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Energy conversion technologies like fuel cells and metal-air batteries require oxygen reduction reaction (ORR) electrocatalysts with low cost and high catalytic activity. Herein, N-doped carbon spheres (N-CS) with rich micropore structure have been synthesized by a facile two-step method, which includes the polymerization of pyrrole and formaldehyde and followed by a facile pyrolysis process. During the preparation, zinc chloride (ZnCl2) was utilized as a catalyst to promote polymerization and provide a hypersaline environment. In addition, the morphology, defect content and activity area of the resultant N-CS catalysts could be regulated by controlling the content of ZnCl2. The optimum N-CS-1 catalyst demonstrated much better catalytic activity and durability towards ORR in alkaline conditions than commercial 20 wt% Pt/C catalysts, of which the half-wave potential reached 0.844 V vs. RHE. When applied in the Zn-air batteries as cathode catalysts, N-CS-1 showed a maximum power density of 175 mW cm-2 and long-term discharging stability of over 150 h at 10 mA cm-2, which outperformed 20 wt% Pt/C. The excellent performance could be due to its ultrahigh specific surface area of 1757 m2 g-1 and rich micropore channels structure. Meanwhile, this work provides an efficient method to synthesize an ultrahigh surface porous carbon material, especially for catalyst application.

Biodegradable magnesium (Mg) and its alloy show huge potential as temporary bone substitute due to the favorable biocompatibility and mechanical compatibility. However, one issue deserves attention is the too fast degradation. In this work, mesoporous bioglass (MBG) with high pore volume (0.59 cc/g) and huge specific surface area (110.78 m2/g) was synthesized using improved sol-gel method, and introduced into Mg-based composite via laser additive manufacturing. Immersion tests showed that the incorporated MBG served as powerful adsorption sites, which promoted the in-situ deposition of apatite by successively adsorbing Ca2+ and HPO42−. Such dense apatite film acted as an efficient protection layer and enhanced the corrosion resistance of Mg matrix, which was proved by the electrochemical impedance spectroscopy measurements. Thereby, Mg based composite showed a significantly decreased degradation rate of 0.31 mm/year. Furthermore, MBG also improved the mechanical properties as well as cell behavior. This work highlighted the advantages of MBG in the fabrication of Mg-based implant with enhanced overall performance for orthopedic application.

High surface area cerium oxide was synthesized via the reverse microemulsion method and assessed for CO2 reduction to CO via reverse water gas shift. The resulted ceria nanoparticles (ca. 4 nm) were 100% selective to CO formation, while attaining a nearly equilibrium CO2 conversion at 600 °C. As compared to ceria synthesized by wet precipitation, the reverse microemulsion-synthesized ceria exhibited enhanced surface stability and a more stable catalytic performance (declining from 63% to 50% over 100 h on stream). No significant carbon formation was detected and a relatively small decline in conversion was related to the specific surface area reduction induced by the growth of ceria nanoparticles under the reaction conditions.

Improving catalytic performance is a yet still challenge in thermal catalytic oxidation. Herein, uniform mesoporous MnO2 nanosphere-supported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO2 template strategy for the total catalytic degradation of volatile organic compounds at low temperature. The introduction of mesopores into the MnO2 support induces a large specific surface area and pore size, thus providing numerous accessible active sites and enhanced diffusion properties. Moreover, the addition of a secondary noble metal can adjust the Oads/Olatt molar ratios, resulting in high catalytic activity. Among them, the catalyst having a Pt/Pd molar ratio of 7:3 exhibits optimized catalytic activity at a weight hourly space velocity of 36,000 ml g−1 h−1, reaching 100% toluene oxidation at 175 °C with a lower activation energy (57.0 kJ mol−1) than the corresponding monometallic Pt or non-Pt-based catalysts (93.8 kJ mol−1 and 214.2 kJ mol−1). Our findings demonstrate that the uniform mesoporous MnO2 nanosphere-supported bimetallic Pt–Pd nanoparticles catalyst is an effective candidate for application in elimination of toluene.

Sustainable development based on the value-added utilization of furfural residues (FRs) is an effective way to achieve a profitable circular economy. This comprehensive work highlights the potential of FRs as precursor to prepare porous carbons for high performance supercapacitors (SCs). To improve the electrochemical performance of FR-based carbon materials, a facile route based on methanol pretreatment coupled with pre-carbonization and followed KOH activation is proposed. More defects could be obtained after methanol treatment, which is incline to optimize textural structure. The activated methanol treated FR-based carbon materials (AFRMs) possess high specific surface area (1753.5 m2 g−1), large pore volume (0.85 cm3 g−1), interconnected micro/mesoporous structure, which endow the AFRMs with good electrochemical performance in half-cell (326.1 F g−1 at 0.1 A g−1, 189.4 F g−1 at 50 A g−1 in 6 M KOH). The constructed symmetric SCs based on KOH, KOH–K3Fe(CN)6 and KOH-KI electrolyte deliver energy density up to 8.9, 9.9 and 10.6 Wh kg−1 with a capacitance retention of over 86% after 10,000 cycles. Furthermore, the self-discharge can be restrained by the addition of K3Fe(CN)6 and KI in KOH electrolyte. This study provides an effective approach for high-valued utilization of FR waste.

Transition metal sulfides (TMSs) have been regarded as greatly promising electrode materials for supercapacitors because of abundant redox electroactive sites and outstanding conductivity. Herein, we report a self-supported hierarchical Mn doped Co9S8@Co(OH)2 nanosheet arrays on nickel foam (NF) substrate by a one-step metal–organic-framework (MOF) engaged approach and a subsequent sulfurization process. Experimental results reveal that the introduction of manganese endows improved electric conductivity, enlarged electrochemical specific surface area, adjusted electronic structure of Co9S8@Co(OH)2 and enhanced interfacial activities as well as facilitated reaction kinetics of electrodes. The optimal Mn doped Co9S8@Co(OH)2 electrode exhibits an ultrahigh specific capacitance of 3745 F g−1 at 1 A g−1 (5.618 F cm−2 at 1.5 mA cm−2) and sustains 1710 F g−1 at 30 A g−1 (2.565 F cm−2 at 45 mA cm−2), surpassing most reported values on TMSs. Moreover, a battery-type asymmetric supercapacitor (ASC) device is constructed, which delivers high energy density of 50.2 Wh kg−1 at power density of 800 W kg−1, and outstanding long-term cycling stability (94% capacitance retention after 8000 cycles). The encouraging results might offer an effective strategy to optimize the TMSs for energy-storage devices.

Rational synthesis of robust layered double hydroxides (LDHs) nanosheets for high-energy supercapacitors is full of challenges. Herein, we reported an ultrasonication-assisted strategy to eco-friendly fabricate NiFe-LDHs nanosheets for the enhanced capacitive behavior. The experimental results combined with different advanced characterization tools document that the utilization of ultrasonication has a profound effect on the morphology and thickness of the as-obtained NiFe-LDHs, alternatively affecting the capacitive behavior. It shows that NiFe-LDHs nanosheets prepared with two-hour ultrasonic treatments display the exceptional capacitive performance because of the synergetic effect of ultrathin thickness, large specific surface area, and high mesoporous volume. The maximum specific capacitance of Ni3Fe1-LDHs nanosheets with the thickness of 7.39 nm and the specific surface area of 77.16 m2 g-1 reached 1923 F g-1, which is competitive with most previously reported values. In addition, the maximum specific energy of the assembled NiFe-LDHs//AC asymmetric supercapacitor achieved 49.13 Wh kg-1 at 400 W kg-1. This work provides a green technology to fabricate LDHs nanosheets, and offers deep insights for understanding the relationship between the morphology/structure and capacitive behavior of LDHs nanosheets, which is helpful for achieving high-performance LDHs-based electrode materials.

Heavy metals that are adhered to the surfaces of microplastics in the natural marine environment pose potential threats to marine life. However, little is known about their adsorption mechanisms and composite risks. This study collected seawater, suspended particulate matter (SPM), plankton, and microplastic samples from the waters surrounding Hong Kong, established a method for analyzing 13 heavy metals in the plastisphere, and explored the extrinsic and intrinsic sources of the heavy metals by analyzing natural matrices (seawater, SPM, and plankton) and anthropogenic plastics. We found that heavy metals in the plastisphere were significantly affected by the surrounding matrices, as indicated by its positive correlations with the heavy metals in SPM and plankton at most of the sampling sites. Heavy metals in plankton usually occurred as traces of oxides such as As2O3 and ZnO. The partition coefficients of the studied heavy metals between seawater and the plastisphere were identical to those between the SPM and the plastisphere. No correlations were found between the concentrations of heavy metals in the plastisphere and the heavy metal concentrations, masses, quantities, or surface areas of the microplastics, although some polymer types contained extremely high Cd (676 mg/kg), Pb (1,742 mg/kg), and Zn (1,712 mg/kg) concentrations. Only the Cr, Cu, and Ni concentrations were positively correlated with the specific surface area of the microplastics. A cluster analysis showed that Cr, Cu, and Ni were derived from anthropogenic sources, indicating that adventive heavy metals could be adsorbed by plastics with large specific surface areas. We also established a new composite risk assessment method for heavy metals and microplastics that leverages the specific surface areas of microplastics. The assessment results showed that Cd from Tolo Harbor had a strong ecological risk, while As and Cd from the eastern waters off Hong Kong had moderate composite ecological risks.

Methanol, a versatile chemical, fuel additive and potential H2 carrier, has attracted great attention. Despite of the wide industrialization, improvement of Cu-based methanol-synthesis catalysts is highly anticipated. Accordingly, a series of Cu/ZnO/Al2O3 with designed precursor structures were prepared, and its structure–function relationship was investigated to make progress on this area. Results showed the catalyst derived from highly zinc-substituted malachite demonstrated the best catalytic performance in this work. It was found that the well-behaved catalyst possessed relatively high Cu specific surface area and exposed Cu concentration, and the well Cu/ZnO synergy. CuZn alloy was found by In-situ XRD tests, and its effect on the catalyst's thermostability was discussed. Fractional precipitation, which facilitated the Cu2+ substitution by Zn2+ in malachite lattice, could be an efficient preparation method of the Cu/ZnO/Al2O3 catalyst.

Catalysis today 376, S0920586121002856 (1-10) (2021). doi:10.1016/j.cattod.2021.06.018, The objective of this research was to investigate how the photocatalytic activity of pure TiO$_2$ can be improved bySnO$_2$ modification. Different molar ratios of tin to titanium were prepared. The correlation between tin concentration and structural properties was investigated to explain the mechanism of photocatalytic efficiency and to optimize the synthesis conditions to obtain enhanced activity of the SnO$_2$-modified TiO$_2$ photocatalysts under UV-irradiation. The SnO$_2$-modified TiO$_2$ photocatalysts were prepared by a low-temperature sol-gel method based on organic tin and titanium precursors. The precursors underwent sol-gel reactions separately to form SnO$_2$-TiO$_2$ sol. The sol-gels were deposited on a glass substrate by a dip-coating technique and dried at 150 °C to obtain the photocatalysts in the form of a thin film. To test the thermal stability of the material, an additional set of photocatalysts was prepared by calcining the dried samples in air at 500 °C. The photocatalytic activity of the samples was determined by measuring the degradation rate of an azo dye. An increase of up to 30% in thephotocatalytic activity of the air-dried samples was obtained when the TiO$_2$ was modified with the SnO$_2$ in a concentration range of 0.1–1 mol.%. At higher SnO$_2$ loadings, the photocatalytic activity of the photocatalystwas reduced compared to the unmodified TiO$_2$. The calcined samples showed an overall reduced photocatalyticactivity compared to the air-dried samples. Various characterization techniques (UV-Vis, XRD, N2-physisorption,TEM, EDX, SEM, XAS and photoelectrochemical characterization) were used to explain the mechanism for the enhanced and hindered photocatalytic performances of the SnO$_2$-modified TiO$_2$ photocatalysts. The results showed that the nanocrystalline cassiterite SnO$_2$ is attached to the TiO$_2$ nanocrystallites through the Sn-O-Ti bonds. In this way, the coupling of two semiconductors, SnO$_2$ and TiO$_2$, was demonstrated. Compared to single-phase photocatalysts, the coupling of semiconductors has a beneficial effect on the separation of charge carriers, which prolongs their lifetime for accessibility to participate in the redox reactions. The maximum increase in activity of the thin films was achieved in the low concentration range (0.1–1 mol.%), which means that an optimal ratio and contact of the two phases is achieved for the given physical parameters such as particle size, shape and specific surface area of the catalyst., Published by Elsevier, Amsterdam

Graphitic carbon nitride (g-C3N4) is a fascinating photocatalyst for solar energy utilization in photo-catalysis. Nevertheless, it often suffers from moderate photo-catalytic activity due to its low specific surface area and fast recombination rate of photogenerated electrons upon photo-excitation. Herein, we overcome the bottlenecks by constructing a porous g-C3N4 nanosheet (PCNS) through a simple thermal oxidation etching method. Benefited from its porous layer structure, the obtained PCNS exhibits large specific surface area, efficient separation of photogenerated charge carriers, as well as high exposure of active sites. As a result, it is robust and universal in visible light-driven dehydrogenation of alcohols in water under oxidant-free condition. Almost quantitative yields (>99%) of various valuable carbonyl compounds were obtained over PCNS, while bulk g-C3N4 was far less efficient. Moreover, the photo-catalyst was highly stable and could be facilely recovered from the aqueous system for efficient reuse. The easy preparation and excellent performance made PCNS a promising and competitive photocatalyst for the solar applications.

Particle size and content of RDX are the two main factors that affect the burning stability of RDX-based propellants. However, these effects and the corresponding mechanisms are still controversial. In this work, we investigated the physicochemical processes during burning and the corresponding mechanisms through the technologies of structure compactness analysis on the base of voidage measurement and theoretical interfacial area estimation, apparent burning rate measurement using closed vessel (CV) and extinguished burning surface characterization relying on interrupted closed vessel (ICV) and scanning electron microscope (SEM). The results indicate that the voidage increased with the increase of RDX content and particle size due to the increasing interfacial area and increasing interface gap size, respectively. The apparent burning rate increased with the increase of RDX particle size because of the decreasing RDX specific surface area on the burning surface, which could decrease the heat absorbing rates of the melting and evaporation processes of RDX in the condensed phase. Similarly, the apparent burning rate decreased with the increase of RDX content at pressures lower than around 55 MPa due to the increasing RDX specific surface area. Whereas, an opposite trend could be observed at pressures higher than around 55 MPa, which was attributed to the increasing heat feedback from the gas phase as the result of the increasing propellant energy. For propellants containing very coarse RDX particles, such as 97.8 and 199.4 μm average size, the apparent burning rate increased stably with a flat extinguished surface at pressures lower than around 30 MPa, while increased sharply above around 30 MPa with the extinguished surface becoming more and more rugged as the pressure increased. In addition, the turning degree of u-p curve increased with the increase of coarse RDX content and particle size, and could be reduced by improving the structure compactness.

Nano-TATB was developed in microchannels by physical method and chemical method, respectively. The effects of total flow rate, number of microreactor plates, solvent/non-solvent ratio and temperature on the particle size of TATB in the physical method were studied. Prepared TATB were characterized by Nano Sizer, Scanning Electron Microscopy, Specific surface aperture analyzer, X-ray diffraction, Fourier transform infrared spectroscopy and Differential Scanning Calorimetry. The results show that the TATB obtained by physical method and chemical method are spherical, with average particle size of 130.66 nm and 108.51 nm, respectively. Specific surface areas of TATB obtained by physical and chemical methods are 21.37 m2/g and 21.91 m2/g, respectively. Compared with the specific surface area of micro-TATB (0.0808 m2/g), the specific surface area of nano-TATB is significantly increased. DSC test results show that the smaller the particle size of TATB, the lower the thermal decomposition temperature. In addition, by simulating the mixing state of fluid in microchannels and combining with the classical nucleation theory, the mechanism of preparing nano-TATB by microchannels was proposed.

Sustainable conversion of waste plastics into valuable carbon materials for diverse applications provides a promising strategy to dispose the municipal and industrial waste plastics. However, it remains a challenge to precisely control the crosslinking reaction for transforming waste polyesters into N-doped porous carbon (NPC) with well-defined microstructures. Herein, we put forwards a strategy of stepwise crosslinking using melamine and ZnCl2/NaCl eutectic salts to convert poly (ethylene terephthalate) (PET) into NPC at 550 °C. We prove that firstly melamine reacts with PET degradation products to form a crosslinking structure, and subsequently ZnCl2/NaCl promote the dehydration and decarboxylation of the crosslinking structure to generate a more thermally stable crosslinking structure. The coordination of two tandem crosslinking reactions is critical to control the microstructure of NPC. Without activations, NPC shows large specific surface area of 1173 m2 g−1, abundant N dopants, and rich oxygen-containing groups. These combined features endure NPC with excellent performance in CO2 capture and solar steam generation, e.g., high CO2 adsorption capacity of 6.47 mmol g−1 and evaporation rate of 1.62 kg m−2 h−1. More importantly, NPC is compared to or prevails over previous carbon-based CO2 adsorbents or photothermal materials. This work will advance the research on “green” reutilization of low-cost polyester wastes to prepare sustainable carbon for solar energy conversion, environmental protection, etc.

Co-catalytic removal of multiple pollutants was able to reduce operating costs of enterprises, which was the main development direction for the waste incineration industry. In this work, series W-Zr-Ox/Ti-Ce-Mn-Ox (WZ/TCM) catalysts were designed to investigate independent NH3-SCR, dioxins oxidation and co-catalytic removal of NO and chlorobenzene (CB, the substitute of dioxins). The W-Zr-Ox mainly provided solid super acids; CeO2 and MnO2 enhanced the redox performance; and TiO2 provided a large specific surface area. All these factors guaranteed the excellent performance of WZ/TCM catalyst. The NO conversion of WZ/TCM reached 100 %, and the oxidation activity of CB was also higher than 85 % at 350–500 ℃. Meanwhile, the WZ/TCM had high N2 selectivity and excellent resistances to sulfur and water. In situ infrared diffuse reflectance spectra confirmed that ammonia gas mainly adsorbed on the Lewis acidic sites of the WZ/TCM catalyst and participated in the SCR reaction at low temperature. The ammonia species (NH4+) at the Bronsted sites participated in the reaction at high temperature. Furthermore, the chlorine atom on the chlorobenzene molecule was mainly removed to reduce toxicity when the oxidation of CB was at low temperature, which was deeply oxidized and had a variety of intermediate products at high temperature.

The effects of support materials on catalytic performance were investigated in catalytic removal of toluene. And the Mn–Ce binary oxides as active components were supported on ZrO2, SiO2, γ-Al2O3 and TiO2 support materials. Many techniques, including X-ray diffraction (XRD), Brunauer–Emmett–Teller method (BET), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and NH3-temperature-programmed desorption (NH3-TPD), were used to characterize physicochemical properties. Among the different catalysts, the MnCe/ZrO2 catalyst with the lowest specific surface area (39.7 m2/g) shows the best catalytic activity. In terms of toluene conversion, the activity order is as follows: MnCe/ZrO2 > MnCe/TiO2 ≈ MnCe/SiO2 > MnCe/Al2O3. The better performance of MnCe/ZrO2 should be attributed to the low-temperature reducibility, and abundant surface species (Mn4+ and lattice oxygen). And XPS and TPR results reveal that more surface abundant Mn and Ce elements generate good interaction in MnCe/ZrO2. The weak interaction between metal oxide and support also boosts the dispersion and complete reduction of MnCe oxides at low temperature. In addition, the in-situ DRIFTS results clarify that the carbonate species are main intermediates in MnCe/ZrO2 sample during surface reaction process.

In this paper, a series of Rh/CeO2 catalysts with three-dimensional porous nanorod frameworks and large specific surface area were prepared by chemical dealloying Al-Ce-Rh precursor alloys and then calcining in pure O2. The effect of the Rh content and calcination temperature on CO oxidation and CH4 combustion were studied, and the results revealed that the Rh/CeO2 catalysts produced by dealloying melt-spun Al91.3Ce8Rh0.7 alloy ribbons and then calcining at 500 °C exhibited the best catalytic activity, the reaction temperatures for the complete conversion of CO and CH4 were as low as 90 and 400 °C, respectively. Furthermore, after 150 h of continuous testing at high concentrations of H2O and CO2, the nature of the catalyst was not irreversibly destroyed and could still return to its initial level of activity. This excellent catalytic activity was attributed to a portion of Rh being uniformly distributed on the CeO2 nanorod surface in the form of nanoparticles, forming strong Rh-CeO2 interfacial synergy. Another portion of Rh permeated into the CeO2 lattice, which resulted in a significant increase in the number of oxygen vacancies in CeO2, thus allowing more surface active oxygen to be adsorbed and converted from the gas phase. Moreover, the catalytic reaction could proceed even in an oxygen-free environment due to the excellent oxygen storage performance of the Rh/CeO2 catalyst.

In this study, Ni/Al2O3 was prepared with an impregnation method for CO2 hydrogenation into carbon nanofibers (CNFs). High purity CNFs were acquired from CO2 hydrogenation at 500 °C and 1 atm over Ni/Al2O3 catalyst after a liquid phase extraction process, removing the used catalysts and by-products. The particle properties of as-prepared Ni/Al2O3 have been well characterized for comparison with the commercial ones. The results of XPS spectra and XRPD patterns indicated that the commercial, as-prepared, and used Ni/Al2O3 were multicomponent with various crystal phases. The as-prepared Ni/Al2O3 can be sufficiently exposed in CO2 atmosphere for higher catalytic performances owing to its unique microstructure with higher specific surface area (429.2 m2/g). Both EXAFS and XANES spectra have shown that the first shell of Ni atom in commercial, as-prepared, and used Ni/Al2O3 were Ni O with bond distances of 1.61, 1.63, and 1.62 A, respectively. The configuration of fabricated CNFs was characterized by its unique ID/IG (Intensities of D-band/G-band) ratio of 0.23 in the Raman spectrum. Solid tubular shape with 30 nm diameter of CNFs was observed using FE–SEM and HR–TEM. Thermodynamic analyses indicate that CO2 hydrogenation into CNFs is a spontaneous and exothermic reaction with an optimal temperature of 500 °C.

Zn-air batteries (ZABs), especially the secondary batteries, have engrossed a great interest because of its high specific energy, economical and high safety. However, due to the insufficient activity and stability of bifunctional electrocatalysts for air-cathode oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) processes, the practical application of rechargeable ZABs is seriously hindered. In the effort of developing high active, stable and cost-effective electrocatalysts, transition metal nitrides (TMNs) have been regarded as the candidates due to their high conductivity, strong corrosion-resistance, and bifunctional catalytic performance. In this paper, the research progress in TMNs-based material as ORR and OER electrocatalysts for ZABs is discussed with respect to their synthesis, chemical/physical characterization, and performance validation/optimization. The surface/interface nanoengineering strategies such as defect engineering, support binding, heteroatom introduction, crystal plane orientation, interface construction and small size effect, the physical and chemical properties of TMNs-based electrocatalysts are emphasized with respect to their structures/morphologies, composition, electrical conductivity, specific surface area, chemical stability and corrosion resistance. The challenges of TMNs-based materials as bifunctional air-cathode electrocatalysts in practical application are evaluated, and numerous research guidelines to solve these problems are put forward for facilitating further research and development.

Herein, sodium dodecylbenzene sulfonate (SDBS) was used as a template to control the synthesis of Ca0.5Pr0.5FeO3. Its microstructure, composition, and morphology were detected via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The properties of catalyzing bagasse lignin (BL) pyrolysis were determined by thermogravimetric analysis (TG) test and evaluation of a fixed bed alumina microreactor. The results show that the sample Ca0.5Pr0.5FeO3 regulated by SDBS has a cubic crystal phase, and the addition of SDBS does not cause phase transition. Moreover, when the SDBS concentration is 0.10 mol/L, the particle size is 200–500 nm and the specific surface area is 11.26 m2/g. The yields of gas, liquid, and solid products in the BL catalytic pyrolysis are 39.58 wt%, 26.76 wt% and 32.36 wt%, respectively. The contents of CO2 and CO decrease from 54.07% and 4.98% to 45.29% and 3.23%, respectively. The liquid products are mainly guaiacol, syringol, and phenol, and the total selectivity of phenols is 83.67%, accompanied by a small amount of non-aromatic oxygen-containing compounds (five-membered ring (furan) or ester). Compared with the BL pyrolysis and Ca0.5Pr0.5FeO3 catalytic pyrolysis products, the selectivity of guaiacol compounds increases by 43.26%, while those of syringol compounds and phenylketones decrease by 30.08% and 3.39%, respectively. The selectivity of 2,6-dimethoxyphenol is 28.37%. After five catalytic pyrolysis-regeneration cycles, the characteristic peaks of the catalyst do not change significantly and the particles are uniform, suggesting that the catalyst has good crystal phase stability and regeneration stability.

Preparation of natural-product-capped ZnO nanoparticles via a solvothermal method has been demonstrated. The stem extracts of Dalbergia parviflora namely formononetin and pinocembrin were used as capping agents for preparation of ZnO denoted as Capped-ZnO-1 and Capped-ZnO-2, respectively. The ZnO photocatalysts showed hexagonal structure with a spherical morphology and band gap energy of 3.22 eV. The Capped-ZnO-2 photocatalyst showed the smallest average diameters of 10 nm with the greatest specific surface area of 36.19 m2 g−1. The photocatalyst provided 100 % and 98 % removal of RR141 dye and OFL antibiotic, respectively, due to high surface area and high charge-carriers separation rate at the interface. The photocatalyst showed structural stability after three successive runs. The photocatalyst also showed the same performance after three times of use indicating its advantage of good cycling ability. The present work demonstrates the promising potential of the ZnO photocatalyst for environmental remediation.

In this study, a series of CuMgAl layered double oxides (CuMgAl-LDOs) were obtained via calcination of CuMgAl layered double hydroxides (CuMgAl-LDHs) synthesised via a co-precipitation method. The results show that CuMgAl-LDO can be prepared using an optimal Cu:Mg:Al molar ratio of 3:3:2, NaOH:Na2CO3 molar ratio of 2:1, and calcination temperature of 600 °C. CuMgAl-LDO is a characteristic of mesoporous material with a lamellar structure and large specific surface area. The removal efficiency of sulfameter (SMD) based on CuMgAl-LDO/persulfate (PS) can reach > 98% over a wide range of initial SMD concentrations (5–20 mg·L−1). The best removal efficiency of 99.49% was achieved within 120 min using 10 mg·L−1 SMD, 0.3 g·L−1 CuMgAl-LDO, and 0.7 mM PS. Kinetic analysis showed that the degradation of SMD was in accordance with a quasi-first-order kinetic model. The stability of the CuMgAl-LDO catalyst was verified by the high SMD removal efficiency (>97% within 120 min) observed after five recycling tests and low copper ion leaching concentration (0.89 mg·L−1), which is below drinking water quality standard of 1.3 mg·L−1 permittable in the U.S. Radical scavenging experiments suggest that SO 4 · − is the primary active species participating in the CuMgAl-LDO/PS system. Moreover, our mechanistic investigations based on the radical scavenging tests and X-ray photoelectron spectroscopy (XPS) results indicate that Cu(II)–Cu(III)–Cu(II) circulation is responsible for activating PS in the degradation of SMD and the degradation pathway for SMD was deduced. Accordingly, the results presented in this work demonstrate that CuMgAl-LDO may be an efficient and stable catalyst for the activation of PS during the degradation of organic pollutants.

Preparation of bismuth oxybromide (BiOBr) photocatalyst via PVP-assisted solvothermal method has been demonstrated. The PVP capping agent plays an important role in controlling morphological structure, specific surface area and photoactivity. The PVP capped BiOBr provides 94 % and 99.8 % removal of ofloxacin (OFL) and norfloxacin (NOR) antibiotics under visible light illumination. The enhanced photoactivity of the PVP capped BiOBr is due to the flower-like microstructures with high surface area and the suppression of electron-hole pairs recombination at the interfaces. Photogenerated hole and electron play the key role in degradation of the antibiotics. The photocatalyst retains its efficiency after the fifth run indicating structural stability and reusability. The prepared PVP capped BiOBr photocatalyst shows high potential for environmental protection. The present finding offers a new avenue for fabrication of the visible-light-responsive catalyst for detoxification of antibiotics in wastewater.

In Rechargeable Battery, anode electrode plays a crucial role as it directly influences the electrochemical performance (High power and energy). This leads to synthesize a novel anode electrode material. Manganese oxide is one of the prominent transition metal oxides. Hence in the present work Dimanganese trioxide (Mn2O3) nanoparticles are synthesized using Green combustion synthesis process. Manganese (II) nitrate tetrahydrate is used as precursor and Tamarind seed powder is used as fuel in the synthesis process. Precursor weight is kept constant and fuel concentration is varied as 0.1 g, 0.2 g and 0.3 g. The precursor and fuel are mixed and calcinated at 700 °C to produce Mn2O3 nanoparticles. The Structural, Electrical and Electrochemical properties of the synthesized Mn2O3 nanoparticles are studied using XRD (X-ray diffraction), FTIR (Fourier Transform Infrared), SEM (Scanning Electron microscopy) and TEM (Transmission Electron Microscopy), UVDRS (Ultraviolet Differential Reflectance Spectroscopy), EIS (Electrochemical Impedance Spectroscopy) and BET (Brunauer-Emmett-Teller). XRD result confirms that the synthesized Mn2O3 nanoparticles are highly crystalline with cubic structure. The FTIR spectrum is drawn from (400 to 4000)cm−1. The FTIR peaks in the range of (490 to 600cm−1) correlates to Mn-O bending vibrations. The study of SEM images of synthesized Mn2O3 nanoparticles depicts the porous material. Interplanar distance is analyzed using TEM images and is found to be 0.21 nm for sample with 0.2 g fuel concentration. The study of UVDRS analysis gives the band gap ranging from 1.30 eV to 1.36 eV. EIS of the synthesized Mn2O3 nanoparticles gives the impedance in the range from 274.6 Ω to 323.8 Ω. The BET results confirm the sample Mn200 is of Type-II isotherm with the specific surface area about 2.4862 m2 /g. The Mn2O3 nanoparticles prepared using 0.2 g fuel concentration exhibit improved Structural, Electrical and Electrochemical properties. Hence these nanoparticles may be used as electrode material in rechargeable batteries.

This article presents a study on the electrification of reforming processes, in which the heat required for the reaction is directly supplied by the surface of the structured catalyst, realized by using commercial silicon carbide (SiC) heating elements as catalyst carriers, so eliminating all resistances to heat transfer. Three commercial ceramic supports were loaded with a 5 wt% nickel and tested in the steam reforming reaction. The best performance was obtained by the silica-mullite composite based support with the highest specific surface area. The structured catalyst was prepared by washcoating a SiC heating element, using a slurry based on the silica-mullite composite, subsequently impregnated in a solution of the nickel precursor, and tested in the steam and dry reforming reactions. The experimental tests were properly designed in order to reach the goals of (i) obtaining the kinetic parameters for the MSR reaction, and (ii) evaluating the energy consumption for both processes. The catalysts were characterized by means of X-ray diffraction, specific surface area, ED-XRF, SEM-EDS and Hg porosimetry. The results of the tests demonstrated that is possible to heat the system up to 800 °C, and sustain the reaction obtaining a methane conversion higher than 85 % both in the case of steam and dry reforming. The analysis of the energy consumption in terms of kWh Nm−3H2 has shown that it is comparable with the one of the modern electrolysers. The results of these experiments unequivocally demonstrate that it is possible to realize a process by reversing the flow of heat, from the inside of the catalytic bed to the outside.

Recently, metal-based carbon materials have been verified to be an effective persulfate activator, but secondary pollution caused by metal leaching is inevitable. Hence, a green metal-free 3D macroscopic N-doped porous carbon nanosheets (NPCN) was synthesized successfully. The obtained NPCN showed high adsorption capacity of tetracycline (TC) and excellent persulfate (PS) activation ability, especially when calcined at 700 °C (NPCN-700). The maximum adsorption capacity of NPCN-700 was 121.51 mg/g by H-bonds interactions. Moreover, the adsorption process followed pseudo-second-order kinetics model and Langmuir adsorption isotherm. The large specific surface area (365.27 mg/g) and hierarchical porous structure of NPCN-700 reduced the mass transfer resistance and increased the adsorption capacity. About 96.39% of TC was removed after adding PS. The effective adsorption of the catalyst greatly shortened the time for the target organic molecules to migrate to the catalyst. Moreover, the NPCN-700 demonstrated high reusability with the TC removal rate of 80.23% after 4 cycles. Quenching experiment and electron paramagnetic resonance (EPR) test confirmed the non-radical mechanism dominated by 1O2. More importantly, the C = O groups, defects and Graphitic N acted as active sites to generate 1O2. Correspondingly, electrochemical measurement revealed the direct electron transfer pathway of TC degradation. Finally, multiple degradation intermediates were recognized by the LC-MS measurement and three possible degradation pathways were proposed. Overall, the prepared NPCN had excellent application prospects for removal of antibiotics due to its remarkable adsorption and catalytic degradation capabilities.

Electrochemical synthesis of ammonia has the advantages of low energy consumption and promising environmental protection, as compared to the traditional Haber-Bosch process. However, the commercial utilization of this novel system is limited by the low Faradaic efficiency, poor ammonia yield and high overpotential due to the strong N N bond and the dominant competing reaction of hydrogen evolution reaction (HER). Herein, a BiOCl-modified two-dimensional (2D) titanium carbide MXenes nanocomposite (BiOCl@Ti3C2Tx) is proposed as a promising electrocatalyst for ambient nitrogen (N2) reduction reaction with excellent catalytic performance and superior long-term stability at low overpotential. In 0.1 M HCl, this catalyst attains a high Faradic efficiency of 11.98% and a NH3 yield of 4.06 µg h−1 cm−2 at -0.10 V (vs. RHE), benefiting from its strong interaction of Bi 6p band with the N 2p orbitals, combined with its large specific surface area and the facile electron transfer.

Surface oxygen vacancy defects of mesoporous CeO2 nanosheets assembled microspheres (D-CeO2) are engineered by polymer precipitation, hydrothermal and surface hydrogenation strategies. The resultant D-CeO2 with a main pore diameter of 9.3 nm has a large specific surface area (~102.3 m2/g) and high thermal stability. The mesoporous nanosheets assembled microsphere structure prevents the nanosheets from aggregation, which is beneficial to effective mass transfer and shortens the migration distance of charge carriers. After surface hydrogenation, the photoresponse extends to long wavelength region, combing with the band gap from 2.63 eV reduced to 2.39 eV. Under AM 1.5 G radiation, the photocatalytic degradation rate of tetracycline (TC) can be up to 99.99%, which is three times as high as that of pristine CeO2 microspheres. The excellent solar-driven photocatalytic performance can be attributed to the efficient surface oxygen vacancy engineering and the mesoporous nanosheets assembled microsphere structure, which narrows the band gap, shortens the migration distance of carriers, promotes the spatial separation of photogenerated electron-hole pairs and favors mass transfer. The strategy provides new insights for fabricating other high-efficient oxide photocatalysts .

Solvent-assisted ligand exchange in the zirconium metal-organic framework (MOF) UiO-67 [Zr6O4(OH)4(PhPh)6; H2PhPh = biphenyl-4,4?-dicarboxylic acid] with the heterocyclic linkers H2TpTp (2,2?-bithiophene-5,5?-dicarboxylic acid) and H2TzTz (2,2?-bithiazole-5,5?-dicarboxylic acid) in an equimolar [Zr6] : linker ratio led to the corresponding MIXMOFs UiO-67-TpTp [Zr6O4(OH)4(PhPh)5(TpTp)] and UiO-67-TzTz [Zr6O4(OH)4(PhPh)5(TzTz)]. Both MOFs have been thoroughly characterized in the solid state. They show the same structural topology and crystal structure of UiO-67, as confirmed by powder X-ray diffraction. Their BET specific surface area is lower than that of their parent material (1700 and 1310 m2 g-1 for UiO-67-TpTp and UiO-67-TzTz, respectively, vs. 1877 m2 g-1 for UiO-67), while the thermal stability of UiO-67 (Tdec = 819 K) is maintained. The "diluted"inclusion, in the UiO-67 3D framework, of luminescent heterocyclic linkers emitting in the blue-green visible region induces luminescence in the final MOFs (emission ?max = 442 and 420 nm for UiO-67-TpTp and UiO-67-TzTz, respectively), preventing self-quenching effects caused by the proximity of the emitters in the crystal structure. Both MOFs have been tested as sensors for contaminants of emerging concern (CECs) in water: an emission intensity increase has been observed when suspended in contact with diclofenac sodium, fluoxetine, ibuprofen and sulfamethoxazole. In particular, UiO-67-TzTz has shown a linearly increasing trend for a specific concentration range (up to 30-40 ?M for diclofenac, fluoxetine and ibuprofen; up to 100 ?M for sulfamethoxazole). UiO-67-TzTz also behaves as an adsorbent vs. diclofenac, with a maximum adsorption capacity (Xm) of 62.5 mg g-1. These findings pave the way to the practical utilization of UiO-67-TzTz as a multifunctional material (i.e. CECs luminescent sensor and adsorbent at one time) for environmental remediation. This journal is

Herein, a series of niobium oxide supported cerium nanotubes (CeNTs) catalysts with different loading amount of Nb2O5 (0–10 wt.%) were prepared and used for selective catalytic reduction of NOx with NH3 (NH3-SCR) in the presence of CH2Cl2. Commercial V2O5-WO3-TiO2 catalyst was also prepared for comparison. The physcial properties and chemical properties of the Nb2O5 loaded cerium nanotubes catalysts were investigated by X-ray diffractometer, Transmission electron microscope, Brunauer-Emmett-Teller specific surface area, H2-temperature programmed reduction, NH3-temperature programmed desorption and X-ray photoelectron spectroscopy. The experiment results showed that the loading amount of Nb2O5 had a significant effect on the catalytic performance of the catalysts. 10 wt.% Nb-CeNTs catalyst presented the best NH3-SCR performance and degradation efficiency of CH2Cl2 among the prepared catalysts, due to its superior redox capability, abundant surface oxygen species and acid sites, the interaction between Nb and Ce, higher ratio of Nb4+/(Nb5++ Nb4+) and Ce3+/(Ce3+ + Ce4+), as well as the special tubular structure of cerium nanotube. This study may provide a practical approach for the design and synthesis of SCR catalysts for the simultaneously removal NOx and chlorinated volatile organic compounds (CVOCs) emitted from the stationary industrial sources.

Transitional metal selenides have high conductivity, even metal quality, which makes them great for using as electrode materials for fabricating supercapacitors. Here, hierarchical Ni3Se2 nanosheet-on-nanorods on Ni foam (NSR-Ni3Se2/Ni) was fabricated by a facile three-dimensional (3D) substrate-assisted confinement assembly method, and used as a freestanding electrode material for hybrid supercapacitors (HSCs). In this design, metallic Ni3Se2 with hybrid 1D/2D architecture could effectively enhance the active specific surface area of electrode and improve space utilization, as well as significantly facilitate electrons transport, while Ni foam served as the Ni source of Ni3Se2 and provided 3D multi-electron transport channels, thus boosting the specific capacity. The constructed hierarchical NSR-Ni3Se2 electrode delivered a superior areal specific capacity of 1.068 mAh/cm2 (7.69 F/cm2) at 2 mA/cm2 and retained 68.2% of the initial capacity when the current density increases by 15 times. Furthermore, the as-assembled NSR-Ni3Se2 device exhibited an ultrahigh energy density of 56.4 Wh/kg and high power density of 4640.3 W/kg, and a capacity retention of 92.6% even after 6000 cycles.

The development of high-efficiency photocatalysts is the primary goal in the field of photocatalytic antibacterial research. In this work, the GaN:ZnO solid solution nanoparticles (NPs) photocatalyst with strong visible absorption and large specific surface area was synthesized via the sol-gel and nitridation reaction process. Also, we systematically investigated the removal efficiency of the organic pollutant and antibacterial activity on E. coli and S. aureus. Notably, methylene blue solution could be completely degraded after 100 min of visible light illumination using 2 mg/mL GaN:ZnO catalyst. Moreover, ~94% of the E. coli were inactivated within 120 min, whereas 100% antibacterial activity against S. aureus was achieved after 90 min of visible light illumination mediated by GaN:ZnO NPs. We further explore the potential mechanism of visible light photocatalytic antibacterial activity enhanced by GaN:ZnO NPs photocatalyst. The current work not only provides a new and efficient photocatalytic antibacterial nanomaterial but also demonstrates its promising applications in environmental and biological fields.

Diatomite supported nano zero valent iron (nZVI) catalyst (NDA) with complex network structure was prepared via a mild reduction precipitation method in this work. The pore structure and pore distribution of NDA can be regulated and controlled through adjusting the loading amount of nZVI. In general, the nano three-dimensional network formed by nZVI and diatomite channels greatly increase the specific surface area and pore volume of NDA, and further formed more active sites, which made NDA have better performance in activating PMS to degrade BPA than pure nZVI. The pseudo-first-order reaction rate constant of 50-NDA (50%-nZVI/diatomite) is almost 3 times higher than that of pure nZVI. Besides, the electron paramagnetic resonance (EPR) and radical quenching experiments showed that the activation process was dominated by the sulfate radical (SO4•−) and hydroxyl radical (•OH) produced by Fe0 oxidation. The generated electrons promote the self-decomposition of PMS to produce singlet oxygen (1O2), and then the valence state of iron changes to produce free radicals. In addition, the possible degradation pathway of BPA was inferred from the intermediate products identified by liquid chromatograph-mass spectrometer (LC-MS). This study provides a novel strategy for the design and preparation of three-dimensional composite catalysts derived from natural mineral.

Environmental remediation has become more effective when using nanotechnologies. In this study, iron oxide (α-Fe2O3) nanospheres with different cobalt doping levels (xCo-Fe2O3) were synthesised and applied in the heterogeneous activation of peroxymonosulfate (PMS) for the degradation of p-hydroxybenzoic acid (p-HBA). The catalyst (3Co-Fe2O3) with 3% Co doping exhibits the best performance for PMS activation, possibly because of the larger specific surface area and the tailored catalyst surface as confirmed by X-ray photoelectron spectroscopy (XPS). Reaction parameters were investigated to optimise the degradation efficiency. The metal ions leaching tests confirmed the higher stability of the catalyst, thanks to the leaching suppression by the doping of Co2+. The main contribution of free radicals (SO4•- and •OH) was confirmed by electron paramagnetic resonance (EPR) spectra, whereas partial contribution of oxygen anions and singlet oxygen (O2•-, 1O2) was observed during the quenching tests. Finally, a radical based degradation mechanism was proposed for the removal of p-HBA. It is expected to open up a novel perspective for the application of iron oxide as a potential catalyst for the removal of emerging contaminants.

It is critical to develop carbon material anodes with high initial Coulombic efficiency and energy density for sodium ion batteries. Herein, a novel mushroom spore with chitin as carbon precursor is first reported for energy storage, and its special porous spherical structure, fine structure and oxygen functional groups can be accurately controlled by carbonization temperature. The hollow porous carbon spheres obtained from mushroom spore at 1400 °C have appropriate porous structure, d002 spacing (0.364 nm), 7.12% oxygen content and ultra-low specific surface area of 5.5 m2 g−1. It could obtain 81.2% initial Coulombic efficiency and has reversible discharge capacity of 411.1 mA h g−1, wherein about 75% (308 mA h g−1) of its total capacity is derived from low-potential plateau (below 0.1 V Na+/Na), and the capacity is 384.5 mA h g−1 after 50 cycles. Furthermore, Density functional theory calculation showed that the residual oxygen functional groups (C O) in carbon materials are beneficial to sodium into graphite-like layers, and graphite-like layers spacing is smaller than the reported unadulterated carbon with 0.37 nm. Therefore, the excellent electrochemical performance and low-cost of natural mushroom spore derived hollow porous carbon spheres provide advantages for sodium ion batteries in large-scale storage devices.

Hollow structures draw much attention for high energy density supercapacitors due to their large hollow cavities, high specific surface area, and low interfacial contact resistance. However, constructing hierarchical hollow structures remains a challenge. Herein, we reported a facile template-free method for a novel urchin-like hollow nickel cobalt sulfide (NiCo2S4). The hollow interior and urchin exterior remarkably improved the specific capacitance and accommodated structural collapse caused by electrochemical reactions. Owing to these features, the urchin-like hollow NiCo2S4 spheres exhibited an impressive capacitance of 1398F g−1 at 1 A g−1 and maintained 1110F g−1 with a large current density of 10 A g−1. The hybrid supercapacitor fabricated by NiCo2S4 and active carbon possesses an energy density of 39.3 Wh kg−1 at a power density of 749.6 W kg−1 and an outstanding cycling stability of 74.4% retention after 5000 cycles. Our work presents a facile method of constructing a hollow structure of binary sulfide materials and also makes progress on highly efficient supercapacitors.

Here, an agricultural waste (the stem pith of helianthus annuus, SPHA) is firstly used as the precursor for preparing three-dimensional (3D) porous carbon sponge (PCS). The as-prepared 3D PCS (SPHA-700) possesses unique sponge-like structure, large specific surface area (SSA) and high nitrogen doping level (4.52 at.%), which benefit the enhancement of conductivity (5.8 S cm−1) and wettability. As a binder-free electrode for solid-state symmetric supercapacitor, SPHA-700 delivers a relatively high specific capacitance of 137.1 F g−1 at 0.5 A g−1. Moreover, activated SPHA-700 (SPHA-ac-700–2) displays an even higher specific capacitance (403.6 F g−1 at 0.5 A g−1) in 6.0 M KOH electrolyte. The SPHA-ac-700–2-based symmetrical supercapacitor can offer high specific capacitance (271 F g−1 at 1 A g−1) and good rate capability (82.1% of capacitance retention at 1–80 A g−1) in 6.0 M KOH electrolyte, together with high energy density (23.3 Wh kg−1 at 450 W kg−1) in 1.0 M Na2SO4 electrolyte. Such excellent performance of SPHA-ac-700–2 is believed to have originated from the crushed sponge-like structure, O/N-co-doping (10.6 at.% O and 3.3 at.% N), high SSA, large total pore volume, and hierarchical pore structure.

Thin films of crystalline and porous metal-organic frameworks (MOFs) have great potential in membranes, sensors, and microelectronic chips. While the morphology and crystallinity of MOF films can be evaluated using widely available techniques, characterizing their pore size, pore volume, and specific surface area is challenging due to the low amount of material and substrate effects. Positron annihilation lifetime spectroscopy (PALS) is introduced as a powerful method to obtain pore size information and depth profiling in MOF films. The complementarity of this approach to established physisorption-based methods such as quartz crystal microbalance (QCM) gravimetry, ellipsometric porosimetry (EP), and Kr physisorption (KrP) is illustrated. This comprehensive discussion on MOF thin film porosimetry is supported by experimental data for thin films of ZIF-8. ispartof: ADVANCED MATERIALS vol:33 issue:17 ispartof: location:Germany status: published

Thermal oxidation of carbon electrodes is a common approach to improving flow battery performance. Here, we investigate how thermal pretreatment increases electrode surface area and the effect this...

The indoor low-concentration formaldehyde (HCHO) removal in cobalt-based catalysts is still a “hot potato”. In this work, metal–organic-frameworks (MOF)-derived and Zinc (Zn)-modulated new cobalt nanoparticles catalyst (CZ-Co@NC-800) was designed and prepared. The CZ-Co@NC-800 performed outstanding elimination activities for ~1 ppm HCHO at 25 °C. In the static test condition, it achieves complete HCHO removal in 3 h at a relative humidity (RH) of ~55%. Moreover, 90.18% HCHO removal ratio is held after five recycle tests. In the dynamic test condition, it remains the characteristic to eliminate around 95.89% of HCHO within 8 h under an RH of ~55% and a gas hourly space velocity (GHSV) of ~150,000 mL·h−1g−1. Such advanced results should be ascribed to large specific surface area bringing about more cobalt active sites; and it is also because residual Zn metal affects the electronic structure of CZ-Co@NC-800 and enhance the surface charge transfer rate, thus the activation and dissociation ability of oxygen is promoted. Besides, a short HCHO reaction path over CZ-Co@NC-800 which was clarified by the In situ DRIFTs is also a reason for excellent catalytic performance. This work represents a crucial addition to expand the family of cobalt-based catalysts for indoor HCHO elimination.

Rational design and precise regulation over the morphology, structure, and pore size of functional conducting mesoporous polymers with enriched active sites and shorten electron–ion transport pathway are extremely important for developing high-performance micro-supercapacitors (MSCs), but still remain a great challenge. Herein, a general dual-colloid interface co-assembly strategy is proposed to fabricate hollow mesoporous polypyrrole nano-bowls (mPPy-nbs) for high-energy-density solid-state planar MSCs. By simply adjusting the size of block copolymer micelles, the diameter of polystyrene nanospheres and the amount of pyrrole monomer, mesopore size of the shell, void and shell thickness of mPPy-nbs can be simultaneously controlled. Importantly, this strategy can be further utilized to synthesize other hollow mesoporous polymers, including poly(tris(4-aminophenyl)amine), poly(1,3,5-triaminobenzene) and their copolymers, demonstrative of excellent universality. The structurally optimized mPPy-nb exhibits high specific surface area of 122 m2 g−1and large capacitance of 225 F g−1 at 1 mV s−1. Furthermore, the MSCs assembled by mPPy-nbs deliver impressive volumetric capacitance of 90 F cm−3 and energy density of 2.0 mWh cm−3, superior to the most reported polymers-based MSCs. Also, the fabricated MSCs present excellent flexibility with almost no capacitance decay under varying bending states, and robust serial/parallel self-integration for boosting voltage and capacitance output. Therefore, this work will inspire the new design of mesoporous conducting polymer materials toward high-performance microscale supercapacitive devices.

Interconnectivity is the key characteristic of bone tissue engineering scaffold modulating cell migration, blood vessels invasion and transport of nutrient and waste. However, efforts and understanding of the interconnectivity of porous Mg is limited due to the diverse architectures of pore struts and pore size distribution of Mg scaffold systems. In this work, biomimetic hierarchical porous Mg scaffolds with tailored interconnectivity as well as pore size distribution were prepared by template replication of infiltration casting. Mg scaffold with better interconnectivity showed lower mechanical strength. Enlarging interconnected pores would enhance the interconnectivity of the whole scaffold and reduce the change of ion concentration, pH value and osmolality of the degradation microenvironment due to the lower specific surface area. Nevertheless, the degradation rates of five tested Mg scaffolds were no different because of the same geometry of strut unit. Direct cell culture and evaluation of cell density at both sides of four typical Mg scaffolds indicated that cell migration through hierarchical porous Mg scaffolds could be enhanced by not only bigger interconnected pore size but also larger main pore size. In summary, design of interconnectivity in terms of pore size distribution could regulate mechanical strength, microenvironment in cell culture condition and cell migration potential, and beyond that it shows great potential for personalized therapy which could facilitate the regeneration process.

The manuscript describes the key aspects of Zn-Al mixed oxides prepared by different methods (the so-called urea method and co-precipitation methods using either NaOH/Na2CO3 alkaline solution or solution of NaOH) affording high conversion and selectivity values in aldol condensation of furfural with acetone. The structure, composition and acid-base properties of Zn-Al mixed oxides were described by using of TGA, XRD, N2-adsorption, TPD-NH3/CO2 and in-situ diffuse reflectance spectroscopy and correlated with the catalytic performance of a series of Zn-Al mixed-oxides catalysts. Along with the impact of specific surface area and basicity on the furfural conversion, the conversion of furfural also increased with the increasing value of the edge of UV-vis spectrum of Zn-Al mixed oxide reflecting ZnO-Al2O3 interaction. We have introduced a simple method based on diffuse reflectance spectroscopy with a potential to predict furfural conversion over Zn-Al mixed oxides in aldol condensation of furfural with acetone.

At present, frequent outbreaks of bacteria and viruses have seriously affected people's normal lives. Therefore, the study of broad-spectrum antibacterial nanocomposites is very promising. However, most antibacterial materials have some disadvantages, such as single bactericidal mechanisms and unrepeatable use. Based on the current situation, a kind of nanocomposite with three structures of graphene oxide (GO), quaternary ammonium salt (QAs) and N-halamine was prepared, which showed synergistic effect to improve antibacterial activity and combined with a variety of sterilization mechanisms. Meanwhile, GO can provide richer ways of sterilization and high specific surface area, which is conducive to the grafting of quaternarized N-halamine. The advantages of physical sterilization of GO, charge adsorption of QAs, reuse of N-halamine and efficient sterilization are fully utilized. The results showed that the quaternarized N-halamine-grafted GO was obtained successfully. GO grafted with quaternarized N-halamine polymer showed strong speedy bactericidal activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (99%). It had good storage and regeneration properties.

The feasibility of fluoride adsorption from aqueous solutions using naturally available bentonite clay in both modified and unmodified forms is investigated in this report. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy analysis was applied to describe the structure and nature of modified and unmodified bentonite clay. The physicochemical characteristics of the adsorbent were also investigated for moisture content, pH, apparent density, specific surface area, cation exchange capacity and its point-of-zero charge. SEM images reveal particles are dispersed homogeneously and are irregular in shape. XRD and EDX analyses reveal that the bentonite is composed of seven materials: calcite, silica, alumina, hematite, bornite and green cinnabar, and chloride which are considered as impurities. Raw bentonite clays have shown very low fluoride removal efficiency (47.19%). Modification of the clay surface with HCl and aluminum oxide, on the other hand, increased fluoride removal efficiency to 79.77% and 94.38%, respectively. At 5 mg/L initial fluoride concentration, 10 cm bed depth packed dose of adsorbent, and 180 min breakthrough time, a 2.88 mg/g of fluoride removal capacity was observed. As a result, aluminum oxide modified bentonite clay was chosen for further investigation and the results are not presented here. HIGHLIGHTS Clay minerals adsorption experimentation for low fluoride concentrations (5, 10, and 12 mg/L) was successful.; Most of the experimentation done so far are in batches using clay-based minerals and leads to shorter reaction times and thus are not at equilibrium.; Column experimentation using clay minerals was difficult, but this study used the clay as a filter media through surface modification of the adsorbent.

In the present study, an innovative carbon self-doped g-C3N4 (CCN) loaded with ultra-low CeO2 (0.067–0.74 wt%) composite photocatalyst is successfully synthesized via a facile one-pot hydrothermal and calcination method. The CeO2/CCN exhibits superior photocatalytic performance for tetracycline degradation (78.9% within 60 min), H2O2 production (151.92 μmol L-1 within 60 min), and Cr(VI) reduction (99.5% within 40 min), which much higher than that of g-C3N4, CCN, CeO2, and CeO2/g-C3N4. The enhanced photocatalytic performance is originated from the fact that the doping of C can efficaciously broaden the utilization range of solar light and improve the reduction ability of photogenerated electrons. Meanwhile, the ultra-low loading of CeO2 can effectually promote the migration of photogenerated electrons and enhance the specific surface area. Besides, the experiments of pH effect and cycle ability indicate that CeO2/CCN has excellent durability and stability. Finally, the photocatalytic mechanism of CeO2/CCN is systematically discussed. This work proves that combining element doping and semiconductor coupling is a promising strategy to design high-efficiency g-C3N4-based photocatalysts.

A series of La1‒xSrxMnO3 samples were prepared by sol–gel method and used to degrade rhodamine B (RhB) in water. All samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption, temperature-programmed reduction of H2 (H2-TPR) and temperature-programmed desorption of O2 (O2-TPD). The results show that the degradation of RhB is highly dependent on the initial pH value of solution. Sr doping enhances the degradation ability of LaMnO3 for RhB in the time range of 0–40 min under a strong acidic environment, but all samples exhibit similar degradation rate from 40 to 60 min. In La0.7Sr0.3MnO3–RhB reaction system, there are two different degradation pathways, including N-de-ethylation, chromophore cleavage, ring-opening and mineralization. La1‒xSrxMnO3 (x ≤ 0.3) has the perovskite structure of La–Mn oxides, while La0.6Sr0.4MnO3 exhibits a Sr0.4MnLa0.6O2.98 perovskite phase. Sr doping leads to distortion of rhombohedral crystal structure and increases the relative content of Mn4+. The perovskite structure is stable in strong acidic environment during RhB degradation, but the relative content of Mn4+ and Mn3+ on the material surface changes. Sr doped LaMnO3 achieves specific surface area of 58.8 m2/g and total pore volume of 0.152 cm3/g. Furthermore, Sr2+ doping improves redox properties of La–Mn oxides, and the presence of defects makes oxygen diffusion easier compared with the undoped samples.

Nanomaterials offer innovations in water purification technology with decreased operational and capital cost, reduced dosage, and improved pollutant selectivity. In particular, inorganic nanoparticles (NPs)/cellulose hybrid nanocomposites have attracted growing interest due to the unique properties of cellulose and high specific surface area of NPs and their pollutant selectivity. The integration with cellulose brings benefits to inorganic NPs for water treatment, including preventing agglomeration, ensuring colloidal stability, and allowing for separation by magnetic nanoparticles after purification. In this review, firstly, conventional water treatment technologies are introduced (Section 1). Following this, an overview of inorganic NPs/cellulose composites for water treatment (Section 2) is presented. Moreover, engineering of such hybrid composites is discussed (Section 3). Furthermore, water purification of inorganic NPs/cellulose through adsorption of pollutants (Section 4) and non-adsorption (catalytic, photocatalytic, and antibacterial) activities (Section 5) are highlighted. Finally, conclusions and outlook are provided (Section 6).

Absorbing materials can convert electromagnetic wave (EMW) energy into heat and other energy and dissipate it. Carbon materials can attenuate EMW by generating large conduction losses due to their high conductivity. The introduction of low dielectric materials can improve impedance matching caused by high conductivity. However, the density of materials compounded with carbon materials is too large, which affects the overall density of composite materials. Therefore, this problem is solved by matching melamine foam with ZIF-67. As an ultra-light material, the melamine foam-based carbon material can significantly reduce the density of composite materials, and its developed three-dimensional structure can cause multiple scattering of EMW. The large specific surface area and evenly distributed metal oxides obtained after annealing of ZIF-67 can provide ultra-low-density carbon materials and abundant interfacial polarization to further attenuate EMW. So far, the methods of self-growing materials on the surface of melamine foam have not been reported. We prepared a 500 nm Co3O4 nanosheet/carbon foam (CF) composite material coated on the surface by a two-step method. The sample had a maximum reflection loss of −46.58 dB at 10.72 GHz, and an effective absorption bandwidth (EAB) of 5.4 GHz. This research provides a new idea for the growth of porous materials on the surface of melamine foam-based carbon materials.

A sensitive pressure sensor based on ultralight and superelastic supercapacitive borophene-graphene aerogel as dielectric layer is reported. The borophene-graphene aerogel not only combines large specific surface area of reduced graphene oxide and high conductivity of borophene, but also exhibits rich porous structure. The strong synergy and intercalation between two different two-dimensional materials benefit electron transfer and electrolyte ion diffusion. On the one hand, the aerogel exhibits greater mass specific capacitance of 330 F g−1 than pure graphene aerogel. More importantly, serving as dielectric layer for pressure sensors with a symmetrical structure, the sensor represents ultra-high sensitivity (0.90 KPa−1) in the pressure range (