Stacking textured films on lattice-mismatched transparent conducting oxides via matched Voronoi cell of oxygen sublattice.

Transparent conducting oxides are a critical component in modern (opto)electronic devices and solar energy conversion systems, and forming textured functional films on them is highly desirable for property manipulation and performance optimization. However, technologically important materials show varied crystal structures, making it difficult to establish coherent interfaces and consequently the oriented growth of these materials on transparent conducting oxides. Here, taking lattice-mismatched hexagonal α-Fe2O3 and tetragonal fluorine-doped tin oxide as the example, atomic-level investigations reveal that a coherent ordered structure forms at their interface, and via an oxygen-mediated dimensional and chemical-matching manner, that is, matched Voronoi cells of oxygen sublattices, [110]-oriented α-Fe2O3 films develop on fluorine-doped tin oxide. Further measurements of charge transport characteristics and photoelectronic effects highlight the importance and advantages of coherent interfaces and well-defined orientation in textured α-Fe2O3 films. Textured growth of lattice-mismatched oxides, including spinel Co3O4, fluorite CeO2, perovskite BiFeO3 and even halide perovskite Cs2AgBiBr6, on fluorine-doped tin oxide is also achieved, offering new opportunities to develop high-performance transparent-conducting-oxide-supported devices.

Revealing *OOH key intermediates and regulating H2O2 photoactivation by surface relaxation of Fenton-like catalysts.

Hydrogen peroxide (H2O2) molecules play important roles in many green chemical reactions. However, the high activation energy limits their application efficiency, and there is still huge controversy about the activation path of H2O2 molecules over the presence of *OOH intermediates. Here, we confirmed the formation of the key species *OOH in the heterogeneous system, via in situ shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS), isotope labeling, and theoretical calculation. In addition, we found that compared with *H2O2, *OOH was more conducive to the charge transfer behavior with the catalyst and the activation of an O-O bond. Furthermore, we proposed to improve the local coordination structure and electronic density of the YFeO3 catalyst by regulating the surface relaxation with Ti modification so as to reduce the activation barrier of H2O2 and to improve the production efficiency of •OH. As a result, the kinetics rates of the Fenton-like (photo-Fenton) reaction had been significantly increased several times. The •OH free radical activity mechanism and molecular transformation pathways of 4-chloro phenol (4-CP) were also revealed. This may provide a clearer vision for the further study of H2O2 activation and suggest a means of designing catalysts for efficient H2O2 activation.

Bony Congenital Nasolacrimal Duct Obstruction: A Novel Phenotype of Aplasia of Lacrimal and Major Salivary Glands.

PURPOSE: Aplasia of lacrimal and salivary glands (ALSG) is a syndromic disorder characterized by aplasia of lacrimal and salivary systems. Reported ophthalmic manifestations of ALSG include aplasia of lacrimal glands, punctal agenesis, lacrimal sac mucocele, and membranous congenital nasolacrimal duct obstruction (CNLDO). Bony CNLDO, a rare clinical entity, has not been associated with any syndromic disorder. This study investigated the relationship between genetic mutations and bony CNLDO in 3 Chinese families with ALSG. DESIGN: Single-center observational case study. PARTICIPANTS: Three Chinese families with bony CNLDO, including 7 affected and 9 healthy family members. METHODS: Slit-lamp ophthalmic examination, comprehensive physical examination, orbital computed tomography (CT) imaging, cervicofacial magnetic resonance imaging, audiometry, and whole exome sequencing on periphery blood were performed. Variants were cross-referenced with 1000 control genomes and various population databases. Pathologic variants were identified using bioinformatic tools. MAIN OUTCOME MEASURES: Clinical examination, diagnostic imaging, whole exome sequencing, and bioinformatic analysis findings. RESULTS: Affected patients showed decreased tear production on the Schimer I test and reduced tear breakup time. Bony CNLDO was observed on CT, showing unilateral or bilateral bony termination at the middle or terminal segment of the nasolacrimal canal. Magnetic resonance imaging showed aplasia or absence of lacrimal, parotid, and submandibular glands. Physical examination revealed normal ears, digits, and facial morphology. Audiometry and dental assessment were conducted on the pediatric patients and yielded normal results. The clinical characteristics of patients aligned with a diagnosis of ALSG. Genomic analysis revealed 3 novel heterozygous missense mutations of the Fgf10 gene: c.316T→C, c.327C→G, and c.332T→G. The inheritance pattern was autosomal dominant with variable penetrance. These variants were not observed in 1000 control genomes and population databases. These variant positions also were shown to be highly conserved across various animal species. Mutated genes and proteins were predicted as deleterious with most computational models, with a few suggesting they may be benign. CONCLUSIONS: Bony CNLDO was identified as a novel phenotype of ALSG implicated by missense mutations of highly conserved residues in the Fgf10 gene. These cases broadened our knowledge of Fgf10-related phenotypes and prompted clinicians to consider syndromic associations in patients with bony CNLDO. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Lattice Oxygen in Photocatalytic Gas-Solid Reactions: Participator vs. Dominator.

Lattice-oxygen activation has emerged as a popular strategy for optimizing the performance and selectivity of oxide-based thermocatalysis and electrolysis. However, the significance of lattice oxygen in oxide photocatalysts has been ignored, particularly in gas-solid reactions. Here, using methane oxidation over a Ru1@ZnO single-atom photocatalyst as the prototypical reaction and via 18O isotope labelling techniques, we found that lattice oxygen can directly participate in gas-solid reactions. Lattice oxygen played a dominant role in the photocatalytic reaction, as determined by estimating the kinetic constants in the initial stage. Furthermore, we discovered that dynamic diffusion between O2 and lattice oxygen proceeded even in the absence of targeted reactants. Finally, single-atom Ru can facilitate the activation of adsorbed O2 and the subsequent regeneration of consumed lattice oxygen, thus ensuring high catalyst activity and stability. The results provide guidance for next-generation oxide photocatalysts with improved activities and selectivities.

Spatial Decoupling of Redox Chemistry for Efficient and Highly Selective Amine Photoconversion to Imines.

Light-driven primary amine oxidation to imines integrated with H2 production presents a promising means to simultaneous production of high-value-added fine chemicals and clean fuels. Yet, the effectiveness of this strategy is generally limited by the poor charge separation of photocatalysts and uncontrolled hydrogenation of imines to secondary amines. Herein, a spatial decoupling strategy is proposed to isolate redox chemistry at distinct sites of photocatalysts, and CoP core-ZnIn2S4 shell (CoP@ZnIn2S4) coaxial nanorods are assembled as the proof-of-concept photocatalyst. Directional and ultrafast carrier separation occurs between the CoP core and the ZnIn2S4 shell, as confirmed by in situ X-ray photoelectron spectroscopy, surface photovoltage spectroscopy, and transient absorption spectroscopy analyses. Toward the photoconversion of model substrate benzylamine to N-benzylbenzaldimine, CoP@ZnIn2S4 exhibits a 48-time higher production rate and >99% selectivity when compared to ZnIn2S4 (ca. 20% selectivity), and the detailed reaction mechanism has been verified by in situ diffuse reflectance infrared Fourier transform spectroscopy.

Narrowing the band gap and suppressing electron-hole recombination in ß-Fe2O3 by chlorine doping.

The effects of halogen (F, Cl, Br, I, and At) doping in the direct-band-gap ß-Fe2O3 semiconductor on its band structures and electron-hole recombination have been investigated by density functional theory. Doping Br, I, and At in ß-Fe2O3 leads to transformation from a direct-band-gap semiconductor to an indirect-band-gap semiconductor because their atomic radii are too large; however, F- and Cl-doped ß-Fe2O3 remain as direct-band-gap semiconductors. Due to the deep impurity states of the F dopant, this study focuses on the effects of the Cl dopant on the band structures of ß-Fe2O3. Two impurity levels are introduced when Cl is doped into ß-Fe2O3, which narrows the band gap by approximately 0.3 eV. After doping Cl, the light-absorption edge of ß-Fe2O3 redshifts from 650 to 776 nm, indicating that its theoretical solar to hydrogen efficiency for solar water splitting increases from 20.6% to 31.4%. In addition, the effective mass of the holes in halogen-doped ß-Fe2O3 becomes significantly larger than that in undoped ß-Fe2O3, which may suppress electron-hole recombination.

Effects of transition metal doping on electronic structure of metastable ß-Fe2O3 photocatalyst for solar-to-hydrogen conversion.

Metastable ß-Fe2O3 is a promising photocatalyst with a band gap of approximately 1.9 eV, while its intrinsic material properties remain rarely studied by theoretical calculations. Here, using density functional theory, we studied the electronic band structure and effective mass of carriers in Zr, Sn, and Ti doped ß-Fe2O3. The calculation results show that, through the doping of Zr, Sn, or Ti, the dipole moment of FeO6 octahedra in ß-Fe2O3 increases, which favors the separation of photo-excited electron-hole pairs. The electron and hole effective masses in the close-packed orientation [111] in cubic ß-Fe2O3 have the smallest absolute values. After doping with Zr, Sn, and Ti, the absolute values of electron and hole effective masses in the [111] orientation are further reduced. Furthermore, the relative ratio (D) mostly became larger after doping with Zr, Sn, and Ti, which indicates that the photoexcited carriers in the doped structure are effectively separated. Construction of Zr, Sn, and Ti doped ß-Fe2O3 in the [111] orientation may be effective to improve the photocatalytic efficiency.

A Water-Soluble Highly Oxidizing Cobalt Molecular Catalyst Designed for Bioinspired Water Oxidation.

Herein, we present a stable water-soluble cobalt complex supported by a dianionic 2,2'-([2,2'-bipyridine]-6,6'-diyl)bis(propan-2-ol) ligand scaffold, which is a rare example of a high-oxidation species, as demonstrated by structural, spectroscopic and theoretical data. Electron paramagnetic resonance (EPR) spectroscopy and magnetic susceptibility measurements revealed that the CoIV center of the mononuclear complex in the solid state resides in the high spin state (sextet, S=5/2). The complex can effectively catalyze water oxidation via a single-site water nucleophilic attack pathway with an overpotential of only 360 mV in a phosphate buffer with a pH of 6. The key intermediate toward water oxidation was speculated based on theoretical calculations and was identified by in situ spectroelectrochemical experiments. The results are important regarding the accessibility of high-oxidation state metal species in synthetic models for achieving robust and reactive oxidation catalysis.

2D High-Entropy Hydrotalcites.

High-entropy materials (HEMs) with unique configuration and physicochemical properties have attracted intensive research interest. However, 2D HEMs have not been reported yet. To find out unique properties of combining 2D materials and HEMs, a series of 2D high-entropy hydrotalcites (HEHs) is created by coprecipitation method, including quinary, septenary, and even novenary metallic elements. It is found that the fast synthetic kinetics of coprecipitation process conquers the thermodynamically solubility limitation of different elements, which is the prerequisite condition to form HEHs. As the oxygen evolution reaction (OER) electrocatalysts, HEHs show significantly decreased apparent activation energy compared with low-entropy hydrotalcites (LEHs) due to the lattice distortion induced by the multimetallic character of HEHs. This work opens up a new avenue for the development of 2D HEMs, which broadens the family of HEMs and presents a most promising platform for exploring the unknown properties of HEMs.

Modulation of Disordered Coordination Degree Based on Surface Defective Metal-Organic Framework Derivatives toward Boosting Oxygen Evolution Electrocatalysis.

Seeking potential electrocatalysts with both large-scale application and robust activity for the oxygen evolution reaction allows for no delay. Herein, a squarate-based metal-organic framework (MOF) ([Co3 (C4 O4 )2 (OH)2 ]⋅3H2 O) is reported for electrocatalytic water oxidation. A facile, green, and low-cost strategy is proposed to introduce defects by not only rationally breaking CoO bonds to form defective coordination environment and electronic reconfiguration, but also systematically modulates defect concentration to optimize electrochemical performance. As a result, the post-treated surface defective MOF derivative (Co-MOF-3h) achieves a current density of 50 mA cm-2 at an overpotential of 380 mV, owing to larger active surface area, more opened active sites, and favorable conducting channels. Finally, density functional theory calculations have further validated the effect of defective coordination in regard to electronic structure for electrocatalysts. This study delivers inspirations in defect engineering and is in favor of developing high-efficiency electrocatalysts.

Interfacial Engineering of Hierarchical Transition Metal Oxide Heterostructures for Highly Sensitive Sensing of Hydrogen Peroxide.

Hydrogen peroxide (H2 O2 ) is a major messenger molecule in cellular signal transduction. Direct detection of H2 O2 in complex environments provides the capability to illuminate its various biological functions. With this in mind, a novel electrochemical approach is here proposed by integrating a series of CoO nanostructures on CuO backbone at electrode interfaces. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction, and X-ray photoelectron spectroscopy demonstrate successful formation of core-shell CuO-CoO hetero-nanostructures. Theoretical calculations further confirm energy-favorable adsorption of H2 O2 on surface sites of CuO-CoO heterostructures. Contributing to the efficient electron transfer path and enhanced capture of H2 O2 in the unique leaf-like CuO-CoO hierarchical 3D interface, an optimal biosensor-based CuO-CoO-2.5 h electrode exhibits an ultrahigh sensitivity (6349 µA m m-1 cm-2 ), excellent selectivity, and a wide detection range for H2 O2 , and is capable of monitoring endogenous H2 O2 derived from human lung carcinoma cells A549. The synergistic effects for enhanced H2 O2 adsorption in integrated CuO-CoO nanostructures and performance of the sensor suggest a potential for exploring pathological and physiological roles of reactive oxygen species like H2 O2 in biological systems.

Bi2 MoO6 Nanostrip Networks for Enhanced Visible-Light Photocatalytic Reduction of CO2 to CH4.

A three-dimensional Bi2 MoO6 nanostrip architecture was synthesized by the hydrothermal method using sodium oleate as a surfactant. The generated Bi2 MoO6 nanostrips intercross with each other to form a unique network structure with a band gap of 2.92 eV, corresponding to visible-light wavelength. Time-evolution experiments reveal the formation mechanism of the Bi2 MoO6 network. The photocatalytic reduction of CO2 to CH4 catalyzed by the Bi2 MoO6 architecture was evaluated and compared with the process catalyzed by a Bi2 MoO6 nanoplate analogue synthesized in the absence of sodium oleate as well as with the solid-state reaction. The Bi2 MoO6 nanostrips exhibit the best photocatalytic activity, which can be attributed to their high specific surface area, high light-absorption intensity, suitable thickness for fast charge-carrier migration, and the presence of pores for reactant transport.

Improved charge separation efficiency of hematite photoanodes by coating an ultrathin p-type LaFeO3 overlayer.

Many metal-oxide candidates for photoelectrochemical water splitting exhibit localized small polaron carrier conduction. Especially hematite (α-Fe2O3) photoanodes often suffer from low carrier mobility, which causes the serious bulk electron-hole recombination and greatly limits their PEC performances. In this study, the charge separation efficiency of hematite was enhanced greatly by coating an ultrathin p-type LaFeO3 overlayer. Compared to the hematite photoanodes, the solar water splitting photocurrent of the Fe2O3/LaFeO3 n-p junction exhibits a 90% increase at 1.23 V versus the reversible hydrogen electrode, due to enlarging the band bending and expanding the depletion layer.

Three-Dimensional Hierarchical Architectures Derived from Surface-Mounted Metal-Organic Framework Membranes for Enhanced Electrocatalysis.

Inspired by the rapid development of metal-organic-framework-derived materials in various applications, a facile synthetic strategy was developed for fabrication of 3D hierarchical nanoarchitectures. A surface-mounted metal-organic framework membrane was pyrolyzed at a range of temperatures to produce catalysts with excellent trifunctional electrocatalytic efficiencies for the oxygen reduction, hydrogen evolution, and oxygen evolution reactions.

Theoretical study on the surface stabilities, electronic structures and water adsorption behavior of the Ta3N5(110) surface.

A recent experiment revealed that the Ta3N5 semiconductor with orientation along the (110) surface exhibited improved photoelectrochemical activities, but the role of the (110) surface in the improved photoelectrochemical activity remains unclear. In this study, density functional theory calculations were performed to investigate the surface stabilities, surface electronic structures and water splitting behavior of the Ta3N5(110) surface with and without oxygen impurities. The results showed that, on the clean and oxygen impurity containing (110) surfaces, the energy barriers of water splitting were as low as 0.05 and 0.06 eV, respectively, suggesting that the Ta3N5(110) surface is a promising candidate for water splitting. The lower energy barriers of water splitting on the Ta3N5(110) surface may be ascribed to the easy migration of the H atom from the surface Ta atom to the nearby N atom. Furthermore, the surface energies and surface electronic structures revealed that the Ta3N5(110) surface contained less oxygen impurities, which is in accordance with the experimental observations.

PKM2 regulates neural invasion of and predicts poor prognosis for human hilar cholangiocarcinoma.

BACKGROUND: The therapeutic and prognostic value of the glycolytic enzymes hexokinase, phosphofructokinase, and pyruvate kinase (PK) has been implicated in a variety of cancers, while their roles in treatment of and prognosis for hilar cholangiocarcinoma (HC) remain unclear. In this study, we determined the expression of PKM2 in and its impact on biology and clinical outcome of human HC. METHODS: The regulation and function of PKM2 in HC pathogenesis was evaluated using human tissues, molecular and cell biology, and animal models, and its prognostic significance was determined according to its impact on patient survival. RESULTS: We found that expression of hexokinase 1 and the M2 splice isoform of PK (PKM2) was upregulated in HC tissues and that this expression correlated with tumor recurrence and outcome. PKM2 expression was increased in HC cases with chronic cholangitis as demonstrated by isobaric tags for relative and absolute quantification. High PKM2 expression was highly correlated with high syndecan 2 (SDC2) expression and neural invasion. PKM2 downregulation led to a decrease in SDC2 expression. Treatment with metformin markedly suppressed PKM2 and SDC2 expression at both the transcriptional and posttranscriptional levels and inhibited HC cell proliferation and tumor growth. CONCLUSIONS: PKM2 regulates neural invasion of HC cells at least in part via regulation of SDC2. Inhibition of PKM2 and SDC2 expression contributes to the therapeutic effect of metformin on HC. Therefore, PKM2 is an independent prognostic factor and potential therapeutic target for human HC.

A hybrid density functional theory study of the anion distribution and applied electronic properties of the LaTiO2N semiconductor photocatalyst.

Although the crystallographic space group has been determined, detailed first principles calculations of the LaTiO2N semiconductor photocatalyst crystal have not been performed because of the nitrogen/oxygen sosoloid-like anion distribution. In this study, based on the Heyd-Scuseria-Ernzerhof method and experimental anion content, we present the possibility of determining detailed information about the LaTiO2N sosoloid-like anion distribution by dividing the anions into possible primitive cells. The detailed information about the anion distribution based on the characteristics of the energetically acceptable primitive cell structures suggests that the LaTiO2N structure is composed of aperiodic stacks of six building-block primitive cells, the non-vacancy primitive cells are located at the surface as effective photoreaction sites, and vacancy structures are located in the bulk. The surface oxide-rich structures increase the near-surface conduction band minimum rise and strengthen photoelectron transport to the bulk, while the content of the bulk vacancy structures should be balanced because of being out of photoreactions. This study is expected to provide a different perspective to understanding the LaTiO2N sosoloid-like anion distribution.

Unraveling the mechanism of 720 nm sub-band-gap optical absorption of a Ta3N5 semiconductor photocatalyst: a hybrid-DFT calculation.

The Ta3N5 semiconductor photocatalyst possesses a 720 nm (about 1.72 eV) sub-band-gap optical absorption but the mechanism of this optical absorption is still controversial. In this study, the hybrid density functional theory calculations are performed to unravel the mechanism of 720 nm sub-band-gap optical absorption of Ta3N5. By studying the possible optical absorption initiated by the ON impurity and the VN defect, we find that the 720 nm sub-band-gap optical absorption of Ta3N5 may be ascribed to the electron transition from V(·)(N) to V(···)(N). In addition, we propose that the 720 nm sub-band-gap optical absorption can be used to qualitatively evaluate the photocatalytic water splitting ability of Ta3N5.

Effects of oxygen impurities and nitrogen vacancies on the surface properties of the Ta3N5 photocatalyst: a DFT study.

Surface defects and impurities play important roles in the photocatalytic performance of semiconductors. In this study, DFT calculations are performed to investigate the effects of oxygen impurities and nitrogen vacancies on the surface stability and electronic structures of Ta3N5(100), (010) and (001) low-index surfaces. The results show that, for each surface, the oxygen impurities and nitrogen vacancies are beneficial and harmful, respectively, to the surface stability of Ta3N5. The oxygen impurities and nitrogen vacancies have mainly two effects on the surface electronic structures of Ta3N5. One is saturating surface states on the clean surface, and the other is inducing the downshift of conduction band minimum. In addition, the Ta3N5(100) surface with oxygen impurities is expected to have the strongest reduction ability in practice, providing useful guidance for further investigations of Ta3N5 in the photocatalytic hydrogen evolution.

Ge-mediated modification in Ta3N5 photoelectrodes with enhanced charge transport for solar water splitting.

Ta3 N5 is a promising photoanode candidate for photoelectrochemical water splitting, with a band gap of about 2.1 eV and a theoretical solar-to-hydrogen efficiency as high as 15.9 % under AM 1.5 G 100 mW cm(-2) irradiation. However, the presently achieved highest photocurrent (ca. 7.5 mA cm(-2) ) on Ta3 N5 photoelectrodes under AM 1.5 G 100 mW cm(-2) is far from the theoretical maximum (ca. 12.9 mA cm(-2) ), which is possibly due to serious bulk recombination (poor bulk charge transport and charge separation) in Ta3 N5 photoelectrodes. In this study, we show that volatilization of intentionally added Ge (5 %) during the synthesis of Ta3 N5 promotes the electron transport and thereby improves the charge-separation efficiency in bulk Ta3 N5 photoanode, which affords a 320 % increase of the highest photocurrent comparing with that of pure Ta3 N5 photoanode under AM 1.5 G 100 mW cm(-2) simulated sunlight.