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Cost-efficient and durable oxygen evolution catalysts are in great demand, which are dominated not only by the component of the electrocatalysts but also by their molecular structure and crystallinity. Herein, we developed an efficient cobalt–vanadium spinel-type electrocatalyst with an extremely high concentration of Co 3+ ions by tuning the balanced vanadium ions’ concentration in crystallinity-modulated Co 2–xV xO 4 nanoplates. This resulted in the lowest overpotential of 240 mV at 10 mA/cm 2, the smallest Tafel slope of 45 mV dec –1, and a current density of 100 mA/cm 2 at an overpotential of 280 mV for water oxidation, which is remarkably 20 times better than that of the benchmark RuO 2 catalyst, along with excellent stability. Such excellent performance is due to the very high Co 3+/Co 2+ ratio of 2.84 achieved in situ in the low-crystallinity Co 2–xV xO 4 (LC-Co 2–xV xO 4) sample, which is 40% higher than that of the widely reported Co 3O 4, as evidenced by both operando X-ray absorption near-edge spectroscopy and in situ X-ray photoelectron spectroscopy. These findings stimulate the opportunities to explore Co 2–xV xO 4 as a class of nonprecious-metal-based efficient OER electrocatalysts.

Layered perovskite (La1−xSrx)2CoO4±δ (x = 0.3, 0.4, 0.5) oxides were prepared using sol–gel route and evaluated as the cathode materials for intermediate-temperature solid-oxide fuel cells. (La1−xSrx)2CoO4±δ has a tetragonal structure with space group of I4/mmm in all cases of x levels. The average thermal expansion coefficient of (La1−xSrx)2CoO4±δ is relatively low and slightly increases with x, which can be ascribed to the sway of Sr doping on the spin-state transition of Co ions. X-ray photoelectron spectroscopy and thermogravimetric analysis show that Co ions exist in mixed oxidation states, but the lattice oxygen content considerably varies with x. Regarding transport property, (La1−xSrx)2CoO4±δ behaves like a semiconductor in the temperature range of 200–800 °C, and the electrical conductivity significantly increases with x. As one of the most important results, electrochemical performance of (La1−xSrx)2CoO4±δ cathode is affected by x in a complex manner, and x = 0.4 cathode, i.e., La1.2Sr0.8CoO4±δ, has the most favored area-specific resistance of 0.062 Ω cm2 and the highest power density of 630 mW cm−2 in an electrolyte-supported single cell at 800 °C, showing a rapid kinetics toward oxygen reduction reaction. This study demonstrates that the structural, transport, thermal, and electrochemical properties of (La1−xSrx)2CoO4±δ cathodes significantly depend on the La/Sr ratio at the A-site of lattice. Rietveld refinement profile and temperature-dependent electrochemical performance for La1.2Sr0.8CoO4±δ cathode material

In this study, the effects of carbon quantum dot (CQD) doping on the photocatalytic performance of semiconductor BiOCl microspheres were investigated. Highly dispersed CQDs with up-conversion luminescence properties were prepared using the hydrothermal method, and visible-light-responsive CQDs@BiOCl photocatalysts with regular morphology were prepared via CQD doping. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ultraviolet–visible (UV–Vis) spectroscopy were used to investigate the morphology and light absorption properties of the materials. The degradation rate of rhodamine B (RhB) was 76.1% after 180 min of visible-light irradiation when CQDs@BiOCl were used and only 19.4% when pure BiOCl was used. The photoluminescence (PL), UV–Vis diffuse reflectance spectra (UV–Vis DRS) and electron paramagnetic resonance (EPR) results were analyzed to determine the possible reasons for the increased photocatalytic activity of CQDs@BiOCl microspheres. The results showed CQD doping expanded the visible light absorption range, CQDs exhibited fast photoinduced electron transfer, and CQDs@BiOCl possessed high mesoporosity, which promoted the effective separation of photogenerated electron–hole pairs. In addition, the microsphere structure of CQDs@BiOCl exhibited a larger specific surface area and a more regular morphology than its sheet-like structure. These features increased the number of photocatalytic reaction sites and the surface adsorption of the catalyst. In addition, the electronic conjugated structure of CQDs was demonstrated to function as an effective electron trap. CQD doping effectively inhibited the photogenerated electron–hole pair recombination of the composite photocatalyst, which enhanced the photocatalytic performance of the system.

A novel NASICON-type K0.24Na2.76Fe2(PO4)3 (K0.24NFP) is synthesized via a simple solid-state reaction method. K-doped method can enlarge lattice distance and restrain the structure dilapidation from Na3Fe2(PO4)3 to Na5Fe2(PO4)3. Comparison with undoped-Na3Fe2(PO4)3 (NFP) sample (82.1 mAh g−1), K0.24NFP electrode shows a 101.3 mAh g−1 discharge capacity at 10 mA g−1, which up to 97% of theoretical capacity. As for rate capability performance, a high reversible capacity of 73.6 mAh g−1 at 1000 mA g−1. The cycle stability performance measurement results indicate that the discharge capacity of K0.24NFP electrode is up to 93.7 mAh g−1 after 500 cycles at 100 mA g−1. The excellent electrochemical performance is attributed to the improvement of structural stability and the highest intercalation-deintercalation kinetic of sodium-ions (DNa+ = 3.98 × 10−11) due to K-doped. Hence, the K-doped iron-based phosphate (K0.24Na2.76Fe2(PO4)3) should be a potential cathode material in sodium-ions batteries for scale energy storage.

The use and control of the extraordinary optical transmission through subwavelength hole arrays has enormous application potential in photonic devices. In this paper, we propose a subwavelength hole array with inner tunnels, for which the Smith-Purcell radiation (SPR) with this enhanced transmission phenomenon in THz is excited when the transmission peak locates in the SPR band. The SPR is monitored using particle-in-cell simulations in order to analyze the mechanisms responsible for improving the radiation coherence. Analysis of the electron energy loss reveals that the proposed subwavelength hole array with inner tunnels outperforms a conventional subwavelength grating array with respect to SPR generation efficiency. As SPR plays a significant role in research on particle diagnosis and terahertz radiation sources, the performance of the proposed structure suggests that it has high application potential.

With the rapid development of infrastructure construction, it is an inevitable trend to replace natural sand in short supply with manufactured sand to meet sustainable development. In this paper, the relationship between the particle shape characteristics of manufactured sand and concrete performance is discussed using a morphological analysis and concrete experiments. The particle shape parameters of five types of manufactured sand were obtained by using the aggregate image measurement system (AIMS) and digital image processing (DIP) techniques, and the correlations between different parameters were analyzed. Moreover, the properties of concrete with the five kinds of manufactured sand were tested. The results show that particle size and type have a significant impact on particle shape parameters. Particle shape parameters, especially angularity, correlate well with the workability and compressive strength of concrete while having little effect on the durability of concrete. An accurate understanding of the morphological characteristics of manufactured sand is conducive to the optimization of concrete mix designs. Therefore, it is suggested that a manufactured-sand shape test be included in aggregate specification.

Iron-based phosphates as a low cost and high structural stability cathode materials for sodium ion batteries (SIBs) have been widely studied. However, the working potential basing on Fe3+/Fe2+ redox is very low (less than 3.05 V vs. Na/Na+), which has obviously affect on the energy/power density. In this work, we choose the non-precious metal manganese (Mn) to improve the working potential of Na3Fe2(PO4)(P2O7) (NFFPP). A series of mixed-phosphate Na3Fe2-xMnx(PO4)(P2O7) (x = 0.0, 0.5, 1.0, 1.5 and 2.0) compounds are firstly proposed as cathode materials for SIBs. After optimization, the as-prepared Na3FeMn(PO4)(P2O7) (NFMPP) could deliver a higher average working potential of 3.27 V (vs. Na/Na+) with a theoretical capacity of 120 mAh g-1. Furthermore, the carbon coating NFMPP cathode shows a reversible initial specific capacity of 105 mAh g-1 at 0.1 C with a corresponding coulombic efficiency of 99%. The in-situ XRD and ex-situ XPS results indicate that this cathode material goes through the reversible redox Fe3+/Fe2+ and Mn3+/Mn2+ with a reversible two Na-ion insertion/deinsertion process.

Introducing secondary metal ions into host electrode materials may result in extra redox sites and regulating the electronic structure to increase electrochemical properties. With the assistance of microwave, Mn cation was in-situ isomorphism doped into porous CoCo2O4 nanowires during a hydrothermal process. Ex-situ characterizations reveal that the doped Mn2+ and Mn3+ in CoCo2O4 provides additional redox reaction by forming reversible Mn4+, which effectively improved electrochemical storage capacity. The added redox reaction of Mn cations is also helpful to effectively suppress the water-splitting, which expanded the operating voltage window. As a result, the as-obtained Mn-doped CoCo2O4 nanowire array electrodes exhibited an enlarged specific capacity (1528.0C g−1/424.4 mA h g−1 at 1 A g−1) with a widened operating voltage window of 1.1 V and superior cycling stability (91.5 % retention after 5000cycles). Correspondingly, the battery-supercapacitor hybrid device constructed by Mn2CoCo2O4 porous nanowire array electrode and biomass-derived N doped porous carbon delivered a stable working voltage of 1.9 V and superior energy density of 58.6 Wh kg−1 at power density of 950 W kg−1 as well as excellent stability (83.7 % specific capacity retained at 10 A g−1 for 8000cycles). This work provides a feasible route for the construction of energy storage devices with high energy density and high power density.

With the new municipal solid waste classification policy implemented in China, attention on achieving the waste-to-energy disposal of “dry waste” has been growing. Pyrolysis conversion of organic waste into value-added chemicals is a promising method to treat solid waste. However, after removing the non-combustible components of “dry waste”, the obtained high-organic solid waste (HSW) contains various heavy metals, which requires urgent attention during thermochemical conversion. To mitigate heavy metals risk, kaolin was employed as additive during HSW pyrolysis, and intercalation–exfoliation and thermal activation modifications were performed on the kaolin to further immobilize and stabilize heavy metals in the derived chars. The characterization results illustrated that the interlayer spacing, pore volume and diameter of kaolin were expanded after intercalation–exfoliation modification, providing more opportunities for the adsorption of metals. The thermal activation method favored the transformation of kaolin into metakaolin via dehydroxylation to enhance its nonhexacoordinated Al proportion and chemisorption. During 450–650 °C, kaolin exhibited an effective solid enrichment performance for targeting heavy metals, and the intercalation–exfoliation and thermal activation modification further enhanced the adsorption capacity of the kaolin for Cd, Cr, Pb and Cr, Cu, Pb, Zn, respectively. Compared with Cu and Zn, additives demonstrated better stabilization effects for Cd, Pb, and Cr, transforming more bioavailable fractions to the residual speciation. Overall, a higher pyrolytic temperature (650 °C) and the addition of effective additives could simultaneously increase the residual fraction and decrease the bioavailable fraction of heavy metals in HSW-derived chars, reducing the potential ecological risk.

Herein, we design an O-incorporated hierarchical NiCoP/Ni2P hybrid electrodes (O-NiCoP/Ni2P) through a simple progressive phosphatization and dip-coating strategy to overcome the additional cost caused by heteroatom doping. The resulting O-NiCoP/Ni2P displays an ultra-low overpotential of 58 mV at 10 mA cm−2 and long-term stability over 24 h for efficient alkaline hydrogen evolution reaction (HER). Based on the density functional theory simulations, the O doping is beneficial to optimize the free energy of hydrogen/water absorption, which accelerates the HER process. Besides, the strong coupling of O-NiCoP/Ni2P has a positive effect on the electron transfer, thereby improving its catalytic performance. This work provides a potential pathway to the rational design of transition-metal phosphides based HER electrocatalysts and element-doping for energy conversion applications.

The recycling ratio of industrial solid waste, e.g., steel slag (SS), phosphogypsum (PG) is still comparatively low in developing countries. This work aims to utilize industrial solid waste in a sustainable slow-setting slight-expansive road base course binder (RBCB) production involving the performance regulation, hydration characteristics and practical application. The results indicates that RBCB obtained the ideal retarding effect without additional retarder and avoided the strength loss which caused by the fast hardening during the rolling compaction process. The relatively high content of PG preferably stimulated the pozzolanic activity of fly ash (FA), and more effectively compensated the shrinkage through inhibiting the conversion of AFt to AFm in the later hydration stage. In addition, SS adjusted the setting time, improved the strength and regulated the expansion ratio of RBCB. Each kilometer of road base course absorbed 688.8 t solid wastes and saved 6.53% cost of materials compared with P·S 32.5 (Portland slag cement, strength grade is 32.5) in practical application. Excellent pavement performance, obvious environmental and economic benefits were achieved in the field experiment of RBCB containing high solid wastes. This investigation provides a promising and value-added way for the utilization of various original solid waste.

Potassium (K) has a significant effect on wheat yield and quality. Owing to the limitations of irrigation and production costs, soil-based applications of potassium fertilizer are not performed in wheat production on the Loess Plateau of China. In the late growth stage of wheat, potassium deficiency occurs even under sufficient nitrogen/phosphorus (N/P) levels, so it is necessary to supplement potassium through foliar spraying. However, there are few studies on the effect of the foliar application of potassium fertilizer (KFA) on wheat quality. Field experiments were conducted at two experimental sites for 2 years to study the effects of different potassium fertilizer application levels and periods on wheat yield and quality. The results showed that KFA had no significant effect on the yield of the wheat variety Xinong 20 (XN20) but increased the yield of the wheat variety Xiaoyan 22 (XY22). The improvement effect of KFA on the wet gluten content and stabilization time (ST) of XN20 was better than that on these parameters of XY22, while the sedimentation value (SV) and formation time (FT) showed the opposite trend. KFA significantly reduced the albumin content of the two varieties but had no significant effect on the globulin content. Compared with that at the other two stages, the potassium application in the form of potash fertilizer spray at a concentration of 60 mmol L−1 (K2) at the flowering stage (BBCH 65) significantly increased the protein content, wet gluten content, SV and gluten protein content in XN20 grains, whereas the application at 10 days after flowering (AA10, BBCH 71) at the K2 concentration was more beneficial to prolonging the dough FT. For XY22, the application of potassium fertilizer at the K2 concentration at the flowering stage increased the wet gluten and gluten protein levels and dough development time. There were significant genotypic differences in the composition and content of HMW-GS between the two varieties. KFA significantly increased the levels of the 1, 7 + 8, and 4 + 12 subunits in XN20 and the 1 subunit in XY22, but had no significant effect on the 2 + 12 subunit in XY22. Partial least squares path modelling (PLS-PM) analysis showed that the processing quality indexes (SV, FT, ST) and gluten protein and HMW-GS levels were regulated by the potassium fertilizer foliar spraying stage and concentration and revealed in part that KFA affected the processing quality by affecting the HMW-GS content.

In this research, a composite material (MWCNT@BiVO4) was prepared using a one step hydrothermal method. The prepared composite material was characterized by energy-dispersive X-ray analysis, X-ray diffraction, scanning electron microscopy, EDS, UV-Vis diffuse-reflectance spectroscopy, electron spin resonance (ESR), X-ray photoelectron spectroscopy, and photoluminescence spectroscopy. The scanning electron microscopic images showed that MWCNTs were successfully embedded into BiVO4. MWCNT@BiVO4 showed a strong visible-light absorption capacity, high efficiency for electron–hole separation, and excellent stability. The degradation test of RhB was conducted under visible light irradiation. Compared with BiVO4 (K = −0.05657) and P25 (K = −0.03227), MWCNT@BiVO4 (K = −0.11894) realized the highest removal ratio of Rhodamine B (RhB) under visible light irradiation, therefore, MWCNT@BiVO4 might be promoted to practical applications. The stability of MWCNT@BiVO4 was also verified via recycling and reusing experiments. After 5 cycles, MWCNT@BiVO4 could still maintain the removal rate of RhB at 95.96%. In addition, this paper deduced the growth mechanism of MWCNT@BiVO4 and the degradation mechanism of RhB, proving that MWCNT@BiVO4 can be used in future practices.

Purpose The application of metagenomic next-generation sequencing (mNGS) in the diagnosis of tuberculous meningitis (TBM) remains poorly characterized. Here, we retrospectively analyzed data from patients with TBM who had taken both mNGS and conventional tests including culture of Mycobacterium tuberculosis (MTB), polymerase chain reaction (PCR) and acid-fast bacillus (AFB) stain, and the sensitivity and specificity of these methods were compared. Methods We retrospectively recruited TBM patients admitted to the hospital between December 2015 and October 2018. The first collection of cerebrospinal fluid (CSF) samples underwent both mNGS and conventional tests. In addition, patients with bacterial/cryptococcal meningitis or viral meningoencephalitis were mNGS positive controls, and a patient with auto-immune encephalitis was an mNGS negative control. Results Twenty three TBM patients were classified as 12 definite and 11 clinical diagnoses, which were based on clinical manifestations, pathogen evidence, CSF parameters, brain imaging, and treatment response. The mNGS method identified sequences of Mycobacterium tuberculosis complex (MBTC) from 18 samples (18/23, 78.26%). In patients with definite TBM, the sensitivity of mNGS, AFB, PCR, and culture to detect MTB in the first CSF samples were 66.67, 33.33, 25, and 8.33%, respectively. The specificity of each method was 100%. Among the four negative mNGS cases (4/23, 17.39%), three turned out positive by repeated AFB stain. The agreement of mNGS with the total of conventional methods was 44.44% (8/18). Combination of mNGS and conventional methods increased the detection rate to 95.65%. One patient was diagnosed as complex of TBM and cryptococcal meningitis, in which AFB stain and cryptococcal antigen enzyme immunoassay were positive and the DNA of Cryptococcus neoformans was detected by mNGS. Conclusion Our study indicates that mNGS is an alternative method to detect the presence of mycobacterial DNA in CSF samples from patients with TBM and deserves to be applied as a front-line CSF test.

Dual improvement on electronic conductivity and ionic conductivity of TiNb2O7 (TNO) is of great significance for realizing high-performance lithium-ion batteries. In this work, the V5+-doped TNO microspheres (denoted as Vx-TNOMs, x = 0, 0.015, 0.030 and 0.045) were synthesized via a simple solvothermal approach. X-ray diffraction coupled with Rietveld refinements and Raman spectra analyses verified that V5+ not simply possessed substitution doping mode but also inserted into the interstices of the TNOMs lattice. The density functional theory (DFT) calculations indicated that the improved electronic conductivity could originate from the formation of impurity bands after the V5+ doping. Meanwhile, the climbing image-nudged elastic band (CI-NEB) demonstrated that a TNOMs framework with faster ion transport pathways is achieved by the V5+ doping. Served as anode material of lithium-ion batteries, the V0.030-TNOMs electrode presents an impressive discharge capacity of 163.5 mAh/g at 10 C and long cycle life up to 2000 cycles with a capacity fading of merely 0.014% per cycle. Furthermore, the full battery employing V0.030-TNOMs as an anode and commercial LiCoO2 as a cathode exhibits superior electrochemical performances with promising application prospect. Our present study sheds new light on constructing high-performance electrodes for electrochemical energy storage.

Due to the particular nature of ownership, the motivations for state-owned enterprises to participate in the mixed ownership M&A include not only the realization of corporate capital appreciation and value creation, but also some strategic factors at the national level, such as concentrating state-owned economic power to promote the development of the industry and maintaining stable social development. Based on the characteristics of the self-development of state-owned enterprises and the maximization of interests, this paper constructs the evaluation system of trust mechanism from five dimensions of shareholders’, creditors’, suppliers’, buyers’ and enterprises’ sincerity; constructs the evaluation system of innovation mechanism from three dimensions of technological innovation ability, market competitiveness and sustainable development ability; and the evaluation system of the mixed ownership M&A value of state-owned enterprises from four dimensions of Tobin’s Q, operating cash flow, return on total assets and corporate governance.

This study describes the synthesis of Ag–bismuth vanadate (Ag–BiVO4) microspheres, a highly efficient visible light photocatalyst for the degradation of methylene blue, via a one-step hydrothermal method. Multiple characterization techniques showed that bulk, monoclinic, needle-like BiVO4 and Ag nanoparticles (50 nm diameter) formed microspheres (3–7 μm diameter) with a uniform size distribution. Compared with pure BiVO4, the Bi–Ag microspheres showed significantly enhanced absorption of visible light (480 to 700 nm) during measurement of UV-Vis diffuse reflectance. Electron paramagnetic resonance measurements indicated that Ag doping enhanced photocatalytic performance because it facilitated separation and transfer of photo-generated electrons and electron holes. This study provides a cost-effective approach for synthesizing Bi–Ag microspheres with enhanced photocatalyst performance for environmental and energy applications.

An iron-base phosphate Na4Fe3(PO4)2(P2O7) nano-sphere growing on the multi-walled carbon nanotubes (MCNTs) is scalable synthesized via a convenient spray drying way. The Na4Fe3(PO4)2(P2O7)@MCNTs composite as cathode material for sodium-ion battery (SIBs) exhibits a high discharge capacity of 115.7 mA h g−1 at 0.1 C and an outstanding cycle stability with a with a capacity retention of 95% after 1200th at 2 C rate. It also shows an excellent rate capability with a capacity of 62.8 mA h g−1, even at high rate of 20 C. The outstanding electrochemical performance of Na4Fe3(PO4)2(P2O7)@MCNTs cathode are attributed to its' particular P2O7 dimers for reducing the rotation/distortion and higher electronic conductivity improves by MCNTs. A sodium-ion battery using the Na4Fe3(PO4)2(P2O7)@MCNTs cathode and the hard carbon anode shows a working voltage of 3.04 V with a specific energy of 210 Wh Kg−1 bases on the total weight of both electrode materials.

A pervious concrete with carbonated ground steel slag powder as binder and crushed steel slag as aggregate was prepared, which provided the key material for construction of sponge city and explored a new approach to massively utilize steel slag. This paper presented series of experimental studies on the properties of steel slag carbonized consolidation matrix and carbonated steel slag pervious concrete. Results indicated that the phosphogypsum promoted the carbonization ratio of steel slag. When the content of phosphogypsum was 2.5%, strength and carbonization ratio of carbonated steel slag from pressing formation reached 82.6 MPa and 52.1% respectively. The main product of the carbonated steel slag was calcite and C–S–H. The strength and porosity of carbonated steel slag pervious concrete reached 9.4 MPa and higher than 20% respectively. And it also had a good plantability when it is used in sponge city construction. Compared with ordinary pervious concrete, carbonated steel slag pervious concrete saved 75.8% cost of materials, was 100% made of solid waste and absorbed around 100 kg/m3 of CO2, which turns out to be a green and high-efficiency approach to utilize the solid waste steel slag, saving the natural resource and reducing the carbon footprint of the construction of sponge city.

The welding of glasses is widely used in many fields, such as optics, microfluidics, and microelectromechanical systems. In this paper, two pieces of 1 mm soda lime glass substrates were welded using a 1064 nm nanosecond laser assisted with a 14 nm titanium-coated thin film coating. Results show that after the laser irradiation, the welded area becomes highly transparent much like uncoated glass. The maximum change rate of transmittance of the welded zone is 8.88% in the wavelength range of 400–1800 nm, compared to a piece of 2 mm glass substrate. The chemical reaction process between the titanium film and the glass substrate of the highly transparent welded sample was analyzed by x-ray photoelectron spectroscopy. Welded quality and shear strength were characterized by scanning acoustic microscopy and shear tests.

Many studies have focused on the use of BiVO4 as a photocatalyst, but few have investigated the production of free radicals during the photocatalytic process. Following synthesis of flowerlike BiVO4 and characterization by X-ray diffraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM) Scanning electron microscopy (EDX), UV-Vis and XPS, we successfully prepared BiVO4. Then we used electron spin resonance (ESR) to determine the production and degradation of individual active free radicals, including the superoxide radical (·O2-) and the hydroxyl radical (·OH). In the first experiment, we used ESR to detect the signals of free radicals (·O2- and ·OH) under varying oxygen conditions. The results shown that in addition to production by ·O2-, ·OH could also be produced by oxidation of h+ to OH−. In the next experiment, we detected ·OH under varying pH to identify the result of the first experiment, and found that signal intensities increased with increasing pH, indicating the mechanism for ·OH production. Finally, we conducted a trapping experiment to examine free radical degradation mechanisms. We identified ·OH and h+ as the main active free radicals and showed the complete production about ·OH. These results improve current knowledge of free radical production mechanisms, which can be used to enhance the photocatalytic performance of BiVO4.

The band gaps of bismuth vanadate (BiVO4) and bismuth sulfide (Bi2S3) are about 2.40 eV and 1.30 eV, respectively. Although both BiVO4 and Bi2S3 are capable of strong visible light absorption, electron–hole recombination occurs easily. To solve this problem, we designed a one-step hydrothermal method for synthesizing a Bismuth sulfide (Bi2S3)/Bismuth vanadate (BiVO4) heterojunction using polyvinylpyrrolidone K-30 (PVP) as a structure-directing agent, and 2-Amino-3-mercaptopropanoic acid (l-cysteine) as a sulfur source. The pH of the reaction solution was regulated to yield different products: when the pH was 7.5, only monoclinic BiVO4 was produced (sample 7.5); when the pH was 8.0 or 8.5, both Bi2S3 and BiVO4 were produced (samples 8.0 and 8.5); and when the pH was 9.0, only Bi2S3 was produced (sample 9.0). In sample 8.0, Bi2S3 and BiVO4 were closely integrated with each other, with Bi2S3 particles formed on the surface of concentric BiVO4 layers, but the two compounds grew separately in a pH solution of 8.5. Visible-light photocatalytic degradation experiments demonstrated that the degradation efficiency of the Bi2S3/BiVO4 heterojunction was highest when prepared under a pH of 8.0. The initial rhodamine B in the solution (5 mg/L) was completely degraded within three hours. Recycling experiments verified the high stability of Bi2S3/BiVO4. The synthesis method proposed in this paper is expected to enable large-scale and practical use of Bi2S3/BiVO4.

The band gaps of bismuth vanadate (BiVO4) and bismuth sulfide (Bi2S3) are about 2.40 eV and 1.30 eV, respectively. Although both BiVO4 and Bi2S3 are capable of strong visible light absorption, electron–hole recombination occurs easily. To solve this problem, we designed a one-step hydrothermal method for synthesizing a Bismuth sulfide (Bi2S3)/Bismuth vanadate (BiVO4) heterojunction using polyvinylpyrrolidone K-30 (PVP) as a structure-directing agent, and 2-Amino-3-mercaptopropanoic acid (l-cysteine) as a sulfur source. The pH of the reaction solution was regulated to yield different products: when the pH was 7.5, only monoclinic BiVO4 was produced (sample 7.5); when the pH was 8.0 or 8.5, both Bi2S3 and BiVO4 were produced (samples 8.0 and 8.5); and when the pH was 9.0, only Bi2S3 was produced (sample 9.0). In sample 8.0, Bi2S3 and BiVO4 were closely integrated with each other, with Bi2S3 particles formed on the surface of concentric BiVO4 layers, but the two compounds grew separately in a pH solution of 8.5. Visible-light photocatalytic degradation experiments demonstrated that the degradation efficiency of the Bi2S3/BiVO4 heterojunction was highest when prepared under a pH of 8.0. The initial rhodamine B in the solution (5 mg/L) was completely degraded within three hours. Recycling experiments verified the high stability of Bi2S3/BiVO4. The synthesis method proposed in this paper is expected to enable large-scale and practical use of Bi2S3/BiVO4.

We prepared a unique leaf-like BiVO4-reduced graphene oxide (BiVO4-rGO) composite with prominent adsorption performance and photocatalytic ability by a single-step method. Multiple characterization results showed that the leaf-like BiVO4with average diameter of about 5 um was well dispersed on the reduced graphene oxide sheet, which enhanced the transportation of photogenerated electrons into BiVO4, thereby leading to efficient separation of photogenerated carriers in the coupled graphene-nanocomposite system. The characterization and experiment results also indicated that the outstanding adsorption ability of such composite was closely associated with the rough surface of the leaf-like BiVO4and doped rGO. The surface photocurrent spectroscopy and transient photocurrent density measurement results demonstrated that the doped rGO enhanced separation efficiency and transfer rate of photogenerated charges. As a result, the BiVO4-rGO exhibited higher photocatalytic capacity toward the degradation of rhodamine B dye under visible-light irradiation compared with pure BiVO4and P25.

Three-dimensional (3D) multi-cellular aggregates (MCAs), as a model scaffold-free tissue construct, are useful for engineering cell-dense and matrix-poor tissues for repair and regeneration applications. To facilitate rapid MCA formation with high degrees of linker consistency and performance, we synthesized a class of dendrimer hydrazides with 8, 16 and 32 arms that can react with the aldehyde on the modified cell surfaces to form MCAs. DAB-AM-16 hydrazide with 32 arms demonstrated the best cell aggregation ability as compared to the dendrimer hydrazides with fewer arms, facilitating MCA formation at lower linker concentrations, minimizing cytotoxicity. Characterization of the MCAs formed with 2 microm of DAB-AM-16 hydrazide indicated that the cells proliferated well, maintained 3D cell-cell interaction and 3D cell morphology even as the inter-cellular linker gradually disappeared from the cell surfaces. Cells cultured as MCAs also demonstrated improved cell functions than the cells cultured in 2D monolayer. The dendrimer hydrazides would be a class of consistent, economical, and high performance multivalent transient inter-cellular linkers useful in forming scaffold-free 3D tissue constructs for soft-tissue engineering and regenerative medicine.

Correction for ‘One-step synthesis of composite material MWCNT@BiVO4 and its photocatalytic activity’ by Deqiang Zhao et al., RSC Adv., 2017, 7, 33671–33679.

Three-dimensional (3D) in vitro cultures are recognized for recapitulating the physiological microenvironment and exhibiting high concordance with in vivo conditions. In cancer research, the multi-cellular tumor spheroid (MCTS) model is an established 3D cancer model that exhibits microenvironmental heterogeneity close to that of tumors in vivo. However, the established process of MCTS formation is time-consuming and often uncontrolled. Here, we report a method for engineering MCTS using a transient inter-cellular linker which facilitates cell-cell interaction. Using C3A cells (a hepatocellular carcinoma cell line) as a model, we formed linker-engineered spheroids which grew to a diameter of 250 microm in 7 days, as compared to 16 days using conventional non-adherent culture. Seven-day old linker-engineered spheroids exhibited characteristics of mature MCTS, including spheroid morphology, gene expression profile, cell-cell interaction, extracellular matrix secretion, proliferation and oxygen concentration gradients, and cellular functions. Linker-engineered spheroids also displayed a resistance to drug penetration similar to mature MCTS, with dose-dependent extracellular accumulation of the drug. The linker-engineered spheroids thus provide a reliable accelerated 3D in vitro tumor model for drug penetration studies.