Search

One-step assembled CdSe/CdS (core/shell) quantum dots (QDs) were deposited onto ZnO nanowires (NWs) and characterized for their structure, morphology and optical analyses. As deposited ZnO NWs array were wurtzite in structure. During a single hydrothermal cycle a layer of ∼4 nm CdSe/CdS QDs was formed onto ZnO NWs and overgrowth evidenced with an additional 2–5 layers due to which, (a) absorbance density, and (b) Raman Shift of 1LO mode (from 286 cm −1 to 296 cm −1 ) increased and (c) the photoluminescence intensity of the near band-edge emission peak at ∼379 nm decreased. Due to more accumulation of CdSe/CdS, photoelectrochemical cells of ZnO-based photoelectrodes designed for 1–4 cycles of CdSe/CdS onto indium-tin-oxide substrate demonstrated increasing power conversion efficiency trend from 0.18% to 1.29% whereas, for 5th cycle power conversion efficiency, due to an increased series resistance, decreased to 1.12% on account of an accumulation of several QDs. [ABSTRACT FROM AUTHOR]

Porous microspheres copper cobalt carbonate hydroxides (Cu x Co 2−x CH) pseudocapacitive electrode material comprised of nanoplates via a facile hydrothermal method were presented. Significantly, the crystalline structure, morphology and electrochemical performance of the Cu x Co 2−x CH can be readily manipulated by varying the Cu/Co molar ratios. Among various stoichiometries of Cu x Co 2−x CH porous microspheres studied, Cu 1.79 Co 0.21 CH consisted of nanoplates with a mean thickness of ∼35 nm showed a high specific capacitance of 789 F g −1 at a current destiny of 1 A g −1 and good rate ability. Furthermore, the optimized Cu 1.79 Co 0.21 CH electrode also exhibited remarkable high cycling stability, ca 77.5% after 3000 charge/discharge cycles at current density of 5 A g −1 . An asymmetric device was constructed from optimized Cu 1.79 Co 0.21 CH materials on nickel foam (NF) as cathode electrode and graphene on NF as anode electrode in a 6 M KOH electrolyte. The asymmetric Cu 1.79 Co 0.21 CH/NF//graphene/NF supercapacitor device delivered a specific capacitance of 60.5 F g −1 in a potential range of 0–1.6 V. A high energy density of 21.5 W h kg −1 was achieved at the power density of 200 W kg −1 . More significantly, the designed device exhibited excellent cycling stability with 73.3% capacity retention after 5000 cycles. [ABSTRACT FROM AUTHOR]

Al–Ni co-doped ZnO (NiAl:ZnO) thin films were deposited on glass substrates using a sol–gel method. Based on a previous study, Zn 1 − x Al x O (AZO; Al/Zn = 1.5 mol%) thin films optimized with a Ni content of 0.5 mol% were annealed at different temperatures from 450 to 600 °C in N 2 /H 2 (95/5) forming gas for 1 h. The effects of the annealing temperature on the structural, electrical and optical properties were determined. X-ray diffraction showed that NiAl:ZnO thin film annealed at 500 °C exhibited the best crystallization quality. XPS revealed the presence of metallic Ni and Ni 2 O 3 states, as well as Ni and Al atoms were successfully doped in NiAl:ZnO films, which did not result in a change in ZnO crystal structure and orientation. Scanning electron microscopy showed that the films were smooth and compact, and the grain size increased with increasing annealing temperature from ~ 23.8 nm to ~ 34.6 nm. According to the Hall Effect measurements, when the temperature reached 500 °C, the resistivity of the thin film showed the lowest value of 1.05 × 10 − 3 (Ω cm), which is the lowest resistivity reported for NiAl:ZnO films. The UV–Vis transmission spectra showed a high transmittance of more than 80% in the visible light range, and the band gap of the films was increased from 3.30 to 3.55 eV. This study showed that the annealing temperature in the forming gas is a vital factor affecting the quality of thin films. In addition, 500 °C was found to be the most appropriate annealing temperature for NiAl:ZnO films. This study provides a simple and efficient method for preparing high quality, high transparency and low resistivity NiAl:ZnO films for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Abstract: We reported on the facile synthesis of N-doped multilayer graphene (N-MLG) from milk powder that uses melamine as a nitrogen-doping source with Fe2+ ions as catalytic growth agents. We showed that milk powder could be used as a precursor for large-scale N-MLG synthesis through heat treatment at 1000°C under N2 atmosphere for 45–120min. In addition, heating time has a remarkable effect on N content and type in N-MLG. The resulting N-MLG exhibited higher catalytic activity than undoped graphene and carbon nanotubes (CNTs), as well as comparable catalytic activity to commercial Pt/C catalyst toward oxygen reduction reaction (ORR). Furthermore, the catalytic activity was sensitive to N content and type, particularly the ratio of pyridinic-N to total N atoms. Results showed that Fe atoms in N-MLG were found to function not as synergetic catalysts for ORR but as catalytic growth agents for N-MLG formation, thereby promoting and stabilizing N atoms. The present method could lead to the synthesis of bulk amounts of N-MLG, which is promising for applications in electrochemical energy devices, such as fuel cells and metal–air batteries. [Copyright &y& Elsevier]

Highlights: [•] Porous carbons were prepared using endothelium corneum gigeriae galli as precursor. [•] Surface and structural properties strongly depend on carbonization temperatures. [•] Resultant carbons possess nitrogen heteroatom and high surface areas. [•] ECGG-900 sample exhibits excellent electrochemical capacitive performances. [ABSTRACT FROM AUTHOR]

Highlights: [•] A green facile chemical approach to control the dimensions of Ag nanoparticles–graphene oxide (AgNPs/GO) composites was performed at room temperature. [•] With decreasing ultrasonication time, the size of the Ag nanoparticles decreased and became uniformly distributed over the surface of the GO nanosheets. [•] The as-prepared AgNPs/rGO composite films were then formed using a spin coating method and reduced at 500°C under N2/H2 gas flow for 1h. [•] The lowest sheet resistance of 270Ω/sq was obtained in the film corresponding to 1min of ultrasonication, which showed a 40 times lower resistivity than the rGO film (10.93kΩ/sq). [ABSTRACT FROM AUTHOR]

Abstract: A green chemical approach to control the dimensions of Ag nanoparticle-decorated graphene oxide (AgNP–GO) composites was proposed by in situ ultrasonication of a mixture of AgNO3 and GO solution with the assistance of vitamin C acting as an environmentally friendly reducing agent at room temperature. The AgNP–GO composites were characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, Raman spectra and ultraviolet–visible absorption spectra. The results demonstrated that Ag nanoparticles with an average diameter of ∼15nm were uniformly dispersed on the surface of GO nanosheets by in situ ultrasonication of 1min with vitamin C. Increasing the ultrasonication times resulted in Ag nanoparticles with tunable dimensions ranging from 15 to 55nm being formed on the surface of GO nanosheets. The amount of silver nitrate and the ultrasonication time play a key role in the control of the dimension of Ag nanoparticles on GO, and a formation mechanism of the as-prepared AgNP–GO composites is proposed. This study provides a guide to controlling the dimensions of AgNP–GO composites, which may hold promise as advanced materials for various analytical applications such as catalysis, sensors and microchips. [Copyright &y& Elsevier]

Highlights: [•] LiNi0.5Sm x Mn1.5−x O4 (x =0, 0.01, 0.03, and 0.05) spinel have been synthesized. [•] The Sm-doping improves the spinel structural stability. [•] LiNi0.5Sm x Mn1.5−x O4 exhibit enhanced cycling stability and rate performance. [•] LiNi0.5Sm x Mn1.5−x O4 display low charge transfer impedance. [ABSTRACT FROM AUTHOR]

Abstract: Spinel cobalt oxide (Co3O4) nanowires grown on Ni foam are successfully synthesized using a novel microwave-assisted template-free method. The effect of reaction temperature, concentration of reactants, and reaction time on the morphology and crystalline structures of the prepared nanowires is studied. The present work has demonstrated that uniform Co3O4 nanowires with diameters of 500–580nm and lengths of 6–8μm can be synthesized under proper reaction condition. Moreover, the proposed microwave-assisted template-free method can significantly reduce reaction time, increase reaction efficiency, and provide better control over the geometry of the nanostructures. [Copyright &y& Elsevier]

Abstract: High performance ultraviolet (UV) detectors based on ZnO metal–semiconductor–metal (MSM) and p–n heterojunctions, p-NiO/n-ZnO, were fabricated and their UV photo-responsivity was measured at room temperature. High-quality ZnO and NiO thin films were deposited on quartz substrates at room temperature under optimized RF reactive sputtering conditions. For ZnO-based MSM UV detectors using Al as a contact metal, the linear current–voltage (I–V) characteristics under a forward bias exhibited ohmic metal–semiconductor contact. A maximum photocurrent and photo-responsivity of 2.5mA and 1410A/W, respectively, at 365nm under 5V bias was observed, indicating the high photo-responsivity of the ZnO MSM detector. In comparison, a p-NiO/n-ZnO p–n heterojunction UV detector demonstrated clear rectifying I–V characteristics with an ideality factor, forward threshold voltage and photo-responsivity of 2, 0.9V and 0.09A/W, respectively, at 362nm under a reverse bias of 4V, which is close to that of the commercial GaN UV detector (∼0.1A/W). [Copyright &y& Elsevier]

Abstract: Highly transparent Cu2O-doped p-type Zn1−x Al x O (AZO; Al/Zn=1.5at%) conducting oxide films were synthesized on glass substrates using a cost effective low temperature sol–gel method. X-ray diffraction of the Cu2O-doped AZO (AZO:Cu2O) films revealed a polycrystalline Cu2O (110) peak. The I–V measurements of the p–n junction (ITO/AZO:Cu2O) revealed rectifying I–V characteristics, showing that these AZO:Cu2O films exhibit p-type conductivity. p-Type conductivity was achieved by annealing the AZO:Cu2O films in N2/H2 forming gas at 400°C. The hole concentration, hole mobility and resistivity of the 0.5–2mol% AZO:Cu2O films were 5.41×1018 to 1.99×1020 cm−3, 8.36–21.6cm2/Vs and 1.66×10−2 to 6.94×10−3 Ωcm, respectively. These results show that post-annealing in a forming gas is effective and practicable in producing p-type AZO. [Copyright &y& Elsevier]

Abstract: High quality Al–N co-doped ZnO (AZO:N) nanorods were synthesized using an ammonia-assisted hydrothermal method. The AZO:N nanorods exhibited p-type characteristics according to Hall Effect measurements, revealing low resistivity in the order of 10−2 Ωcm. At room temperature, the electrical properties of the AZO:N nanorod showed a hole concentration, hole mobility and resistivity of 2.83×1018–2.28×1019 cm−3, 2.19–2.86cm2/Vs, and 1.01–9.58×10−2 Ωcm, respectively. The I–V measurements of the p–n junction (p-AZO:N nanorods/n-Si) showed rectifying I–V characteristics, confirming that these AZO:N nanorods exhibit p-type conductivity. This study opens the possibility of developing highly conducting p-type AZO nanorods for optoelectronic devices. The effect of the ammonia concentration on the structural and electrical properties of AZO:N nanorods is discussed. [Copyright &y& Elsevier]

Abstract: NiO-doped p-type AZO (Al/Zn=1.5at.%) films were synthesized on glass substrates using a simple and low cost sol–gel solution method. p-type conductivity could be achieved by annealing the NiO:AZO films in N2/H2 forming gas at 550°C. The real Al/Zn and Ni/Zn ratio, hole concentration, hole mobility and resistivity of the 1.5–2mol% NiO-doped AZO films were 0.26–0.29, 0.06–0.09, 3.15×1018–2.18×1020 cm−3, 2.33–12.76cm2/Vs, and 2.39×10−1–1.24×10−2 Ωcm, respectively. I–V measurements of the p–n junction (ITO/NiO:AZO) revealed rectifying I–V characteristics, confirming that these NiO:AZO films exhibit p-type conductivity. This study opens the possibility of developing highly conductive p-type composite transparent conducting oxides for optoelectronic devices. [Copyright &y& Elsevier]

Abstract: This study investigated the variance of color chromaticity of a vertically-stacked LEDs device with respect to the viewing angles. The LED chips with truncated inverted pyramid geometry were fabricated by laser micromachining. The sidewalls of the truncated inverted pyramid LED chips were coated with a thin layer of highly reflective silver film. The red, green and blue truncated inverted pyramid LED chips were vertically-stacked to form the white LEDs with color tunable function. A well mix of colors from the polychromatic LED chips was achieved in the layout of the vertically-stacked LEDs without utilizing additional optics. Compared to the commercial RGB LEDs, the stacked LEDs device showed insignificant angular dependence of color chromaticity. A luminous efficacy of 33 lm/W was achieved without any optimization of the fabrication process. [Copyright &y& Elsevier]

Abstract: A proof-of-concept of applying laser micro-machining to fabricate high performance GaN light-emitting diode (LED) was presented in this study. Laser micro-machining was applied to fabricate GaN LED chip with angled sidewalls (ALED). The inclined sapphire sidewalls were coated with highly reflective silver film which functions as an efficient light out-coupling medium for photons within the LED structure. Thus, more laterally-propagating photons can be redirected to the upward direction of the ALED with silver coating (Ag-ALED). Performances of the Ag-ALED, ALED and conventional planar GaN LED were evaluated. At an injection current of 30mA, the light output intensity of Ag-ALED was significantly improved by 97% and 195% as compared to ALED and conventional planar LED, respectively. The corresponding wall-plug efficiency of Ag-ALED was remarkably increased by 95% and 193% as compared to ALED and conventional planar LED, respectively. The results of this study demonstrated that the Ag-ALED showed a pronounced increase in light output intensity compared to conventional planar LED, which may have many potential applications in the field of display engineering. [Copyright &y& Elsevier]

Abstract: Methane is a potent greenhouse gas. It has a global warming potential (GWP) 23 times greater than carbon dioxide. Reducing methane emissions would lead to substantial economic and environmental benefits. This study investigated the performance of multi-transition-metal-(Cu, Cr, Ni, and Co)-ion-exchanged zeolite 13X catalysts in methane emissions abatement. The catalytic activity in methane combustion using multi-ion-exchanged catalysts was studied with different parameters including the molar percentage of metal loading, the space velocity, and the inlet methane concentration under atmospheric pressure and at a relatively low reaction temperature of 500 °C. The performance of the catalysts was determined in terms of the apparent activation energy, the number of active sites of the catalyst, and the BET surface area of the catalyst. This study showed that multi-ion-exchanged catalysts outperformed single-ion-exchanged and acidified 13X catalysts and that lengthening the residence time led to a higher methane conversion percentage. The enhanced catalytic activity in the multi-ion-exchanged catalysts was attributed to the presence of exchanged transition ions instead of acid sites in the catalyst. The catalytic activity of the catalysts was influenced by the metal loading amount, which played an important role in affecting the apparent activation energy for methane combustion, the active sites, and the BET surface area of the catalyst. Increasing the amount of metal loading in the catalyst decreased the apparent activation energy for methane combustion and also the BET surface area of the catalyst. An optimized metal loading amount at which the highest catalytic activity was observed due to the combined effects of the various factors was determined. [Copyright &y& Elsevier]

Abstract: This study investigates analytically and experimentally the influence of preheat temperature on flame propagation and extinction of premixed methane–air flame in single quartz tubes with inner tube diameters of 3.9, 3, 2 and 1mm respectively. The effects of preheat temperature, tube diameter, equivalence ratio and mixture flow rate on the flame speed and extinction conditions are determined. The analytical results show that high preheat temperature of the mixture can effectively suppress flame quenching, and the occurrence of stable solution in the slow flame branch extends the flammability limit leading to possible flame propagation in mini channels. Experimental results confirm that the flame speed increases and the flammability limit shifts toward the fuel lean direction either through increasing the preheat temperature or decreasing the mixture flow rate, or both. Decrease of propagating flame speed is observed before the stoichiometric equivalence ratio at high preheat temperatures. The analytical model provides insights into how propagating flame in mini channels can be sustained; however, the model is only good at predicting flame speed near the fuel lean branch. Influence of Cu2+ ions exchanged zeolite 13X catalyst on flame speed is also addressed. It is noted that the zeolite based catalyst can lower the preheat temperature requirement in order to sustain the flame propagation in narrow channels. [Copyright &y& Elsevier]

Abstract: The present study reports a green synthesis method for preparing pure (free of fly ash) and ordered MCM-41 materials from coal fly ash at room temperature (25°C) during 24h of reaction. It was shown that the impurities in the coal fly ash were not detrimental to the formation of MCM-41 at the tested conditions. The influence of initial synthesis pH on material properties of calcined MCM-41 samples was investigated by various techniques such as XRF, XPS, XRD, FTIR, DR–UV–vis, solid state NMR, N2 physisorption, TG-DTA, SEM and TEM. The experimental results showed that the amount of trace elements such as Al, Na, Ti and Fe incorporated into the sample increased with synthesis pH value. More aluminum species were incorporated with tetrahedral coordination in the framework under a high pH value. The particle size of the sample decreased with the synthesis pH value. Samples synthesized at high pH values had a larger pore size and were more hydrothermally stable than those at low pH values. From thermal analysis, it was observed that the synthesized MCM-41 samples showed a high thermal stability. These properties made the synthesized MCM-41 suitable for further processing into more useful materials in a wide range of applications. [Copyright &y& Elsevier]

Abstract: Single phase chamfered-edge zeolite 4A samples in pure form with a high crystallinity were synthesized by applying step-change of synthesis temperature during hydrothermal treatment of coal fly ash. The calcium binding capacity of these zeolite 4A samples (prepared from coal fly ash) and the commercial detergent grade zeolite 4A were tested for usage as a detergent builder. The results show that these zeolite 4A samples behaved similarly as the commercial one in removing calcium ions during the washing cycle. Moreover, from the leaching tests (evaluation of toxicological safety), the results show that these zeolite 4A samples leached the same elements (Sb, As, Se and Tl) as the commercial one with the concentrations in the same order of magnitude. This shows that the toxicological effect of the coal fly ash converted zeolite 4A was not worse than that of the commercial sample. Finally, economic and environmental aspects of converting coal fly ash to useful products were discussed. [Copyright &y& Elsevier]

Abstract: Pure form, single phase and high crystalline zeolite 4A samples were synthesized by applying step-change of synthesis temperature during hydrothermal treatment of coal fly ash prepared solution. The results indicate that step-change of synthesis temperature during hydrothermal treatment plays an important role in reducing the overall synthesis time while maintaining a high degree of crystallinity for the samples. In order to obtain similar quality of zeolite 4A sample, a reduction by half of the total synthesis time could be achieved by applying step-change of synthesis temperature compared to using constant temperature throughout the synthesis process. Generally, the crystallinity of the synthesized zeolite 4A samples was in the range of 75–87%. The yielding (quantity) of pure zeolite 4A samples obtained in all the experiments was about 15–18%. In addition, crystals of smaller particle size existing in a narrower particle size distribution were synthesized. [Copyright &y& Elsevier]

Abstract: The removal performance and the selectivity sequence of mixed metal ions (Co2+, Cr3+, Cu2+, Zn2+ and Ni2+) in aqueous solution were investigated by adsorption process on pure and chamfered-edge zeolite 4A prepared from coal fly ash (CFA), commercial grade zeolite 4A and the residual products recycled from CFA. The pure zeolite 4A (prepared from CFA) was synthesized under a novel temperature step-change method with reduced synthesis time. Batch method was employed to study the influential parameters such as initial metal ions concentration, adsorbent dose, contact time and initial pH of the solution on the adsorption process. The experimental data were well fitted by the pseudo-second-order kinetics model (for Co2+, Cr3+, Cu2+ and Zn2+ ions) and the pseudo-first-order kinetics model (for Ni2+ ions). The equilibrium data were well fitted by the Langmuir model and showed the affinity order: Cu2+ >Cr3+ >Zn2+ >Co2+ >Ni2+ (CFA prepared and commercial grade zeolite 4A). The adsorption process was found to be pH and concentration dependent. The sorption rate and sorption capacity of metal ions could be significantly improved by increasing pH value. The removal mechanism of metal ions was by adsorption and ion exchange processes. Compared to commercial grade zeolite 4A, the CFA prepared adsorbents could be alternative materials for the treatment of wastewater. [Copyright &y& Elsevier]

Abstract: In this study, highly hierarchically porous NiO nanosheet arrays were synthesized on glass by a hydrothermal growth method. The effects of temperature and the reactant concentrations on the morphology of the nanosheets were examined. SEM revealed uniform and hierarchical porous NiO nanosheets at 50mM of a nickel nitrate hexahydrate solution at 90°C in 2h. After heat treatment in oxygen at 450°C for 1h, the resistivity of the annealed NiO nanosheet samples was five orders of magnitude lower than the as-prepared samples. In addition, the resistivity of the nanosheet arrays decreased significantly with increasing reactant concentration. The hierarchically porous nanosheets synthesized under optimal conditions were 200–400nm in thickness and 6–8μm in height. These nanosheets might have potential electrochromic applications. [Copyright &y& Elsevier]

Abstract Highly active and stable electrocatalysts for ethanol oxidation reaction (EOR) are very important for applications in fuel cells. Even though huge efforts have been devoted to enhancing their catalytic activity, preparation of open-structure electrodes by a green and binder-free method remains a challenge. It is obvious in graphene aerogel (GA) based materials due to the destruction of the original GA structure by traditional fabrication methods. In this report, Pd 1 Pt x alloy NPs/GA/nickel foam electrodes (Pd 1 Pt x /GA/NF) were prepared by a green, simple and binder-free one-step method. The results show that the mean particle size and distribution of Pd 1 Pt x alloy NPs and the Pd 1 Pt x loading ratios (at%; x = 2.92, 1.31, 1.03) on the electrodes are strongly dependent on the initial concentration of PtCl 6 2− ions in the synthesis solution. The Pd 1 Pt x /GA/NF electrodes were evaluated for EOR. The Pd 1 Pt 1.03 /GA/NF electrode exhibits high activity and stability in EOR under a long operation (1000 cycles), which are attributed to the synergistic effect of the bimetallic Pd 1 Pt x alloy NPs on the electrode. This study introduced a binder-free, current-collector-free electrode preparation method which may provide new opportunities to develop high-performance electrodes for energy generation and storage technologies. Highlights • Low loading of bimetallic Pd 1 Pt x /GA/NF electrode was successfully prepared. • The synthesis method was green and binder-free under mild conditions. • The Pd 1 Pt 1.03 /GA/NF electrode showed a good activity in EOR. • The overall electrode performance was the best at Pd/Pt ratio of 1:1.03. [ABSTRACT FROM AUTHOR]

Many 2D graphene-based catalysts for electrooxidation of glucose involved the use of binders and toxic reducing agents in the preparation of the electrodes, which potentially causes the masking of original activity of the electrocatalysts. In this study, a green method was developed to prepare binder-free 3D graphene aerogel/nickel foam electrodes in which bimetallic Pd-Pt NP alloy with different at% ratios were loaded on 3D graphene aerogel. The influence of Pd/Pt ratio (at%: 1:2.9, 1:1.31, 1:1.03), glucose concentration (30 mM, 75 mM, 300 mM, 500 mM) and NaOH concentration (0.1 M, 1 M) on electrooxidation of glucose were investigated. The catalytic activity of the electrodes was enhanced with increasing the Pd/Pt ratio from 1:2.9 to 1:1.03, and changing the NaOH/glucose concentration from 75 mM glucose/0.1 M NaOH to 300 mM glucose/1 M NaOH. The Pd 1 Pt 1.03 /GA/NF electrode achieved a high current density of 388.59 A g −1 under the 300 mM glucose/1 M NaOH condition. The stability of the electrodes was also evaluated over 1000 cycles. This study demonstrated that the Pd 1 Pt 1.03 /GA/NF electrode could be used as an anodic electrode in glucose-based fuel cells. [ABSTRACT FROM AUTHOR]

In this work, a facile two-step hydrothermal method was reported to grow hierarchical flower-like NiAl layered double hydroxide (LDH) directly on 3D nickel foam (NF) which was further coated with 2D graphene nanosheets (GNS) layers as binder-free supercapacitor electrode. The positive and negative effects of GNS on the electrochemical performance of LDH-NF electrode were investigated in detail. The prepared LDH-NF/GNS electrode maintained an enhanced specific capacity of 165.6 C g −1 after 4000 cycles at a high current density of 40 A g −1 . Furthermore, a hybrid supercapacitor, with LDH-NF/GNS and GNS-NF as the positive and negative electrodes, achieved an energy density (31.5 Wh kg −1 at a power density of 400 W kg −1 ) and super long-term cycle stability (a specific capacity of 67.2 C g −1 at 5 A g −1 after 5000 cycles with 80% retention). This study not only opens up the possibility of engineering LDH-NF/GNS into a promising electrode, but also highlights the positive and negative roles of GNS on LDH-NF as binder-free electrodes for further development of high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Highlights: [•] 3D Co(II) ions modified graphene aerogels were prepared by one-step hydrothermal process. [•] The aerogel electrodes showed hybrid supercapacitor behaviors. [•] The aerogel electrodes exhibited high rate capability and long-term cycling stability. [Copyright &y& Elsevier]

Highlights: [•] Ni–Al co-doped ZnO (NiAl:ZnO) composite thin films were deposited by DC magnetron sputtering at room temperature. [•] All films showed a highly preferential (002) c-axis orientation. [•] XPS revealed the presence of metallic Ni, NiO, and Ni2O3 states, and Ni atoms were successfully doped in the NiAl:ZnO films. [•] NiAl:ZnO (3wt% Ni) film showed the lowest electrical resistivity of 2.59×10−3 Ωcm. [•] Band gap widening (4.18eV) was observed in the NiAl:ZnO films with 5wt% Ni. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ni–Al co-doped ZnO (NiAl:ZnO) composite thin films were deposited by DC sputtering at low sputtering power. [•] All films showed a highly preferential (002) c-axis orientation. [•] NiAl:ZnO (5wt% Ni) film deposited at 40W at 6.0mTorr has the lowest resistivity of 2.19×10−3 Ωcm. [ABSTRACT FROM AUTHOR]

Abstract: “The Low Carbon, Green Growth” was declared as Korean national agenda in 2008. Korea has been enhancing the green growth for the sustainable economic development and fostering energy. To improve Korean national energy security and promote the “Low Carbon, Green Growth”, we established a long term strategic energy technology roadmap. In this paper, five criteria, such as economical impact, commercial potential, inner capacity, technical spin-off, and development cost, were used to assess the strategic energy technologies against high oil prices. We developed the integrated two-stage multi-criteria decision making (MCDM) approach which was used to evaluate the relative weights of criteria and measures the relative efficiency of energy technologies against high oil prices. On the first stage, the fuzzy analytic hierarchy process, reflecting the vagueness of human thought with interval values instead of crisp numbers, allocated the relative weights of criteria effectively instead of the AHP approach. On the second stage, the data envelopment analysis approach measured the relative efficiency of energy technologies against high oil prices with economic viewpoints. The relative efficiency score of energy technologies against high oil prices can be the fundamental decision making data which help decision markers to effectively allocate the limited R&D resources. [Copyright &y& Elsevier]

Abstract: ZnO thin films were deposited onto quartz substrates by radio frequency (RF) reactive magnetron sputtering using a Zn target. The structural and optical properties of the ZnO thin films were investigated comprehensively by X-ray diffraction (XRD), ultraviolet–visible and photoluminescence (PL) measurements. The effects of the oxygen content of the total oxygen–argon mixture and sputtering voltage in the sputtering process on the structural and optical properties of the ZnO films were studied systemically. The microstructural parameters, such as the lattice constant, crystallite size, stress and strain, were also calculated and correlated with the structural and optical properties of the ZnO films. In addition, the results showed that the crystalline quality of ZnO thin films improved with increasing O2/Ar gas flow ratio from 2:8 to 8:2. XRD and PL spectroscopy revealed 800V to be the most appropriate sputtering voltage for ZnO thin film growth. High-quality ZnO films with a good crystalline structure, tunable optical band gap as well as high transmittance could be fabricated easily by RF reactive magnetron sputtering, paving the way to obtaining cost-effective ZnO thin films transparent conducting oxides for optoelectronics applications. [Copyright &y& Elsevier]

Abstract: Li-doped NiO thin films (Li:NiO) were deposited on glass substrates using a facile sol–gel method. The effects of Li doping concentration on the structural, electrical and optical properties of Li:NiO films were examined. The structural properties of Li:NiO films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy. XRD revealed the Li:NiO films to have a polycrystalline bunsenite structure. The surface morphology of the Li:NiO films exhibited nanocrystalline grains with a randomly oriented morphology. The resistivity decreased substantially to 1.33kΩcm at 0.11mol%, which is one order of magnitude lower than that of the undoped NiO film. The mean transmittance decreased from 70% to 60% with increasing Li doping concentration from 0.02mol% to 0.19mol%. [Copyright &y& Elsevier]

Abstract: Anatase TiO2 nanotubes grown on Ni foam substrates were successfully synthesized by treating TiO2 nanocrystals coated on an Ni foam in alkaline solution using a facile microwave-assisted hydrothermal method. The as-synthesized TiO2 nanotubes were characterized by SEM, TEM, and XRD. The effects of NaOH concentration, reaction time, hydrothermal temperature, and calcination temperature on the morphology, as well as crystal structure, of the nanotubes were investigated. TiO2 nanotubes synthesized under the optimal conditions were polycrystalline anatases with 4 to 5 multilayers, approximately 10nm wide, and several tens of nanometers long. The possible formation mechanism for TiO2 nanotubes was also discussed in the current paper. [Copyright &y& Elsevier]

Abstract: Polystyrene (PS) microspheres with a mean diameter of 69nm were prepared by emulsion polymerization. The PS microspheres were successfully decorated to multi-walled carbon nanotubes (MWNTs) induced by benzoyl peroxide in water during a high temperature refluxing process under nitrogen atmosphere. The as-prepared multi-walled carbon nanotube/polystyrene (MWNT/PS) nanocomposites were characterized by FTIR spectroscopy, Raman spectroscopy, SEM, TEM, differential scanning calorimetry (DSC), and electrical resistance measurements. The results reveal that PS microspheres are mainly covalently grafted onto the walls of MWNTs. The PS-decorated MWNTs show high solubility in toluene and xylene without sedimentation after 24h. With MWNTs in the hybrids, PS achieved a considerable increase in electrical conductivity and glass-transition temperature (T g). In particular, the obtained MWNT/PS composites were examined for electrorheological (ER) fluids, which showed thin and dense chains of particles after the application of an electric field. The facile and environmentally friendly technique presented in the present study could be an effective and promising method for the functionalization of MWNTs by other polymers. [Copyright &y& Elsevier]

Abstract: The adsorption characteristics of basic yellow 87 from aqueous solution were investigated using two mesoporous materials: MCM41 and carbon aerogel (MCA). The adsorbents were analyzed by N2 adsorption–desorption technique and transmission electron microscopy to elucidate the effect of pore properties on the adsorption behavior of basic yellow 87. Three adsorption isotherms were used to model the equilibrium adsorption of basic yellow 87 on two mesoporous adsorbents. The result indicates that the Redlich–Peterson isotherm model describes the adsorption of basic yellow 87 extremely well. The adsorption process of MCM41 was exothermic and that of MCA was endothermic. Kinetic studies show that the adsorption of MCM41 and MCA followed the pseudo-second-order kinetic model. Batch experiments were conducted to study the effects of pH (1.2–13.0), dosage (0.025–0.200g/50mL), and particle size (5–10, 10–20, 20–40, and ≥200 mesh) on dye adsorption. The mesoporous adsorbents were highly effective as adsorbents for basic yellow 87 from aqueous solution. In particular, the initial adsorption rate of MCM41 was faster than that of MCA, but its adsorption capacity in dilute solutions was lower than that of MCA. The relatively low cost and high capabilities of MCM41 and MCA make them potentially attractive adsorbents for the removal of dyes from aqueous solution. [Copyright &y& Elsevier]

Abstract: The current study describes the catalytic ozonation of toluene using MCM-41 catalysts modified by different transition metals (Cu and Co) and methods (in situ synthesis and impregnation). The characteristic hexagonal channel array of the MCM-41 pore system was not destroyed by the transition metal modification, but the order and surface area were decreased. Large particles of copper oxide exposed on the (111) lattice plane, which were indicative of severe sintering, were found on the catalyst modified by Cu via in situ synthesis. Such particles were not observed on the other catalysts. Using the modified catalysts in toluene ozonation revealed that with increased reaction temperature, toluene conversion under a steady state increased, whereas ozone conversion decreased. The transition metal-modified MCM-41s also had largely improved catalytic activities compared with pure MCM-41. Catalytic performance was found to depend on the metal type and modification method. The method that resulted in improved catalytic performance was in situ synthesis for the Co-modified MCM-41, and was impregnation for the Cu-modified MCM-41. The relatively superior performance of the transition metal-modified catalysts over pure MCM-41 is attributed to two main features. One is the well dispersion of metal oxides, and the other is the strong capacity to decompose built-up organic byproducts on the catalyst surface. [Copyright &y& Elsevier]

Ozonation of toluene over NaX, NaY and MCM-41 adsorbents was studied targeting for indoor air purification. The combined use of ozone and the various micro- or meso-porous adsorbents aimed to take advantage of the strong oxidizing capability of ozone. At the same time the residual ozone would be minimized due to the enhanced catalytic reaction in the porous structure. To lower the residual ozone level is a crucial issue as ozone is itself an indoor pollutant. The Lewis acid sites in the adsorbents were believed to decompose ozone into atomic oxygen, and the subsequent reactions would then convert the adsorbed toluene into CO2 and H2O. In the dry conditions, the MCM-41 required the smallest amount of material to achieve the 90% reduction target, followed by NaY and NaX. In the more humid environment (50% RH), extra amounts of MCM-41 and NaX adsorbents were required to reach the target as compared with the dry conditions. Desorption experiments were also conducted to study the amounts of various major species held in the adsorbents during the catalytic process. A material balance analysis of the major species in both the effluents and the adsorbents showed that within our experimental conditions, about 20–40% of the removed toluene was carried out via catalytic ozonation while adsorption covered the rest. Trace amount of intermediate species such as aldehydes and organic acids were identified in the desorbed gas indicating that they were withheld by the adsorbents during the air purification process and those in the effluent were below detection levels. [Copyright &y& Elsevier]

This study investigated the performance of a combined ozone and zeolite system in eliminating gaseous toluene which is a major contaminant in many industrial and indoor environments. The hypothesis that the removal of toluene by ozone can be substantially affected by confining the oxidation reaction in a zeolite structure was evaluated. The degradation of toluene seemed to be contributed by the active oxygen atom generated from the decomposition of ozone at the Lewis acid sites in the zeolite 13X. Air containing toluene levels at 1.5, 2 and 3ppm was injected with ozone in the range of 0–6ppm before being vented into a fixed amount of 3600g zeolite 13X with 90mm bed-length. The experimental results showed that the elimination rate of toluene was significantly enhanced when compared to using zeolite or ozone alone. In particular, over 90% of the 1.5ppm toluene was removed when 6ppm ozone was used at 40% relative humidity level. Deactivation of the zeolite 13X after a few hours of reactions under the current experimental conditions was probably due to the adsorbed water, carbon dioxide and the reaction by-products. The residue species left in the zeolite and the intermediate species in the exhaust gas stream were characterized by FT-IR, GC–MS and HP-LC methods, respectively. A distinctive peak of O atom attached to the Lewis acid site at 1380cm−1 was found in the FT-IR spectrum and trace amount of aldehydes was found to be the reaction by-products. [Copyright &y& Elsevier]

The electrocatalytic reduction of carbon dioxide into organic fuels and feedstocks is a fascinating method to implement the sustainable carbon cycle. Thus, a rational design of advanced electrocatalysts and a deep understanding of reaction mechanisms are crucial for the complex reactions of carbon dioxide reduction with multiple electron transfer. In situ and operando techniques with real‐time monitoring are important to obtain deep insight into the electrocatalytic reaction to reveal the dynamic evolution of electrocatalysts' structure and composition under experimental conditions. In this paper, the reaction pathways for the CO2 reduction reaction (CO2RR) in the generation of various products (e.g., C1 and C2) via the proposed mechanisms are introduced. Moreover, recent advances in the development and applications of in situ and operando characterization techniques, from the basic working principles and in situ cell structure to detailed applications are discussed. Suggestions and future directions of in situ/operando analysis are also addressed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights: • The high phosphate adsorption capacity reach 80.43 mg/g for 250 mg L−1 KH 2 PO 4 solution. • An optimization of preparation conditions and important operating parameters are provided. • The uptake of phosphate by Mg-Al LDHs/AC under circumneutral pH reach maximum uptake level. • The ionic strength mainly affects the CDI by the electric double layer instead of intercalation. Abstract The efficient uptake of phosphate from aqueous solutions was achieved on layered double hydroxides (LDHs)-based electrodes via capacitive desalination in our previous study. The current follow-up work was mainly carried out to study the influence of various experimental parameters on the capacitive removal of phosphate using LDHs/activated carbon (LDHs/AC) composite electrodes. A series of batch experiments were implemented to investigate the experimental factors, including Mg2+/Al3+ ratios (2, 3, and 4), trivalent metal cations (Al3+, Fe3+, Cr3+), initial solution pH (from 3 to 10), coexisting anions (NO 3 −, Cl−, SO 4 2−), and ion strengths, in capacitive deionization. The electrode materials before and after capacitive deionization were characterized to reinforce the analysis of the adsorption mechanisms by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray, cyclic voltammetry, and electrochemical impedance spectroscopy. Results indicated that the Mg-Al LDHs/AC electrodes exhibited higher phosphate adsorption capacity (80.43 mg PO 4 3−/g), more regular morphology, and higher degree of crystallinity than that of Mg-Fe LDHs/AC and Mg-Cr LDHs/AC. Increasing Mg2+/Al3+ ratios enhanced the adsorption capacity of phosphate. The uptake of phosphate by Mg-Al LDHs/AC under circumneutral pH and low ion strength reached the maximum level. Furthermore, the presence of coexisting anions lowered the adsorption capacity of phosphate mainly due to the occurrence of a compressed electrical double layer. Therefore, the influence of different experimental parameters on phosphate removal via capacitive deionization by Mg-Al LDHs/AC necessitates a systematic investigation to optimize the preparation conditions of LDHs-based electrodes and several important operating parameters. [ABSTRACT FROM AUTHOR]

A series of CuCe0.75Zr0.25Ox catalysts (CCZ) were synthesized based on the environmental‐friendly bacterial cellulose (BC) by using the sol‐gel method. The corresponding synthesis mechanism, physicochemical properties of the catalysts and catalytic performances for toluene oxidation were comprehensively studied. In the presence of BC without sugar, the CCZ−A synthesized by ethanol‐gel exhibits better catalytic activity than the CCZ−W synthesized by water‐gel, which may be due to the different roles of BC in different solvents. However, it is worth noting that the graft copolymerization between BC and active metal (Ce4+, Cu2+) is the same process in both water‐gel and ethanol‐gel. The activity of CCZ‐SW synthesized by water‐gel using BC with sugar is obviously higher than that of CCZ−W and CCZ−A. The temperature of complete degradation of toluene over CCZ‐SW is 205 °C, which is 35 °C lower than that of CCZ−W. The results from BET, Raman and H2‐TPR indicate that the larger the specific surface area, the more oxygen vacancies and better low‐temperature reducibility, that are mainly responsible for the excellent activity of CCZ‐SW. The existence of sugar in BC could hinder the agglomeration of active metal particles during the calcination process. Combined with the results of in situ DRIFT, the adsorbed toluene on the catalyst surface is oxidized into alkoxide, aldehydic and carboxylic acid species as intermediates before the complete oxidation into CO2 and H2O. [ABSTRACT FROM AUTHOR]

Abstract Phosphorus removal is essential to avoid eutrophication in water bodies. Layered double hydroxides (LDHs) are widely used to scavenge phosphate through intercalated ion exchange or surface complexation. Moreover, LDHs have attracted increasing attention as electrode modifiers for supercapacitors. Researchers have begun to re-delve the electrosorption technology according to the fundamental principle of electrical double layers. Herein, we propose a new phosphate removal method inspired by the adsorption characteristic and electrical double-layer capacitive properties of LDHs through electrosorption via capacitive deionization. We present a series of experiments to study the enhanced phosphate removal under an electric field via multiple mechanisms on the MgAl-LDHs/AC electrode. The uptake of phosphate by MgAl-LDHs/AC was investigated as a function of phosphate concentration, applied voltage, electrode materials, and temperature. The MgAl-LDHs/AC electrode possessed a salt removal capacity of 67.92 mg PO 4 3−·g−1 (1.2 V, 250 mg·L−1 KH 2 PO 4 , 30 °C). The electrosorption kinetics of phosphate ions onto the capacitive deionization electrode followed the pseudo-second-order kinetics model rather than the pseudo-first-order kinetics model. Furthermore, the adsorption isotherms of phosphate on the MgAl-LDHs/AC electrode fitted the Freundlich model better than the Langmuir model. The proposed method could be used for phosphate removal. Graphical abstract Unlabelled Image Highlights • A new phosphate removal method was proposed under electrostatic field. • Phosphate removal capacity reaches 67.92 mg PO 4 3−·g−1 for 250 mg·L−1 KH 2 PO 4 solution. • Influence of different experimental parameters on the electrosorption was examined. • Multiple mechanisms exist in electrosorption of phosphate on MgAl-LDHs/AC electrode. [ABSTRACT FROM AUTHOR]

Highlights • A novel microchannel with interlaced configuration is fabricated. • Side walls of channel as the main heat transfer surfaces is realized. • Experimental investigation on the thermal and hydraulic performance is performed. • A better heat transfer performance of interlaced microchannel is obtained. Abstract In this study, a novel interlaced microchannel with a “cold water-hot water-cold water” counterflow arrangement was designed. The influences of microchannel configurations on the thermal and hydraulic performance were studied by comparing the proposed microchannel configuration with parallel and traditional spiral configurations. The results showed that the effective heat transfer area of the interlaced microchannel was 6.4 and 8.4 times that of the parallel and spiral configurations, respectively. For interlaced microchannels, the maximum temperature difference between the cross sections was 0.07 °C, and the temperature rise along the flow direction was only 6 °C. When the Reynolds number was 492, the Nusselt number of the interlaced microchannels was 2 and 10 times that of the parallel and spiral microchannels, respectively. The heat transfer performance of interlaced microchannels was improved by 83.46% compared with that in the literature. The influence of microchannel configurations on the pressure drop and the entrance length were negligible. The interlaced microchannel exhibited its lowest thermal resistance of 0.015 °C/W and lowest entropy production of 22.6 W/ °C at a Reynolds number of 492. The heat transfer enhancement coefficient of the interlaced microchannel and parallel microchannel were 5 and 2.8 times that of the traditional spiral microchannel, respectively. The maximum heat load of loop heat pipe was enhanced by 4 times with the integration of interlaced microchannel as the condenser. [ABSTRACT FROM AUTHOR]

We report the synthesized mixture of MXene and Ni Co LDH on nickel foam by an electrodeposition technique. The specific capacitance of the mixture attained 983.6 F g −1 at a discharge current of 2 A g −1 , which is greater than that of pure MXene. Compared to Ni Co LDH, the sample created through electrodeposition provided a better rate capability of 983.6 F g −1 at 2 A g −1 and 536.6 F g −1 at 50 A g −1 and cycling stability with 76% retention after 5000 cycles at 30 A g −1 . Moreover, a solid-state asymmetric supercapacitor with MXene-LDH as the positive electrode and multi-walled carbon nanotube coated on the nickel foam as the negative electrode delivers high energy density (36.70 Wh kg −1 at the power density of 1.44 kW kg −1 ), which outperforms the other devices reported previously. [ABSTRACT FROM AUTHOR]

Smooth and rough porous copper fiber sintered sheets, employed here as wicks for loop heat pipes for the first time, were fabricated using a low-temperature solid-phase sintering method. The capillary performance of these porous copper fiber sintered sheets were analyzed and discussed. The influence of the surface morphology, filling ratio, and working fluid on the thermal resistance, evaporator wall temperature, and start-up time of the loop heat pipes were investigated. The results showed that the capillary pumping amount of working fluid for both smooth and rough porous copper fiber sintered sheets initially increases rapidly, and then gradually attains a stable state. The curve of the capillary pumping amount of working fluid can be described as a function that increases exponentially over time. When rough porous copper fiber sintered sheets are used as wicks and deionized water is used as the working fluid, the capillary pumping amount is maximized. Compared to smooth porous copper fiber sintered sheets, loop heat pipes with rough porous copper fiber sintered sheets exhibit a shorter start-up time, lower thermal resistance, and lower evaporator wall temperature. For a filling ratio in the range of 15–45%, loop heat pipes with rough porous copper fiber sintered sheets and a 30% filling ratio show lower thermal resistance and a lower evaporator wall temperature. Ultimately, the use of deionized water as the working fluid with a 30% filling ratio enables loop heat pipes with rough porous copper fiber sintered sheets to be stably operated at a heat load of 200 W. [ABSTRACT FROM AUTHOR]

In this study, the cascading metal foams were used as catalyst supports for constructing a new type of cylindrical laminated methanol steam reforming microreactor for hydrogen production. The two-layer impregnation method was used to load the Cu/Zn/Al/Zr catalysts, and the ultrasonic vibration method was then employed to investigate the loading performance of metal foams with different types and thicknesses. Furthermore, the effect of the type of catalyst placement, pores per inch (PPI) and foam type on the performance of methanol steam reforming microreactor was studied by varying the gas hourly space velocity (GHSV) and reaction temperature. Compared with two other types of catalyst placement studied, the microreactor containing catalyst-loaded metal foams without clearance cascading (3 × 2) showed the highest hydrogen production performance. When the PPI of the metal foam was increased from 50 to 100, both the methanol conversion and the H 2 flow rate gradually increased. Our results also showed that a microreactor with Cu foam as a catalyst support exhibits increased hydrogen production and higher stability than those of a microreactor with Ni foam. [ABSTRACT FROM AUTHOR]

The catalytic ozonation of VOCs is a promising approach for degradation of indoor VOCs, such as gaseous toluene. However, the mechanism and relevant kinetic steps involved in this reaction remain unclear. In this study, the catalytic ozonation of toluene over MnO 2 /graphene was investigated using the empirical power law model and classic Langmuir-Hinshelwood single-site (denoted as L-H s ) mechanism. The apparent activation energy determined using the power law model was 29.3 ± 2.5 kJ mol −1 . This finding indicated that the catalytic ozonation of toluene over MnO 2 /graphene was a heterogeneous reaction, and the Langmuir-Hinshelwood mechanism was applicable. However, the L-H s mechanism did not fit the experimental data, suggesting that the reaction was non-single-site governed. A novel Langmuir-Hinshelwood dual-site (denoted as L-H d ) mechanism was then proposed to explain the experimental observations of the catalytic ozonation of toluene over MnO 2 /graphene through a steady-state kinetic study. This mechanism was based on the hypothesis that MnO 2 was responsible for ozone decomposition and toluene adsorption on graphene; these two types of adsorption were coupled by an adjacent attack. Furthermore, XPS results confirmed the presence of a strong connection between MnO 2 and graphene sites on the surface of MnO 2 /graphene. This connection allowed the adjacent attack and validated the dual-site mechanism. The L-H d model was consistent with the predicted reaction rate of toluene removal with a correlation coefficient near unity (r 2 = 0.9165). Moreover, the physical criterion was in accordance with both enthalpy and entropy of toluene adsorption constraints. Fulfillment of mathematical and physical criteria indicated the catalytic ozonation of toluene over MnO 2 /graphene can be well described by the L-H d mechanism. This study helps understand the catalytic ozonation of toluene over MnO 2 /graphene in a closely mechanistic view. [ABSTRACT FROM AUTHOR]

A novel porous copper fiber sintered felt (PCFSF) as catalyst support is fabricated to construct the methanol steam reforming microreactor for hydrogen production. In this study, the heat and mass transfer properties of PCFSF with different porosities is experimentally investigated. The results show that the PCFSF with different porosities exhibits good uniform heat transfer. The thermal conductivity is decreased with increasing porosity in the porosity range of 70–90%. With lower gas feed rate, no great change of the pressure drop is observed. However, larger pressure drop is produced with the higher gas feed rates. Moreover, we found that the resident time in the PCFSF is gradually decreased with increasing porosity. Much longer resident time is obtained when the lower gas feed rate is selected. The PCFSF with 80% porosity as catalyst support presents better reaction performance because of the enhancement of heat and mass transfer resulting from the unique porous structure. [ABSTRACT FROM AUTHOR]

Compared to traditional super absorbent polymers using raw materials from petrochemical industry, natural polymer absorbents are more favorable because they are sustainable and biodegradable. In this study, composite absorbents were developed by crosslinking carrageenan with sodium alginate using calcium chloride. Effect of composition on absorption was tested. Absorption was improved by increasing carrageenan content. The super absorbent exhibited the maximal swelling ratio of 13.1 g/g in 0.9% saline water in just 5 min. The maximal tensile strength was reached with a value of 12.8 MPa. Water contact angle revealed that carrageenan is more hydrophobic than sodium alginate. Presence of sulfate groups might be a key factor promoting absorption. The scanning electron microscopic images showed that the composite material had a structure with alginate arranged at the outside surface. These results demonstrate that a sustainable and biodegradable absorbent was successfully developed with a matrix of properties for potential application in diapers. [ABSTRACT FROM AUTHOR]

Highlights: [•] Surface reaction plays the major role in O3/MnO x /SBA-15 for the removal of oxalic acid. [•] MnO x /SBA-15 benefits adsorption of oxalic acid and initiation of hydroxyl radicals. [•] Protonated surface hydroxyl groups are claimed to be the main active centers. [•] Multivalent MnO x with higher oxidation states contribute to electron transfer. [•] A possible mechanism of catalytic ozonation is proposed. [ABSTRACT FROM AUTHOR]