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The NM2.7Mg0.3PP@C cathode displays a considerable discharge capacity, an improved rate capability, superior cycling performance and stable structure.

Two interfaces formed after carbothermal reduction reaction was investigated by transmission electron microscopy and invariant line calculation. The crystallographic features of the two phase transition system have been successfully interpreted.

The NiFe-oxyhydroxide/C OER catalyst is prepared through the hydrolysis of nickel and iron salts in the presence of carbon black. It exhibits an overpotential of 269.6 mV at 10 mA cm−2 and a mass activity of 593.1 A g−1 at an overpotential of 320 mV.

A defect-type AlOx nanointerface containing Al2+ has been constructed on the surface of NaMn0.6Al0.4O2 by surface segregation and reconstruction, which exhibits excellent Na-storage performance as the cathode of SIBs over a wide temperature range.

The development of nonprecious metal-based electrocatalysts for oxygen reduction reaction (ORR) is a central task in renewable electrochemical energy conversion and storage technologies. Iron-nitrogen doped carbon-based (Fe−N/C) materials are promising alternatives to Pt-based ORR electrocatalysts. Owing to large specific surface area and outstanding electrical conductivity, carbon black is an inborn support for electrocatalysts. Unfortunately, the direct incorporation of Fe−Nx moieties onto the surface of carbon black has not been realized to date. Herein, Fe−Nx moieties are directly incorporated onto the surface of carbon black through surface modification and the following Fe and N co-doping. The obtained Fe and N co-doped carbon back (Fe−N/CB) catalyst has very large specific surface area and abundant accessible Fe−Nx moieties. As a result, Fe−N/CB electrocatalyst exhibits a more positive half-wave potential (0.86 V) than Pt/C. The Fe−N/CB catalyst also displays better stability and methanol resistance than Pt/C. The Zn-air battery with Fe−N/CB as cathodic catalyst shows a maximum power density of 68 mW cm−2 and a specific capacity of 676 mAh gZn-1. Our finding provides a convenient and low-cost approach to fabricating efficient M−N/C-based catalysts and will be helpful to the development of renewable electrochemical energy conversion and storage technologies.

Few-layer Mg-deficient borophene nanosheets with a stoichiometric ratio Mg0.22B2 are prepared by oxidizing with I2 and delaminating from MgB2. The flakes have Mg atom deintercalation rate of 78% while maintaining the hexagonal structure of boron.

Oxygen reduction reactions (ORR) and oxygen evolution reactions (OER) are two very important electrochemical processes for renewable energy conversion and storage devices. Electrocatalysts are needed to accelerate their sluggish kinetics to improve energy conversion efficiencies. Hence, extensive efforts have been devoted to the development of OER and ORR electrocatalysts with high activity and stability as well as low cost. Among these developed electrocatalysts, metal/metal oxide heterostructures attract a great deal of research interest because their catalytic performances can be tuned by interface engineering. In this Review, the latest achievements in interface engineering of metal/metal oxides heterostructures toward ORR and OER are described. The effects of the metal/metal oxide interface on catalysis are first discussed. Then, the approaches for interface engineering are illustrated. The developments of interface engineering in OER and ORR catalysis as well as bifunctional electrocatalysis are further introduced. Lastly, a perspective for future development of interface engineering in metal/metal oxide for OER and ORR is discussed.

The optical plasmonic cavity (OPC) including the metallic optical nanoantennas and a metal film exhibits extreme field enhancement for the increased spontaneous emission rate of emitters. The resonance wavelength of the OPC can be easily controlled by the volume of the OPC and the localized surface plasmonic resonances (LSPRs) of the nanoantennas, facilitating the effective coupling of OPC and the emitters. However, involving the OPC into the light emission-enhanced solution-processed devices is still a difficult challenge. The trade-off between the metallic structure of OPC and the solution procedures limits the performance enhancement of the electrical-driven devices. In this work, we construct a device-compatible OPC that allows the characterization of the carrier dynamics of quantum dot (QD) films in the real devices in-suit. The radiative recombination rate and relaxation rate of carriers in QDs are increased by the LSPR effect of the silver nanocubes for luminescence enhancement. The OPC further increases the spontaneous emission rate of QD films, achieving a Purcell factor of 166 and improving the electroluminescence of the OPC-based QD light-emitting diodes (QLEDs). The design of the OPC-involved QLEDs offers a solution for addressing the limitation of fabrication of OPC-combined solution-processed optoelectronic light sources.

The geometric and electronic structures of different octahedron RuRh clusters are studied using density functional theory calculations. The binding energy, electronic structure, and energy gap of the clusters have been obtained to determine the possible stable structures. The results show that the Ru4Rh2 cluster is the most stable structure which has D4h symmetry with the largest ionization potential, smallest affinity energy and larger energy gap. Furthermore, the information on adsorption and dissociation of multiple nitrogen molecules and the density of state for the octahedral Ru4Rh2 cluster is analyzed. The dissociation barrier of three nitrogen molecules further decreases to 1.18 eV with an increase in the number of N2 molecules. The co-adsorption of multiple N2 molecules facilitates the dissociation of N2 on the Ru4Rh2 cluster. The strong interaction between the antibonding orbital of N2 and the d orbital of the Ru4Rh2 cluster is illustrated by calculating and analyzing the results of PDOS, which stretches the N−N bond length and reduces the activation energy to dissociation. The antibonding orbital of the nitrogen molecule shows distinct and unique catalytic activity for the dissociation of the adsorbed nitrogen molecule on the octahedral Ru4Rh2 cluster.

The design of nanomedicine for cancer therapy, especially the treatment of tumor metastasis has received great attention. Proteasome inhibition is accepted as a new strategy for cancer therapy. Despite being a big breakthrough in multiple myeloma therapy, carfilzomib (CFZ), a second-in-class proteasome inhibitor is still unsatisfactory for solid tumor and metastasis therapy. In this study, hollow titanium nitride (TiN) nanoshells are synthesized as a drug carrier of CFZ. The TiN nanoshells have a high loading capacity of CFZ, and their intrinsic inhibitory effect on autophagy synergistically enhances the activity of CFZ. Due to an excellent photothermal conversion efficiency in the second near-infrared (NIR-II) region, TiN nanoshell-based photothermal therapy further induces a synergistic anticancer effect. In vivo study demonstrates that TiN nanoshells readily drain into the lymph nodes, which are responsible for tumor lymphatic metastasis. The CFZ-loaded TiN nanoshell-based chemo-photothermal therapy combined with surgery offers a remarkable therapeutic outcome in greatly inhibiting further metastatic spread of cancer cells. These findings suggest that TiN nanoshells act as an efficient carrier of CFZ for realizing enhanced outcomes for proteasome inhibitor-based cancer therapy, and this work also presents a "combined chemo-phototherapy assisted surgery" strategy, promising for future cancer treatment.

Nitrogen fixation is an essential process for sustaining life. Tremendous efforts have been made on the photodriven fixation of nitrogen into ammonia. However, the disproportionation of dinitrogen to ammonia and nitrate under ambient conditions has remained a grand challenge. In this work, the photodriven disproportionation of nitrogen is realized in water under visible light and ambient conditions using Fe-doped TiO2 microspheres. The oxygen vacancies associated with the Fe dopants activate chemisorbed N2 molecules, which can then be fixed into NH3 with H2 O2 as the oxidation product. The generated H2 O2 thereafter oxidizes NH3 into nitrate. This disproportionation reaction can be turned to the reductive one by loading plasmonic Au nanoparticles in the doped TiO2 microspheres. The generated H2 O2 can be effectively decomposed by the Au nanoparticles, resulting in the transformation of the disproportionation reaction to the completely reductive nitrogen photofixation.

Transition metal- and N-codoped carbon nanotubes (CNTs) have superior catalytic activity because the curling surface enhances the bonding ability of atoms within CNTs to other species. However, it is a great challenge to prepare CNTs with transition metal- and N-doped at high level during the growth of CNTs. Here, (Fe,N-codoped CNT)/(Fe-based nanoparticle) (Fe,N-CNT/FeNP) hybrid nanostructures are for the first time prepared through the carbonization of Fe-doped g-C3N4. The doping of Fe and N is simultaneously realized during the formation of CNTs. Meanwhile, the abundant and homogeneous Fe and N in Fe-doped g-C3N4 ensure high-level and uniform doping of Fe and N in CNTs. The Fe,N-CNT/FeNP hybrid nanostructures have several types of active components, including homogeneously distributed coordinating Fe moieties (FeCxNy or FeNx) and CFe15.1 nanoparticles embedded in Fe,N-CNTs, towards oxygen reduction reaction (ORR). A superior ORR electrocatalytic performance is therefore obtained on the Fe,N-CNT/FeNP nanohybrids. Our preparation method opens an avenue to preparation of CNTs with transition metal- and N-doping at high-level, and the superior performance of Fe,N-CNT/FeNP nanostructures for ORR will be very helpful to the development of fuel cells and metal-air batteries.

Electromagnetic absorption and electromagnetic interference (EMI) shielding materials, especially absorption-based EMI shielding materials, are urgently desired to eliminate increasingly serious electromagnetic radiation pollution. Metal carbides exhibit great promise in realizing excellent EMI shielding owing to their outstanding electrical conductivity. However, because of the same reason, the electromagnetic wave reflection from the metal carbide films is hardly diminished and thereby metal carbides cannot realize absorption-based EMI shielding. Herein, metal carbide/Ni hybrid nanostructures are designed to realize electromagnetic absorption and absorption-based EMI shielding. The hybrid nanostructures are prepared by in situ reduction of Ni on metal carbide nanosheets. The loading of Ni greatly increases the impedance matching and attenuation constants. Metal carbide/Ni hybrids achieve a reflection loss of −41.7 dB at 10.8 GHz with a thickness of 1.8 mm. An EMI shielding effectiveness larger than 60 dB is achieved in the whole X-band with a metal carbide/Ni hybrid film of 50 μm. Particularly, the absorption contributes 98.9% of total EMI shielding effectiveness, indicating the absorption-based EMI shielding. In addition, the metal carbide/Ni hybrid film exhibits very good mechanical properties and long-term stability in water. Our findings are very important for the development of electromagnetic absorption and absorption-based EMI shielding materials.

Hydrogen sulfide plays a significant role in living beings, while its abnormal concentration is related to many diseases. Besides, H2S gas is harmful to human beings and the environment. The detection of H2S has therefore attracted much attention in the past several decades. Herein, highly sensitive and selective H2S plasmonic nanoprobes (gold triangular nanoplate core)@(silver shell) (AuTNP@Ag) are reported. By virtue of the high refractive index sensitivity of Au TNPs to the surrounding medium and facile sulfurization of silver by sulfur ions, AuTNP@Ag exhibits great sensitivity to both sulfur ions and H2S gas. The shifts of the plasmon peak are as large as 16 nm for the ventilation of 1 ppm hydrogen sulfide. AuTNP@Ag nanoprobes also exhibit very good sensing linearity at low concentrations of sulfur ions. Moreover, excellent sensing selectivity for sulfur ions is obtained. A type of test gel, which can produce a naked-eye observable color change when exposed to 1-100 ppm hydrogen sulfide gas, is developed using AuTNP@Ag nanoprobes. Owing to the high sensitivity, linearity, and selectivity of the Au TNP@Ag nanoprobes for hydrogen sulfide sensing, this work paves the way for the plasmonic detection of hydrogen sulfide in both biological and environmental applications.

Suzuki coupling is of paramount importance in C-C coupling reactions. However, Suzuki coupling reactions are generally catalyzed by homogeneous catalysts under thermal heating, which results in difficulties in the catalyst separation and consumes a relatively large amount of energy. g-C3 N4 /Pd has been successfully prepared for photocatalytic Suzuki coupling reactions. The g-C3 N4 /Pd is prepared through the reduction of a Pd source in the presence of g-C3 N4 . The Pd is found to exist as Pd nanoparticles and Pd(II) species on g-C3 N4 . Owing to the good light absorption of g-C3 N4 and the excellent catalytic activity of the Pd species, the g-C3 N4 /Pd shows an excellent photocatalytic performance in Suzuki coupling reactions with a TOF of 47.3 h-1 , which is almost twice that of a commercial homogeneous catalyst Pd(PPh3 )4 , under thermal heating. Moreover, g-C3 N4 /Pd displays very good recyclability and wide applicability for Suzuki coupling reactions. Our findings provide a green and sustainable method for the catalysis of Suzuki coupling reactions.

Hydroxysafflor yellow A (HSYA), a major active water-soluble component in Carthamus tinctorius L., is considered a potential antioxidant with protective effects against myocardial injury. However, its pharmacokinetic characteristics in normal and diabetic cardiomyopathy (DCM) mice remain unknown. This study was designed to investigate the differences in the pharmacokinetics of HSYA between normal and streptozotocin-induced DCM mice. HSYA in the mouse plasma was quantified by liquid chromatography-tandem mass spectrometry. Compared with the normal group, the DCM group showed a significantly higher area under curve (AUC(0-t) , AUC(0-∞) ) value and peak plasma concentration, suggesting a higher uptake of HSYA in the DCM mice, and a significantly lower plasma clearance and apparent volume of distribution, suggesting slower elimination of HSYA in the DCM mice. The serum superoxide dismutase and glutathione peroxidase levels were significantly higher and malondialdehyde content was significantly lower in DCM mice than in normal mice, indicating the antioxidative stress effect of HSYA. Furthermore, the correlation analysis revealed that the serum HSYA content in the DCM mice significantly positively correlated with antioxidant enzyme levels. These results showed that the pharmacokinetics of HSYA changed significantly in the DCM mice, and this may improve the antioxidative stress effect of the drug.

Graphitic carbon nitride (CN) generally needs to be exfoliated into ultrathin nanosheets to reduce photocarrier recombination. However, the exfoliation of CN into nanosheets also reduces the light absorption. How to simultaneously realize low photocarrier recombination and high light absorption remains a challenge in the practical application of CN in photocatalysis. Herein, the light absorption of CN nanosheets was enhanced by introducing hollow TiO2 (h-TiO2) dielectric resonators. The h-TiO2/CN heterostructures were prepared by thermally polymerizing dicyandiamide in the presence of h-TiO2. The electromagnetic resonances of the h-TiO2 resonator creates strong electric field enhancement within, inside, and near external surface of the introduced h-TiO2 nanoshells. The enhanced electric field greatly improves the light absorption of CN located in these regions. The largest hydrogen evolution rate for h-TiO2/CN can reach 6.3 mmol g−1h−1, which is over 3-fold that of pure CN (2.0 mmol g−1h−1). It is also found that the small amount of CN within and inside h-TiO2 majorly contributes to the photocatalytic performance. These findings open a new avenue by which to enhance the performance of photocatalysts and will be helpful in the design of highly efficient photocatalysts for various reactions.

The interface between two material phases typically exhibits unique electronic states distinct from their pure phases, thus, providing a very promising channel to construct catalysts with excellent activity and stability. Here, water-induced formation of Ni

Development of highly stabilized and reversible cathode materials has become a great challenge for sodium-ion batteries. O'3-type layered Mn-based oxides have deserved much attention as one of largely reversible-capacity cathodes featured by the resource-rich and low-toxic elements. However, the fragile slabs structure of typical layered oxides, low Mn-ion migration barriers, and Jahn-Teller distortion of Mn3+ have easily resulted in the severe degradation of cyclability and rate performances. Herein, a new queue-ordered superstructure is built up in the O'3-NaMn0.6 Al0.4 O2 cathode material. Through the light-metal Al substitution in O'3-NaMnO2 , the MnO6 and AlO6 octahedrons display the queue-ordered arrangements in the transition metal (TM) slabs. Interestingly, the presence of this superstructure can strengthen the layered structure, reduce the influence from Jahn-Teller effect, and suppress the TM-ions migrations during long-terms cycles. These characteristics results in O'3-NaMn0.6 Al0.4 O2 cathode deliver a high capacity of 160 mAh g-1 , an enhanced rate capability and the excellent cycling performance. This research strategy can provide the broaden insight for future electrode materials with high-performance sodium-ions storage.

Physical and geochemical characteristics of shale play conclusive role in confirming operation measures during drilling and stimulation. The properties of shale samples from Jiyang depression were investigated through X-ray diffraction, scanning electron microscope, adsorption isothermal, high pressure mercury intrusion, methylene blue trihydrate, pressure pulse decay, tests of specific water wettability and shale stability index. Correlations, geological and engineering significances of them were discussed. Results show that shale reservoir in Jiyang depression has exploitation value corroborated by good characteristic parameters: 2.86% TOC, 69.9% brittle mineral, 26.14% clay mineral, high permeability of 0.011 × 10-3μm2, large Langmuir volume (5.82 cm3/g) and Langmuir specific area (0.91 m2/g), effective porosity (3.77%) and thickness (130.66m). Langmuir specific area is the key control on methane adsorption and storage verified by its moderate positive relativity with Langmuir volumes rather than TOC. High illite content (69.29%) may lead to instability of borehole and velocity sensitivity damage. Microfractures provide channels for filtration, invasion and loss of drilling fluid. Large specific water wettability (4.36 × 10-7g/m2) and smaller shale stability index (19.99 mm) dispalyed that shale formation were unstable once contacting with fresh water. Countermeasures must be adopted during drilling and fracturing to reduce reservoir damage and complex downhole conditions.

Highly asymmetric Au nanostructures, such as split Au nanorings and Au nanocups, exhibit attractive plasmonic properties because of their asymmetric geometries. To facilitate their plasmonic applications, effective and facile synthetic methods for producing asymmetric Au nanostructures with controllable sizes and uniform shapes are highly desirable. Herein, we report on an approach for the synthesis of largely asymmetric colloidal Au nanobottles with synthetically tunable overall and opening sizes. Au nanobottles with overall sizes in the range of ∼100-230 nm are obtained through sacrificial templating with differently sized PbS nano-octahedra. The opening sizes of the produced Au nanobottles can be tailored from ∼10 to ∼120 nm by either adjusting the Au/PbS molar ratio in the growth process or controlling the oxidation degree. The achieved size tunability allows the plasmon resonance wavelength of Au nanobottles to be varied in the range of ∼600-900 nm. Our uniform Au nanobottles, which possess controllable sizes, large cavity volumes, and tunable plasmon resonance wavelengths in the visible to near-infrared range, have been further applied for anticancer drug delivery and photothermal therapy. The effects of surface coating and the opening size of Au nanobottles on the drug encapsulation efficiency (EE) and initial burst drug release are systemically evaluated. A high doxorubicin EE and low initial burst drug release are realized with the dense silica-coated Au nanobottles having an opening size of 44 nm. In addition, chemo-photothermal combined therapy has been demonstrated with the doxorubicin-loaded Au nanobottles. Our results will be helpful for the design of Au nanobottles with different sizes and plasmonic properties as well as provide ample opportunities for exploring various plasmon-enabled applications of Au nanobottles.

The carbothermal reduction reaction (CRR) is the most commonly used method for synthesizing Magneli-phase reduced titanium oxide nanocrystals. Though the reaction process has been investigated from thermodynamics and kinetics perspectives, research focused on the detailed formation mechanism of the interfaces from reactant to product is still limited. In this work, the structures and formation mechanisms of the interfaces between different TinO2n−1 phases were investigated using comprehensive XRD, Raman spectroscopy, and TEM characterization. Both XRD and Raman spectroscopy results indicated that the formation sequence of the TinO2n-1 phases during the CRR was TiO2 → TinO2n−1 (n = 4–9) → Ti3O5 → Ti2O3 → TiO, regardless of the method used to introduce the carbon source. Furthermore, the surface encapsulation of polydopamine (PDA) on TiO2 precursor effectively reduced the reaction temperature compared with samples prepared by ball-mill mixing of TiO2 and carbon. The interfaces of Ti4O7/Ti5O9 and Ti3O5/Ti4O7 were obtained from the CRR using different carbon source introduction methods. TEM results suggested the different coherency of these interfaces, which might be due to different formation mechanisms. By calculating the Gibbs free energies in the temperature range of 298–1598 K for some involved reactions, it was noted that the reaction between TiO2 and carbon proceeds spontaneously to form TinO2n−1 phases (n = 2–10) over the whole temperature range. In contrast, the reaction between TinO2n−1 phases with different n values was not spontaneous when n ≤ 3 from 298 K to 1598 K, which further validated the oriented attachment growth mechanism of the Ti3O5/Ti4O7 interface rather than direct CRR. Finally, the growth mechanisms of the two types of interfaces were summarized at both atomic level and nanoscales.

The intercalation and delamination processes of Ti3C2Tx are systematically investigated by using alkylammonium hydroxides (TAAOH) with different chain lengths. TAA+ cations have a key function for the intercalation reaction of Ti3C2Tx nanosheets, and the basal spacing and the crystal phase of TAA+-intercalated Ti3C2Tx at different stages are closely related to the size of the intercalated TAA+ ions, and they are hardly changed with the addition of molar equivalents of TAAOH per mole of Ti3C2Tx and the drying conditions. Moreover, the intercalation process is very rapid and it can be carried out by just 4 h treatment. TAA+-intercalated Ti3C2Tx can be delaminated into Ti3C2Tx nanosheets by hand shaking or repeated washing. By introducing a graphene oxide nanosheet suspension into the Ti3C2Tx nanosheet suspension, Ti3C2Tx/RGO fibers are firstly prepared by a wet-spinning method followed by reducing Ti3C2Tx/GO fibers in HI/CH3COOH solution. Then the Ti3C2Tx/RGO fiber is soaked in KMnO4 solution with different concentrations at room temperature, and a MnO2/Ti3C2Tx/RGO ternary hybrid fiber with good flexibility and capacitance is prepared. The MnO2/Ti3C2Tx/RGO ternary hybrid fiber electrode shows the largest volumetric capacitance of 851 F cm−3 in 1 M Na2SO4 electrolyte and good flexibility. By twisting two of these fiber electrodes together, an all-solid-state symmetric MnO2/Ti3C2Tx/RGO//MnO2/Ti3C2Tx/RGO fiber supercapacitor with PVA–LiCl gel electrolyte is assembled. It not only exhibits a volumetric capacitance of 24 F cm−3 and superior cycle stability of 92% after 10 000 cycles, but also shows outstanding flexibility and mechanical properties in which the volumetric capacitance has no obvious change after bending the supercapacitor at 90° 1000 times. Furthermore, the assembled symmetric supercapacitor shows the maximum volumetric energy density of 2.13 mW h cm−3 at a volumetric power density of 8.16 mW cm−3. This work will open a new application field of Ti3C2Tx-based fibers for new wearable energy storage devices with good energy density and flexibility.

As the next generation of electrochemical energy storage devices, lithium sulfur (Li–S) batteries have many advantages such as high theoretical specific capacity (1675 mAh g−1) and energy density (2600 kw h kg−1), non-toxicity and low cost. However, the poor electrical conductivity of sulfur cathodes and the shuttling effect of lithium polysulfides during cycling strongly hinder the commercial application of Li–S batteries. In this study, Magneli phase Ti4O7 nanoparticles were successfully prepared on the surface of hollow carbon spheres (HCS) through a carbothermal reduction reaction. The synthesized HCS@Ti4O7 with a mesoporous structure exhibited a uniform spherical morphology with a large specific surface area (512 m2 g−1) and the pore volume of 0.58 cm3 g−1. The introduction of a polydopamine (PDA) layer during the preparation was confirmed to effectively inhibit the grain coarsening of Ti4O7. Moreover, the high content of sulfur loading (70%) did not affect the morphology of HCS@Ti4O7, which suggested its stable architecture. The assembled coin cells exhibited the superior reversible capacity of 1427 mAh g−1 at 0.1C and favorable cycling stability from 1168 mAh g−1 to 601 mAh g−1 after 800 cycles at 0.5C with the capacity decay rate of only 0.06% per cycle. This excellent performance and stability were attributed to the strong chemical binding effects of Ti4O7 on lithium polysulfides and the stable morphology maintenance during cycling. This study provides a novel conception to design and synthesize nanocomposites between reduced metal oxides and carbon with uniform and stable mesoporous structures for high-performance Li–S batteries.

Transition metal- and N-codoped carbon nanotubes (CNTs) have superior catalytic activity because the curling surface enhances the bonding ability of atoms within CNTs to other species. However, it is a great challenge to prepare CNTs with transition metal- and N-doped at high level during the growth of CNTs. Here, (Fe,N-codoped CNT)/(Fe-based nanoparticle) (Fe,N-CNT/FeNP) hybrid nanostructures are for the first time prepared through the carbonization of Fe-doped g-C

Single-atom (SA) catalysis bridging homogeneous and heterogeneous catalysis offers new opportunities for organic synthesis, but developing SA catalysts with high activity and stability is still a great challenge. Herein, a heterogeneous catalyst of Pd SAs anchored in 3D ordered macroporous ceria (Pd-SAs/3DOM-CeO2 ) is developed through a facile template-assisted pyrolysis method. The high specific surface area of 3DOM CeO2 facilitates the heavily anchoring of Pd SAs, while the introduction of Pd atoms induces the generation of surface oxygen vacancies and prevents the grain growth of CeO2 support. The Pd-SAs/3DOM-CeO2 catalyst exhibits excellent activity toward Suzuki coupling reactions for a broad scope of substrates under ambient conditions, and the Pd SAs can be stabilized in CeO2 in long-term catalytic cycles without leaching or aggregating. Theoretical calculations indicate that the CeO2 supported Pd SAs can remarkably reduce the energy barriers of both transmetalation and reductive elimination steps for Suzuki coupling reactions. The strong metal-support interaction contributes to modulating the electronic state and maintaining the stability of Pd SA sites. This work demonstrates an effective strategy to design and synthesize stable single-atom catalysts as well as sheds new light on the origin for enhanced catalysis based on the strong metal-support interactions.

MoS2 shows a great promise as a low-cost and highly active alternative to platinum-based catalysts for electrochemical hydrogen production from water. The activity of MoS2 is believed from the edge, defect sites, and the basal plane of metallic phase (M-MoS2). Here we report on a facile hydrothermal method for the preparation of MoS2 nanopetals that are in metallic phase and have abundant edges. The amount of sulfur precursors are found to play a critical role on the formation of MoS2 nanopetals. The MoS2 nanopetals exhibit remarkable electrocatalytic activities for the hydrogen evolution reaction (HER), with a low overpotential of 210 mV at the current density of 10 mA cm–2 and a Tafel slope of 44 mV per decade. The MoS2 nanopetals also display very good durability, with a very small negative shift of 11 mV at the current density of 10 mA cm–2, and negligible shift at the current density of 50 mA cm–2 after 2000 cycles. Our facile preparation method and high electrocatalytic activity of MoS2 nanopetals f...

Mn3O4/reduced graphene oxide/single-walled carbon nanotube flexible hybrid film with outstanding flexibility and electrochemical performance is prepared via a vacuum filtration method. The three-dimensional interconnect structure is constructed by reduced graphene oxide and single-walled carbon nanotube, and Mn3O4 nanoplates with pesudocapacitance are embedded into the interconnect structure. The regular interconnect structure and a synergetic effect between graphene oxide/single-walled carbon nanotube and Mn3O4 make the Mn3O4/reduced graphene oxide/single-walled carbon nanotube flexible film electrode exhibit a large areal capacitance of 796 mF cm−2. All-solid-state Mn3O4/reduced graphene oxide/single-walled carbon nanotube flexible supercapacitor is prepared by using the hybrid film as electrodes and sandwiching the PVA–KOH gel electrolyte, it exhibits a large area specific capacitance of 360 mF cm−2 and the capacitance maintains 95% after 5000 charge/discharge cycles. The assembled supercapacitor exhibits both outstanding mechanical performance and a high areal energy density of 32 μW h cm−2 at an areal power density of 0.392 mW cm−2. The Mn3O4/reduced graphene oxide/single-walled carbon nanotube flexible supercapacitors exhibit significant potentiality in flexible and wearable electronics owing to their excellent flexibility, high energy density and long cycle life.

Graphitic carbon nitride (g-C3N4) has been believed to be a promising photocatalyst for water splitting due to its right band gap and band edges. However, the kinetics of hydrogen evolution on g-C3N4 is very slow. Cocatalysts are usually needed to improve the catalytic kinetics. Herein, palladium-doped graphitic carbon nitride (g-C3N4–Pd) is designed by virtue of the tenacious coordination of Pd atoms with the pyridinic nitrogen atoms of six-fold cavities in g-C3N4. The introduction of Pd does not affect the structure and morphology of g-C3N4. Palladium is found to exist as Pd ions in g-C3N4–Pd catalysts. g-C3N4–Pd catalysts exhibit clearly higher hydrogen evolution activities than g-C3N4. The highest hydrogen evolution activity on g-C3N4–Pd is 15.3 times that of g-C3N4. The improvement of hydrogen evolution activity is found to arise from both the alternation of the electron excitation manner and the acceleration of hydrogen evolution kinetics induced by Pd doping. Our findings provide a promising way to...