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As new members of the two-dimensional materials family, MoSi2N4 and WSi2N4 exhibit unique physical properties. However, their optical properties in consideration of spin–orbit coupling (SOC) have not been discussed. In this work, the excited-state properties of MoSi2N4 and WSi2N4 monolayers are studied by means of many-body perturbation theory in combination with first-principles calculations. We find that the quasiparticle correction leads to a large band gap renormalization of more than 1 eV for MoSi2N4 and WSi2N4 monolayers. Because of the SOC, characteristic A and B excitons form with large binding energies of about 1 eV. The excitation energy difference of A and B excitons can be used to well address the spin–valley splitting. MoSi2N4 shows more abundant excitons (A′, B′ and C excitons), turning out to be a promising candidate to explore intra- and inter-exciton transitions. The exciton wave function indicates that the low-energy excitons in MoSi2N4 and WSi2N4 monolayers are confined in the middle MoN2/WN2 layer, which is unfavorable for excitonic photocatalysis. On the other hand, the valley states based on excitons can be protected by SiN layers from both sides. [ABSTRACT FROM AUTHOR]

The valence state Mn 3 O 4 /MnCO 3 heterojunctions were synthesized using a facile, wet chemical oxidation method during hydrothermal process. Their crystal structures, morphologies and optical properties were systematically investigated. The obtained Mn 3 O 4 /MnCO 3 exhibited photo and thermal synergistic catalysis which have been estimated via degradation of methylene blue (MB) and HCHO under visible light ( λ > 420 nm) irradiation at different temperature (20 °C, 60 °C and 80 °C). Mn 3 O 4 and MnCO 3 possessed matching band potentials that could prevent the recombination rate of photogenerated electrons and holes in the reaction, which proved by the PL intensity of the samples, resulting in a great enhancement on their catalytic efficiency. Catalytic activity of Mn 3 O 4 /MnCO 3 under photo and thermal effect was not the simple summation of photocatalysis and thermocatalysis, but a synergistic effect was existed in Mn 3 O 4 /MnCO 3 composites which possessed much lattice oxygen to capture the holes leading to efficiently oxidizing reaction at high temperature. A possible mechanism was proposed based on valence state heterojunction to illustrate the synergistic effect between photo and thermal catalysis on degradation of organic pollutions. [ABSTRACT FROM AUTHOR]

In the search for photocatalysts that can directly utilize near-IR (NIR) light, we investigated three oxides Cu3(OH)4SO4 (antlerite), Cu4(OH)6SO4, and Cu2(OH)3Cl by photodecomposing 2,4-dichlorophenol over them under NIR irradiation and by comparing their electronic structures with that of the known NIR photocatalyst Cu2(OH)PO4. Both Cu3(OH)4SO4 and Cu4(OH)6SO4 are NIR photocatalysts, but Cu2(OH)3Cl is not. Thus, in addition to the presence of two different CuO m and Cu′O n polyhedra linked with CuOCu′ bridges, the presence of acceptor groups (e.g., SO4, PO4) linked to the metal oxygen polyhedra is necessary for NIR photocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] In contrast to their more often detrimental role, large-angle (60°) grain boundaries (GBs) provide opportunities to tailor the properties of two-dimensional (2D) transition metal dichalcogenides (TMDCs), bringing new functionalities and exciting opportunities to form intrinsic electronic heterostructures within monolayer TMDCs. In domains facing the GBs, polarization vectors along armchair direction are inversed and thus polar discontinuity arises at the GBs, as a consequence of nonzero bulk polarization of TMDCs. In order to screen the polarization charge, which gives rise to an electric field, depending on the bonding nature at GBs free electrons or holes are driven to accumulate on the GBs leading to the dispersive boundary states of metallicity. In particularly, 60° GBs in 2D TMDCs can behave as one-dimensional (1D) metallic quantum wires, serving as 1D channels for free carriers or excitons. [ABSTRACT FROM AUTHOR]

It is found that the electrochemical corrosion of a silver sheet anode in NaCl solution gives rise to a fast and continuous way of generating AgCl nanocubes with good uniform morphology. We examined the factors affecting the size and morphologies of AgCl nanocubes, which include the applied voltage, the concentration of NaCl, and that of Na2SO4 added to enhance the conductivity of the NaCl solution as well as the physical ways of solution mixing and the placement of the Ag sheet anode with respect to the Pt cathode. Analysis of these factors indicates that the fast and continuous generation of AgCl nanocubes requires the presence of the interface reaction layer formed by the kinetic diffusion of Ag+ and Cl− ions. The AgCl nanocubes possess {001} facets and uniform morphology, and the Ag@AgCl nanocubes have much higher photocatalytic activity than do the irregularly-shaped Ag@AgCl particles made from the conventional precipitation method. [ABSTRACT FROM AUTHOR]

Electrify your chemistry! Pyroelectric heterolayered BiOIO3 nanoplates efficiently separate photogenerated electron‐hole pairs due to the combined effect of their heterolayered structure and internal polar field (see scheme). Pyroelectric BiOIO3 nanoplates, synthesized by a simple hydrothermal method, were found to possess a superior photocatalytic activity under UV irradiation. [ABSTRACT FROM AUTHOR]

Silver sheet is used as an anode in Na3PO4 solution to synthesize Ag3PO4 microcrystals through an electrochemical oxidation process. Ag3PO4 microcrystals with a novel concave surface are obtained in a fast-generation manner. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used to investigate the microstructure and growth process of Ag3PO4 concave microcrystals. The growth mechanism of the Ag3PO4 concave microcrystals is illustrated by the preferential overgrowth along ＜111＞ and ＜110＞ directions of Ag3PO4 seeds during the growth process. With the high-index facets exposed on the concave surface, the Ag3PO4 concave microcrystals have higher photocatalytic activity than that of irregularly-shaped particles made from the traditional precipitation method. [ABSTRACT FROM AUTHOR]

Abstract: Cu2ZnSnS4(CZTS) is acknowledged as a promising alternative to traditional p-type solar energy absorbers. However, no facile approach using chemical techniques has been reported to the compositing of CZTS with other n-type semiconductors. Here, we reported the synthesis of CZTS@SnO2 nanocomposites via a simple one-pot solvothermal process. The structures and morphologies of the as-prepared nanocomposites were investigated systematically by X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and high resolution transmission electron microscope (HR-TEM), etc. An in situ growth mechanism was proposed to explain the formation of CZTS@SnO2 nanocomposites based on the experimental results. The as-prepared CZTS@SnO2 nanocomposites exhibit enhanced photo-response, which could be attributed to the special structures with improved separation of photo-induced charge carriers. [Copyright &y& Elsevier]

A novel 3D AgCl hierarchical superstructure, with fast growth along the 〈111〉 directions of cubic seeds, is synthesized by using a wet chemical oxidation method. The morphological structures and the growth process are investigated by scanning electron microscopy and X-ray diffraction. The crystal structures are analyzed by their crystallographic orientations. The surface energy of AgCl facets {100}, {110}, and {111} with absorbance of Cl− ions is studied by density functional theory calculations. Based on the experimental and computational results, a plausible mechanism is proposed to illustrate the formation of the 3D AgCl hierarchical superstructures. With more active sites, the photocatalytic activity of the 3D AgCl hierarchical superstructures is better than those of concave and cubic ones in oxygen evolution under irradiation by visible light. [ABSTRACT FROM AUTHOR]

Abstract: Large quantities of amorphous SiO x nanowires have been synthesized by vapor phase transport process under atmospheric pressure in a horizontal furnace. The fabricated materials have been fully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). The nanowires have a typical length up to several tens of micrometers and a diameter in the range of 100nm to 300nm. The formation mechanism of the nanowires has also been discussed. The covering boats and the weight ratio of the raw materials were regarded to play an important role during the growth of the nanowires. [Copyright &y& Elsevier]

Abstract: SrTiO3 hollow microspheres built by regular nanocubes were synthesized by a general and facile hydrothermal method. The resulting samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) measurements. Owing to the special hollow structure, the synthesized SrTiO3 microspheres exhibit a superior photocatalytic activity in photoreduction of Cr(VI). As anatase and titanate contain common structural features, it makes this in situ phase transition from anatase to titanate relatively easy. Therefore, this method is rather convenient for controlling the morphology of the products by varying the presynthesized anatase TiO2 precursor. [Copyright &y& Elsevier]

Abstract: The gas sensitivity of pure CdIn2O4 hollow spheres for hydrocarbons was measured and the effect of morphologies on gas sensing was investigated. The dependence of sensitivities on the concentration of C2H5OH and the response and recovery characteristics of CdIn2O4 had been studied. The gas sensitivity of CdIn2O4 hollow spheres on exposure to 50 ppm of C2H5OH was measured to be 2.5 times that of the material obtained by grinding the spheres. Though the response and recovery times of CdIn2O4 hollow spheres are a little longer than that of the sample after grinding, the gas sensitivity of CdIn2O4 hollow spheres is much higher than that of the sample after grinding within the same reaction time. Moreover, a plausible transient responding mechanism on CdIn2O4 hollow spheres was proposed. [Copyright &y& Elsevier]

The near-spherical AgCl micro-crystals were prepared by an ionic liquids-assisted hydrothermal method. The influence of ionic liquids (CxMimCl x= 4, 8, 12, 16) on (001) facet growth of AgCl was studied systemically. The composition of the as-prepared samples was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and FTIR spectra. The morphological structures were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Based on experimental data and the classical crystal growth theory, a plausible growth mechanism of the near-spherical AgCl was proposed. The plasmonic photocatalyst Ag@AgCl prepared from the near-spherical AgCl showed higher activity than that of cubic morphologies. [ABSTRACT FROM AUTHOR]

Abstract: Amorphous C–Si–O particles, prepared by pyrolyzing PDMS in a horizontal furnace using the carrier gas N2/H2 at 900°C, were characterized by electron microscopy, X-ray diffraction, FTIR spectroscopy, X-ray photoelectron spectroscopy and fluorescence spectroscopy. The particles possess four luminescence peaks at 440, 465, 533 and 620nm, and produce stable red, green or blue light emissions at room temperature when irradiated with appropriate wavelengths, the four peaks attribute to different defect centers in the particles. And the particles exhibit the highest photoluminescence intensity when annealed at 600°C. [ABSTRACT FROM AUTHOR]

Abstract: ZnO twin-prisms were prepared by a simple solvothermal process with glutamic acid as surface modification agent in ethanol. Compared with the twin-cones that were obtained when glutamic acid was absent, the ZnO twin-prisms have optimized crystallinity with high symmetry, sharp crystal edges and few defects. Probable reaction mechanism between ZnO and glutamic acid was proposed based on our experimental analysis. Then it was verified by a series of comparison experiments by employing glycine, acetic acid and ethylamine as surface modification agents. Our results indicate that both alkaline and acidic groups play an important role on the formation of ZnO twin-prisms, and when either of them was absent, twin-prism structures cannot be obtained. The photoluminescence properties of as-prepared ZnO twin-prisms and twin-cones were also studied. [Copyright &y& Elsevier]

Abstract: The visible-light responsive photocatalyst BiVO4 was synthesized, and its photocatalytic reduction of CO2 in water was examined. Our study shows the selective formation of ethanol under the condition of high intensity visible-light irradiation, and suggests that intense irradiation generates a large number of C1 intermediate species anchored on the surface of BiVO4, which dimerize to form ethanol. For the photocatalytic reduction of CO2 into ethanol, monoclinic BiVO4 is more efficient than tetragonal BiVO4. [Copyright &y& Elsevier]

Abstract: Metastable Bi20TiO32 samples were synthesized by a high-temperature quenching method using α-Bi2O3 and anatase TiO2 as raw materials. The photocatalytic activity of the as-prepared samples was measured with the photodegradation of methyl orange at room temperature under visible light irradiation. The Bi20TiO32 samples exhibited good absorption in the visible light region with a band gap of about 2.38eV and the band structure of Bi20TiO32 was studied. Photodegradation against methyl orange was much better than α-Bi2O3 prepared by the same way. The photocatalytic activity of Bi20TiO32 samples is supposed to be associated with the hybridized Bi 6s and O 2p orbitals. In addition, the dispersive characteristic of Bi 6s orbital in the hybridized valence band facilitates the mobility of the photogenerated carriers and hampers their recombination. [Copyright &y& Elsevier]

Abstract: Cerium-doped Bi2Ti2O7 (BCTO) thin films have been grown on P-type Si 〈100〉 substrates by a chemical solution deposition (CSD) method. X-ray diffraction (XRD) analysis was carried out, which confirms that the crystallinity of the films increased with the enhancement of annealing temperature ranging from 550 to 750°C. The chemical stability of Bi2Ti2O7 was improved, since some Bi ions are substituted with the Ce ions. The AFM image of surface morphology of (Bi0.88Ce0.12)2Ti2O7 thin film was investigated. The section morphology was studied and the thickness was measured. The relaxation time and the leakage current behavior of (Bi0.88Ce0.12)2Ti2O7 thin films annealed at various temperatures were discussed. The current–voltage characteristics were explored, accordingly dielectric constant (DC) and dielectric loss (DL) were calculated at the frequency ranging from 1 to 2000kHz. At the characteristic frequency of 100kHz, DC and DL are calculated to be 214 and 0.06 respectively. The results showed that the film annealed at 700°C had good insulating properties and was considered using in advanced MOS transistors. [Copyright &y& Elsevier]

Ce-doped Bi2Ti2O7 thin films have been successfully prepared on P-type Si substrates by a chemical solution deposition method. The structural properties of the films were studied by X-ray diffraction. The phase of Ce-doped Bi2Ti2O7 was more stable than that of Bi2Ti2O7 without Ce substitution. The films exhibited good insulating properties at room temperature. The dielectric constant of the films annealed at 700°C at 100 kHz was 168 and the dissipation factor was 0.038. All these results showed that Ce-doped Bi2Ti2O7 thin films could be used as storage capacitors in DRAM and MOS. [ABSTRACT FROM AUTHOR]

We have studied the effects of surface oxygen and its bond structure on the electronic properties of silicon nanoclusters by means of density functional theory calculations. The results of the energy gap as a function of the nanocluster size in hydrogen-terminated and oxygen-adsorbed silicon clusters provide a well interpretation of several experiments. The nature of electronic and optical properties of silicon nanoclusters has been discussed and attributed to the oxygen in both the Si=O double bond structure and Si–O–Si bridge structure. [ABSTRACT FROM AUTHOR]

Abstract: Lanthanum-doped Bi2Ti2O7 thin films have been prepared using chemical solution deposition method, and then treated by different annealing temperatures. X-ray diffraction analysis confirmed that the crystallinity of the films increased with increasing annealing temperature and the optimum temperature was found to be 800 °C. The effects of relaxation time and various annealing temperatures and films thickness on the leakage current density were investigated. The results showed that the film annealed at 800°C had good insulating properties and can be considered using in advanced MOS transistors. [Copyright &y& Elsevier]

The mechanism of surface conductivity (SC) in diamond, concerning the role of dangling-bond, hydrogen and adsorbate, has been investigated by density functional theory calculations of simulating clusters. We have deduced two possible mechanisms for the SC: one originates from the transport of electron in the localized states near the Fermi level, and another one from the holes in the extended states at about the mobility edge. These models may help one understand most of the experimental results qualitatively or quantitatively in order. [Copyright &y& Elsevier]

By 532 nm laser pumped PL spectral and Xe pumped fluorescence spectral, characterized InGaAsP/In[sub 0.5](Ga[sub x]Al[sub 1-x])[sub 0.5]P quantum well on substrates 2°, 15° tilted to (110) the optical property dependence of substrates tilt. The PL wavelength varies from 755 nm of the quantum well on substrate of 2° to the 780 nm of the quantum well on substrate of 15°. From fluorescence excitation spectral to excite about 760 nm wavelength of quantum well, the absorption light peak wavelength is 508 nm in common, and has another absorption peak wavelength of 622 nm. Excited by 508 nm and 622 nm wavelength, the fluorescence spectral intensity of the 15° quantum well is about 300 and 10[sup 4] accordingly. Lifetime of charge recombination is about 1.26 ns for this material. [ABSTRACT FROM AUTHOR]

Through loading photo-reduced graphene oxide (rGO), photocatalytic hydrogen evolution activity of CH(NH 2) 2 PbBr 3 is greatly elevated from 74.5 µmol/h to 386.7 µmol/h (100 mg, AM1.5G, 100 mW cm−2), making CH(NH 2) 2 PbBr 3 /rGO composite an efficient photocatalyst in aqueous HBr solution saturated with CH(NH 2) 2 PbBr 3 perovskite. [Display omitted] Solar hydrobromic acid (HBr) splitting using perovskite photocatalysts provides an attractive avenue to store solar energy into hydrogen (H 2) and bromine (Br 2), while an efficient photocatalytic system is still demanded. As for the semiconductor photocatalyst, formamidinium perovskites show some superiorities in structural stability, light adsorption and charge dynamics compared to their methylammonium counterparts, which are fitter for the photocatalysis process. Herein, the composite of formamidinium lead bromide perovskite (FAPbBr 3) with reduced graphene oxide (rGO) is prepared using a facile photoreduction method. Under simulated sunlight irradiation (AM1.5G, 100 mW cm−2), this FAPbBr 3 /rGO composite (100 mg) demonstrates a noteworthy enhancement in photocatalytic H 2 evolution activity of 386.7 μmol h−1, and it exhibits a notable stability with no significant decrease after 50 h of repeated tests. The single particle PL (photoluminescence) microscope is employed to study the charge dynamics, revealing that rGO in the composite effectively promotes the carrier separation. This work provides a highly efficient and stable photocatalyst for HBr splitting, and offers an effective modification strategy on lead bromide perovskites. [ABSTRACT FROM AUTHOR]

We present a strategy for realizing the nonvolatile electrical control of noncollinear magnetism based on first-principles calculations. We confirm that the VAl2S4 monolayer, a rare two-dimensional type-II multiferroic material, shows an in-plane noncollinear 120°-ordered antiferromagnetic ground state and spin spiral order induced out-of-plane ferroelectricity. In VAl2S4 bilayers, we clarify the spin spiral chirality–sliding ferroelectricity locking effect, which enables flexible electrical switching of noncollinear magnetism and corresponding spin spiral chirality through interlayer sliding. Our work provides another perspective for the development of magnetoelectric physics and information storage devices. [ABSTRACT FROM AUTHOR]

Stable Ti3+ self-doped TiO2 with tunable phase composition and highly efficient visible-light photoactivity (ca. 32.7 times stronger than an undoped sample for ṖOH formation) was synthesized via a facile metallic zinc-assisted method. The surface Ti3+ species can be stabilized by Zn doping, and the photocatalytic selectivity can be regulated by the phase composition. [ABSTRACT FROM AUTHOR]

A novel Ag/AgBr/BiOBr hybrid was prepared by a rational in situion exchange reaction between BiOBr hierarchical microspheres and AgNO3in ethylene glycol followed by light reduction, which displayed superior visible light driven photocatalytic activities in sterilization of pathogenic organism and degradation of organic dye compared to N-doped P25. [ABSTRACT FROM AUTHOR]

Abstract: ZnO films with morphologies of nanorods, nanowires and nanosheets were grown on F-doped SnO2 glass substrate, which may have potential application in solar cells. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the structures and morphologies of the as-synthesized samples. The photoluminescence (PL) and the photoelectrochemical properties of ZnO films were also measured. The results showed that ZnO nanorods preferentially oriented along the c-axis and had the largest photocurrent density which is as high as 60μA/cm2. [Copyright &y& Elsevier]

Abstract: Well-aligned ZnO nanorod arrays were synthesized on SnO2:F (FTO) glass substrates by hydrothermal method with the addition of polyvinyl alcohol. Morphology and optical properties of the well-aligned ZnO nanorod arrays were studied. The transmittance of the as grown samples was dramatically increased by the addition of polyvinyl alcohol. PVA was regarded to play an important role in improving the optical transmittance and its role in hydrothermal growth process is also discussed in this work. [Copyright &y& Elsevier]

Abstract: Well-aligned ZnO nanorod arrays have been synthesized by a simple hydrothermal method with polyvinyl alcohol as surfactant on F:SnO2 conductive glasses substrates. Visible violet photoluminescence has been observed at room temperature. A series of annealing treatments in different environments have been made in order to investigate the nature of these emissions. The violet emission shows no change after annealing in air, while shifts to the ultra-violet region after annealing in H2. It is concluded that the violet emission is due to V Zn − defect formed at the surface of the ZnO nanorods. [Copyright &y& Elsevier]

Abstract: Copper nanoparticles were synthesized using carbon nanotubes as a template. The process involved neither pre-purification nor an additional reducing agent. This method was simple and the Cu nanoparticles were uniformly loaded on the carbon nanotubes. TEM, SEM, XRD and EDX were used to examine the morphology of the Cu particles. The diameter of the carbon nanotubes is about 70–90 nm and the size of the nanoparticles is about 50–70 nm. [Copyright &y& Elsevier]

The contradiction between the optical absorption depth and carrier diffusion length has emerged as a significant problem constraining the performance of BiVO4 photoanodes. Fabricating a one-dimensional (1D) structure is considered a promising strategy to address the above problem. However, the synthesis of BiVO4 photoanodes consisting of 1D monoclinic scheelite remains a great challenge. In this study, a 1D molybdenum (Mo) doped BiVO4 photoanode (Mo:1D-BVO) consisting of monoclinic scheelite BiVO4 submicron rods (SMRs) through a phase transition from a 1D tetragonal zircon BiVO4 precursor was successfully prepared. It was found that Mo doping could lower the phase transition barrier from tetragonal zircon to monoclinic scheelite BiVO4. Due to the Mo:1D-BVO photoanode's remarkable light absorption efficiency, efficient carrier separation, and superior conductivity, it yields a photocurrent density of 2.08 mA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE), which is 3.5 times higher than that of pristine BiVO4. Upon the introduction of the co-catalyst, the photocurrent density of Co–Pi/Mo:1D-BVO attains 3.18 mA cm−2 at 1.23 V vs. RHE, accompanied by a carrier separation efficiency of 91%. Our study introduces a novel approach for the production of remarkably efficient 1D monoclinic scheelite BiVO4 photoanodes. [ABSTRACT FROM AUTHOR]

Partially occupied orbitals play a pivotal role in enhancing the performance of electrocatalyst by facilitating electron acceptance and donation, thus enabling the activation of molecular bonds. According to this principle, the basal plane of most 2D semiconductors is inert for electrocatalysis because of the fully occupied orbitals at the surface. Here, taking monolayer CrX (X = P, As, Sb) and Cr2PY (Y = As, Sb) as examples and through first‐principles calculations, it is revealed that even with fully occupied surface orbitals, the basal planes exhibit remarkable catalytic activity for the nitrogen oxide reduction reaction (NORR). This leads to the concept of the pseudo‐inert electrocatalyst. The underlying physics behind such pseudo‐inert character can be attributed to the reversal‐activation mechanism: contrary to conventional expectations, the adsorbed NO molecule reversely triggers the activity of the inert basal plane first, and then the basal plane activates NO molecules, forming the intriguing "Reversal Activation‐Transfer‐Donation‐Backdonation" process. This study further predicts that such pseudo‐inert character can demonstrate many distinctive properties, for example, it can introduce a novel type of surface catalysis, one that selectively targets radicals possessing an inherent dipole moment such as NO. The explored phenomena and insights greatly enrich the realms of electrocatalysis and 2D materials. [ABSTRACT FROM AUTHOR]

Understanding the CO2 transformation mechanism on materials is essential for the design of efficient electrocatalysts for CO2 reduction. In aconventional adsorbate evolution mechanism (AEM), the catalysts encounter multiple high‐energy barrier steps, especially CO2 activation, limiting the activity and selectivity. Here, lattice carbonate from Cu2(OH)2CO3 is revealed to be a mediator between CO2 molecules and catalyst during CO2 electroreduction by a 13C isotope labeling method, which can bypass the high energy barrier of CO2 activation and strongly enhance the performance. With the lattice carbonate mediated mechanism (LCMM), the Cu2(OH)2CO3 electrode exhibited ten‐fold faradaic efficiency and 15‐fold current density for ethylene production than the Cu2O electrode with AEM at a low overpotential. Theoretical calculations and in situ Raman spectroscopy results show that symmetric vibration of carbonate is precisely enhanced on the catalyst surface with LCMM, leading to faster electron transfer, and lower energy barriers of CO2 activation and carbon–carbon coupling. This work provides a route to develop efficient electrocatalysts for CO2 reduction based on lattice‐mediated mechanism. [ABSTRACT FROM AUTHOR]

Recently, amorphous materials have gained great attention as an emerging kind of functional material, and their characteristics such as isotropy, absence of grain boundaries, and abundant defects are very likely to outrun the disadvantages of crystalline counterparts, such as low conductivity, and ultimately lead to improved charge transfer efficiency. Herein, we investigated the effect of amorphization on the charge transfer process and photocatalytic performance with a phosphonate‐based metal–organic framework (FePPA) as the research object. Comprehensive experimental results suggest that compared to crystalline FePPA, amorphous FePPA has more distorted metal nodes, which affects the electron distribution and consequently improves the photogenerated charge separation efficiency. Meanwhile, the distorted metal nodes in amorphous FePPA also greatly promote the adsorption and activation of O2. Hence, amorphous FePPA exhibits a better performance of photocatalytic C(sp3)−H bond activation for selective oxidation of toluene to benzaldehyde. This work illustrates the advantages of amorphous MOFs in the charge transfer process, which is conducive to the further development of high performance MOFs‐based photocatalysts. [ABSTRACT FROM AUTHOR]

Recently, amorphous materials have gained great attention as an emerging kind of functional material, and their characteristics such as isotropy, absence of grain boundaries, and abundant defects are very likely to outrun the disadvantages of crystalline counterparts, such as low conductivity, and ultimately lead to improved charge transfer efficiency. Herein, we investigated the effect of amorphization on the charge transfer process and photocatalytic performance with a phosphonate‐based metal–organic framework (FePPA) as the research object. Comprehensive experimental results suggest that compared to crystalline FePPA, amorphous FePPA has more distorted metal nodes, which affects the electron distribution and consequently improves the photogenerated charge separation efficiency. Meanwhile, the distorted metal nodes in amorphous FePPA also greatly promote the adsorption and activation of O2. Hence, amorphous FePPA exhibits a better performance of photocatalytic C(sp3)−H bond activation for selective oxidation of toluene to benzaldehyde. This work illustrates the advantages of amorphous MOFs in the charge transfer process, which is conducive to the further development of high performance MOFs‐based photocatalysts. [ABSTRACT FROM AUTHOR]

The acidic electrochemical CO2 reduction reaction (CO2RR) for direct formic acid (HCOOH) production holds promise in meeting the carbon‐neutral target, yet its performance is hindered by the competing hydrogen evolution reaction (HER). Understanding the adsorption strength of the key intermediates in acidic electrolyte is indispensable to favor CO2RR over HER. In this work, high‐density Sn single atom catalysts (SACs) were prepared and used as catalyst, to reveal the pH‐dependent adsorption strength and coverage of *CO2− intermediatethat enables enhanced acidic CO2RR towards direct HCOOH production. At pH=3, Sn SACs could deliver a high Faradaic efficiency (90.8 %) of HCOOH formation and a corresponding partial current density up to −178.5 mA cm−2. The detailed in situ attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopic studies reveal that a favorable alkaline microenvironment for CO2RR to HCOOH is formed near the surface of Sn SACs, even in the acidic electrolyte. More importantly, the pH‐dependent adsorption strength of *CO2− intermediate is unravelled over the Sn SACs, which in turn affects the competition between HER and CO2RR in acidic electrolyte. [ABSTRACT FROM AUTHOR]

The acidic electrochemical CO2 reduction reaction (CO2RR) for direct formic acid (HCOOH) production holds promise in meeting the carbon‐neutral target, yet its performance is hindered by the competing hydrogen evolution reaction (HER). Understanding the adsorption strength of the key intermediates in acidic electrolyte is indispensable to favor CO2RR over HER. In this work, high‐density Sn single atom catalysts (SACs) were prepared and used as catalyst, to reveal the pH‐dependent adsorption strength and coverage of *CO2− intermediatethat enables enhanced acidic CO2RR towards direct HCOOH production. At pH=3, Sn SACs could deliver a high Faradaic efficiency (90.8 %) of HCOOH formation and a corresponding partial current density up to −178.5 mA cm−2. The detailed in situ attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopic studies reveal that a favorable alkaline microenvironment for CO2RR to HCOOH is formed near the surface of Sn SACs, even in the acidic electrolyte. More importantly, the pH‐dependent adsorption strength of *CO2− intermediate is unravelled over the Sn SACs, which in turn affects the competition between HER and CO2RR in acidic electrolyte. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bi-based MOF (Bi-HHTP) was used for the photo-driven CO 2 cycloaddition reaction and a relatively high yield was obtained. • Bi has more flexible and diverse coordination modes, which can provide abundant adsorption sites for epoxide and CO 2. • Bi-HHTP exhibits a photothermal and photocatalytic synergistic effect towards photo-driven CO 2 cycloaddition. The cycloaddition reaction between CO 2 and epoxide is an efficient way to convert CO 2 into high value-added chemicals. Therefore, it is particularly important to develop efficient catalysts that can catalyze the reaction under mild conditions. In this work, a metal–organic framework (Bi-HHTP, consisting of bismuth (Bi) as metal dots and 2,3,6,7,10,11-hexahydroxy-triphenylene (HHTP) as organic linkers) with zigzagging corrugated topology was successfully synthesized, which shows excellent catalytic activity under visible light irradiation. Various characterizations suggest that the excellent activity is derived from the following reasons: (1) the abundant exposed Bi sites provide Lewis sites for adsorption of epoxides and CO 2 ; (2) the free holes produced over Bi-HHTP under light irradiation which could oxidize epoxide, which consequently facilitateing the subsequent ring-opening reaction; and (3) the existence of synergistic photocatalytic and photothermal effect in Bi-HHTP. This study provides a new avenue of developing bismuth-based metal organic frameworks to promote the efficiency of cycloaddition of CO 2 under mild conditions. [ABSTRACT FROM AUTHOR]

Chiral quasiparticles, such as magnetic skyrmions, are fundamental phenomena in the field of condensed‐matter physics. So far, several chiral quasiparticles with nontrivial topology have been theoretically predicted and experimentally confirmed, most characterized by carrying a nonzero topological charge. Here, through model analysis, a mechanism of realizing chiral magnetic quasiparticles with zero topological charge in the 2D lattice is proposed. The physics is related to the marriage of layer‐dependent staggered Dzyaloshinskii‐Moriya interaction and interlayer exchange interaction, and the nontrivial topology is protected indirectly. By means of first‐principles calculations and atomic spin model simulations, this mechanism in a real material of bilayer Tl2NO2 is further demonstrated. The realized chiral quasiparticles with zero topological charge can be considered as the superposition of vortex and anti‐vortex. Even though the topological charge is zero, their topologies are nontrivial, indirectly protected by the correlated magnetic bimerons. The finding opens up a new direction for the research on topological spin structures in 2D lattice. [ABSTRACT FROM AUTHOR]

A conductive 2D trimetallic π-d conjugated MOF FeCoNi-BHT is (BHT means 1,2,3,4,5,6-benzenehexathiol) is successfully fabricated, which processes abundant Co-S 4 , Fe-S 4 , Ni-S 4 single-atom sites, large specific surface area and high conductivity. Benefiting from the synergistic effect of the Co, Fe, Ni single-atomic sites and its metallic behavior, FeCoNi-BHT exhibits prominent oxygen evolution reaction performance. [Display omitted] The poor electrically conductivity of metal–organic frameworks (MOFs) is the main factor hinder their application in electrocatalysis field. In this work, we synthesize a conductive two-dimensional (2D) trimetallic π-d conjugated metal–organic framework (MOF) FeCoNi-BHT (BHT = 1,2,3,4,5,6-benzenehexathiol) through coordinating Co, Fe and Ni ions with 1,2,3,4,5,6-benzenehexathiol ligands. FeCoNi-BHT is demonstrated possessing homogeneously dispersed abundant Co-S 4 , Fe-S 4 , Ni-S 4 single-atom active sites (14.26 wt% of the metal elements) and a large specific surface area (267.05 m2g−1). The room temperature conductivity of FeCoNi-BHT is measured to be 92 S m−1, indicating its metallic behavior. DFT theoretical calculation reveals that the π–d conjugation structure of FeCoNi-BHT is responsible for its metallic behavior. In addition, FeCoNi-BHT exhibits prominent oxygen evolution reaction (OER) activity (an overpotential of 266 mV vs. RHE at 10 mA cm−2 and a Tafel value of 58 mV dec-1) in alkaline media. The combined experimental and DFT studies reveal that the synergistic effect of Co, Fe, Ni sites of FeCoNi-BHT contribute to its prominent OER activity. This work paves a new avenue of developing 2D π-d conjugated MOFs with different metal centers as highly efficient eletrocatalysts. [ABSTRACT FROM AUTHOR]

In recent years, 2D valley physics has attracted tremendous attention in both fundamental research and device applications. The search for a coupling valley with exotic physical properties can enable the exploration of novel quantum devices and is therefore of significant interest. Here, using model analysis, a novel mechanism is proposed that realizes strong coupling between strain and valley physics in a 2D antiferromagnetic honeycomb lattice in a controllable fashion. This idea is to modulate the exchange interactions through strain, thereby mediating the inversion and time‐reversal symmetries. As valley physics are connected with the symmetries, this enables a strong strain‐valley coupling. On the basis of first‐principles calculations, the validity of this mechanism is further demonstrated in a series of single‐layer systems, i.e., AuCl3, CrI3, and VPTe3, which are predicted to host valley polarization and anomalous valley Hall effect. The change in bonding angle is found to play a crucial role in mediating the exchange interaction and thus the strain‐valley coupling process. The microscopic origin is also discussed. These explored phenomena and insights greatly enrich the valley physics and 2D materials research. [ABSTRACT FROM AUTHOR]

In order to study many-body effects in ZnO structures with reduced-dimensionality, electronic and optical absorption properties of ZnO monolayer and armchair ZnO nanoribbons (AZnONRs) are studied by means of Green's function perturbation theory using the GW+Bethe-Salpeter equation approach. In both ZnO monolayer and AZnONRs, as a consequence of enhanced quantum confinement, the quasi-particle corrections are significant and the optical absorption properties are dominated by strong excitonic effects with considerable binding energies (1-2 eV) assigned to the lowest-energy bound excitons. It reveals that inclusion of excitonic effects, which are neglected in calculations at single-particle approximation, is crucial to qualitatively and quantitatively describe the optical properties of such materials with reduced-dimensionality. [ABSTRACT FROM AUTHOR]

Photoconversion of CO2 and H2O into ethanol is an ideal strategy to achieve carbon neutrality. However, the production of ethanol with high activity and selectivity is challenging owing to the less efficient reduction half‐reaction involving multi‐step proton‐coupled electron transfer (PCET), a slow C−C coupling process, and sluggish water oxidation half‐reaction. Herein, a two‐dimensional/two‐dimensional (2D/2D) S‐scheme heterojunction consisting of black phosphorus and Bi2WO6 (BP/BWO) was constructed for photocatalytic CO2 reduction coupling with benzylamine (BA) oxidation. The as‐prepared BP/BWO catalyst exhibits a superior photocatalytic performance toward CO2 reduction, with a yield of 61.3 μmol g−1 h−1 for ethanol (selectivity of 91 %).In situ spectroscopic studies and theoretical calculations reveal that S‐scheme heterojunction can effectively promote photogenerated carrier separation via the Bi−O−P bridge to accelerate the PCET process. Meanwhile, electron‐rich BP acts as the active site and plays a vital role in the process of C−C coupling. In addition, the substitution of BA oxidation for H2O oxidation can further enhance the photocatalytic performance of CO2 reduction to C2H5OH. This work opens a new horizon for exploring novel heterogeneous photocatalysts in CO2 photoconversion to C2H5OH based on cooperative photoredox systems. [ABSTRACT FROM AUTHOR]

Photoconversion of CO2 and H2O into ethanol is an ideal strategy to achieve carbon neutrality. However, the production of ethanol with high activity and selectivity is challenging owing to the less efficient reduction half‐reaction involving multi‐step proton‐coupled electron transfer (PCET), a slow C−C coupling process, and sluggish water oxidation half‐reaction. Herein, a two‐dimensional/two‐dimensional (2D/2D) S‐scheme heterojunction consisting of black phosphorus and Bi2WO6 (BP/BWO) was constructed for photocatalytic CO2 reduction coupling with benzylamine (BA) oxidation. The as‐prepared BP/BWO catalyst exhibits a superior photocatalytic performance toward CO2 reduction, with a yield of 61.3 μmol g−1 h−1 for ethanol (selectivity of 91 %).In situ spectroscopic studies and theoretical calculations reveal that S‐scheme heterojunction can effectively promote photogenerated carrier separation via the Bi−O−P bridge to accelerate the PCET process. Meanwhile, electron‐rich BP acts as the active site and plays a vital role in the process of C−C coupling. In addition, the substitution of BA oxidation for H2O oxidation can further enhance the photocatalytic performance of CO2 reduction to C2H5OH. This work opens a new horizon for exploring novel heterogeneous photocatalysts in CO2 photoconversion to C2H5OH based on cooperative photoredox systems. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is an environmentally friendly and effective energy storage method. However, it is still a huge challenge to prepare non‐noble metal based electrocatalysts that possess high activity and long‐term durability to realize efficient water splitting. Here, we present a novel method of low‐temperature phosphating for preparing CoP/Co3O4 heterojunction nanowires catalyst on titanium mesh (TM) substrate that can be used for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and overall water splitting. CoP/Co3O4@TM heterojunction showed an excellent catalytic performance and long‐term durability in 1.0 M KOH electrolyte. The overpotential of CoP/Co3O4@TM heterojunction was only 257 mV at 20 mA cm−2 during the OER process, and it could work stably more than 40 h at 1.52 V versus reversible hydrogen electrode (vs. RHE). During the HER process, the overpotential of CoP/Co3O4@TM heterojunction was only 98 mV at −10 mA cm−2. More importantly, when used as anodic and cathodic electrocatalyst, they achieved 10 mA cm−2 at 1.59 V. The Faradaic efficiencies of OER and HER were 98.4 % and 99.4 %, respectively, outperforming Ru/Ir‐based noble metal electrocatalysts and other non‐noble metal electrocatalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

Weyl semimetals (WSMs) have attracted great attentions that provide intriguing platforms for exploring fundamental physical phenomena and future topotronics applications. Despite the fact that numerous WSMs are achieved, WSMs with long‐distance distribution of Weyl points (WPs) in given material candidates remain elusive. Here, the emergence of intrinsic ferromagnetic WSMs in BaCrSe2 with the nontrivial nature explicitly confirmed by the Chern number and Fermi arc surface states analysis is theoretically demonstrated. Remarkably, unlike previous WSMs for which opposite chirality WPs are located very close to each other, the WPs of BaCrSe2 host a long‐distance distribution, as much as half of the reciprocal space vector, suggesting that the WPs are highly robust and difficult to be annihilated by perturbations. The presented results not only advance the general understanding of magnetic WSMs but also put forward potential applications in topotronics. [ABSTRACT FROM AUTHOR]