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Tellurene, probably one of the most promising two-dimensional (2D) system in the thermoelectric materials, displays ultra-low thermal conductivity. However, a linear thickness-dependent thermal conductivity of unique tellurium nanoribbons in this study reveals that unprecedently low thermal conductivity can be achieved via well-defined nanostructures of low-dimensional tellurium instead of pursuing dimension-reduced 2D tellurene. For thinnest tellurium nanoribbon with thickness of 144 nm, the thermal conductivity is only ∼1.88 ± 0.22 W·m−1·K−1 at room temperature. It’s a dramatic decrease (45%), compared with the well-annealed high-purity bulk tellurium. To be more specific, an expected thermal conductivity of tellurium nanoribbons is even lower than that of 2D tellurene, as a result of strong phonon-surface scattering. We have faith in low-dimensional tellurium in which the thermoelectric performance could realize further breakthrough.

In this work, hierarchically porous carbon spheres co-doped by iron and nitrogen were synthesized via in situ dehalogenation. The rich porous structure and relatively high specific surface area (210 m2/g) facilitate the formation of an ultra-fine Fe2N active phase and FeN4 active centers within the carbon matrix. Transmission electron microscopy and X-ray photoelectron spectroscopy analysis further reveal the presence of a dominant Fe2N phase and minor FeN4 bonds in the as-prepared Fe-N-C-pd-800 samples. Because of this, the oxygen reduction reaction (ORR) process can more readily take place on Fe2N than on FeN4, and the Fe2N phase enriched Fe-N-C-pd-800 carbon spheres exhibit a promising onset potential (Eonset=1.02 V) and half-wave potential (E1/2=0.86 V) in alkaline media. In addition, Fe-N-C-pd-800 also shows excellent methanol resistance and long-cycling stability.

An efficient Cu(I)/DMAP/air system for the one-pot synthesis of 4-oxo-4H-cinnolin-2-ium-1-ides, which are often difficult to prepare by traditional routes from substituted 2-alkynylanilines and nitrosoarenes, was developed. These 4-oxo-4H-cinnolin-2-ium-1-ides have practical applications as mechanoluminescent materials. Preliminary mechanistic experiments were performed, and a plausible mechanism for this tandem process is proposed. The use of an inexpensive copper catalyst and molecular oxygen as the oxygen source and the oxidant make this an attractive green protocol with potential synthetic applications.

The ability to craft high-performance and cost-effective bifunctional oxygen catalysts opens up pivotal perspectives for commercialization of zinc–air batteries (ZABs). Despite recent grand advances in the development of synthetic techniques, the overall performance of electrocatalytic processes enters the bottleneck stage through focusing only on the design and modification of bifunctional catalyst materials. Herein, we report a simple yet robust strategy to markedly boost the performance of ZABs via capitalizing on the photothermal effect. Concretely, a bifunctional electrocatalyst comprising Co3O4 nanoparticles encapsulated within N-doped reduced graphene oxide (denoted as Co3O4/N-rGO) acted as both active material and photothermal component. Upon light illumination, the compelling photothermal effect of Co3O4/N-rGO rendered a localized and instant heating of the electrode with more active sites, enhanced electrical conductivity and improved release of bubbles. As such, a prominently reduced indicator ΔE of 0.635 V was realized, significantly outperforming recently reported systems (usually >0.68 V). Corresponding rechargeable ZABs based on Co3O4/N-rGO air electrodes possessed an excellent maximum power density of 299 mW cm−2 (1.8 times that of Pt/Ru-based ZABs) assisted by the photothermal effect with a superb cycling stability (over 500 cycles). This intensification strategy opens vast possibilities to ameliorate the performance of catalysts via innovatively and conveniently utilizing their photothermal feature, which may advance future application in high-performance ZABs and other energy conversion and storage systems.

A novel titanium, nitrogen co-doped carbon material was designed via a one-step solvothermal reaction at a moderate temperature. Characterization by scanning electron microscopy and transmission electron microscopy illustrates that carbon materials without titanium doping possess a morphology of porous flakes, whereas the inclusion of titanium results in the deposition/intercalation of island-shaped TiO2 nanoparticles on these carbon flakes. Both the volumetric energy density and the cycling stability are significantly improved by titanium doping. Electrochemical measurements show that the introduction of titanium leads to a high volumetric capacitance of 285.5 F cm−3 at 0.5 A g−1 current density. Electrodes prepared with the new materials also exhibit excellent cycling stability, where there is no capacitance loss after 40 000 cycles in the 6 M KOH electrolyte at a high charge/discharge current of 30 A g−1. The volumetric energy density of the as-obtained symmetrical supercapacitor reaches 11.99 W h L−1, which is competitive to that of lithium thin-film batteries (1–10 W h L−1).

The development of electric and hybrid electric vehicles has emerged as one of the most promising strategies for solving the global shortage of fossil energy problem. High-energy and high-power lithium-ion batteries are essential for achieving the large-scale commercialization of electric vehicles. Ni-rich layered-structure oxides appear to be one of the most ideal candidates for electrode materials owing to their high-energy density. However, severe degradation issues associated with chemical and structural instabilities have limited their further applications. This review summarizes recent progress toward the fundamental understanding of ternary layered-structure oxides with a particular focus on the key issues of ion intermixing, chemo-mechanical degradation, and phase evolution on the particle surface. The possible strategies, as well as perspectives for addressing these problems, are also proposed in this review as an effort to provide guidance on the further design of advanced layered-structure oxides.

Sub-5 nm monodispersed metal oxides have been attracting much attention in energy storage due to their large electrolyte ion-accessible surface areas and high specific capacities. However, the high surface free energy of ultrasmall nanoparticles inevitably results in their serious aggregation, leading to degraded electrochemical activities and poor cycling stability. Herein, a two-stage microimpinging stream reactor (TS-MISR) strategy that combines a first homogeneous premixing stage with a subsequent microimpinging stream reacting stage has been constructed for the controllable synthesis of Ni–Co–O/RGO composites (NCG). Benefiting from the enhanced micromixing efficiency and better process control of TS-MISR, monodispersed ultrasmall Ni–Co–O particles (3–4 nm) are evenly grown on the RGO flakes to generate a large specific surface area (293.2 m2 g−1), quantities of desirable mesopores (2–4 nm), as well as a strong synergistic effect between Ni–Co–O particles and conductive RGO flakes, hence providing more superficial electroactive sites, fast electron transfer and short diffusion paths for electrolyte ions to participate in faradaic redox reactions. The as-prepared NCG-MM exhibits a large specific capacity of 912.4 C g−1 (capacitance of 2281 F g−1) at the current density of 1 A g−1, good rate capability and cycling stability. Coupled with the activated carbon (AC) negative electrode, the assembled pouch-type NCG//AC asymmetric supercapacitor displays a prominent areal energy density (0.898 mW h cm−2 at 0.8 mW cm−2) and an excellent cycling stability (∼90.5% capacity retention after 8000 cycles). In addition, this strategy opens up an important prospect for the controllable synthesis of monodispersed metal oxide/graphene composites for application in batteries, sensors and catalysis.

The emerging applications of electrochemical gas sensors (EGSs) in Internet of Things-enabled smart city and personal health electronics bring out a new challenge for common EGSs, such as alcohol fuel cell sensors (AFCSs) to reduce the dependence on a pricy Pt catalyst. Here, for the first time, we propose a low-cost novel N,S-codoped metal catalyst (FeNSC) to accelerate oxygen reduction reaction (ORR) and replace the Pt catalyst in the cathode of an AFCS. The optimal FeNSC shows high ORR activity, stability, and alcohol tolerance. Furthermore, the FeNSC-based AFCS not only demonstrates excellent linearity, low detection limit, high stability, and superior sensitivity to that of the commercial Pt/C-based AFCS but also outperforms commercial Pt/C-based AFCS in the exposed cell regarding great linearity, high sensitivity, and great stability. Such a promising sensor performance not just proves the concept of the FeNSC-based ACFS but enlightens the next-generation designs toward low-cost, highly sensitive, and durable EGSs.

The development of multi-component photothermal agents has attracted increasing attention due to their potential applications in energy conversion, medical treatments, etc. Herein, a dumbbell shaped PbS–Te heterostructure was prepared via a one-pot microwave-assisted decomposition of lead dimethyl dithiocarbamate and tellurium diethyl dithiocarbamate. The as-obtained PbS–Te hybrids exhibit excellent photothermal stability and strong optical absorption over a broad wavelength range spanning from ultraviolet to near-infrared, where the photothermal conversion efficiency could reach as high as 12.1%. Such promising photothermal performance demonstrates the advantages of one-pot synthesis that results in more intimate contacts among individual components.

Ni-rich LiNi1-x-y Mnx Coy O2 (NMC) layered compounds are the dominant cathode for lithium ion batteries. The role of crystallographic defects on structure evolution and performance degradation during electrochemical cycling is not yet fully understood. Here, we investigated the structural evolution of a Ni-rich NMC cathode in a solid-state cell by in situ transmission electron microscopy. Antiphase boundary (APB) and twin boundary (TB) separating layered phases played an important role on phase change. Upon Li depletion, the APB extended across the layered structure, while Li/transition metal (TM) ion mixing in the layered phases was detected to induce the rock-salt phase formation along the coherent TB. According to DFT calculations, Li/TM mixing and phase transition were aided by the low diffusion barriers of TM ions at planar defects. This work reveals the dynamical scenario of secondary phase evolution, helping unveil the origin of performance fading in Ni-rich NMC.

We present a strategy of interfacially bridging covalent network within tobacco mosaic virus (TMV) virus-like particles (VLPs). We arranged T103C cysteine to laterally conjugate adjacent subunits. In the axis direction, we set A74C mutation and systematically investigated candidate from E50C to P54C as the other thiol function site, for forming longitudinal disulfide bond chains. Significantly, the T103C-TMV-E50C-A74C shows the highest robustness in assembly capability and structural stability with the largest length, for TMV VLP to date. The fibers with lengths from several to a dozen of micrometers even survive under pH 13. The robust nature of this TMV VLP allows for reducer-free synthesis of excellent electrocatalysts for application in harshly alkaline hydrogen evolution.

On the road to find complementary candidates to the present commercial lithium ion batteries, electrode materials with high performance for both sodium ion batteries and potassium ion batteries are attracting more and more attention. Herein, hierarchical hollow CoP and carbon composites were obtained through a facile synthetic method, where carbonization and phosphorization of the precursor were completed within one single step. The composites are composed of hollow CoP@C spheres, which are further made up of CoP nanoparticles with a thin outer carbon layer. Electrochemical performances of the prepared CoP@C composites as anodes for sodium and potassium storage were evaluated and compared. In-situ TEM, in-situ synchrotron XRD and density functional theory calculation were conducted to study the structural evolution and the interaction between Na/K and CoP during cycling processes. Benefiting from the synergistic effect of conductive carbon layer and hierarchical hollow structure, the as-prepared CoP@C composites demonstrate superior sodium and potassium storage capability as anode materials for rechargeable batteries.

Rational design of hollow micro- and/or nano-structured cathodes as sulfur hosts has potential for high-performance lithium-sulfur batteries. However, their further commercial application is hindered because infusing sulfur into hollow hosts is hard to control and the interactions between high loading sulfur and electrolyte are poor. Herein, we designed hierarchical porous hollow carbon nanospheres with radially inwardly aligned supporting ribs to mitigate these problems. Such a structure could aid the sulfur infusion and maximize sulfur utilization owing to the well-ordered pore channels. This highly organized internal carbon skeleton can also enhance the electronic conductivity. The hollow carbon nanospheres with further nitrogen-doping as the sulfur host material exhibit good capacity and excellent cycling performance (0.044 % capacity degradation per each cycle for 1000 cycles).

High-energy density lithium-rich layered oxides are among the most promising candidates for next-generation energy storage. Unfortunately, these materials suffer from severe electrochemical degradation that includes capacity loss and voltage decay during long-term cycling. Present research efforts are primarily focused on understanding voltage decay phenomena while origins for capacity degradation have been largely ignored. Here, we thoroughly investigate causes for electrochemical performance decline with an emphasis on capacity loss in the lithium-rich layered oxides, as well as reaction pathways and kinetics. Advanced synchrotron-based X-ray two-dimensional and three-dimensional imaging techniques are combined with spectroscopic and scattering techniques to spatially visualize the reactivity at multiple length-scales on lithium- and manganese-rich layered oxides. These methods provide direct evidence for inhomogeneous manganese reactivity and ionic nickel rearrangement. Coupling deactivated manganese with nickel migration provides sluggish reaction kinetics and induces serious structural instability in the material. Our findings provide new insights and further understanding of electrochemical degradation, which serve to facilitate cathode material design improvements.

The oxygen evolution reaction (OER) is pivotally involved in proton exchange membrane water electrolyzers (PEMWEs). However, the commercialized iridium‐based catalysts often suffer from severe sluggish kinetics, eventually deteriorating the polarization and overall PEMWEs performance. Therefore, to develop OER electrocatalysts with promising reaction kinetics and high stability is of great significance for PEMWEs. Compared to iridium, the ruthenium‐based catalysts possess lower price and higher activity in acidic water oxidation, which promises Ru‐based materials to replace the state‐of‐the‐art IrOx. Yet, the less stable ruthenium than iridium impedes its real applications. In this mini review, recent knowledge of feasible engineering strategies for migrating the Ru‐based electrocatalysts' stability is summarized. In order to improve performance and durability, basic fundamentals of acidic OER on nanoscale and molecular engineered Ru‐based electrocatalysts are briefly introduced. In the end, the challenges and outlook for engineering novel Ru‐based electrocatalysts are presented.

This study is dedicated to expand the family of lithium-tellurium sulfide batteries, which have been recognized as a promising choice for future energy storage systems. Herein, a novel electrochemical method has been applied to engineer micro-nano TexSy material, and it is found that TexSy phases combined with multi-walled carbon nanotubes endow the as-constructed lithium-ion batteries excellent cycling stability and high rate performance. In the process of material synthesis, the sulfur was successfully embedded into the tellurium matrix, which improved the overall capacity performance. TexSy was characterized and verified as a micro-nano-structured material with less Te and more S. Compared with the original pure Te particles, the capacity is greatly improved, and the volume expansion change is effectively inhibited. After the assembly of Li-TexSy battery, the stable electrical contact and rapid transport capacity of lithium ions, as well as significant electrochemical performance are verified.

Nickel/Nickel phosphides electrodes are prepared through in-situ reduction of NiSO4 and NaH2PO2 on carbon cloth substrates using square-wave and cyclic voltammetry methods. Nickel/nickel phosphide nanospheres prepared with the pulse deposition procedure exhibits higher activity in the hydrogen evolution reaction (HER), outperforming those prepared through cyclic voltammetry approach. Scanning electron microscopy measurements indicate that pulse-deposition offers a better control on the nucleation process and the size of nanospheres, leading to the formation of nano-cracks within the spheres and creating more active sites for the HER. The as-obtained nickel/nickel phosphide/carbon cloth electrodes exhibit cathodic currents of 10 mA cm−2 at the overpotential of 164 mV in a 0.5 M H2SO4 solution and the obtained Tafel plot has a slope of 76 mV dec−1.

As a promising cathode material for rechargeable lithium ion batteries, tellurium has attracted a great deal of attention due to its high conductivity and high theoretical capacity. Yet, the large volume expansion (~104 vol%) during Li-Te alloying process prevents the application of Li-Te battery. Here, by using a novel one-step nonlinear electrochemical approach, we prepared a TexSy@polyaniline nanorod composites, in which elemental sulfur is successfully embedded into tellurium matrix to effectively tackle the volumetric variation problem. In situ transmission electron microscopy (TEM) of the Li-Te (de)alloying process on single TexSy@polyaniline particle demonstrated that the volumetric variation was efficiently suppressed in comparison to the situation of pristine Te particles. Moreover, polyaniline binder effectively trapped Te and sulfur species in its network and guaranteed stable electric contact and fast transport of Li ions, which resulted in significant improvement of the battery performance. Interestingly, the as-obtained composites display a high initial capacity of 1141 mA h g−1 with typical Li-S battery characteristics at a low current density of 0.1 A g−1, while it shows a good cycling stability at high current density of 5 A g−1 with Li-Te battery features.

Layered P2-type Na2/3Ni1/3Mn2/3O2 was successfully synthesized through a facile sol–gel method and subsequent heat treatment. Resulting from different phase transformation and sodium ion diffusion rates, its electrochemical performance is highly related to the cut-off voltage and the electrolyte used. When the cut-off voltage is set up to 4.5 V or lowered to 1.5 V, capacity fade happens due to the occurrence of P2–O2 transformation and electrolyte decomposition or the redox reaction of the Mn4+/Mn3+ ionic pair and P2–P2′ transformation. The electrode maintained 89.0 mA h g−1 with good cycling stability and excellent structural preservation between 4.0 and 2.0 V. The capacity retention is 71.2% even after 1200 cycles at 10C. It can be expected that P2-type Na2/3Ni1/3Mn2/3O2 is very promising as a cathode material for sodium ion batteries.

Developing efficient electrocatalysts for energy storage and oxygen reduction reaction (ORR) is of great significance for the utilization of renewable energy. In particular, designing catalysts with both promising activity and long stability for ORR in pH-universal electrolytes still remain as a tremendous challenge. To tackle such a problem, metal-free nitrogen and sulfur co-doped porous carbon sheet (NSPCS) was rationally designed in this work in order to integrate the two reported routes of enhancing the electrocatalytic activity of graphene. The as-prepared NSPCS has an onset potential of 0.89 V vs. RHE, and half-wave potential E1/2 ≈ 0.75 V during ORR in acidic solution, making it as the most active ORR catalyst. Moreover, the resulting NSPCS also shows a 0.03 V positive shift of half-wave potential than commercial Pt/C for ORR and excellent charge capacitive performance in alkaline media. Electron microscopy revealed high degree of defects on NSPCS surface. This, coupled with synergistic doping effects of nitrogen and sulfur, optimized the active sites and charge transfer, rationalized the outstanding performance in both oxygen reduction reactions and supercapacitors.

This study is dedicated to expand the family of lithium-tellurium sulfide batteries, which have been recognized as a promising choice for future energy storage systems. Herein, a novel electrochemical method has been applied to engineer micro-nano TexSy material, and it is found that TexSy phases combined with multi-walled carbon nanotubes endow the as-constructed lithium-ion batteries excellent cycling stability and high rate performance. In the process of material synthesis, the sulfur was successfully embedded into the tellurium matrix, which improved the overall capacity performance. TexSy was characterized and verified as a micro-nano-structured material with less Te and more S. Compared with the original pure Te particles, the capacity is greatly improved, and the volume expansion change is effectively inhibited. After the assembly of Li-TexSy battery, the stable electrical contact and rapid transport capacity of lithium ions, as well as significant electrochemical performance are verified.

Though solar cells are one of the promising technologies to address the energy crisis, this technology is still far from commercialization. Thermoelectric materials offer a novel opportunity to convert energy between thermal and electrical aspects, which show the feasibility to improve the performance of solar cells via heat management and light harvesting. Polymer–inorganic thermoelectric nanocomposites consisting of inorganic nanomaterials and functional organic polymers represent one kind of advanced hybrid nanomaterials with tunable optical and electrical characteristics and fascinating interfacial and surface chemistry. During the past decades, they have attracted extensive research interest due to their diverse composition, easy synthesis, and large surface area. Such advanced nanomaterials not only inherit low thermal conductivity from polymers and high Seebeck coefficient, and high electrical conductivity from inorganic materials, but also benefit from the additional interface between each component. In this review, we provide an overview of interfacial chemistry engineering and electrical feature of various polymer–inorganic thermoelectric hybrid nanomaterials, including synthetic methods, properties, and applications in thermoelectric devices. In addition, the prospect and challenges of polymer–inorganic nanocomposites are discussed in the field of thermoelectric energy.

Summary Metal organic framework (MOF) derivatives have been extensively used as bifunctional oxygen electrocatalysts. However, the utilization of active sites is still not satisfactory owing to the sluggish mass transport within their narrow pore channels. Herein, interconnected macroporous channels were constructed inside MOFs-derived Co-Nx-C electrocatalyst to unblock the mass transfer barrier. The as-synthesized electrocatalyst exhibits a honeycomb-like morphology with highly exposed Co-Nx-C active sites on carbon frame. Owing to the interconnected ordered macropores throughout the electrocatalyst, these active sites can smoothly “exhale/inhale” reactants and products, enhancing the accessibility of active sites and the reaction kinetics. As a result, the honeycomb-like Co-Nx-C displayed a potential difference of 0.773 V between the oxygen evolution reaction potential at 10 mA cm−2 and the oxygen reduction reaction half-wave potential, much lower than that of bulk-Co-Nx-C (0.842 V). The rational modification on porosity makes such honeycomb-like MOF derivative an excellent bifunctional oxygen electrocatalyst in rechargeable Zn-air batteries., Graphical Abstract, Highlights • A deep-breathing oxygen electrocatalyst with highly dispersed active sites was built • Sculpturing ordered macropores in MOF derivatives enables fast mass transport • The honeycomb-like Co-Nx-C nanopolyhedron worked well in rechargeable Zn-air battery, Catalysis; Inorganic Materials; Electrochemical Energy Storage.

Urchin-shaped Bi2S3/Cu2S/Cu3BiS3 nanocomposites were successfully prepared in this study through one-pot synthesis, which involved microwave-assisted simultaneous pyrolysis of two precursors. The as-prepared Bi2S3/Cu2S/Cu3BiS3 hybrids exhibit stronger absorption in the near-infrared regime than the individual components, i.e., Bi2S3, Cu2S, and Cu3BiS3. The photothermal conversion efficiency (η) of Bi2S3/Cu2S/Cu3BiS3 composites can even reach 43.8%, which is significantly higher than that seen with most of the transition metal chalcogenide materials. The excellent photothermal performance of Bi2S3/Cu2S/Cu3BiS3 hybrids is likely arising from its unique urchin-like structure, in which needle-like Bi2S3/Cu2S nanocomposites grow from the core of Cu3BiS3. The copresence of Bi2S3 and Cu2S also leads this newly synthesized composite to produce high contrast for X-ray computer tomography imaging, an important property required for a great potential application in theranostic cancer treatment.

A hydrogel-embedded tight ultrafiltration membrane composed of sodium polyacrylate-modified polyacrylonitrile (PAAS-m-PAN) is fabricated by a modified phase inversion process. The as-prepared membrane with excellent anti-dye-fouling property can effectively separate dyes from salts with permeance as high as >140 L m−2 h−1 bar−1, which is several times that of traditional polymeric filtration membranes with a similar rejection performance.

An efficient one-pot synthesis of α , β -unsaturated esters through the aerobic oxidation – Wittig tandem reaction of alcohols and phosphorous ylide is developed. This new method operates under mild reaction conditions, and uses CuI/TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidine- N -oxyl) as co-catalyst and air (O 2 ) as the oxidant. It tolerates a wide range of functionalized benzylic alcohol and aliphatic alcohols.

Developing highly-efficient and stable hydrogen evolution reaction (HER) electrocatalysts plays a crucial role in realizing the hydrogen production from electrocatalytic water splitting. Herein, ultra-small and nitrogen-doped molybdenum carbide (N-Mo2C) nanoparticles with oxidized surfaces are facilely synthesized with the assistance of cationic surfactants and simultaneously anchored onto three-dimensional nitrogen-doped flower-like carbon nanospheres (NFCNS), and the N-Mo2C/NFCNS composites are further investigated as HER electrocatalysts. Analysis results reveal that nitrogen atoms are doped into both the lattice and the carbon framework of Mo2C, resulting in low desorption energy of Mo-H bond for the easy evolution of hydrogen gas. Moreover, the high specific area of NFCNS enables enrichment of N-Mo2C nanoparticles, and its open framework facilitates fast ion diffusion. As a result, the N-Mo2C/NFCNS composites exhibit impressive HER activities with low overpotential, small Tafel slope, and excellent durability in both acidic and alkaline media, which outperform most of the reported Mo-based HER catalysts and are also highly comparable to the commercial Pt/C catalyst. Not limited to HER electrocatalysts, this work should open a new avenue for tailoring highly-efficient carbon/metal compounds-based electrocatalysts for oxygen reduction reaction, oxygen evolution reaction, nitrogen reduction reaction, etc.

A general method for the synthesis of α,β-unsaturated esters, ketones, and nitriles is successfully achieved by a one-pot copper-catalyzed oxidation with O2 in air as oxidant. The solvent mixture of acetonitrile and formamide (1:1) is optimized to ensure the oxidation of alcohols, deprotonation of phosphonium salt, and Wittig reaction occur efficiently in one pot. A broad range of substrates has been explored for this process, including three electron-withdrawing group (CO2Et, COPh, CN) functionalized phosphonium salts. They reacted not only with benzylic and heteroaromatic alcohols, but also with aliphatic alcohols, forming the corresponding α,β-unsaturated esters, ketones, and nitriles in moderate to excellent yields.

A class of urchin-shaped nanocomposites composed of MoS 2 and Cd 0.8 Zn 0.2 S nanoparticles were fabricated in this study, yielding the highest hydrogen evolution rate of 1401 μmol/g/h when they are applied as the photocatalysts of water splitting reaction. The greatly enhanced photocatalytic activity could last over 24 h. Such great improvement in the photocatalytic activity, which is nearly 11 times higher than that of pure CdS and 9 times of Cd 0.7 Zn 0.3 S, and 1.7 times of MoS 2 –CdS, may be attributed to that the one-step synthetic procedure resulted in tighter interfacial contact of the urchin-like MoS 2 –Cd 0.8 Zn 0.2 S composites. Specifically, solvothermal reaction of molybdenum(V) dimethyldithiocarbamate, diethyldithiocarbamato cadmium(II) and zinc di(benzimidazol-2-yl) disulphide took place simultaneously in one-pot. Characterizations with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM) etc. illustrate that a class of novel urchin-shaped nanocomposite composed of MoS 2 and Cd 0.8 Zn 0.2 S nanoparticles were formed in this one-pot synthesis. This study therefore presents a simple and effective route to prepare chalcogenide-based photocatalysts for more efficient production of hydrogen from water.

Combining the advantages of homogeneous and heterogeneous catalysts, single-atom catalysts (SACs) are bringing new opportunities to revolutionize ORR catalysis in terms of cost, activity and durability. However, the lack of high-performance SACs as well as the fundamental understanding of their unique catalytic mechanisms call for serious advances in this field. Herein, for the first time, we develop an Ir-N-C single-atom catalyst (Ir-SAC) which mimics homogeneous iridium porphyrins for high-efficiency ORR catalysis. In accordance with theoretical predictions, the as-developed Ir-SAC exhibits orders of magnitude higher ORR activity than iridium nanoparticles with a record-high turnover frequency (TOF) of 24.3 e- site-1 s-1 at 0.85 V vs. RHE) and an impressive mass activity of 12.2 A mg-1 Ir , which far outperforms the previously reported SACs and commercial Pt/C. Atomic structural characterizations and density functional theory calculations reveal that the high activity of Ir-SAC is attributed to the moderate adsorption energy of reaction intermediates on the mononuclear iridium ion coordinated with four nitrogen atom sites.

The design of carbon-based materials with a high mass density and large porosity has always been a challenging goal, since they fulfill the demands of next-generation supercapacitors and other electrochemical devices. We report a new class of high-density heteroatom-doped porous carbon that can be used as an aqueous-based supercapacitor material. The material was synthesized by an in situ dehalogenation reaction between a halogenated conjugated diene and nitrogen-containing nucleophiles. Under the given conditions, pyridinium salts can only continue to perform the dehalogenation if there is residue water remaining from the starting materials. The obtained carbon materials are highly doped by various heteroatoms, leading to high densities, abundant multimodal pores, and an excellent volumetric capacitive performance. Porous carbon tri-doped with nitrogen, phosphorous, and oxygen exhibits a high packing density (2.13 g cm-3 ) and an exceptional volumetric energy density (36.8 Wh L-1 ) in alkaline electrolytes, making it competitive to even some Ni-MH cells.

In this work, based on the principle of high temperature polymer electrolyte membrane (HT-PEMFC), a first-ever acetone fuel cell sensor (AFCS) is proposed and developed to detect acetone vapor in the environment and human breath for the safety control during industrial processing and the health monitoring and diagnosis for diabatic patients. The newly-developed HT-PEM-ACFS has the intrinsic advantages of insensitivity to relative humidity, excellent water management, and high sensor response and sensitivity due to the use of phosphoric acid (H3PO4) doped porous polybenzimidazole (pPBI) membrane and relatively-high operational temperature (100-180 °C). The optimal HT-PEM-ACFS employs 100-μm-thick pPBI membrane doped in 5 mol L-1 H3PO4 for 72 hours as HT-PEM, showing the best sensor response to acetone vapor at 140 °C. Moreover, the HT-PEM-ACFS with acid-doped pPBI membrane demonstrates superior sensitivity, linearity, and selectivity to acetone over alcohol as opposed to the sensor employed acid-doped solid PBI membrane. The promising sensor performance not merely proves the concept of HT-PEM-ACFS, but also highlights HT-PEM-AFCS as the next-generation sensor technology for acetone vapor measurement in the environment.

A high yield one-pot synthesis of β-amino alcohols from nitroarenes and 1,2-epoxides was developed, which utilizes inexpensive iron dust as a reducing agent and NH 4 Cl as the only additive in a 50% (v/v) ethanol solution. This new efficient synthetic approach tolerates a wide range of functionalities. The mild reaction conditions (e.g., 60 °C), together with the use of low cost and readily available starting materials, make this synthetic approach an attractive alternative to the current synthesis of β-amino alcohols.

Both microwave and conventional oil bath heating approaches are investigated for the fabrication of CdS nanocrystals through the thermolysis of a single source precursor cadmium diethyldithiocarbamate (CED), which allows us to gain further insight into the thermodynamic aspect of the synthesis. The analysis illustrates that nearly monodispersed sea-urchin-shaped CdS nanocrystals are obtained with the microwave method, whereas nanospheres covered by chunky protuberances are achieved with an oil bath approach. Such experiments suggest that microwave heating facilitates the growth of CdS along the [002] direction. In addition, we explored the catalytic activity of CdS in the photodegradation of rhodamine B, in which the CdS prepared through a microwave approach greatly outperformed that prepared through oil bath heating and the commercial CdS nanoparticles. Such enhancement arises from the higher specific surface area and crystallinity of the sea-urchin-shaped nanocrystals.

Nickel-cobalt borides (denoted as NCBs) have been considered as a promising candidate for aqueous supercapacitors due to their high capacitive performances. However, most reported NCBs are amorphous that results in slow electron transfer and even structure collapse during cycling. In this work, a nanocrystallized NCBs-based supercapacitor is successfully designed via a facile and practical microimpinging stream reactor (MISR) technique, composed of a nanocrystallized NCB core to facilitate the charge transfer, and a tightly contacted Ni-Co borates/metaborates (NCBi ) shell which is helpful for OH- adsorption. These merits endow NCB@NCBi a large specific capacity of 966 C g-1 (capacitance of 2415 F g-1 ) at 1 A g-1 and good rate capability (633.2 C g-1 at 30 A g-1 ), as well as a very high energy density of 74.3 Wh kg-1 in an asymmetric supercapacitor device. More interestingly, it is found that a gradual in situ conversion of core NCBs to nanocrystallized Ni-Co (oxy)-hydroxides inwardly takes place during the cycles, which continuously offers large specific capacity due to more electron transfer in the redox reaction processes. Meanwhile, the electron deficient state of boron in metal-borates shells can make it easier to accept electrons and thus promote ionic conduction.

The formidable sustainability challenges in advancing energy storage technologies call for game-changing research in battery designs. The previous pursuing of novel cathode materials with high redox potentials impedes the vast applications due to the simultaneous electrolyte decomposition at high potentials, though they are expected to deliver high specific capacities. Eventually, people start thinking in an opposite way, desirable anode materials with low redox potentials can also own high specific capacities. Among all the promising candidates, phosphorus-based anodes in sodium ion batteries (SIBs) have received considerable attention owing to the low cost and relatively high natural abundance of phosphorus. More importantly, phosphorus can store three sodium atoms and enable a high theoretical capacity of 2596 mAh g−1, which overwhelms any other SIB anode currently available. However, the poor electronic conductivity and large volume change of phosphorus during cycling severely deteriorate battery performance. The most widely used strategy is to confine phosphorus within well-designed carbon hosts. We thereby introduce a new type of porous hollow carbon with conductive-network interior as phosphorus host, which not only improves the electrical conductivity, but also creates enough interior surface for maximizing phosphorus utilization and shortening the ion's diffusion distance, compared to those conventional hollow carbon hosts. Therefore, the as-prepared red phosphorus-carbon spheres composites (RP/CS) exhibit superior rate performance (~1083 mAh g−1 at 4 A g−1, ~837 mAh g−1 even at 8 A g−1) and excellent cycle life (1027 mAh g−1 at 4 A g−1 more than 2000 cycles).

With the unprecedentedly increasing demand for renewable and clean energy sources, the sodium-ion battery (SIB) is emerging as an alternative or complementary energy storage candidate to the present commercial lithium-ion battery due to the abundance and low cost of sodium resources. Layered transition metal oxides and Prussian blue analogs are reviewed in terms of their commercial potential as cathode materials for SIBs. The recent progress in research on their half cells and full cells for the ultimate application in SIBs are summarized. In addition, their electrochemical performance, suitability for scaling up, cost, and environmental concerns are compared in detail with a brief outlook on future prospects. It is anticipated that this review will inspire further development of layered transition metal oxides and Prussian blue analogs for SIBs, especially for their emerging commercialization.

Understanding the impact of the defects/defect density of electrocatalysts on the activity in the triiodide (I3- ) reduction reaction of dye-sensitized solar cells (DSSCs) is indispensable for the design and construction of high-efficiency counter electrodes (CEs). Active-site-enriched selenium-doped graphene (SeG) was crafted by ball-milling followed by high-temperature annealing to yield abundant edge sites and fully activated basal planes. The density of defects within SeG can be tuned by adjusting the annealing temperature. The sample synthesized at an annealing temperature of 900 °C exhibited a superior response to the I3- reduction with a high conversion efficiency of 8.42 %, outperforming the Pt reference (7.88 %). Improved stability is also observed. DFT calculations showed the high catalytic activity of SeG over pure graphene is a result of the reduced ionization energy owing to incorporation of Se species, facilitating electron transfer at the electrode-electrolyte interface.