Search

Tailoring the surface structure of Earth-abundant perovskite oxides can provide cost-effective, high-efficient, and durable electrocatalysts for oxygen evolution reaction (OER). However, the structural origin leading to high OER performance of perovskite is not fully understood. Here, we present a strategy of tuning the surface energy density of non-stoichiometric perovskite by creating surface defects in the 3D inverse opal LaCoO 3-x (3DIO-LaCoO 3-x) through a colloidal template strategy. The defective 3DIO-LaCoO 3-x , which has an enhanced surface energy density and a shift in the d-band centre of Co relative to the Fermi level, demonstrates significantly improved intrinsic OER activity, with a TOF (0.21 s−1) ten-folder larger than that of conventional LaCoO 3 nanoparticles (0.02 s−1). The defective surfaces of 3DIO-LaCoO 3-x are theoretically proven to alter the rate determining step of OER and significantly reduce the adsorption energies of the intermediate species, resulting in dramatically enhanced OER activity. Moreover, rich surface defects with high electrical conductivity can mitigate structural corrosion by fast transfer of charge through defective conductive channels, and thus enables long-term stability for the defective 3DIO-LaCoO 3-x. These results provide an effective approach for enhancing the intrinsic activity of perovskite for water oxidation towards understanding the surface structure engineering for perovskite-based materials. Image 1 • A surface defective 3D inverse opal LaCoO 3-x perovskite was synthesized. • Rich surface defects modified surface energy density and d-band centre of Co. • Intrinsic activity and stability against OER were significantly increased. • Defective sites reduced the energy barrier of the rate determining step of OER. [ABSTRACT FROM AUTHOR]

Ethanol steam reforming is a promising reaction which produces hydrogen from bio and synthetic ethanol. In this study, the nano-structured Ni-based bimetallic supported catalysts containing Cu, Co and Mg were synthesized through impregnation method and characterized by XRD, BET, SEM, TPR and TPD analysis. The prepared catalysts were tested in steam reforming of ethanol in the S/C = 6, GHSV of 20,000 mL/(g cat h) at the temperature range of 450–600 °C. Among the xNi/CeO 2 (x = 10, 13, 15 wt%) catalyst, the sample containing 13 wt% Ni with surface area of 64 m2/g showed the best performance with 89% ethanol conversion and 71% H 2 selectivity as well as low CO selectivity of 8% at 600 °C and The addition of Cu, Mg, and Co to catalyst structure were evaluated and it was found that the nature of second metal has a strong influence on the catalyst selectivity for H 2 production. Considering to results of TPR analysis, the 13Ni–4Cu/CeO 2 catalyst showed proper reduction which caused in better activity. On the other side based on TPD analysis, the more basic property of 13Ni–4Mg/CeO 2 bimetallic catalyst provided a better condition to methane steam reforming, leading to lower CH 4 selectivity and consequently more H 2 production. The 13Ni–4Cu/CeO 2 exhibited the highest activity and lowest selectivity towards ethanol conversion and CO production about 99% and 4%, while the 13Ni–4Mg/CeO 2 catalyst possessed the highest H 2 selectivity and lowest CH 4 selectivity about 74% and 1% respectively at 600 °C. The Ni–Cu and Ni–Mg bimetallic catalysts shows good stability with time on stream. Image 1 • 13 wt% Ni/CeO 2 catalyst with proper activity and sufficiently hydrogen selectivity at 600 °C. • Increasing the catalytic activity towards ESR reaction by using the promoter of Cu, Mg and Co. • Obtaining almost full conversion over 13Ni–4Cu/CeO 2 catalyst at 600 °C. • Increasing the water-gas shift reaction by using 4 wt% Cu to formulation of 13Ni/CeO 2 catalyst. • High improvement of the methane steam reforming by addition of 4 wt% Mg as promoter. [ABSTRACT FROM AUTHOR]

This study aimed to determine the photocatalytic activity of photo-Fenton reagent in the photodegradation of 4-Nitrophenol. For this purpose, Fe(III) tetraphenyl porphyrin encapsulated NaY zeolite (FeTPP/NaY) was successfully synthesised via the zeolite synthesis method. The effects of catalyst amount, H2O2 and UV illumination, concentration of 4-Nitrophenol and pH value on the photodegradation process were examined. Ultraviolet–Visible spectroscopy studies revealed that catechol, benzoquinone, and nitrate as the key intermediate species for photodegradation of 4-Nitrophenol. The chemical oxygen demand analysis indicated mineralisation of pollutant which exhibits 85% conversion of 4-Nitrophenol after 120 min irradiation. Rational design of FeTPP/NaY Nanocomposite as Fenton reagent for efficient photodegradation of 4-Nitrophenol was reported, and the possible reaction pathways of the photocatalytic reaction were proposed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • One-pot synthesis allows generation of Ni catalysts supported on MgO. • Effect of group VIB metal addition to Ni/MgO on catalytic activity is examined. • The Ni−Cr/MgO catalysts exhibit high catalytic activity and stability. Abstract Mesoporous 55 wt.% Ni/MgO and group VIB metal (Cr, Mo or W)-doped catalysts were prepared using the facile "one-pot" evaporation-induced self-assembly in ethanol and wetness impregnation methods, respectively. Physicochemical properties of the as-prepared catalysts were characterized by means of the BET, XRD, SEM, TEM, HAADF, XPS, H 2 -TPR, TPO, and Raman techniques. The doping of Cr to 55 wt% Ni/MgO improved catalytic activity and stability for the decomposition of methane under harsh reaction conditions. The maximal initial methane conversions of 80, 87, and 75% were achieved over the 55 wt.% Ni− x Cr/MgO (denoted as 55Ni− x Cr/MgO; x = 5, 10, and 15 wt.%) at 675 oC and GHSV = 48,000 mL/(g h), respectively. It is concluded that the high catalytic efficiency of the Cr-doped sample in methane decomposition was associated with its high surface area, high oxygen adspecies concentration, and good low-temperature reducibility. In addition, multi-walled carbon filaments with metal-encapsulated carbon particles were deposited on the Cr-doped catalysts, and the ordered carbon filaments with different diameters and good crystallinity were produced on the surface of the 55Ni−10Cr/MgO catalyst. [ABSTRACT FROM AUTHOR]

A strategy of substrate facet control/doping and uniform Au assembly is employed for catalyst design h -M 0.18 Co 2.82 O 4 and Au/ h -M 0.18 Co 2.82 O 4 are highly active for low-temperature benzene combustion Route for synthesis of Co 3 O 4 hexagonal plates is technically feasible and highly productive Processes for controllable substrate fabrication and governable Au assembly are widely applicable Factors determining catalyst performance both structurally and electronically are elucidated in depth. • A strategy of substrate facet control/doping and uniform Au assembly is employed for catalyst design. • h -M 0.18 Co 2.82 O 4 and Au/ h -M 0.18 Co 2.82 O 4 are highly active for low-temperature benzene combustion. • Route for synthesis of Co 3 O 4 hexagonal plates is technically feasible and highly productive. • Processes for controllable substrate fabrication and governable Au assembly are widely applicable. • Factors determining catalyst performance both structurally and electronically are elucidated in depth. A comprehensive strategy based on the facet control and elemental doping of Co 3 O 4 support plus precise Au assembly was employed to develop the Au/ h -M x Co 3- x O 4 (1 1 2) (h = hexagonal plates; M = Fe, Mn; x = 0.09–0.36) interfaces for low-temperature benzene combustion. The current route in synthesis of Co 3 O 4 hexagonal plates with the most active (1 1 2) exposed facet is free of any organic solvent, surfactant, or coordinator, close to the nominal material yield. Well-controlled Au assembly onto the (1 1 2) facet of h -M 0.18 Co 2.82 O 4 results in very efficient Au/ h -M 0.18 Co 2.82 O 4 for the target reaction. The processes developed for both controllable support fabrication and governable Au assembly are applicable to other systems and utilizations. N 2 sorption, X-ray diffraction, scanning electron microscopy/(high-resolution)transmission electron microscopy, selected-area electron diffraction, energy-dispersive X-ray mapping, inductively coupled plasma mass spectrometry, H 2 temperature-programmed reduction, O 2 temperature-programmed desorption, and X-ray photoelectron spectroscopy were performed to understand the physicochemical properties of various interfaces. Turnover frequency calculation and activation energy determination were used to reveal distinct catalytic behaviors. The factors significantly determining the interface activity are as follows: (1) the critical support orientation and element constitution [ h -M x Co 3- x O 4 (1 1 2) (M = Fe, Mn, x = 0.09–0.18)]; (2) the surface reconstruction [from (1 1 2) to (1 1 1)] owing to increasing dopant content; (3) the evolution of reactive oxygen species (O I − vs. O II −) and the oxidation state of Au entities. [ABSTRACT FROM AUTHOR]

Abstract The concurrent production of CO x -free hydrogen and multi-walled carbon filaments by thermocatalytic decomposition of methane is advantageous in the environmental and energy catalysis. In the present work, a facile "one-pot" evaporation-induced self-assembly strategy was effectively adopted to fabricate the nickel catalysts supported on mesoporous Al 2 O 3 , SiO 2 , TiO 2 , and MgO, and their catalytic activities for methane decomposition were evaluated for the first time. The structural, textural, and redox properties of the as-obtained materials were characterized using a number of analytical techniques. The nitrogen sorption analysis indicated the presence of a mesoporous structure due to homogeneous aggregation of the catalyst particles with a high specific surface area of 32–236 m2/g. Among all of the catalysts, Ni/MgO exhibited the best catalytic activity for methane decomposition (65% methane conversion at 600 °C and GHSV of 48,000 mL/(g h)). The activity increased when Ni loading increased from 25 to 55 wt%. The investigation on the correlation between catalytic performance and promoter doping effect suggests that incorporating copper into the MgO support considerably enhanced the catalytic activity and stability at high temperatures. The XPS results reveal that doping of Cu to Ni/MgO enhanced the adsorption and activation of oxygen molecules. In addition, the disordered crystalline carbon filaments with different diameters and good crystallinity were generated on the surface of the Cu-doped Ni/MgO catalysts. Graphical abstract Unlabelled Image Highlights • The work is focused on pure hydrogen production via catalytic CH 4 decomposition. • One-pot synthesis allows to prepare Ni catalysts supported on various metal oxide. • The catalysts were characterized for their physicochemical properties and activity. • The Ni supported on MgO shows a higher activity than that supported on other metal oxides. • Effect of Ni content and Cu addition in Ni/MgO were investigated in detail. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Amino-MIL-101(Al/Fe) MOFs was applied in high strength phosphate adsorption. • Fast kinetics, high sorption capacity and strong selectivity were demonstrated. • Electrostatic attraction and ligand exchange were identified as the main mechanisms. Abstract Although adsorbents for phosphate removal from eutrophic water have been widely explored, it remains a critical challenge to develop robust and highly selective phosphate adsorbents featuring abundant binding sites and high affinity. In this work, two stable metal-organic frameworks (MOFs) of amine functionalized MIL-101 based on trivalent metal aluminum and iron were synthesized by simple solvothermal methods and applied as adsorbents to capture phosphate ions of high strength. Phosphate adsorption kinetics, isotherm behavior, and solution matrix effects (eg. solution pH, coexisting ions and ionic strength) were reported. Results showed that trivalent metal based NH 2 -MIL-101 MOFs outperformed most adsorbents ever reported, exhibiting fast kinetics and high maximal adsorption capacity above 79.414 mg P/g at 298 K, pH independence in the range from 3 to 11, less sensitivity to ion strength, strong selectivity for phosphate in presence of competing ions and could be easily regenerated and re-applied for phosphate removal. It was noticeable that phosphate adsorption performance varied on the two kinds of trivalent metals based MOFs due to their difference in morphology, surface and interface properties including zeta potential, chemical affinity toward target anion and the types of complexation formed with phosphate. NH 2 -MIL-101(Al) showed faster kinetics, while NH 2 -MIL-101(Fe) has higher affinity toward phosphate. Furthermore, based on Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) spectra and zeta potential analysis, electrostatic attraction and ligand exchange were identified as the main phosphate adsorption mechanisms by NH 2 -MIL-101(Al/Fe). Besides, the functionalized adsorbents with amine group further enhanced the phosphate removal capacities by providing extra surficial positive charges. These findings demonstrate that trivalent metal based NH 2 -MIL-101 is a promising candidate for phosphate adsorption from aqueous solution with high efficiency and selectivity. [ABSTRACT FROM AUTHOR]

Abstract The rate of gas production from coal seam gas reservoirs is highly dependent on coal lithotype, cleat attributes and multiphase flow in cleats. In this paper, we explore and categorize the wettability, roughness data, sorption capacity, and the flow in bright and dull coal lithotypes. The roughness measured on the wall surface of coal fractures indicates different values for each lithotype. Multiphase flow through rough-walled fractures is measured and the pressure variation and relative permeability data are compared for samples from bright and dull bands. Finally, microfluidic experiments are conducted to visualize and analyze the flow in the bright and dull bands. A flow scenario is investigated in which gas is transported through coal regions that have parallel and adjacent lithotypes. It is visualized that the production from these regions can be 53% less than the production from dull band regions. Herein, the impact of coal lithotypes properties on displacement efficiency in coal seams is discussed. Highlights • Microscale properties of coal lithotypes are measured and compared. • Roughness values observed on wall surface of coal fractures are analyzed. • Relative permeability data for dull and bright band coals are estimated. • Microfluidics are utilized to investigate displacement in coal different bands. [ABSTRACT FROM AUTHOR]

Abstract This study presents the synthesis of a novel Mn2+ and Co2+ co-doped TiO 2 (Mn-Co-TiO 2) for the photocatalytic degradation of enoxacin (ENX) under solar light irradiation. The as-synthesized photocatalysts were fully characterized by X-ray diffraction (XRD) analysis, field emission-scanning electron microscopy (FE-SEM), and UV-diffuse reflectance spectroscopy (UV-DRS). The structural appearance of the Mn-Co-TiO 2 suggests porous cylindrical type morphology. Moreover, the co-doping of Mn2+ and Co2+ has successfully reduced the band gap of TiO 2 from 2.81 eV to 2.10 eV. Applying Langmuir Hinshelwood kinetic model, the photocatalytic degradation of ENX by Mn-Co-TiO 2 followed pseudo-first-order kinetics. A total of twelve (12) DPs of ENX were identified by UPLC/MS-MS. The natural water constituents such as CO 3 2−, HCO 3 −, Cl− and Fe3+ had great influence on the photocatalytic degradation of ENX by Mn-Co-TiO 2 under solar light irradiation. The as-synthesized Mn-Co-TiO 2 showed appreciable results for the photocatalytic degradation of ENX in synthetic wastewater (SWW) and real wastewater (RWW) samples. Furthermore, the toxicity assessment of ENX and its DPs towards aquatic organisms (i.e., fish, daphnia and green algae) was measured which are helpful for the practical implementation of this technology for wastewater treatment. The Mn-Co-TiO 2 materials also showed good peroxidase-like activity towards the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 and followed Michaelis-Menten kinetics. Graphical abstract Unlabelled Image Highlights • Efficient Solar light driven photocatalysis of Enoxacin. • Narrowing the band gap of TiO 2 by co-doping with Mn2+ and Co2+ • Total of twelve (12) new photocatalytic degradation byproducts of ENX were found. • Toxicity assessment revealed that some of the degradation byproducts are more toxic than ENX. • Additional peroxidase like activity of Mn/Co-TiO 2 was found. [ABSTRACT FROM AUTHOR]

Free-standing Ni-Co alloy nanowire arrays are synthesized via a modified template-assisted electrodeposition method. The structure and composition analysis have been performed by employing X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The highly ordered nanowire arrays show a strong adherence to an alloy transition layer. Herein, the alloy nanowire arrays show higher electrocatalytic activity in terms of lower onset potential and higher peak current density compared to the sample synthesized by conventional deposition route for urea electro-oxidation. Moreover, the electrocatalytic activity can be facilely optimized by selecting the length of nanowire arrays (or the deposition time). The best sample deposited with a time of 600 s possesses an onset oxidation potential of 0.372 V (vs. Hg/HgO) and a peak current density of 322.82 mA cm −2 in 1 M KOH and 0.33 M urea solutions. The sample also shows good stability and activity even after sonication treatment. The excellent electrocatalytic properties of urea oxidation are considered due to the one-dimensional free-standing nanoscale alloy structure, which can largely boost the active sites, facilitate charge transfer, and improve the duration of urea electro-oxidation. [ABSTRACT FROM AUTHOR]

This paper describes a facile method to produce mesoporous nanostructure Ni/Al 2 O 3 , Ni/MgO, and Ni/xMgO.Al 2 O 3 (x: MgO/Al 2 O 3 molar ratio) catalysts prepared by “one-pot” evaporation-induced self-assembly (EISA) method with some modifications for investigating in the thermocatalytic decomposition of methane. Detailed characterizations of the material were performed with X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and N 2 adsorption/desorption, hydrogen temperature-programmed reduction (H 2 -TPR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and temperature-programmed oxidation (TPO). The characterizations demonstrated that the synthesized catalysts with various MgO/Al 2 O 3 molar ratios possessed mesoporous structure with the high BET area in the range of 216.79 to 31.74 m 2 g −1 . The effect of different surfactants and calcination temperatures on the characterizations and catalytic activity of the catalysts were also examined in details. The experimental results showed that the catalysts exhibited high catalytic potential in this process and the 55 wt.% Ni/2 MgO·Al 2 O 3 catalyst calcined at 600 ο C possessed an acceptable methane conversion (∼60%) under the harsh reaction conditions (GHSV = 48000 (mL h −1 g cat −1 )). [ABSTRACT FROM AUTHOR]

Transition metal oxides have attracted considerable attention as possible electrode materials for lithium-ion batteries. However, poor electrical conductivity and volume change during cycling result in low rate capacity and rapid capacity fading, which hinder the practical applications of those electrodes. In this work, we report a facile approach to modify Co 3 O 4 nanoparticles (NPs) by laser irradiation treatment. The structural and composition of the samples were studied by different techniques. The results show that the surface of the as-prepared particles transforms to a thin CoO layer, and oxygen vacancies are generated after the laser treatment. Compared to the as-prepared Co 3 O 4 NPs, the laser treated sample shows a higher reversible capacity of 833.4 mAhg −1 after 100 cycles at a current density of 0.1 Ag -1 . A capacity of 348.4 mAhg −1 can be obtained at a rate of 5 Ag -1 . The unique microstructure that induced by laser irradiation in the Co 3 O 4 NPs is responsible for the improved lithium storage properties. [ABSTRACT FROM AUTHOR]

In this article, the synthesis, characterization and catalytic performance of the Pd and Pt promoted Ni-Cu/MgO·Al 2 O 3 catalysts were investigated in the thermocatalytic dehydrogenation of methane to highly pure hydrogen. The physicochemical properties of the prepared catalysts were investigated using different characterization methods such as XRD, BET, SEM, TEM, XPS, H 2 -TPR and TPO techniques. The Ni–Cu/MgO·Al 2 O 3 catalyst possessing mesoporous structure and large BET surface area (126.28 m 2  g −1 ) was successfully synthesized by facile simultaneous sol-gel method (SSGM) in the absence of surfactants. The results showed that the addition of Pd significantly improved the catalytic activity and stability. The effect of different nominal loadings of palladium (2, 4 and 6 wt%) on the catalytic performance was also studied. Among the prepared samples, the promoted sample with 4 wt% of palladium showed optimal catalytic performance and stability at higher temperatures towards methane thermocatalytic decomposition. [ABSTRACT FROM AUTHOR]

Palladium-based catalysts are highly active for eliminating volatile organic compounds. Reducing the use of noble metals and enhancing performance of a catalyst are always desirable. The three-dimensionally ordered macroporous (3DOM) Mn 2 O 3 -supported transition metal M ( M = Mn, Cr, Fe, and Co)-doped Au–Pd nanoparticles (NPs) with an Au–Pd– xM loading of 1.86–1.97 wt% were prepared using the modified polyvinyl alcohol-protected reduction method. It is found that the Au–Pd– xM NPs with a size of 3.6–4.4 nm were highly dispersed on the surface of 3DOM Mn 2 O 3 . The 1.94 wt% Au–Pd–0.21Co/3DOM Mn 2 O 3 and 1.94 wt% Au–Pd–0.22Fe/3DOM Mn 2 O 3 samples performed the best for the oxidation of methane and o -xylene, respectively. The methane oxidation rate at 340 °C (339.0 × 10 −6 mol/(g Pd s)) over 1.94 wt% Au–Pd–0.21Co/3DOM Mn 2 O 3 was three times higher than that (93.8 × 10 −6 mol/(g Pd s)) over 1.97 wt% Au–Pd/3DOM Mn 2 O 3 , and the o -xylene reaction rate at 140 °C (2.59 μmol/(g N s) over 1.94 wt% Au–Pd–0.22Fe/3DOM Mn 2 O 3 was two times higher than that (0.93 μmol/(g N s) over 1.97 wt% Au–Pd/3DOM Mn 2 O 3 . It is concluded that doping a certain amount of the transition metal to Au–Pd/3DOM Mn 2 O 3 could modify the microstructure of the alloy NPs, thus improving the oxygen activation and methane adsorption ability. We are sure that the M -doped Au–Pd/3DOM Mn 2 O 3 materials are promising catalysts for the efficient removal of volatile organic compounds. [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous (3DOM) CoFe 2 O 4 , z MnO x /3DOM CoFe 2 O 4 ( z = 4.99–12.30 wt%), and y Pd–Pt/6.70 wt% MnO x /3DOM CoFe 2 O 4 ( y = 0.44–1.81 wt%; Pd/Pt molar ratio = 2.1–2.2) have been prepared using the polymethyl methacrylate microspheres-templating, incipient wetness impregnation, and bubble-assisted polyvinyl alcohol-protected reduction strategies, respectively. All of the samples were characterized by means of various techniques. Catalytic performance of the samples was measured for methane combustion. It is shown that the as-prepared samples exhibited a high-quality 3DOM structure (103 ± 20 nm in pore size) and a surface area of 19–28 m 2 /g, and the noble metal or alloy nanoparticles (NPs) with a size of 2.2–3.0 nm were uniformly dispersed on the macropore wall surface of 3DOM CoFe 2 O 4 . The loading of MnO x on CoFe 2 O 4 gave rise to a slight increase in activity, however, the dispersion of Pd–Pt NPs on 6.70MnO x /3DOM CoFe 2 O 4 significantly enhanced the catalytic performance, with the 1.81Pd 2.1 Pt/6.70MnO x /3DOM CoFe 2 O 4 sample showing the highest activity ( T 10% = 255 °C, T 50% = 301 °C, and T 90% = 372 °C at a space velocity of 20,000 mL/(g h)). We believe that the excellent catalytic activity of 1.81Pd 2.1 Pt/6.70MnO x /3DOM CoFe 2 O 4 was related to its well-dispersed Pd–Pt alloy NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between MnO x or Pd–Pt NPs and 3DOM CoFe 2 O 4 . [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchically structured Fe 2 Ni 3 nanoalloy and N-incorporated flower-like carbon matrix. • Synergism between Fe 2 Ni 3 and NFCM essential to achieve first-rate multifunctional performance. • 1.50 V at 10 mA cm−2 and a maintenance up to 76 h for overall water-splitting. • Power density of ∼ 122 mW cm−2 and robust cycling stability for assembled Zn-air battery. • Active species/sites identified through detailed characterizations/comparison studies. A multifunctional electrocatalyst for water splitting and zinc-air battery involves totally-three reactions, namely, oxygen reduction, oxygen evolution, and hydrogen evolution, and is very demanding and challenging. The current study provided an interesting example to achieve such a goal by establishing hierarchical architecture of Fe 2 Ni 3 nanoalloys/N‑incorporated flower-like carbon matrix (Fe 2 Ni 3 -NFCM). The resulting material is free of noble metals and can simultaneously promote the three reactions with excellent activity and robust durability. Significantly, the outstanding parameters ƞ 10 = 280 mV (oxygen evolution), ƞ 10 = 144 mV (hydrogen evolution), and E 1/2 = 0.84 V vs RHE (oxygen reduction) can be accomplished over Fe 2 Ni 3 -NFCM. Moreover, a voltage as low as 1.50 V (10 mA cm−2) and a 76-h durability for water-splitting has been achieved. The assembled Zn-air battery employing the current material as the electrodes can provide the power density being ∼ 122 mW cm−2 plus robust cyclic durability. The multifunctional performance reaches the top level among the various counterparts, the structure-performance correlation has been elucidated and the active species/sites identified through the advanced characterizations and detailed comparison investigations. [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered mesoporous Co 3 O 4 ( meso -Co 3 O 4 ) and its supported Au, Pd, and Au–Pd alloy ( x Au y Pd/ meso -Co 3 O 4 ; x = 0.43–2.94 wt%; Au/Pd molar ratio ( y ) = 0.43–0.50) nanocatalysts were prepared using the KIT-6-templating and polyvinyl alcohol-protected reduction methods, respectively. It is found that the meso -Co 3 O 4 with a high surface area of 106 m 2 /g was cubic in crystal structure and the noble metal nanoparticles (NPs) with a size of 2.7–4.5 nm were uniformly dispersed on the surface of meso -Co 3 O 4 . The 2.94Au 0.50 Pd/ meso -Co 3 O 4 sample performed the best for methane combustion, showing the T 10% , T 50% , and T 90% (temperatures required for achieving methane conversions of 10%, 50%, and 90%) of 230, 280, and 324 °C at a space velocity of 20,000 mL/(g h) and the lowest apparent activation energy of 44.4 kJ/mol. Furthermore, the effects of CO 2 , SO 2 , and H 2 O addition on the catalytic stability of 2.94Au 0.50 Pd/ meso -Co 3 O 4 were also examined. It is concluded that the excellent catalytic performance of 2.94Au 0.50 Pd/ meso -Co 3 O 4 was associated with its porous structure, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Au–Pd alloy NPs and meso -Co 3 O 4 . [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous (3DOM) Mn 2 O 3 -supported AuPd y alloy ( x AuPd y /3DOM Mn 2 O 3 ; x = 1.0–3.8 wt%; Pd/Au molar ratio : y = 1.85, 1.92) catalysts were prepared using the polymethyl methacrylate-templating and polyvinyl alcohol-protected reduction methods, respectively. Physicochemical properties of the samples were characterized by means of numerous techniques, and their catalytic activities were evaluated for toluene oxidation. It is found that the AuPd y alloy nanoparticles (NPs) with an particle size of 2–4 nm were uniformly dispersed on the surface of 3DOM Mn 2 O 3 , and the 3.8AuPd 1.92 /3DOM Mn 2 O 3 sample performed the best: the temperature at 90% toluene conversion was 162 °C at 40,000 mL/(g h). Furthermore, the 3.8AuPd 1.92 /3DOM Mn 2 O 3 sample was highly active even after calcination at 700 °C. The introduction of water vapor to the feedstock induced a positive effect on toluene oxidation over 3.8AuPd 1.92 /3DOM Mn 2 O 3 , but a negative effect over 1.9Au/3DOM Mn 2 O 3 or 1.9Pd/3DOM Mn 2 O 3 . The excellent catalytic activity, thermal stability, and water resistance of 3.8AuPd 1.92 /3DOM Mn 2 O 3 were associated with its good activation adsorption of oxygen on AuPd 1.92 NPs and strong interaction between noble metal NPs and 3DOM Mn 2 O 3 . The 3DOM Mn 2 O 3 -supported AuPd y alloy NPs are promising industrial catalysts for efficient removal of volatile organic compounds. [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous (3DOM) photocatalysts BiVO 4 (denoted as 3D-BiV), AgBr/3D-BiV, and 0.17 wt% M/AgBr/3D-BiV (M Au, Pt, and Pd) were prepared using the polymethyl methacrylate-templating, low-temperature deposition, and polyvinyl alcohol-protected reduction methods, respectively. The as-prepared BiVO 4 possessed a good-quality 3DOM structure and a high surface area. It is found that the AgBr and noble metals were uniformly distributed on the surface of 3D-BiV. Among the M/AgBr/3D-BiV samples, the 0.17 wt% Pd/AgBr/3D-BiV sample showed the highest photocatalytic activity for the degradation of 4-chlorophenol (4-CP) under visible light illumination (i.e., complete 4-CP degradation could be achieved within 150 min), which was associated with its good 3DOM structure, high surface oxygen adspecies concentration, easy transfer and separation of photogenerated carriers, and synergistic effect between AgBr or Pd nanoclusters and BiVO 4 . [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous (3DOM) InVO 4 –BiVO 4 (InBi-3D) and its supported noble metal M nanoparticles ( x M/InBi-3D; x = 0.08–0.13 wt%; M = Au, Ag, Pd, Pt) were prepared using the polymethyl methacrylate-templating and polyvinyl alcohol- or polyvinyl pyrrolidone-assisted reduction methods, respectively. Physical properties of the materials were characterized by a number of analytical techniques. Photocatalytic activities of the x M/InBi-3D samples were evaluated for the degradation of rhodamine B (RhB), methylene blue (MB), and their mixture. It is found that the as-fabricated samples possessed a surface area of 17–30 m 2 /g, a M particle size of 2.5–3.8 nm, and a bandgap energy of 2.50–2.56 eV. The x M/InBi-3D photocatalysts showed high activities for the degradation of RhB, MB, and RhB + MB in the presence of a small amount of H 2 O 2 under visible-light irradiation, among which complete degradation of RhB, MB, and RhB + MB was achieved within 50, 90, and 120 min over 0.08 wt% Au/InBi-3D, respectively. The degradation of MB and RhB fellow the zero- and first-order reaction mechanisms with respect to dye concentration, respectively. It is concluded that the high photocatalytic efficiency of the Au-loaded sample in the removal of organic dyes was associated with its high surface area, high-quality 3DOM hierarchical architecture, InVO 4 –BiVO 4 composite, and high dispersion of gold nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: In this work, cerium–tungsten oxide catalysts were prepared by three methods: single step sol–gel (SG), impregnation (IM), and solid processing (SP). The catalysts were used for selective catalytic reduction (SCR) of NO x with ammonia over a wide temperature range. The results indicated that the catalysts prepared by the SP and IM methods exhibited better SCR activity than that prepared via the SG method in 175–500°C. The excellent activity can be attributed to larger surface area, higher surface concentrations of Ce and Ce3+, enhanced NO oxidization ability, and greater number of surface acid sites. [Copyright &y& Elsevier]

Abstract: Three-dimensionally ordered macroporous (3DOM) monoclinic InVO4 and its supported chromia (yCrO x /3DOM InVO4, y denotes as the weight percentage of Cr2O3, y = 5, 10, 15, and 20 wt%) photocatalysts were fabricated using the ascorbic acid-assisted polymethyl methacrylate-templating and incipient wetness impregnation methods, respectively. Physicochemical properties of the materials were characterized by means of a number of analytical techniques. Photocatalytic activities of the samples were evaluated for the degradation of rhodamine B (RhB) in the presence of H2O2 under visible-light illumination. Compared to 3DOM InVO4 and 15CrO x /bulk InVO4, yCrO x /3DOM InVO4 showed much better visible-light-driven photocatalytic performance for RhB degradation, with the 15CrO x /3DOM InVO4 sample performing the best. It is concluded that the CrO x loading, higher surface area and surface oxygen vacancy density and lower bandgap energy as well as the better quality of 3DOM structure were responsible for the good photocatalytic performance of 15CrO x /3DOM InVO4 for the degradation of RhB. [Copyright &y& Elsevier]

Highlights: [•] 3DOM La0.6Sr0.4MnO3 (LSMO) is prepared by polymethyl methacrylate-templating method. [•] xAu/LSMO catalysts are prepared by the polyvinyl alcohol-protected reduction method. [•] xAu/LSMO perform excellently in the oxidation of CO and toluene. [•] Activity is governed by Oads content, reducibility, and strong Au–LSMO interaction. [ABSTRACT FROM AUTHOR]

Highlights: [•] 3DOM LaCoO3 is prepared by the polymethyl methacrylate-templating method. [•] xAu/3DOM LaCoO3 are prepared by the polyvinyl alcohol-protected reduction method. [•] xAu/3DOM LaCoO3 show high surface area and Oads concentration and good reducibility. [•] xAu/3DOM LaCoO3 perform excellently in the oxidation of CO and toluene. [•] Activity is governed by Oads content, reducibility, and strong Au–LaCoO3 interaction. [Copyright &y& Elsevier]

Highlights: [•] 3DOM InVO4 with nanovoid-like walls are obtained using the PMMA-templating method. [•] 3DOM InVO4 possesses a surface area of 35–52m2/g. [•] 3DOM InVO4 possesses a lower bandgap energy and a higher oxygen vacancy density. [•] 3DOM InVO4 performs excellently for methylene blue photodegradation. [ABSTRACT FROM AUTHOR]

Abstract: The addition of Ge and Mn to CeO2–WO3 catalysts for NH3–SCR of NO x was investigated. The effect of calcination temperature and the influence of SO2 on SCR activity were studied, and heat treatment with H2 was used to regenerate sulfated catalysts. The results showed that doping with Ge and Mn enhanced the SCR activity of Ce3W2O x (molar ratio of Ce:W=3:2) at 100–250°C. More than 95% NO x conversions were obtained between 200 and 470°C over (Ce3W2)0.9Ge0.1O x -500 (molar ratio of (Ce+W):Ge=9:1, calcined at 500°C) catalyst. The characterization results indicated that the formation of amorphous phase and high atomic ratio of W/Ce on the surface might contribute to the high activity over (Ce3W2)0.9Ge0.1O x -500. The NO x conversions decreased over Ce3W2O x series catalysts calcined at 700°C, however, the activities of (Ce3W2)0.9Ge0.1O x calcined at 700°C were higher than those of the others, suggesting the addition of Ge weakened the effect of high calcination temperature. The deactivation of (Ce3W2)0.9Ge0.1O x -500 by SO2 was much slower than that of Ce3W2O x -500. The sulfated (Ce3W2)0.9Ge0.1O x -500 catalysts could be easily regenerated by heat treating with H2 at 300°C since the sulfates species were unstable over these catalysts. H2 regeneration is an effective way to recycle GeO2–CeO2–WO3 catalyst. [Copyright &y& Elsevier]

Transition metal oxide (TMO) anodes show promising applications in energy storage due to the unique physical and chemical properties and high theoretical capacity to storage ions. Their practical usages are restricted by low intrinsic electronic conductivity, sluggish ionic diffusion, and large volume change during continuous cycling. In this work, we propose a strategy of selective solution-phase reduction on specific crystalline planes to generate the defect chemistry and thus improve the intrinsic electronic conductivity. Taking Co 3 O 4 electrode as a typical example, we prepared the structures with different exposed planes, which were then subjected to solution-phase reduction at room temperature. When used as the electrodes for lithium ion batteries, the optimized material possesses a high reversible capacity of 873.5 mAh g−1 at a current of 0.1 A g−1, even at a large current density of 5 A g−1, a remarkable discharge capacity of 569.1 mA h g−1 can still be achieved. The improved performance is attributed to the synergistic effects of the optimized amount of Co2+ species and oxygen vacancies. The current strategy can be extended to other TMO electrodes, paving an alternative way to optimize the electrochemical performance for different applications. Selective solution-phase reduction on specific exposed crystalline planes generates defect structures and thus improves the lithium storage properties in a given material. Image 1 • Exposed crystalline planes are selective reduced in solution. • Defect structures can be generated. • The optimized sample exhibits enhanced lithium storage properties. [ABSTRACT FROM AUTHOR]

The synthesis of mesoporous organosilicas (MOs) using co-condensation for a high ratio of a long and flexible chained organosiloxane bridge with silica precursor (e.g. tetraethylorthosilicate (TEOS)) is a complex and challenging task. By complementing the experimental characterisations with density functional calculations, The critical ratio of the urea-based organosiloxane bridge (BTPU) to tetraethyl orthosilicate of 1:8 was identified to delivers reliably stable urea bridged MO (MO-urea) with relatively large surface area and mesoporosity. Moreover, the Pd nanoparticles supported on the pore channels of MO-urea achieve a narrow distribution size averaging at a diameter of ~2 nm. This fine distribution is driven by the Pd nanoparticles nucleating only on the exposed SiO 2 section of MO-urea while the BTPU bridges punctuate the growth of the Pd nanoparticles limiting their size. As a result, the obtained Pd@MO-urea exhibits excellent multifunctional catalytic activity for hydrogen production from formic acid and p-nitrophenol (PN) reduction in aqueous media with four folds increase in yield compared to the non-punctuated Pd nanoparticles. Image 1 • Urea-based bridges in mesoporous organosilica punctuate the growth of Pd nanoparticles. • Pd nanoparticles on urea-bridged mesoporous organosilica grow uniformly at ~2 nm. • Leading to a multifunctional catalyst, e.g. H 2 production from formic acid and nitroaromatic reduction. [ABSTRACT FROM AUTHOR]

Producing green hydrogen in a cost-competitive manner via water electrolysis will make the long-held dream of hydrogen economy a reality. Although platinum (Pt)-based catalysts show good performance toward hydrogen evolution reaction (HER), the high cost and scarce abundance challenge their economic viability and sustainability. Here, a non-Pt, high-performance electrocatalyst for HER achieved by engineering high fractions of stacking fault (SF) defects for MoNi 4 /MoO 2 nanosheets (d-MoNi) through a combined chemical and thermal reduction strategy is shown. The d-MoNi catalyst offers ultralow overpotentials of 78 and 121 mV for HER at current densities of 500 and 1000 mA cm -2 in 1 M KOH, respectively. The defect-rich d-MoNi exhibits four times higher turnover frequency than the benchmark 20% Pt/C, together with its excellent durability (> 100 h), making it one of the best-performing non-Pt catalysts for HER. The experimental and theoretical results reveal that the abundant SFs in d-MoNi induce a compressive strain, decreasing the proton adsorption energy and promoting the associated combination of *H into hydrogen and molecular hydrogen desorption, enhancing the HER performance. This work provides a new synthetic route to engineer defective metal and metal alloy electrocatalysts for emerging electrochemical energy conversion and storage applications., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Metal-organic frameworks (MOFs) are highly regarded as valuable adsorbent materials in materials science, particularly in the field of CO 2 capture. While numerous single-metal-based MOFs have demonstrated exceptional CO 2 adsorption capabilities, recent advancements have explored the potential of bimetallic MOFs for enhanced performance. In this study, a CuCe-BTC MOF was synthesized through a straightforward hydrothermal method, and its improved properties, such as high surface area, smaller pore size, and larger pore volume, were compared with those of the bare Ce-BTC. The impact of the Cu/Ce ratio (1:4, 1:2, 1:1, and 3:2) was systematically investigated to understand how adding a second metal influences the CO 2 adsorption performance of the Ce-BTC MOF. Various characterization techniques, including scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and N 2 BET surface area analysis, were employed to assess the physical and chemical properties of the bare Ce-BTC and CuCe-BTC samples. Notably, CuCe-BTC-1:2 exhibited superior surface area (133 m 2 g -1 ), small pore size (3.3 nm), and large pore volume (0.14 cm 3 g -1 ) compared to the monometallic Ce-BTC. Furthermore, CuCe-BTC-1:2 demonstrated a superior CO 2 adsorption capacity (0.74 mmol g -1 ), long-term stability, and good CO 2 /N 2 selectivity. This research provides valuable insights into the design of metal-BTC frameworks and elucidates how introducing a second metal enhances the properties of the monometallic Ce-BTC-MOF, leading to improved CO 2 capture performance.

Green hydrogen, derived from water splitting powered by renewable energy such as solar and wind energy, provides a zero-emission solution crucial for revolutionizing hydrogen production and decarbonizing industries. Catalysts, particularly those utilizing defect engineering involving the strategical introduction of atomic-level imperfections, play a vital role in reducing energy requirements and enabling a more sustainable transition toward a hydrogen-based economy. Stacking fault (SF) defects play an important role in enhancing the electrocatalytic processes by reshaping surface reactivity, increasing active sites, improving reactants/product diffusion, and regulating electronic structure due to their dense generation ability and profound impact on catalyst properties. This review explores SF in metal-based materials, covering synthetic methods for the intentional introduction of SF and their applications in hydrogen production, including oxygen evolution reaction, photo- and electrocatalytic hydrogen evolution reaction, overall water splitting, and various other electrocatalytic processes such as oxygen reduction reaction, nitrate reduction reaction, and carbon dioxide reduction reaction. Finally, this review addresses the challenges associated with SF-based catalysts, emphasizing the importance of a detailed understanding of the properties of SF-based catalysts to optimize their electrocatalytic performance. It provides a comprehensive overview of their various applications in electrocatalytic processes, providing valuable insights for advancing sustainable energy technologies., (© 2024 The Authors. Advanced Materials published by Wiley‐VCH GmbH.)

Developing sustainable energy solutions to safeguard the environment is a critical ongoing demand. Electrochemical water splitting (EWS) is a green approach to create effective and long-lasting electrocatalysts for the water oxidation process. Metal organic frameworks (MOFs) have become commonly utilized materials in recent years because of their distinguishing pore architectures, metal nodes easy accessibility, large specific surface areas, shape, and adaptable function. This review outlines the most significant developments in current work on developing improved MOFs for enhancing EWS. The benefits and drawbacks of MOFs are first discussed in this review. Then, some cutting-edge methods for successfully modifying MOFs are also highlighted. Recent progress on nickel (Ni) and iron (Fe) based MOFs have been critically discussed. Finally, a comprehensive analysis of the existing challenges and prospects for Ni- and Fe-based MOFs are summarized.

Materials derived from metal-organic frameworks (MOFs) have demonstrated exceptional structural variety and complexity and can be synthesized using low-cost scalable methods. Although the inherent instability and low electrical conductivity of MOFs are largely responsible for their low uptake for catalysis and energy storage, a superior alternative is MOF-derived metal-based derivatives (MDs) as these can retain the complex nanostructures of MOFs while exhibiting stability and electrical conductivities of several orders of magnitude higher. The present work comprehensively reviews MDs in terms of synthesis and their nanostructural design, including oxides, sulfides, phosphides, nitrides, carbides, transition metals, and other minor species. The focal point of the approach is the identification and rationalization of the design parameters that lead to the generation of optimal compositions, structures, nanostructures, and resultant performance parameters. The aim of this approach is to provide an inclusive platform for the strategies to design and process these materials for specific applications. This work is complemented by detailed figures that both summarize the design and processing approaches that have been reported and indicate potential trajectories for development. The work is also supported by comprehensive and up-to-date tabular coverage of the reported studies., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Li 7 La 3 Zr 2 O 12 (LLZO)-based solid-state Li batteries (SSLBs) have emerged as one of the most promising energy storage systems due to the potential advantages of solid-state electrolytes (SSEs), such as ionic conductivity, mechanical strength, chemical stability and electrochemical stability. However, there remain several scientific and technical obstacles that need to be tackled before they can be commercialised. The main issues include the degradation and deterioration of SSEs and electrode materials, ambiguity in the Li + migration routes in SSEs, and interface compatibility between SSEs and electrodes during the charging and discharging processes. Using conventional ex situ characterization techniques to unravel the reasons that lead to these adverse results often requires disassembly of the battery after operation. The sample may be contaminated during the disassembly process, resulting in changes in the material properties within the battery. In contrast, in situ / operando characterization techniques can capture dynamic information during cycling, enabling real-time monitoring of batteries. Therefore, in this review, we briefly illustrate the key challenges currently faced by LLZO-based SSLBs, review recent efforts to study LLZO-based SSLBs using various in situ / operando microscopy and spectroscopy techniques, and elaborate on the capabilities and limitations of these in situ / operando techniques. This review paper not only presents the current challenges but also outlines future developmental prospects for the practical implementation of LLZO-based SSLBs. By identifying and addressing the remaining challenges, this review aims to enhance the comprehensive understanding of LLZO-based SSLBs. Additionally, in situ / operando characterization techniques are highlighted as a promising avenue for future research. The findings presented here can serve as a reference for battery research and provide valuable insights for the development of different types of solid-state batteries.

Metal tellurides (MTs) have emerged as highly promising candidate anode materials for state-of-the-art lithium-ion batteries (LIBs) and sodium ion batteries (SIBs). This is owing to the unique crystal structure, high intrinsic conductivity, and high trap density of such materials. The present work delivers a detailed discussion on the latest research and progress associated with the use of MTs for LIBs/SIBs with a focus on reaction mechanisms, challenges, electrochemical performance, and synthesis strategies. Further, the prospects and future development of MT anode materials are discussed in terms of strategies to overcome the existing limitations. This review provides both an in-depth understanding of MTs and provides the driving force for expanding research on MTs for energy storage and conversion applications.

Perovskite oxides are regarded as promising electrocatalysts for water splitting due to their cost-effectiveness, high efficiency and durability in the oxygen evolution reaction (OER). Despite these advantages, a fundamental understanding of how critical structural parameters of perovskite electrocatalysts influence their activity and stability is lacking. Here, we investigate the impact of structural defects on OER performance for representative LaNiO 3 perovskite electrocatalysts. Hydrogen reduction of 700 °C calcined LaNiO 3 induces a high density of surface oxygen vacancies, and confers significantly enhanced OER activity and stability compared to unreduced LaNiO 3 ; the former exhibit a low onset overpotential of 380 mV at 10 mA cm -2 and a small Tafel slope of 70.8 mV dec -1 . Oxygen vacancy formation is accompanied by mixed Ni 2+ /Ni 3+ valence states, which quantum-chemical DFT calculations reveal modify the perovskite electronic structure. Further, it reveals that the formation of oxygen vacancies is thermodynamically more favourable on the surface than in the bulk; it increases the electronic conductivity of reduced LaNiO 3 in accordance with the enhanced OER activity that is observed., (© 2021 Wiley-VCH GmbH.)

Oxide perovskites have emerged as an important class of materials with important applications in many technological areas, particularly thermocatalysis, electrocatalysis, photocatalysis, and energy storage. However, their implementation faces numerous challenges that are familiar to the chemist and materials scientist. The present work surveys the state-of-the-art by integrating these two viewpoints, focusing on the critical role that defect engineering plays in the design, fabrication, modification, and application of these materials. An extensive review of experimental and simulation studies of the synthesis and performance of oxide perovskites and devices containing these materials is coupled with exposition of the fundamental and applied aspects of defect equilibria. The aim of this approach is to elucidate how these issues can be integrated in order to shed light on the interpretation of the data and what trajectories are suggested by them. This critical examination has revealed a number of areas in which the review can provide a greater understanding. These include considerations of (1) the nature and formation of solid solutions, (2) site filling and stoichiometry, (3) the rationale for the design of defective oxide perovskites, and (4) the complex mechanisms of charge compensation and charge transfer. The review concludes with some proposed strategies to address the challenges in the future development of oxide perovskites and their applications.

The architectural design of nanocatalysts plays a critical role in the achievement of high densities of active sites but current technologies are hindered by process complexity and limited scaleability. The present work introduces a rapid, flexible, and template-free method to synthesize three-dimensional (3D), mesoporous, CeO 2-x nanostructures comprised of extremely thin holey two-dimensional (2D) nanosheets of centimetre-scale. The process leverages the controlled conversion of stacked nanosheets of a newly developed Ce-based coordination polymer into a range of stable oxide morphologies controllably differentiated by the oxidation kinetics. The resultant polycrystalline, hybrid, 2D-3D CeO 2-x exhibits high densities of defects and surface area as high as 251 m 2 g -1 , which yield an outstanding CO conversion performance (T 90% = 148 °C) for all oxides. Modification by the creation of heterojunction nanostructures using transition metal oxides (TMOs) results in further improvements in performance (T 90% = 88 °C), which are interpreted in terms of the active sites associated with the TMOs that are identified through structural analyses and density functional theory (DFT) simulations. This unparalleled catalytic performance for CO conversion is possible through the ultra-high surface areas, defect densities, and pore volumes. This technology offers the capacity to establish efficient pathways to engineer nanostructures of advanced functionalities for catalysis.

Aluminum trimesate-based MOF (MIL-96-(Al)) has attracted intense attention due to its high chemical stability and strong CO 2 adsorption capacity. In this study, CO 2 capture and selectivity of MIL-96-Al was further improved by the coordination of the second metal Ca. To this end, a series of MIL-96(Al)-Ca were hydrothermally synthesised by a one-pot method, varying the molar ratio of Ca 2+ /Al 3+ . It is shown that the variation of Ca 2+ /Al 3+ ratio results in significant changes in crystal shape and size. The shape varies from the hexagonal rods capped in the ends by a hexagonal pyramid in MIL-96(Al) without Ca to the thin hexagonal disks in MIL-96(Al)-Ca4 (the highest Ca content). Adsorption studies reveal that the CO 2 adsorption on MIL-96(Al)-Ca1 and MIL-96(Al)-Ca2 at pressures up to 950 kPa is vastly improved due to the enhanced pore volumes compared to MIL-96(Al). The CO 2 uptake on these materials measured in the above sequence is 10.22, 9.38 and 8.09 mmol g -1 , respectively. However, the CO 2 uptake reduces to 5.26 mmol g -1 on MIL-96(Al)-Ca4. Compared with MIL-96(Al)-Ca1, the N 2 adsorption in MIL-96(Al)-Ca4 is significantly reduced by 90% at similar operational conditions. At 100 and 28.8 kPa, the selectivity of MIL-96(Al)-Ca4 to CO 2 /N 2 reaches up to 67 and 841.42, respectively, which is equivalent to 5 and 26 times the selectivity of MIL-96(Al). The present findings highlight that MIL-96(Al) with second metal Ca coordination is a potential candidate as an alternative CO 2 adsorbent for practical applications., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

A simple, practical and precise method for the simultaneous analysis of 32 different polycyclic aromatic hydrocarbon (PAHs) including 16 parent PAHs, 8 oxygenated-PAHs (oxy-PAHs), 4 chloro-PAHs, and 4 nitrogen-containing heterocyclic PACs (N-PACs), in groundwater was established via gas chromatography-mass spectrometry (GC-MS) combined with liquid-liquid extraction (LLE). The obtained detection method possesses instrument detection limits (at a signal to noise of 3:1) in the range of 0.05-10 ng/mL and method detection limits in the range of 1.7-13.2 ng/L. The average recoveries of the 32 analytes were in the range of 54.3%-127.0% with relative standard deviations (RSDs) < 20%, and the recoveries of 16 PAH derivatives ranged from 54.3 to 115.1% with RSDs < 17.9%. The method has been successfully applied to the screening of 64 groundwater samples from eastern China. The results revealed that 30 types of targets including 16 PAHs and 14 PAH derivatives were detected and that the groundwater in most areas is slightly polluted, while the pollution of Jiangsu Province and Shandong Province was more serious.

Unique CO 2 methanation catalysts comprising bimetallic Ni-Rh nanoalloy/3DOM LaAlO 3 have been successfully prepared via a poly(methyl methacrylate) microsphere colloidal crystal-templating route, followed by the in situ growth of Ni nanoparticles (NPs). Here, we show that unlike traditional Ni particles deposited on a perovskite support, the exsolution of Ni occurs on both the external and internal surface of the porous perovskite substrate, leading to a strong metal-support interaction. Owing to the exsolution of Ni and the formation of Ni-Rh nanoalloys, a 52% enhancement in the methanation turnover frequency was obtained over the Ni-Rh/3DOM LaAlO 3 [13.9 mol/(mol h)] compared to Rh/3DOM LaNi 0.08 Al 0.92 O 3 [9.16 mol/(mol h)] before reduction treatment. The results show that the low-temperature reducibility, rich surface adsorbed oxygen species, and basic sites of the catalyst greatly improve its activity toward CO 2 methanation. The hierarchically porous structure of the perovskite support provides a high dispersion of bimetallic Ni-Rh NPs.

Highly dispersed Pt nanoparticles supported on high-surface-area 3D ordered macroporous (3DOM) Ce0.6 Zr0.3 Y0.1 O2 (CZY) are synthesized via a bubbling cetyltrimethyl ammonium bromide/P123-assisted reduction route. The 1.1 wt% Pt/3DOM CZY catalyst shows supercatalytic activity for methane combustion, which is attributed to a higher oxygen adspecies amount, larger surface area, better low-temperature reducibility, and unique nanovoid-walled 3DOM structure., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Three-dimensionally ordered macroporous (3DOM) Mn2O3 and its supported gold (xAu/3DOM Mn2O3, x=1.9-7.5wt%) nanocatalysts were prepared using the polymethyl methacrylate-templating and polyvinyl alcohol-protected reduction methods, respectively. The 3DOM Mn2O3 and xAu/3DOM Mn2O3 samples exhibited a surface area of 34-38m(2)/g. The Au nanoparticles (NPs) with a size of 3.0-3.5nm were uniformly dispersed on the skeletons of 3DOM Mn2O3. The 5.8Au/3DOM Mn2O3 sample performed the best, giving the T90% (the temperature required for a conversion of 90%) of -15°C at space velocity (SV)=20,000mL/(gh) for CO oxidation and 244°C at SV=40,000mL/(gh) for toluene oxidation. The apparent activation energies (30 and 54kJ/mol) over 5.8Au/3DOM Mn2O3 were much lower than those (80 and 95kJ/mol) over 3DOM Mn2O3 for CO and toluene oxidation, respectively. The effects of SV, water vapor, CO2, and SO2 on catalytic activity were also examined. It is concluded that the excellent catalytic performance of 5.8Au/3DOM Mn2O3 was associated with its high oxygen adspecies concentration, good low-temperature reducibility, and strong interaction between Au NPs and 3DOM Mn2O3 as well as high-quality porous architecture., (Copyright © 2014 Elsevier B.V. All rights reserved.)