The development of passive NOx adsorbers with cost-benefit and high NOx storage capacity remains an on-going challenge to after-treatment technologies at lower temperatures associated with cold-start NOx emissions. Herein, Cs1Mg3Al catalyst prepared by sol-gel method was cyclic tested in NOx storage under 5 vol% water. At 100 °C, the NOx storage capacity (1219 μmol g-1) was much higher than that of Pt/BaO/Al2O3 (610 μmol g-1). This provided new insights for non-noble metal catalysts in low-temperature passive NOx adsorption. The addition of Cs improved the mobility of oxygen species and thus improved the NOx storage capacity. The XRD, XPS, IR spectra and in situ DRIFTs with NH3 probe showed an interaction between CsOx and AlOx sites via oxygen species formed on Cs1Mg3Al catalyst. The improved mobility of oxygen species inferred from O2-TPD was consistent with high NOx storage capacity related to enhanced formation of nitrate and additional nitrite species by NOx oxidation. Moreover, the addition of Mg might improve the stability of Cs1Mg3Al by stabilizing surface active oxygen species in cyclic experiments.

High-entropy oxides (HEOs) are gaining prominence in the field of electrochemistry due to their distinctive structural characteristics, which give rise to their advanced stable and modifiable functional properties. This review presents fundamental preparations, incidental characterizations, and typical structures of HEOs. The prospective applications of HEOs in various electrochemical aspects of electrocatalysis and energy conversion-storage are also summarized, including recent developments and the general trend of HEO structure design in the catalysis containing oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), supercapacitors (SC), lithium-ion batteries (LIBs), solid oxide fuel cells (SOFCs), and so forth. Moreover, this review notes some apparent challenges and multiple opportunities for the use of HEOs in the wide field of energy to further guide the development of practical applications. The influence of entropy is significant, and high-entropy oxides are expected to drive the improvement of energy science and technology in the near future.

Efficient and selective glucose-to-fructose isomerization is a crucial step for production of oxygenated chemicals derived from sugars, which is usually catalyzed by base or Lewis acid heterogeneous catalyst. However, high yield and selectivity of fructose cannot be simultaneously obtained under mild conditions which hamper the scale of application compared with enzymatic catalysis. Herein, a Li-promoted C3N4 catalyst was exploited which afforded an excellent fructose yield (40.3 wt%) and selectivity (99.5 %) from glucose in water at 50 °C, attributed to the formation of stable Li−N bond to strengthen the basic sites of catalysts. Furthermore, the so-formed N6−Li−H2O active site on Li-C3N4 catalyst in aqueous phase changes the local electronic structure and strengthens the deprotonation process during glucose isomerization into fructose. The superior catalytic performance which is comparable to biological pathway suggests promising applications of lithium containing heterogeneous catalyst in biomass refinery.

A covalent organic frameworks (COFs) material with regular pores and stable structure can be used as the host of lithium-sulfur batteries to improve battery kinetics and polysulfides conversion. Herein, we designed and synthesized two kinds of rod-liked bulk COFs by adjusting different pore sizes (COF-BTD and COF-TFB), unfortunately, the active sites masking and sluggish kinetics have not met our expectations. Generally, the available layered COFs prepared from mechanochemical can expose abundant active sites and favorable kinetics than bulk COFs. Thus, simple mechanical ball milling is applied to activate the above COFs (M-COFs group). It is worth noting that layered R-COF-BTD is directly synthesized from rod-liked precursors by simple morphological reconstruction. A series of characterization methods are used to systematically explore the advantages of the group of M-COFs@S electrodes in the cycling process, including the effects of specific morphology on the kinetics and transformation of polysulfides. Our research provides a feasible plan for the development and selection of the host material of lithium-sulfur batteries.

Low-carbon hydrogen can play a significant role in decarbonizing the world. Hydrogen is currently mainly produced from fossil sources, requiring additional CO2 capture to decarbonize, which energy intense and costly. In a recent Green Energy & Environment paper, Cheng and Di et al. proposed a novel integration process referred to as SECLRHC to generate high-purity H2 by in-situ separation of H2 and CO without using any additional separation unit. Theoretically, the proposed process can essentially achieve the separation of C and H in gaseous fuel via a reconfigured reaction process, and thus attaining high-purity hydrogen of ∼99%, as well as good carbon and hydrogen utilization rates and economic feasibility. It displays an optimistic prospect that industrial decarbonization is not necessarily expensive, as long as a suitable CCS measure can be integrated into the industrial manufacturing process.

At room temperature, the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane (DRM) is quite promising and challenging. Herein, we developed a novel covalent organic porous polymer (TPE-COP) with rapid charge separation of the electron-hole pairs for DRM driven by visible light at room temperature, which can efficiently generate syngas (CO and H2). Both electron donor (tris(4-aminophenyl)amine, TAPA) and acceptor (4,4',4'',4'''-((1E,1'E,1''E,1'''E)-(ethene-1,1,2,2-tetrayltetrakis(benzene-4,1-diyl))tetrakis(ethene-2,1-diyl))tetrakis(1-(4-formylbenzyl)quinolin-1-ium), TPE-CHO) were existed in TPE-COP, in which the push-pull effect between them promoted the separation of photogenerated electron-hole, thus greatly improving the photocatalytic activity. Density functional theory (DFT) simulation results show that TPE-COP can form charge-separating species under light irradiation, leading to electrons accumulation in TPE-CHO unit and holes in TAPA, and thus efficiently initiating DRM. After 20 h illumination, the photocatalytic results show that the yields reach 1123.6 and 30.8 μmol g-1 for CO and H2, respectively, which are significantly higher than those of TPE-CHO small molecules. This excellent result is mainly due to the increase of specific surface area, the enhancement of light absorption capacity, and the improvement of photoelectron-generating efficiency after the formation of COP. Overall, this work contributes to understand the advantages of COP materials for photocatalysis and fundamentally pushes metal-free catalysts into the door of DRM field.

This work uses thermal polymerization of urea nitrate, oxyacetic acid and urea as the raw material to prepare ultra-thin porous carbon nitride with carbon defects and C-O band (OA-UN-CN). Density functional theory (DFT) calculations showed OA-UN-CN had narrower band gap, faster electron transport and a new internal construction electric field. Additionally, the prepared OA-UN-CN significantly enhanced photocatalytic activation of peroxymonosulfate (PMS) due to enhanced light absorption performance and faster electron overflow. As the result, the OA-UN-CN/PMS could entirely degrade bisphenol A (BPA) within 30 min, where the photodegradation rate was 81.8 and 7.9 times higher than that of g-C3N4 and OA-UN-CN, respectively. Beyond, the OA-UN-CN/PMS could likewise degrade other bisphenol pollutants and sodium lignosulfonate efficiently. We suggested possible photocatalytic degradation pathways accordingly and explored the toxicity of its degradation products. This work provides a new idea on the development of advanced photocatalytic oxidation processes for the treatment of bisphenol pollutants and lignin derivatives, via a metal-free photothermal-catalyst.

Li-air batteries have attracted extensive attention because of their ultrahigh theoretical energy density. However, the potential safety hazard of flammable organic liquid electrolytes hinders their practical applications. Replacing liquid electrolytes with solidstate electrolytes (SSEs) is expected to fundamentally overcome the safety issues. In this work, we focus on the development and challenge of solid-stateLi-air batteries (SSLABs). The rise of different types of SSEs, interfacial compatibility and verifiability in SSLABs are presented. The corresponding strategies and prospects of SSLABs are also proposed. In particular, combining machine learning method with experiment and in situ (or operando) techniques is imperative to accelerate the development of SSLABs.

Negatively thermo-responsive 2D membranes, which mimic the stomatal opening/closing of plants, have drawn substantial interest for tunable molecular separation processes. However, these membranes are still restricted significantly on account of low water permeability and poor dynamic tunability of 2D nanochannels under temperature stimulation. Here, we present a biomimetic negatively thermo-responsive MXene membrane by covalently grafting poly (N-isopropylacrylamide) (PNIPAm) onto MXene nanosheets. The uniformly grafted PNIPAm polymer chains can enlarge the interlayer spacings for increasing water permeability while also allowing more tunability of 2D nanochannels for enhancing the capability of gradually separating multiple molecules of different sizes. As expected, the constructed membrane exhibits ultrahigh water permeance of 95.6 L m−2 h−1 bar−1 at 25 °C, which is eight-fold higher than the state-of-the-art negatively thermo-responsive 2D membranes. Moreover, the highly temperature-tunable 2D nanochannels enables the constructed membrane to perform excellent graded molecular sieving for dye- and antibiotic-based ternary mixtures. This strategy provides new perspectives in engineering smart 2D membrane and expands the scope of temperature-responsive membranes, showing promising applications in micro/nanofluidics and molecular separation.

Photocatalysis, a critical strategy for harvesting sunlight to address energy demand and environmental concerns, is underpinned by the discovery of high-performance photocatalysts, thereby how to design photocatalysts is now generating widespread interest in boosting the conversion efficiency of solar energy. In the past decade, computational technologies and theoretical simulations have led to a major leap in the development of high-throughput computational screening strategies for novel high-efficiency photocatalysts. In this viewpoint, we started with introducing the challenges of photocatalysis from the view of experimental practice, especially the inefficiency of the traditional "trial and error" method. Subsequently, a cross-sectional comparison between experimental and high-throughput computational screening for photocatalysis is presented and discussed in detail. On the basis of the current experimental progress in photocatalysis, we also exemplified the various challenges associated with high-throughput computational screening strategies. Finally, we offered a preferred high-throughput computational screening procedure for photocatalysts from an experimental practice perspective (model construction and screening, standardized experiments, assessment and revision), with the aim of a better correlation of high-throughput simulations and experimental practices, motivating to search for better descriptors.

Li metal batteries (LMBs) with LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes could release a specific energy of >500 Wh kg-1 by increasing the charge voltage. However, high-nickel cathodes working at high voltages accelerate degradations in bulk and at interfaces, thus significantly degrading the cycling lifespan and decreasing the specific capacity. Here, we rationally design an all-fluorinated electrolyte with addictive tri(2,2,2-trifluoroethyl) borate (TFEB), based on 3, 3, 3-fluoroethylmethylcarbonate (FEMC) and fluoroethylene carbonate (FEC), which enables stable cycling of high nickel cathode (LiNi0.8Co0.1Mn0.1O2, NMC811) under a cut-off voltage of 4.7 V in Li metal batteries. The electrolyte not only shows the fire-extinguishing properties, but also inhibits the transition metal dissolution, the gas production, side reactions on the cathode side. Therefore, the NMC811||Li cell demonstrates excellent performance by using limited Li and high-loading cathode, delivering a specific capacity >220 mA h g−1, an average Coulombic efficiency >99.6% and capacity retention > 99.7% over 100 cycles.

Solid polymer electrolytes (SPEs) are highly promising for realizing high-capacity, low-cost, and safe Li metal batteries. However, the Li dendritic growth and side reactions between Li and SPEs also plague these systems. Herein, a fluorinated lithium salt coating (FC) with organic-inorganic gradient and soft–rigid feature is introduced on Li surface as an artificial protective layer by the in-situ reaction between Li metal and fluorinated carboxylic acid. The FC layer can improve the interface stability and wettability between Li and SPEs, assist the transport of Li ions, and guide Li nucleation, contributing to a dendrite-free Li deposition and long-lifespan Li metal batteries. The symmetric cell with FC-Li anodes exhibits a high areal capacity of 1 mAh cm-2 at 0.5 mA cm-2, and an ultra-long lifespan of 2000 h at a current density of 0.1 mA cm-2. Moreover, the full cell paired with the LiFePO4 cathode exhibits improved cycling stability, remaining 83.7% capacity after 500 cycles at 1 C. When matching with the S cathode, the FC layer can prevent the shuttle effect, contributing to stable and high-capacity Li-S battery. This work provided a promising way for the construction of stable all-solid-state lithium metal batteries with prolonged lifespan.

Lithium hexafluorophosphate (LiPF6), the most commonly used lithium battery electrolyte salt, is vulnerable to heat and humidity. Quantitative and qualitative determination the variation of LiPF6 have always relied on advanced equipment. Herein, we develop a fast, convenient, high-selective fluorescence detection method based on metal-organic cages (MOC), whose emission is enhanced by nearly 20 times in the presence of LiPF6 with good stability and photobleaching resistance. The fluorescent probe can also detect moisture in battery electrolyte. We propose and verify that the luminescence enhancement is due to the presence of hydrogen bond-induced enhanced emission effect in cages. Fluorescent excitation-emission matrix spectra and variable-temperature nuclear magnetic resonance spectroscopy are employed to clarify the role of hydrogen bonds in guest-loaded cages. Density functional theory (DFT) calculation is applied to simulate the structure of host-guest complexes and estimate the adsorption energy involved in the system. The precisely matched lock-and-key model paves a new way for designing and fabricating novel host structures, enabling specific recognition of other target compounds.

As lead halide perovskite (LHP) semiconductors have shown tremendous promise in many application fields, and particularly made strong impact in the solar photovoltaic area, low dimensional quantum dot forms of these perovskites are showing the potential to make distinct marks in the fields of electronics, optoelectronics and photonics. The so-called perovskite quantum dots (PQDs) not only possess the most important feature of LHP materials, i.e., the unusual high defect tolerance, but also demonstrate clear quantum size effects, along with exhibiting desirable optoelectronic properties such as near perfect photoluminescent quantum yield, multiple exciton generations and slow hot-carrier cooling. Here, we review the advantageous properties of these nanoscale perovskites and survey the prospects for diverse applications which include light-emitting devices, solar cells, photocatalysts, lasers, detectors and memristors, emphasizing the distinct superiority as well as the challenges.

Good crystallinity can reduce the charge recombination centers caused by defects, whilst structures with strong polycondensation have high charge mobility, leading to more charge transfer to the material surface for reaction. Much effort has been put into the preparation of a highly efficient g-C3N4 with defects to improve its application potential under the premise in high crystallinity. Hence, this review paper emphasizes the importance to balance the defect and crystallinity of g-C3N4. In addition, detailed discussion on the relationship between defects and activity of g-C3N4 was carried out based on its applications in environmental purification (e.g., VOCs oxidation, NOx oxidation, H2O2 evolution, sterilization, pesticide oxidation) and energy conversion (H2 evolution, N2 fixation and CO2 reduction). Lastly, the challenge in developing more efficient defective g-C3N4 photocatalytic materials is summarized.

Aluminum (Al), the most abundant metallic element on the earth crust, has been reckoned as a promising battery material for its the highest theoretical volume capacity (8046 mAh cm-3). Being rechargeable in ionic liquid electrolytes, however, the Al anode and battery case suffer from corrosion. On the other hand, Al is irreversible in aqueous electrolyte with severe hydrogen evolution reaction. Here, we demonstrate a water-in-salt aluminum ion electrolyte (WISE) based on Al and lithium salts to tackle the above challenges. In the WISE system, water molecules can be confined within the Li+ solvation structures. This diminished Al3+-H2O interaction essentially eliminates the hydrolysis effect, effectively protecting Al anode from corrosion. Therefore, long-term Al plating/stripping can be realized. Furthermore, two types of high-performance full batteries have been demonstrated using copper hexacyanoferrate (CuHCF, a Prussian Blue Analogues) and LiNi0.8Co0.1Mn0.1O2 (NCM) as cathodes. The reversibility of Al anode laid the foundation for low cost rechargeable batteries suffering for large-scale energy storage.

As a key material for lithium metal batteries (LMBs), lithium metal is one of the most promising anode materials to break the bottleneck of battery energy density and a commonly used active material for reference electrodes. Although lithium anodes are regarded as the holy grail of lithium batteries, decades of exploration have not led to the successful commercialization of LMBs, due mainly to the challenges related to the inherent properties of lithium metal. To pave the way for further investigation, herein, a comprehensive review focusing on the fundamental science of lithium are provided. Firstly, the natures of lithium atoms and their isotopes, lithium clusters and lithium crystals are revisited, especially their structural and energetic properties. Subsequently, the electrochemical properties of lithium metal are reviewed. Numerous important concepts and scientific questions, including the electronic structure of lithium, influence of high pressure and low temperature on the properties of lithium, factors influencing lithium deposition, generation of lithium dendrites, and electrode potential of lithium in different electrolytes, are explained and analyzed in detail. Approaches to improve the performance of lithium anodes and thoughtfulness about the electrode potential in lithium battery research are proposed.

Zeolites have been widely used as catalysts, ion-exchangers, and adsorbents in chemical industries, detergent industry, steel industry, glass industry, ceramic industry, medical and health field, and environmental filed, and recently applied in energy storage. Seed-assisted synthesis is a very effective approach in promoting the crystallization of zeolites. In some cases, the target zeolite cannot be formed in the absence of seed zeolite. In homologous seed-assisted synthesis, the structure of the seed zeolite is the same to that of the target zeolite, while the structure of the seed zeolite is different to that of the target zeolite in the heterologous seed-assisted synthesis. In this review, we briefly summarized the heterologous seed-assisted syntheses of zeolites and analyzed the structure-directing effect of heterologous seeds and surveyed the “common composite building units (CBUs) hypothesis” and the “common secondary building units (SBUs) hypothesis”. However, both hypotheses cannot explain all observations on the heterologous seed-assisted syntheses. Finally, we proposed that the formation of the target zeolite does need nuclei with the structure of target zeolite and the formation of the nuclei of the target zeolite can be promoted by either the undissolved seed crystals with the same CBUs or SBUs to the target zeolite or by the facilitated appropriate distribution of the specific building units due to the presence of the heterologous seed that does not have any common CBUs and SBUs with the target zeolite.

Multiphase microfluidic has emerged as a powerful platform to produce novel materials with tailor-designed functionalities, as microfluidic fabrication provides precise controls over the size, component, and structure of resultant materials. Recently, functional materials with well-defined micro-/nanostructures fabricated by microfluidics find important applications as environmental and energy materials. This review first illustrated in detail how different structures or shapes of droplet and jet templates are formed by typical configurations of microfluidic channel networks and multiphase flow systems. Subsequently, recent progresses on several representative energy and environmental applications, such as water purification, water collecting and energy storage, were overviewed. Finally, it is envisioned that integrating microfluidics and other novel materials will play increasing important role in contributing environmental remediation and energy storage in near future.

The state-of-the-art lithium-ion capacitors (LICs), consisting of high-capacity battery-type anode and high-rate capacitor-type cathode, can deliver high energy density and large power density when comparing with traditional supercapacitors and lithium-ion batteries, respectively. However, the ion kinetics mismatch between cathode and anode leads to unsatisfied cycling lifetime and anode degradation. Tremendous efforts have been devoted to solve the abovementioned issue. One promising strategy is altering high conductive hard carbon anode with excellent structural stability to match with activated carbon cathode, assembling dual-carbon LIC. In this contribution, one-pot in-situ expansion and heteroatom doping strategy was adopted to prepare sheet-like hard carbon, while activated carbon was obtained involving activation. Ammonium persulfate was used as expanding and doping agent simultaneously. While furfural residues (FR) were served as carbon precursor. The resulting hard carbon (FRNS-HC) and activated carbon (FRNS-AC) show excellent electrochemical performance as negative and positive electrodes in a lithium-ion battery (LIB). To be specific, 374.2 mAh g-1 and 123.1 mAh g-1 can be achieved at 0.1 A g-1 and 5 A g-1 when FRNS-HC was tested as anode. When combined with a highly porous carbon cathode (SBET = 2961 m2 g-1) synthesized from the same precursor, the LIC showed high specific energy of 147.67 Wh kg-1 at approximately 199.93 W kg-1, and outstanding cycling life with negligible capacitance fading over 1000 cycles. This study could lead the way for the development of heteroatom-doped porous carbon nanomaterials applied to Li-based energy storage applications.