Facile microwave-assisted synthesis of In2O3 nanocubes and their application in photocatalytic degradation of tetracycline

Novel In₂O₃ nanocube photocatalysts were successfully prepared by a facile microwave-assisted synthesis method. The obtained products are nano-sized with square corners and high crystallinity. The In₂O₃ nanocubes possessed high efficiency of electron–hole separation, resulting in high photocatalytic activities for the degradation of tetracycline under both visible light (λ > 420 nm) and full-range light irradiation (360–760 nm), the ratios of which are 39.3% and 61.0%, respectively. Moreover, the calculated positions of the CB and VB under our experimental conditions at the point of zero for In₂O₃ nanocubes are −0.60 V and +2.17 V, respectively. Note that the redox potentials of [O₂/·O₂⁻] and [·OH/OH⁻] are −0.33 V and +2.38 V, respectively, which means that the irradiated In₂O₃ nanocubes can reduce O₂ into ·O₂⁻ without oxidizing OH⁻ into ·OH. It can be concluded that ·O₂⁻ and h⁺ are the main active species of In₂O₃ in aqueous solution under visible light irradiation and full-range light irradiation.

Novel In₂O₃ nanocube photocatalysts were successfully prepared by a facile microwave-assisted synthesis method.     

Correction: Influence of Cu doping on the visible-light-induced photocatalytic activity of InVO4

Correction for ‘Influence of Cu doping on the visible-light-induced photocatalytic activity of InVO₄’ by Natda Wetchakun et al., RSC Adv., 2017, 7, 13911–13918, DOI: 10.1039/C6RA27138C.

The authors regret errors in Fig. 4, ​,7,7, and 9 in the previously published article. The corrections for the errors in the article are described as follows:Open in a separate windowFig. 4Kubelka–Munk absorbance spectra and band gaps (insets) of the pure InVO₄ (a) and 1.0 mol% Cu-doped InVO₄ (b) samples.Open in a separate windowFig. 7Schematic of the charge migration and separation on Cu-doped InVO₄.(1) The diffuse reflectance spectra of pure InVO₄ and 1.0 mol% Cu-doped InVO₄ are shown in Fig. 4. The absorption margin of 1.0 mol% Cu-doped InVO₄ was shifted to a longer wavelength, indicating a decrease in the band gap with respect to pure InVO₄. The absorption margins of the pure InVO₄ and 1.0 mol% Cu-doped InVO₄ samples were 505 nm and 510 nm, corresponding to band gaps of 2.51 eV and 2.45 eV, respectively (Fig. 4a and b).(2) The band edge positions of the conduction band (CB) and the valence band (VB) of InVO₄ can be calculated by the following equation: E⁰_CB = χ − E^C − 0.5E_g,¹ where χ is the electronegativity of the semiconductor, E^C is the energy of free electrons on the hydrogen scale of 4.5 eV, E_g is the band gap of InVO₄, and the χ value of InVO₄ is 5.74 eV.² The E_g value of InVO₄ evaluated from the UV-vis DRS analysis was about 2.51 eV. The valence band energy (E_VB) can be calculated by the following equation:³E_VB = E_CB + E_g, where E_CB is the conduction band energy. Based on the equation above, the calculated CB and VB edge potentials of InVO₄ were −0.02 eV and 2.49 eV, respectively. Now, we are in a position to discuss the photocatalytic mechanism of Cu-doped InVO₄ for MB degradation (Fig. 7). In the photocatalysis process, when the absorbed photon energy (hν) equals or exceeds the band gap, the Cu-doped InVO₄ generates electron–hole (e⁻/h⁺) pairs. In that case, the generated electrons from the valence band can be transferred to the conduction band of InVO₄. Since the CB edge potential of InVO₄ (−0.02 eV) is higher than the standard redox potential, E⁰(O₂/O₂˙⁻) = −0.33 V vs. NHE at pH 7, this suggests that the electrons in the CB of InVO₄ cannot reduce O₂ to the superoxide radical ion (O₂˙⁻). In addition, the VB of InVO₄ (2.49 eV) is higher than the standard redox potential, E⁰(OH⁻/OH˙) = 1.99 V vs. NHE at pH 7. This indicates that the photogenerated holes in the valence band of InVO₄ can oxidize the hydroxyl ion (OH⁻) or water (H₂O) to form the hydroxyl radical (OH˙).(3) Due to the contradiction between the scavenging test and the proposed photocatalytic mechanism, Fig. 9 was removed from the original article.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.     

Ag2Mo2O7: an oxide solid-state Ag+ electrolyte

Ag₂Mo₂O₇ powders and micro-crystals were prepared at 400 °C for 24 h and 500 °C for 6 h using solid-state reactions. The Ag₂Mo₂O₇ samples crystalized in a triclinic P$\bar{1}$ space group with the cell parameters a = 6.0972(1) Å, b = 7.5073(1) Å, c = 7.6779(2) Å, α = 110.43(1)°, β = 93.17(1)°, γ = 113.51(1)°, and V = 294.17(1) ų from Rietveld refinements. Ag₂Mo₂O₇ powder is homogeneous with size of 2–8 μm and the ceramic pellets are in good sintering conditions with a relative density ∼93%. The indirect band gaps E_g(i) of Ag₂Mo₂O₇ from reflectance measurements and DFT calculations are 2.63(1) and 1.80 eV. The vibrational modes of Ag₂Mo₂O₇ were investigated by first-principles (DFT) calculations and Raman spectrum measurements with 24 of 33 predicted Raman modes recorded. According to DOS analyses, the valence bands (VB) of Ag₂Mo₂O₇ are mainly constituted of O-2p and Ag-4d orbitals, while the conduction bands (CB) are mainly composed of Mo-4d and the O-2p orbitals. Regarding the impedance analysis, Ag₂Mo₂O₇ is a silver oxide ion electrolyte with a conductivity of ∼5 × 10⁻⁴ S cm⁻¹ at 450 °C. The carrier activation energy of Ag₂Mo₂O₇ is 0.88(3) eV from the temperature dependent conductivity measurements.

Ag₂Mo₂O₇ is an oxide solid-state Ag⁺ electrolyte with the conductivity ∼5 × 10⁻⁴ S cm⁻¹ at 450 °C and carrier activation energy 0.88(3) eV.     

Arrangement of water molecules and high proton conductivity of tunnel structure phosphates,KMg1−xH2x(PO3)3·yH2O

A fast proton conductor was investigated in a mixed-valence system of phosphates with a combination of large cations (K⁺) and small cations (Mg²⁺), which resulted in a new phase with a tunnel structure suitable for proton conduction. KMg_1−xH_2x(PO₃)₃·yH₂O was synthesized by a coprecipitation method. A solid solution formed in the range of x = 0–0.18 in KMg_1−xH_2x(PO₃)₃·yH₂O. The structure of the new proton conductor was determined using neutron and X-ray diffraction measurements. KMg_1−xH_2x(PO₃)₃·yH₂O has a tunnel framework composed of face-shared (KO₆) and (MgO₆) chains, and PO₄ tetrahedral chains along the c-direction by corner-sharing. Two oxygen sites of water molecules were detected in the one-dimensional tunnel, one of which exists as a coordination water of K⁺ sites. Multi-step dehydration was observed at 30 °C and 150 °C from thermogravimetric/differential thermal analysis measurements, which reflects the different coordination environments of the water of crystallization. Water molecules are connected to PO₄ tetrahedra by hydrogen bonds and form a chain along the c-axis in the tunnel, which would provide an environment for fast proton conduction associated with water molecules. The KMg_1−xH_2x(PO₃)₃·yH₂O sample with x = 0.18 exhibited high proton conductivity of 4.5 × 10⁻³ S cm⁻¹ at 150 °C and 7.0 × 10⁻³ S cm⁻¹ at 200 °C in a dry Ar gas flow and maintained the total conductivity above 10⁻³ S cm⁻¹ for 60 h at 150 °C under N₂ gas atmosphere.

A fast proton conductor exhibiting high proton conductivity of 7.0 × 10⁻³ S cm⁻¹ at 200 °C in a dry Ar gas flow was developed by designing water chains in a rigid tunnel framework.     

MOF-derived (MoS2, γ-Fe2O3)/graphene Z-scheme photocatalysts with excellent activity for oxygen evolution under visible light irradiation

Constructing Z-scheme heterojunctions is considered as an effective strategy to obtain catalysts of high efficiency in electron–hole separation in photocatalysis. Unfortunately, suitable heterojunctions are difficult to fabricate because the direct interaction between two semiconductors may lead to unpredictable negative effects such as electron scattering or electron trapping due to the existence of defects which causes the formation of new substances. Furthermore, the van der Waals contact between two semiconductors also results in bad electron diffusion. In this work, a MOF-derived carbon material as a Z-scheme photocatalyst was synthesized via one-step thermal treatment of MoS₂ dots @Fe-MOF (MIL-101). Under visible light irradiation, the well-constructed Z-scheme (MoS₂, γ-Fe₂O₃)/graphene photocatalyst shows 2-fold photocatalytic oxygen evolution activity (4400 μmol g⁻¹ h⁻¹) compared to that of γ-Fe₂O₃/graphene (2053 μmol g⁻¹ h⁻¹). Based on ultraviolet photoelectron spectrometry (UPS), Mott–Schottky plot, photocurrent and photoluminescence spectroscopy (PL) results, the photo-induced electrons from the conduction band of γ-Fe₂O₃ could transport quickly to the valence band of MoS₂via highly conductive graphene as an electron transport channel, which could significantly enhance the electron–hole separation efficiency as well as photocatalytic performance.

The heterojunction between MoS₂ and γ-Fe₂O₃ was constructed via linking by in situ formed graphene, which resulted in a good photocatalyst for the oxygen evolution reaction, showing O₂ evolution activity of 4400 μmol g⁻¹ h⁻¹.     

Nanostructured RuO2–Co3O4@RuCo-EO with low Ru loading as a high-efficiency electrochemical oxygen evolution catalyst

Electrochemical water splitting technology is considered to be the most reliable method for converting renewable energy such as wind and solar energy into hydrogen. Here, a nanostructured RuO₂/Co₃O₄–RuCo-EO electrode is designed via magnetron sputtering combined with electrochemical oxidation for the oxygen evolution reaction (OER) in an alkaline medium. The optimized RuO₂/Co₃O₄–RuCo-EO electrode with a Ru loading of 0.064 mg cm⁻² exhibits excellent electrocatalytic performance with a low overpotential of 220 mV at the current density of 10 mA cm⁻² and a low Tafel slope of 59.9 mV dec⁻¹ for the OER. Compared with RuO₂ prepared by thermal decomposition, its overpotential is reduced by 82 mV. Meanwhile, compared with RuO₂ prepared by magnetron sputtering, the overpotential is also reduced by 74 mV. Furthermore, compared with the RuO₂/Ru with core–shell structure (η = 244 mV), the overpotential is still decreased by 24 mV. Therefore, the RuO₂/Co₃O₄–RuCo-EO electrode has excellent OER activity. There are two reasons for the improvement of the OER activity. On the one hand, the core–shell structure is conducive to electron transport, and on the other hand, the addition of Co adjusts the electronic structure of Ru.

The optimized RuO₂/Co₃O₄–RuCo-EO electrode with Ru loading of 0.064 mg cm⁻² exhibits the excellent oxygen evolution activity with an overpotential of 220 mV at the current density of 10 mA cm⁻² and a Tafel slope of 59.9 mV dec⁻¹.     

Atomic layer deposition of dielectric Y2O3 thin films from a homoleptic yttrium formamidinate precursor and water

We report the application of tris(N,N′-diisopropyl-formamidinato)yttrium(iii) [Y(DPfAMD)₃] as a promising precursor in a water-assisted thermal atomic layer deposition (ALD) process for the fabrication of high quality Y₂O₃ thin films in a wide temperature range of 150 °C to 325 °C. This precursor exhibits distinct advantages such as improved chemical and thermal stability over the existing Y₂O₃ ALD precursors including the homoleptic and closely related yttrium tris-amidinate [Y(DPAMD)₃] and tris-guanidinate [Y(DPDMG)₃], leading to excellent thin film characteristics. Smooth, homogeneous, and polycrystalline (fcc) Y₂O₃ thin films were deposited at 300 °C with a growth rate of 1.36 Å per cycle. At this temperature, contamination levels of C and N were under the detectable limits of nuclear reaction analysis (NRA), while X-ray photoelectron spectroscopy (XPS) measurements confirmed the high purity and stoichiometry of the thin films. From the electrical characterization of metal–insulator–semiconductor (MIS) devices, a permittivity of 13.9 at 1 MHz could be obtained, while the electric breakdown field is in the range of 4.2 and 6.1 MV cm⁻¹. Furthermore, an interface trap density of 1.25 × 10¹¹ cm⁻² and low leakage current density around 10⁻⁷ A cm⁻² at 2 MV cm⁻¹ are determined, which satisfies the requirements of gate oxides for complementary metal-oxide-semiconductor (CMOS) based applications.

In this work, the application of tris(N,N′-diisopropyl-formamidinato)yttrium(iii) [Y(DPfAMD)₃] as a precursor in a water-assisted thermal atomic layer deposition (ALD) process for the fabrication of device quality Y₂O₃ thin films is demonstrated.     

Influence of Al2O3 nanoparticle doping on depolarization temperature,and electrical and energy harvesting properties of lead-free 0.94(Bi0.5Na0.5)TiO3–0.06BaTiO3 ceramics

In this research article, the effects of Al₂O₃ nanoparticles (0–1.0 mol%) on the phase formation, microstructure, dielectric, ferroelectric, piezoelectric, electric field-induced strain and energy harvesting properties of the 0.94(Bi_0.5Na_0.5)TiO₃–0.06BaTiO₃ (BNT–6BT) ceramic were investigated. All ceramics have been synthesized by a conventional mixed oxide method. The XRD and Raman spectra showed coexisting rhombohedral and tetragonal phases throughout the entire compositional range. An increase of the grain size, T_F–R, T_m, ε_max and δ_A values was noticeable when Al₂O₃ was added. Depolarization temperature (T_d), which was determined by the thermally stimulated depolarization current (TSDC), tended to increase with Al₂O₃ content. The good ferroelectric properties (P_r = 32.64 μC cm⁻², E_c = 30.59 kV cm⁻¹) and large low-field d₃₃ (205 pC N⁻¹) values were observed for the 0.1 mol% Al₂O₃ ceramic. The small Al₂O₃ additive improved the electric field-induced strain (S_max and ). The 1.0 mol% Al₂O₃ ceramic had a large piezoelectric voltage coefficient (g₃₃ = 32.6 × 10⁻³ Vm N⁻¹) and good dielectric properties (ε_r,max = 6542, T_d = 93 °C, T_F–R = 108 °C, T_m = 324 °C and δ_A = 164 K). The highest off-resonance figure of merit (FoM) for energy harvesting of 6.36 pm² N⁻¹ was also observed for the 1.0 mol% Al₂O₃ ceramic, which is suggesting that this ceramic has potential to be one of the promising lead-free piezoelectric candidates for further use in energy harvesting applications.

In this research article, the effects of Al₂O₃ nanoparticles (0–1.0 mol%) on the phase, microstructure, dielectric, ferroelectric, piezoelectric, electric field-induced strain and energy harvesting of the BNT–6BT ceramic were investigated.     

Photoreduction properties of novel Z-scheme structured Sr0.8La0.2(Ti1−δ4+Tiδ3+)O3/Bi2MoO6 composites for the removal of Cr(vi)

Novel Z-scheme structured Sr_0.8La_0.2(Ti_1−δ⁴⁺Ti_δ³⁺)O₃/Bi₂MoO₆ (LSTBM) composites were prepared via a facile two-step solvothermal method. Several characterization techniques were employed to investigate the phases, microstructures, compositions, valence states, oxygen vacancies, surface oxygen absorption, energy band structures and lifetime of photoproduced carriers. It was found that the lifetime and transfer of the photoproduced carriers of LSTBM were better than those of Bi₂MoO₆ (BMO) and Sr_0.8La_0.2(Ti_1−δ⁴⁺Ti_δ³⁺)O₃ (LSTO). The LSTBM with a molar ratio of BMO/(LSTO + BMO) = 0.07 (denoted as LSTBM7) showed 1.9 and 3.1 times removal rates than those for BMO and LSTO, respectively. Importantly, the built-in electric field in the heterojunction of LSTBM and O_v-s, especially in O_v-s on the higher-Fermi-level side of the heterojunction, had co-played roles in prolonging the lifetime and improving the transfer of photogenerated carriers. The photoproduced e⁻ played a dominant role in reducing Cr(vi) to Cr(iii) and the produced Cr(iii) tends to form Cr(OH)₃ and adsorb onto the surface of the photocatalyst to decrease the nucleation energy. The possible reduction route for Cr(vi) to Cr(iii) over LSTBM7 was figured out. This study implies that inducing O_v-s on the higher-Fermi-level side of the Z-scheme heterojunction is a more effective route for separating the photogenerated electrons and holes and improving the transfer of photogenerated carriers.

Found an effective way to improve the lifetime and transfer of photogenerated carriers: extrinsic O_v-s in the higher-Fermi-level side of the heterojunction. Z-scheme mechanism and O_v-s have synergistic effect on improving photocatalytic performance.     

Silicone/Ag@SiO2 core–shell nanocomposite as a self-cleaning antifouling coating material

The effects of Ag@SiO₂ core–shell nanofiller dispersion and micro-nano binary structure on the self-cleaning and fouling release (FR) in the modelled silicone nano-paints were studied. An ultrahydrophobic polydimethylsiloxane/Ag@SiO₂ core–shell nanocomposite was prepared as an antifouling coating material. Ag@SiO₂ core–shell nanospheres with 60 nm average size and a preferential {111} growth direction were prepared via a facile solvothermal and a modified Stöber methods with a controlled shell thickness. Ag@SiO₂ core–shell nanofillers were inserted in the silicone composite surface via solution casting technique. A simple hydrosilation curing mechanism was used to cure the surface coating. Different concentrations of nanofillers were incorporated in the PDMS matrix for studying the structure–property relationship. Water contact angle (WCA) and surface free energy determinations as well as atomic force microscopy and scanning electron microscope were used to investigate the surface self-cleaning properties of the nanocomposites. Mechanical and physical properties were assessed as durability parameters. A comparable study was carried out between silicone/spherical Ag@SiO₂ core–shell nanocomposites and other commercial FR coatings. Selected micro-foulants were used for biological and antifouling assessments up to 28 days. Well-distributed Ag@SiO₂ core–shell (0.5 wt%) exhibited the preferable self-cleaning with WCA of 156° and surface free energy of 11.15 mN m⁻¹.

The effects of Ag@SiO₂ core–shell nanofiller dispersion and micro-nano binary structure on the fouling release of silicone paints were studied. An ultrahydrophobic PDMS/Ag@SiO₂ core–shell nanocomposite was prepared as an antifouling coating material.     

A luminescent Cd(ii) coordination polymer as a multi-responsive fluorescent sensor for Zn2+, Fe3+ and Cr2O72− in water with fluorescence enhancement or quenching

A luminescent Cd(ii) coordination polymer, namely {[Cd(btic)(phen)]·0.5H₂O}_n (CP-1) (H₂btic = 5-(2-benzothiazolyl)isophthalic acid, phen = 1,10-phenanthroline), was constructed through the mixed-ligand method under solvothermal conditions. CP-1 manifests a chain structure decorated with uncoordinated Lewis basic N and S donors. CP-1 exhibits high sensing towards Zn²⁺, Fe³⁺ and Cr₂O₇²⁻ ions with fluorescence enhancement or quenching. CP-1 exhibited a fluorescence enhancement for Zn²⁺ ions through weak binding to S and N atoms, and a fluorescence quenching for Fe³⁺ and Cr₂O₇²⁻ ions by an energy transfer process. The binding constants were calculated as 1.812 × 10⁴ mol⁻¹ for Zn²⁺, 4.959 × 10⁴ mol⁻¹ for Fe³⁺ and 1.793 × 10⁴ mol⁻¹ for Cr₂O₇²⁻. This study shows CP-1 as a rare multi-responsive sensor material for the efficient detection of Zn²⁺, Fe³⁺ and Cr₂O₇²⁻ ions.

A luminescent Cd(ii) coordination polymer can act as a multi-responsive sensor for efficiently detecting Zn²⁺, Fe³⁺ and Cr₂O₇²⁻ ions.     

Judd–Ofelt parameters and X-ray irradiation results of MNb2O6:Eu3+ (M = Sr,Cd, Ni) phosphors synthesized via a molten salt method

Trivalent Eu-activated MNb₂O₆ (M = Sr, Cd, Ni) ceramic phosphors were produced using the molten salt route, which involves a low sintering temperature and provides improved homogeneity. The photoluminescence (PL) and radioluminescence (RL) spectra of phosphors exhibited characteristic Eu³⁺ emissions with ⁵F₀ → ⁷F_j transitions, and strong peaks occurred at the ⁵D₀ → ⁷F₂ transition. The PL and RL emissions of SrNb₂O₆:Eu³⁺ decreased over 3 mol%, while both emissions for CdNb₂O₆:Eu³⁺ and NiNb₂O₆:Eu³⁺ increased with increasing Eu³⁺ concentration. The spectral properties of phosphors were evaluated by determining Judd–Ofelt intensity parameters (Ω₂, Ω₄) from the PL emission spectrum. The quantum efficiencies (η_QE%) of MNb₂O₆:Eu³⁺ (M = Sr, Cd, Ni) phosphors with the highest emission were found as 61.87%, 41.89%, and 11.87% respectively. Bandwidths (σ_e × Δλ_eff) and optical gains (σ_e × τ) of MNb₂O₆:Eu³⁺ (M = Sr, Cd, Ni) phosphors with highest emissions were found as follows; 24.182 × 10⁻²⁸, 28.674 × 10⁻²⁸, 38.647 × 10⁻²⁸ cm³ and 20.441 × 10⁻²⁵, 13.790 × 10⁻²⁵, 3.987 × 10⁻²⁵ cm² s, respectively, corresponding to the ⁵D₀ → ⁷F₂ transition.

SEM micrographs and PL–RL emissions of MNb₂O₆: Eu³⁺ (M = Sr, Cd, Ni) phosphors.     

Novel easily separable core–shell Fe3O4/PVP/ZIF-8 nanostructure adsorbent: optimization of phosphorus removal from Fosfomycin pharmaceutical wastewater

A new easily separable core–shell Fe₃O₄/PVP/ZIF-8 nanostructure adsorbent was synthesized and then examined for removal of Fosfomycin antibiotic from synthetic pharmaceutical wastewater. The removal process of Fosfomycin was expressed through testing the total phosphorus (TP). A response surface model (RSM) for Fosfomycin adsorption (as mg-P L⁻¹) was used by carrying out the experiments using a central composite design. The adsorption model showed that Fosfomycin adsorption is directly proportional to core–shell Fe₃O₄/PVP/ZIF-8 nanostructure adsorbent dosage and time, and indirectly to initial Fosfomycin concentration. The removal increased by decreasing the pH to 2. The Fosfomycin removal was done at room temperature under an orbital agitation speed of 250 rpm. The adsorption capacity of core–shell Fe₃O₄/PVP/ZIF-8 nanostructure adsorbent reached around 1200 mg-P g⁻¹, which is significantly higher than other MOF adsorbents reported in the literature. The maximum Langmuir adsorption capacity of the adsorbent for Fosfomycin was 126.58 mg g⁻¹ and Fosfomycin adsorption behavior followed the Freundlich isotherm (R² = 0.9505) in the present study. The kinetics was best fitted by the pseudo-second-order model (R² = 0.9764). The RSM model was used for the adsorption process in different target modes.

The synthesis of an easily separable novel core–shell Fe₃O₄/PVP/ZIF-8 nanostructure adsorbent and its usage for Fosfomycin pharmaceutical wastewater treatment.     

Highly enhanced electrical properties of lanthanum-silicate-oxide-based SOFC electrolytes with co-doped tin and bismuth in La9.33−xBixSi6−ySnyO26

Solid oxide fuel cells (SOFCs) are one of the most promising clean energy sources to be developed. However, the operating temperature of SOFCs is currently still very high, ranging between 1073 and 1273 K. Reducing the operating temperature of SOFCs to intermediate temperatures in between 773 and 1073 K without decreasing the conductivity value is a challenging research topic and has received much attention from researchers. The electrolyte is one of the components in SOFCs which has an important role in reducing the operating temperature of the SOFC compared to the other two fuel cell components, namely the anode and cathode. Therefore, an electrolyte that has high conductivity at moderate operating temperature is needed to obtain SOFC with medium operating temperature as well. La_9.33Si₆O₂₆ (LSO) is a potential electrolyte that has high conductivity at moderate operating temperatures when this material is modified by doping with metal ions. Here, we report a modification of the structure of the LSO by partial substitution of La with Bi³⁺ ions and Si with Sn⁴⁺, which forms La_9.33−xBi_xSi_6−ySn_yO₂₆ with x = 0.5, 1.0, 1.5, and y = 0.1, 0.3, 0.5, in order to obtain an electrolyte of LSO with high conductivity at moderate operating temperatures. The addition of Bi and Sn as dopants has increased the conductivity of the LSO. Our work indicated highly enhanced electrical properties of La_7.83Bi_1.5Si_5.7Sn_0.3O₂₆ at 873 K (1.84 × 10⁻² S cm⁻¹) with considerably low activation energy (E_a) of 0.80 eV comparing to pristine La_9.33Si₆O₂₆ (0.08 × 10⁻² S cm⁻¹).

Structure modification of La_9.33Si₆O₂₆ (LSO) as SOFC electrolyte via a bi-doping mechanism provides enhanced electrical properties of La_7.83Bi_1.5Si_5.7Sn_0.3O₂₆ at 873 K (1.84 × 10⁻² S cm⁻¹) with low activation energy of 0.80 eV compared to pristine LSO (0.08 × 10⁻² S cm⁻¹).     

A novel MnO–CrN nanocomposite based non-enzymatic hydrogen peroxide sensor

A MnO–CrN composite was obtained via the ammonolysis of the low-cost nitride precursors Cr(NO₃)₃·9H₂O and Mn(NO₃)₂·4H₂O at 800 °C for 8 h using a sol–gel method. The specific surface area of the synthesized powder was measured via BET analysis and it was found to be 262 m² g⁻¹. Regarding its application, the electrochemical sensing performance toward hydrogen peroxide (H₂O₂) was studied via applying cyclic voltammetry (CV) and amperometry (i–t) analysis. The linear response range was 0.33–15 000 μM with a correlation coefficient (R²) value of 0.995. Excellent performance toward H₂O₂ was observed with a limit of detection of 0.059 μM, a limit of quantification of 0.199 μM, and sensitivity of 2156.25 μA mM⁻¹ cm⁻². A short response time of within 2 s was achieved. Hence, we develop and offer an efficient approach for synthesizing a new cost-efficient material for H₂O₂ sensing.

A MnO–CrN composite was obtained via the ammonolysis of the low-cost nitride precursors Cr(NO₃)₃·9H₂O and Mn(NO₃)₂·4H₂O at 800 °C for 8 h using a sol–gel method.     

Metal-bio functionalized bismuthmagnetite [Fe3−xBixO4/SiO2@l-ArgEt3+I−/Zn(ii)]: a novel bionanocomposite for the synthesis of 1,2,4,5-tetrahydro-2,4-dioxobenzo[b][1,4]diazepine malononitriles and malonamides at room temperature and under sonication

In this work, a new magnetized composite of bismuth (Fe_3−xBi_xO₄) was prepared and functionalized stepwise with silica, triethylargininium iodide ionic liquid, and Zn(ii) to prepare a multi-layered core–shell bio-nanostructure, [Fe_3−xBi_xO₄/SiO₂@l-ArgEt₃⁺I⁻/Zn(ii)]. The modified bismuth magnetic amino acid-containing nanocomposite was characterized using several techniques including Fourier-transform infrared (FT-IR), X-ray fluorescence (XRF), vibrating sample magnetometer (VSM), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX), thermogravimetric/differential scanning calorimetric (TGA/DSC) analysis, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), and inductively coupled plasma-optical emission spectrometry (ICP-OES). The magnetized bionanocomposite exhibited high catalytic activity for the synthesis of 1,2,4,5-tetrahydro-2,4-dioxobenzo[b][1,4]diazepine malononitriles via five-component reactions between 1,2-phenylenediamines, Meldrum''s acid, malononitrile, aldehydes, and isocyanides at room temperature in ethanol. The efficacy of this protocol was also examined to obtain malonamide derivatives via pseudo six-component reactions of 1,4-phenylenediamine, Meldrum''s acid, malononitrile, aldehydes, and isocyanides. When the above-mentioned MCRs were repeated under the same conditions with the application of sonication, a notable decrease in the reaction time was observed. The recovery and reusability of the metal-bio functionalized bismuthmagnetite were examined successfully in 3 runs. Furthermore, the characteristics of the recovered Fe_3−xBi_xO₄/SiO₂@l-ArgEt₃⁺I⁻/Zn(ii) were investigated though FESEM and EDAX analysis.

In this work, a new magnetized composite of bismuth (Fe_3−xBi_xO₄) was prepared and functionalized stepwise with silica, triethylargininium iodide ionic liquid, and Zn(ii) to prepare a multi-layered core–shell bio-nanostructure, [Fe_3−xBi_xO₄/SiO₂@l-ArgEt₃⁺I⁻/Zn(ii)].     

Highly efficient and giant negative electrocaloric effect of a Nb and Sn co-doped lead zirconate titanate antiferroelectric film near room temperature

Adiabatic temperature variation (ΔT), coefficient of performance (COP) and electrocaloric coefficient (ΔT/ΔE) play important roles in evaluating the comprehensive performance of solid-state cooling technology based on the electrocaloric effect (ECE). A Nb and Sn co-doped lead zirconate titanate antiferroelectric film, Pb_0.99Nb_0.02(Zr_0.85Sn_0.13Ti_0.02)O₃ (PNZST), shows a highly efficient and giant negative ECE. The ΔT, |ΔT/ΔE| and COP are about −9.8 K, 0.0488 K cm kV⁻¹ and 35.53 at around 50 °C, respectively. The full width at half maximum of the ΔT peak is about 37 °C. Phenomenological analysis indicates that the highly efficient and giant negative ECE is associated with the first-order transition that has a discontinuous polarization change with increasing temperature.

A giant negative ECE of a PNZST film with a high electrocaloric coefficient and coefficient of performance near room temperature.     

Preparation of biomimetic non-iridescent structural color based on polystyrene–polycaffeic acid core–shell nanospheres

Caffeic acid (CA), as a natural plant-derived polyphenol, has been widely used in surface coating technology in recent years due to its excellent properties. In this work, caffeic acid was introduced into the preparation of photonic band gap materials. By controlling the variables, a reasonable preparation method of polystyrene (PS) @polycaffeic (PCA)–Cu(ii) core–shell microspheres was achieved: 1 mmol L⁻¹ cupric chloride anhydrous (CuCl₂), 3 mmol L⁻¹ sodium perborate tetrahydrate (NaBO₃·4H₂O), 2 mmol L⁻¹ CA and 2 g L⁻¹ polystyrene (PS) were reacted at 50 °C for 10 min to prepare PS@PCA–Cu(ii) core–shell microspheres through rapid oxidative polymerization of CA coated PS of different particle diameters. The amorphous photonic crystal structure was self-assembled through thermal assisted-gravity sedimentation, resulting in structural color nanomaterials with soft and uniform color, no angle dependence, stable mechanical fastness and excellent UV resistance.

Caffeic acid (CA), as a natural plant-derived polyphenol, has been widely used in surface coating technology in recent years due to its excellent properties.     

Intracellular time course, pharmacokinetics, and biodistribution of isoniazid and rifabutin following pulmonary delivery of inhalable microparticles to mice

Intracellular concentrations of isoniazid and rifabutin resulting from administration of inhalable microparticles of these drugs to phorbol-differentiated THP-1 cells and the pharmacokinetics and biodistribution of these drugs upon inhalation of microparticles or intravenous administration of free drugs to mice were investigated. In cultured cells, both microparticles and dissolved drugs established peak concentrations of isoniazid (~1.4 and 1.1 μg/10⁶ cells) and rifabutin (~2 μg/ml and ~1.4 μg/10⁶ cells) within 10 min. Microparticles maintained the intracellular concentration of isoniazid for 24 h and rifabutin for 96 h, whereas dissolved drugs did not. The following pharmacokinetic parameters were calculated using WinNonlin from samples obtained after inhalation using an in-house apparatus (figures in parentheses refer to parameters obtained after intravenous administration of an equivalent amount, i.e., 100 μg of either drug, to parallel groups): isoniazid, serum half-life (t_1/2) = 18.63 ± 5.89 h (3.91 ± 1.06 h), maximum concentration in serum (C_max) = 2.37 ± 0.23 μg·ml⁻¹ (3.24 ± 0.57 μg·ml⁻¹), area under the concentration-time curve from 0 to 24 h (AUC_0-24) = 55.34 ± 13.72 μg/ml⁻¹ h⁻¹ (16.64 ± 1.80 μg/ml⁻¹ h⁻¹), and clearance (CL) = 63.90 ± 13.32 ml·h⁻¹ (4.43 ± 1.85 ml·h⁻¹); rifabutin, t_1/2 = 119.49 ± 29.62 h (20.18 ± 4.02 h), C_max = 1.59 ± 0.01 μg·ml⁻¹ (3.47 ± 0.33 μg·ml⁻¹), AUC_0-96 = 109.35 ± 14.78 μg/ml⁻¹ h⁻¹ (90.82 ± 7.46 μg/ml⁻¹ h⁻¹), and CL = 11.68 ± 7.00 ml·h⁻¹ (1.03 ± 0.11 ml·h⁻¹). Drug targeting to the lungs in general and alveolar macrophages in particular was observed. It was concluded that inhaled microparticles can reduce dose frequency and improve the pharmacologic index of the drug combination.     

Enhanced oxygen reduction activity of Pt shells on PdCu truncated octahedra with different compositions

Pd@Pt core–shell nanocrystals with ultrathin Pt layers have received great attention as active and low Pt loading catalysts for oxygen reduction reaction (ORR). However, the reduction of Pd loading without compromising the catalytic performance is also highly desired since Pd is an expensive and scarce noble-metal. Here we report the epitaxial growth of ultrathin Pt shells on Pd_xCu truncated octahedra by a seed-mediated approach. The Pd/Cu atomic ratio (x) of the truncated octahedral seeds was tuned from 2, 1 to 0.5 by varying the feeding molar ratio of Pd to Cu precursors. When used as catalysts for ORR, these three Pd_xCu@Pt core–shell truncated octahedra exhibited substantially enhanced catalytic activities compared to commercial Pt/C. Specifically, Pd₂Cu@Pt catalysts achieved the highest area-specific activity (0.46 mA cm⁻²) and mass activity (0.59 mA μg_Pt⁻¹) at 0.9 V, which were 2.7 and 4.5 times higher than those of the commercial Pt/C. In addition, these Pd_xCu@Pt core–shell catalysts showed a similar durability with the commercial Pt/C after 10 000 cycles due to the dissolution of active Cu and Pd in the cores.

Pd_xCu@Pt core–shell truncated octahedra were synthesized and exhibited substantially enhanced catalytic properties for oxygen reduction reaction relative to Pt/C.