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities of NiCo silicate, and the simple decomposition of side products by Ni nanoparticles enable outstanding performance of the CNT@Ni@NiCo silicate core–shell nanocomposite as a cathode catalyst for Li–O2 batteries. [ABSTRACT FROM AUTHOR]

Design of multi-metallic nanocrystals with branched structures is very important for catalytic applications. Herein, a one-step synthesis of unique tri-metallic PtPdCu tripods with branched exteriors (PtPdCu TPs) in an aqueous solution is presented. Benefiting from their spatially and locally separated branches and tri-metallic compositions, the PtPdCu TPs exhibit superior activity and durability for the oxygen reduction reaction. The newly designed PtPdCu TPs are quite different from previous tripods in their branched exteriors. The developed one-step method is very feasible for the preparation of Pt-based multi-metallic tripods with designed compositions and desired performances. [ABSTRACT FROM AUTHOR]

In this work, we propose a general template-free strategy for fabricating two-dimensional mesoporous mixed oxide nanosheets, such as metal cobaltites (MCo2O4, M = Ni, Zn) through the self-deconstruction/reconstruction of highly uniform Co-based metal glycerate nanospheres into 2D Co-based metal glycerate/hydroxide nanosheets, induced by the so-called “water treatment” process at room temperature followed by their calcination in air at 260 °C. The proposed ‘self-deconstruction/reconstruction’ strategy is highly advantageous as the resulting 2D metal cobaltite nanosheets possess very high surface areas (150–200 m2 g−1) and mesoporous features with narrow pore size distribution. In addition, our proposed method also enables the crystallization temperature to achieve pure metal cobaltite phase from the precursor phase to be lowered by 50 °C. Using the 2D mesoporous NiCo2O4 nanosheets as a representative sample, we found that they exhibit 6–20 times higher specific capacitance and greatly enhanced capacitance retention compared to the NiCo2O4 nanospheres achieved through the direct calcination of the Ni–Co glycerate nanospheres. This highlights another advantage of the proposed strategy for enhancing the electrochemical performance of the mixed oxide products for supercapacitor applications. Furthermore, the asymmetric supercapacitor (ASC) assembled using the 2D NiCo2O4 nanosheets//graphene oxide (GO) exhibits a maximum energy density of 38.53 W h kg−1, while also showing a high capacitance retention of 91% after 2000 cycles at 5 A g−1. It is expected that the proposed general method may be extended to other transition metal elements for creating 2D mixed oxide nanosheets with enhanced surface areas and improved electrochemical performance. [ABSTRACT FROM AUTHOR]

Mesostructured manganese phosphonate (MnP) with a uniform nanorod morphology has been prepared through an easy surfactant-mediated procedure, in which cetyltrimethylammonium bromide acts as a structure-directing agent and 1-hydroxyethane 1,1-diphosphonic acid is used as the phosphonic bridging molecule. Suitable interaction between the micelles and precursors is proved to play an essential role in the formation of a mesophase. By optimizing the reaction conditions (e.g., Mn/P ratio, pH, and aging time), a mesostructure can be realized in manganese phosphonate. Furthermore, our MnP sample shows great potential as a high-performance pseudocapacitive material due to the abundant accessible active sites and rapid ion/electron transportation arising from the unique mesostructural architecture. [ABSTRACT FROM AUTHOR]