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Cr(VI)-based compounds pollution have attracted global concern due to serious harm to humans and environment. Hence, it is crucial to exploit an effective technique to eliminate Cr(VI) in water. Herein, we in-situ grown BiOI on graphitic carbon nitride to prepare the BiOI/g-C3N4 (BCN) direct Z-scheme heterojunction by solid phase engineering method at room temperature. Experimental result shown the photocatalytic activity of pure BiOI were obviously enhanced by constructing Z-scheme BCN heterostructure, and BCN-3 heterostructure exhibited the optimal photocatalytic degradation of RhB with 98% yield for 2.5 h and reduction of Cr(VI) with more than 99% yield for 1.5 h at pH = 2. Stability test shows BCN-3 still kept more than 98% reduction efficiency after 6 cycles. In addition, we also studied the reduction mechanism that shown the ·O2− radicals essentially helped to reduce the Cr(VI) in aqueous solution under illumination, verified the direct Z-scheme charge transfer path by X-ray photoelectron spectroscopy (XPS) and the free radical trapping experiment. The work open a new way for rationally designing photocatalyst heterostructure to reduce Cr(VI) to Cr(III).

Phase change materials (PCMs) have been applied widely in various energy savings, storage, and efficiency applications, including building and construction, building systems, aerospace, and biological engineering. In order to solve the shortcomings of poor thermal stability and easy leakage of PCMs, a strong adsorbent expanded perlite-aerogel (AEP) composite matrix was prepared and its key thermal properties and effects on PCMs examined. Particularly, when it adsorbed capric-stearic acid, a binary PCM, it reached the level of 200 %. The rate of mass loss after heating could still be less than 1.0 %, indicating that the AEP composite matrix designed here had strong material and thermal stabilities. Various mass ratios of composite components were also tested and compared, and the optimal setting for the best adsorption rate was subsequently determined in this work. Because of these excellent characteristics, this newly designed AEP composite matrix can be used as an appropriate carrier for PCMs for energy savings and efficiency purposes in the building and construction field.

CeO2 and Sc2O3 co-stabilized ZrO2 ceramics have attracted much attention as potential thermal barrier coatings (TBCs) materials for applications above 1300 °C. In this study, a series of Sc0.04CexZr0.96-xO1.98 (SCZ, x = 0.08, 0.10, 0.12, 0.16) ceramic materials were synthesized with the solid-state method and their phase stability, microstructures and thermo-physical properties were systemically investigated by x-ray diffraction (XRD), Raman spectra, field emission scanning electron microscopy (SEM), thermal dilatometer, laser flash apparatus (LFA), and Vickers hardness tester. The results showed that Sc0.04Ce0.12Zr0.84O1.98 (4S12CZ) and Sc0.04Ce0.16Zr0.80O1.98 (4S16CZ) ceramic materials still maintained stable tetragonal phase structure after 100 h high temperature treatment at 1500 °C. SCZ had a high thermal expansion coefficient (TEC), low thermal conductivity, and high fracture toughness. The TEC of the ceramics increased with CeO2 addition because lattice energy reduced with increasing substitution of Zr4+ by bigger Ce4+ while thermal conductivity decreased due to the increase of lattice distortion. Compared with 4S12CZ, 4S16CZ exhibited a higher fracture toughness of 6.48 ± 0.04 MPa m1/2 and showed the better anti-sintering property. Besides, the thermal conductivity, TEC and thermal cycling lifetime of 4S16CZ were optimal. The comprehensive performance of 4S16CZ suggested it could be explored as a promising TBC material for high-temperature application.

The sufficient interface contact in the composite absorbing material is beneficial to increase the dielectric loss and promote the microwave absorption performance. In this paper, the composite nanoparticles (NPs), Fe3O4 covered with ultra-thin carbon layer (Fe3O4/C), were synthesized by simple high temperature solution-phase and subsequent high-temperature steam carbonization methods. Small size Fe3O4/C composite NPs have large heterogeneous interfaces, which can control the polarization loss of composite NPs through the method of interface regulation and achieve high microwave absorption performance. The strongest reflection loss of the composite NPs with an average particle size of 52 nm can reach −58.5 dB at 14.88 GHz with a thickness of 2 mm, and the corresponding effective absorption (RL ≤ -10 dB) bandwidth (EAB) is 5.63 GHz (12.37–18 GHz). In particular, the high-efficiency absorption (RL ≤ -20 dB) bandwidth of Fe3O4/C can reach 15.44 GHz (2–17.44 GHz) with a thickness of 1.7–10 mm. The current method for controlling polarization loss provide a meaningful reference for future microwave absorption research.

Raw SrF2 powders were synthesized by the chemical precipitation method, and the mean particle size was 58.48 nm. Er:SrF2 transparent ceramics were obtained by hot-pressed (HP) technique, and the effect of ErF3 levels on the transparency, microstructure, luminescence spectroscopic and microhardness were studied. The ratio of emission intensities R (Red/Green) increased with the ErF3 doping levels. The addition of ErF3 was found effectively to reduce grain size and has a positive effect on improving the microhardness. The SrF2 ceramic doped with 5 wt.% ErF3 (2 mm thick) showed the best optical transparency, the transmittance at 500 nm and 1200 nm are 87.9 % and 89.5 %, respectively. The average grain size, Vickers hardness (Hv), and fracture toughness (KIC) for the SrF2 ceramic were 21.1 ± 4.5 μm, 1.73 ± 0.04 GPa, and 0.52 ± 0.08 MPa·m1/2, respectively.

In this study, the destabilization resistance of Sc2O3 and CeO2 co-stabilized ZrO2 (SCZ) ceramics was tested in Na2SO4 + V2O5 molten salts at 750°C–1100 °C. The phase structure and microstructure evolution of the samples during the hot corrosion testing were analyzed with X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), energy dispersive X-ray spectrum (EDS), and X-ray photoelectron spectroscopy (XPS). Results showed that the destabilization of SCZ ceramics at 750 °C was the result of the chemical reaction with V2O5 to produce m-ZrO2 and CeVO4, and little ScVO4 was detected in the Sc2O3-rich SCZ ceramics. The primary corrosion products at 900 °C and 1100 °C were CeO2 and m-ZrO2 due to the mineralization effect. The Sc2O3-rich SCZ ceramics exhibited excellent degradation resistance and phase stability owing to the enhanced bond strength and the decreased size misfit between Zr4+ and Sc3+. The destabilization mechanism of SCZ ceramic under hot corrosion was also discussed.

The effects of the partial Y2O3 substituted by Gd2O3 on thermal and mechanical properties of ZrO2-Ta2O5-Y2O3 ceramics were studied. Results indicated the single stable tetragonal phase of zirconia co-doped with 16 mol% YO1.5 +16 mol% TaO2.5 (YTZ) and zirconia co-doped with (16-x) mol% YO1.5+ x mol% GdO1.5+16 mol% TaO2.5 (xGYTZ, x = 2, 4, 8) just existed at and above 1500 °C. The Gd2O3 substitution caused a decrease in phase stability when annealed at 1300 °C and 1400 °C. YTZ and 2GYTZ ceramics exhibited high fracture toughness, large thermal expansion coefficients (TECs), and low thermal conductivity. With the Gd2O3 substitution, the mechanical properties and thermal conductivity showed a decreasing trend, while TECs increased due to the decrease of crystal energy. The thermal durability of YTZ and 2GYTZ TBCs was evaluated. The cycling life of 2GYTZ TBCs was much shorter. The combination of sintering effect and thermal expansion mismatch stresses was significant factor for the failure.

Developing an effective photocatalytic denitrification technology for NO3− and NO2− in water is urgently needed. In this paper, we synthesized a nitrogen-rich g-C3N4, and in-situ grown AgPd nanowires (NWs) on the surface of nitrogen-rich g-C3N4 to build AgyPd10−y/g-CxN4 Mott-Schottky heterojunction. Compared with g-CxN4, AgyPd10−y/g-CxN4 exhibits the enhanced photocatalytic hydrogen production from water and tandem reduction of NO3− and NO2− without the addition of other hydrogen source under 365 nm irradiation. The catalytic activity and selectivity of AgyPd10−y/g-CxN4 were studied by combination of the nitrogen-rich g-C3N4 and the different component of AgyPd10−y nanowires (NWs). Among the AgyPd10−y/g-CxN4 catalyst, the Ag3Pd7/g-C1.95N4 catalyst exhibited the highest photocatalytic activity and selectivity for photocatalytic reduction of NO3− and NO2−, and the removal rate of NO3− and NO2− are 87.4% and 61.8% under 365 nm irradiation at 25 °C, respectively. The strategy opens a new way for making the photocatalytic hydrogen production in tandem with reduction of NO3− and NO2− in water, also extending it to remove metal ion.

A novel transparent SrF2/Nd:SrF2/SrF2 composite ceramic with sandwich-like laminar configuration was designed and successfully fabricated by the hot-pressed sintering method. The composite ceramic possesses an apparent transition interfacial (about 200 μm in thickness) between SrF2 and Nd:SrF2 layers, formed by non-uniform distribution of raw powders and the diffusion of Nd ions during the high temperature sintering. The average grain sizes of SrF2 and Nd:SrF2 layers are about 262.1 μm and 28.6 μm, respectively. For a 2-mm thick transparent SrF2/Nd:SrF2/SrF2 composite ceramic hot-pressed at 900 °C for 2 h, the transmittance at 500 nm and 1200 nm are about 49.6 % and 62.3 %, respectively. The microstructure, emission spectra and thermal conductivities of ceramics are also detected and studied.

Engineering sulfur vacancies in the basal plane of MoS2 is an effective method to enhance its catalytic activity. However, the traditional methods are only effective for multilayer or monolayer MoS2 supported on the substrate (such as Si/SiO wafer or carbon paper), which are not applied in bulk or commercial MoS2. In this work, we developed a simple and general chemical reduction method for engineering S-vacancies in the MoS2 basal plane and additional active edge sites, which can be exploited to improve the HER catalytic performance of MoS2. The optimized MoS2 nanosheets with S-vacancies exhibit excellent HER activity with a small overpotential of 190 mV at large density of 10 mA/cm2 and a low Tafel slope of 54 mV decade−1. Moreover, prominent electrochemical durability was also achieved. This finding proposes an effective strategy to fabricating S-vacancies for activating basal plane of 2D transition metal chalcogenides materials.

The synergistic effect of magnetic and dielectric materials makes this kind of composite as an ideal microwave absorber. So far, composite absorbing materials of Fe3O4 and carbon have been extensively studied and achieved excellent absorption properties. However, this type of absorber always has the problem of narrow effective absorption band (RL ≤ −10 dB). In this article, we have prepared 3D (Fe3O4/ZnO)@C double-core@shell nanocomposites by a clever method. Especially, the electromagnetic parameters and microwave absorption performances of the nanocomposites can be tuned by changing the zinc content. When the molar ratio of Zn to Fe is 1:2, the effective absorption bandwidth of the double-core@shell nanocomposite is 6.4 GHz with 2 mm thickness and 7.11 GHz with 1.9 mm thickness. Besides, when Zn:Fe = 1:1, the double-core@shell nanocomposite achieves a minimum RL value of −40 dB at 15.31 GHz with 2 mm thickness and has a wideband effective absorption of 6.5 GHz and an efficient absorption bandwidth (RL ≤ −20 dB) of 3.4 GHz. The special 3D double-core@shell structure and ingenious introduction of tunable ZnO could improve the microwave absorption performances of the (Fe3O4/ZnO)@C nanocomposites, which can be considered as promising absorbing materials.

Rational construction of MnCo2O4-based core-shell nanomaterials with distinctive and desirable architectures possesses great potential in the advanced electrode material of high-performance supercapacitors. Here, a new class of hierarchical core-shell nanowire arrays (NWAs) with a shell of NiWO4 nanoparticles and a core of MnCo2O4 nanowires is reported, which can significantly improve the electrochemical energy storage properties of supercapacitors. The unique core-shell structure endows the MnCo2O4@NiWO4 NWAs electrode with a high areal specific capacitance of 5.09 F cm−2 at a current density of 1 mA cm−2 and a superior cyclic retention of 96% after 5000 charge-discharge cycles, which are more preferable than those of MnCo2O4 NWAs electrode. More importantly, an aqueous electrochemical energy storage device (core-shell MnCo2O4@NiWO4 NWAs as the positive electrode and active carbon as the negative electrode, MnCo2O4@NiWO4//AC ASC) was assembled and shows a high energy density of 0.23 mWh cm−2 at a power density of 2.66 mW cm−2, and 0.09 mWh cm−2 at 16.00 mW cm−2, indicating hopeful potential for practical applications. This work highlights the significance of NiWO4 as a shell for hierarchical core-shell nanostructures, which can further improve the electron transport characteristic of the electrode material, thereby achieving performance breakthroughs in energy storage devices.

Accurate and sensitive detection of dopamine (DA) is fundamental to monitor and diagnose certain neurological diseases. Herein, highly ordered mesoporous ZnFe2O4 (OM-ZnFe2O4) is prepared via a facile nanocasting method and shows the highly sensitive in the electrochemical detection of DA. The optimized OM-ZnFe2O4-40 shows the most excellent activity for DA oxidation in a wide linear range from 2 to 600 nM with a quick response time of 5 s, high sensitivity of 0.094 nA nM−1 and a lower detection limit of 0.4 nM (S/N = 3). The electrode modified with OM-ZnFe2O4 is further successfully used to monitor the increase of DA concentration induced by K+-stimulation of living PC12 cells in a neurological environment. This work offers a simple and powerful strategy for designing electrodes for detecting DA in biological systems.

Improving energy efficiency and lowering carbon emissions are of great importance to realize the "dual carbon" goal of carbon peak and carbon neutrality. Digital economy is a new engine of economic development, but whether or how it affects energy efficiency and carbon emissions are unclear. Utilizing panel data of China's 30 provinces from 2012 to 2019, this study empirically explores the relationships among digital economy, energy efficiency, and carbon emissions. Meanwhile, from the perspective of energy efficiency, applying mediation models and panel threshold model, it analyzes the direct, indirect, and nonlinear influencing mechanisms of digital economy on carbon emissions. The results reflect that the development of digital economy in China intensifies carbon emissions. Energy efficiency serves as a vital partial mediator between the two. The enhancement of energy efficiency can lower carbon emissions. However, the development of digital economy is not conducive to improving energy efficiency, thereby, indirectly increasing carbon emissions. The mediating effect of energy efficiency accounts for 30.58 % of the total effect of digital economy on carbon emissions. Meanwhile, taking energy efficiency into account, the impact of digital economy on carbon emissions has a significant double-threshold effect and presents an N-shaped trend. [0.824, 0.912] is the optimal range of energy efficiency, within which the growth of the digital economy can empower carbon emission abatement to some extent. In addition, the expansion of population size, the coal-based energy consumption structure, and the industrial structure significantly increase carbon emissions. The improvements in living standards and environmental regulations can help to decrease carbon emissions, but the emission abatement effects are not significant. Those conclusions reveal the importance of optimizing the level and quality of digital economy and adopting differentiated digital economy development policies based on energy efficiency to achieve carbon emission reduction.

Mining industry, well known as the supply foundation of the nation's entire industrial production, is critical in China's endeavor in resource conservation and emission reduction. The spatial and temporal evolution characteristics of the unified inputs-outputs efficiency are firstly studied based on non-radial directional distance function and Malmquist index decomposition. On this basis, panel regression models are built to identify drivers of the measured efficiency evolution in China's mining sector. Our empirical results reveal that: (i) unified inputs-outputs efficiency in China's mining sector exhibits an essentially descending trend on the whole and the regional disparity is not as pronounced as other industries; (ii) state ownership stake exerts a negative effect, whereas private ownership stake exerts a positive influence on the unified input-output efficiency; (iii) government regulation did not impel mining industry toward a more efficient mode of operating but hindered efficiency enhancement, and this is especially distinct in private-owned enterprises; (iv) regional economic development and R&D could be conducive to the improvement of unified input-output efficiency while energy price did not effectively motivate input conservation. The results offer some clues for policy-makers of the mining industry, for improving its sustainable and efficient industrial operating.

Dopamine (DA) detection is significant for the prevention of unfavorable neuronal illness. However, the detection of DA with low concentration still face tremendous challenges. In this study, highly ordered mesoporous Fe3O4 materials were synthesized as a biosensor by using mesoporous silica KIT-6 with different aging temperature as hard template. The ordered mesoporous Fe3O4 with high surface area modified glassy carbon electrode shows the high sensitivity for detecting DA. Fe3O4-40 mesoporous material modified electrode has the highest catalytic activity to DA with a sensitivity of 0.053 nA nM−1 and a detection limit of 0.8 nM (S/N = 3). The results indicating that the mesoporous Fe3O4 material modified electrode exhibits high sensitivity to determine DA at low levels, which can be used for DA real-time monitoring in neutral biological media.

It is extremely desirable but challenging to develop a facile synthesis to directly prepare permanent magnet foam with high coercivity (Hc) and low mass density to meet the requirements of advanced magnets in modern industry. In this work, we developed a facile strategy to synthesize cobalt ferrite foam by solution combustion method and subsequently annealing treatment. The structure and magnetic properties of the foams can be influenced by the ratios of glycine to nitrate (G/N), Co content and annealing treatment temperatures. The increase in the mean grain sizes within the single domain range gives rise to an enhancement in coercivities. The highest Hc of ∼3 kOe with an ultra-low mass density of ∼45 mg/cm3 can be successfully obtained by controlling the preparation process. The work opens up a new way to prepare ultra-light Fe-based oxides for magnetic and catalytic applications.

Oxygen evolution reaction (OER) from water using transition metal-based catalyst is of significance for the wide spread of future renewable energy materials. Herein, we propose a novel strategy to synthesize cobalt iron oxides (CoFe2O4) with different ordered mesoporous structure by using a facial hard template method. Benefiting from the ordered mesoporous structure, the optimized electrocatalyst achieved a small overpotential of 342 mV to reach 10 mA cm−2 current density, a low Tafel slope of 57.1 mV dec−1 in a 1 M KOH aqueous medium, and excellent stability for 15 h, which OER performance is the best after the comparison of lasted reported CoFe2O4-based electrocatalysts. This work not only provides an approach for synthesizing efficient OER catalysts but also highlights a novel tactic to optimize the OER electrocatalysts according to regulate the porous structure.

With the increase of diabetics, the incidence of diabetic wound, a common complication of diabetes, rapidly grows in clinical. Meanwhile, the high recurrence rate and mortality of diabetic wound make its treatment still a great challenge. Here, we design a M2 macrophage exosome loaded multifunctional hydrogel as the diabetic wound dressing. The combined injectable, self-healing, and tissue-adhesive properties of this hydrogel make it form a protective barrier covering the wound timely to stop bleeding quickly and provide a good healing condition for the wound. Then, the continuous releasing of M2 macrophage exosome is able to promote the angiogenesis in wound, therefore accelerating the diabetic wound healing.

The construction of internal electric field (IEF) is usually considered an effective strategy to enhance photocatalytic efficiency because of its significant role in photo-induced carrier separation. Herein, we report a novel method to synthesize phosphorus-doped (P-doped) MoS2/g-C3N4 layer-by-layer composite, which could expose more active sites and generate a strong interaction by forming Mo-N bonds for photocatalytic sterilization. It is experimentally and theoretically confirmed that P-doped MoS2/g-C3N4 heterojunctions not only generate a dual-IEF to drive charge migration, but also facilitate spatially separated redox sites to further promote the separation of photo-induced carrier. The optimized P-doped MoS2/g-C3N4 layered heterojunction exhibits high photocatalytic sterilization efficiency (99.99%) towards E. coli under visible-light irradiation, which is remarkably higher compared with those of P-doped g-C3N4 (44.73%) and P-doped MoS2 (61.69%), respectively. This research will offer a novel method of designing and synthesizing layered composite photocatalyst with a dual-IEF for effective photocatalytic sterilization.

ZnxCd1-xS is a prospective photocatalyst with wide visible-light absorption up to 500 nm, but its stability and activity are still facing huge challenges. Herein, L-Cysteine capped Mo2C (L-Mo2C) nanoplates were used to anchor Zn2+/Cd2+ to in-situ grow Zn0.67Cd0.33S nanomaterial for constructing a highly efficient and robust L-Mo2C/Zn0.67Cd0.33S heterojunction through intimate Mo-S covalent bonds for photocatalytic hydrogen evolution reaction (HER). This work not only suppresses the photo-corrosion of Zn0.67Cd0.33S nanomaterial by the construction of strong L-Mo2C/Zn0.67Cd0.33S Schottky heterojunction but also greatly improves the charge transfer efficiency by generating a strong internal electric field. As a result, the optimized L-Mo2C/Zn0.67Cd0.33S-5 heterojunction exhibits an enhanced HER rate of 34.66 mmol h−1 g−1 without an obvious decrease for continuous 24 h under visible irradiation, which is 4.8 times and 1.23 times than that of pristine Zn0.67Cd0.33S and uncapped Mo2C/Zn0.67Cd0.33S-5. This research highlights the role of Mo2C in photocatalytic HER, which provides a novel method to suppress the photo-corrosion of Zn0.67Cd0.33S-based composite.

The present study was designed to examine the protection of D-β-hydroxybutyrate (BHB) against ischemia/reperfusion (I/R) injury in heart and investigate its underlying mechanism. Male adult mice were exposed to 30 min of ischemia and 24 h of reperfusion. Osmotic pumps were implanted subcutaneously 5 min before reperfusion for continuous delivery of the exogenous BHB (1.6 mmol/kg/24 h). Treatment with BHB reduced infarct size and levels of cardiac troponin I, creatine kinase and lactate dehydrogenase in serum, attenuated apoptosis in myocardium, and preserved cardiac function of I/R mice. Importantly, treatment of I/R mice with BHB promoted autophagic flux, evidenced by reduced the ratio of LC3-II/LC3-I and protein expression of p62 and enhanced protein expression of lysosome associated membrane protein-2 (Lamp2) in myocardium. Treatment of I/R mice with BHB reduced mitochondrial formation of reactive oxygen species, enhanced adenosine triphosphate production, attenuated mitochondrial swelling, and partly restored mitochondrial membrane potential in myocardium. Furthermore, treatment of I/R mice with BHB abated oxidative stress and attenuated endoplasmic reticulum stress in myocardium. Our results indicated that treatment with exogenous BHB protected heart from I/R injury in mice.