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High-quality bulk BiOBr crystal with mm size is obtained by a space-confined chemical vapor transport strategy, & its intrinsic semi-conductive properties are characterized. It is fabricated into two-terminal UV photodetectors, which exhibit good UV detection performance.

The delaminated O-Ti2CTx aqueous solution can be stably stored for 30 days, which is much higher than that of HCl- and LiF-etched Ti2CTx (F-Ti2C) (completely oxidized within 24 hours).

MXenes exhibit great promise for energy storage. Fluorine-based reagents have always been the mainstream of MXenes preparation. However, the high toxicity of fluorine-containing reagents is the bot...

This paper studies the relationship between the level of national education and economic development in 31 provinces and cities in China from 2012 to 2019. Principal component analysis is used to comprehensively evaluate the level of national education, on the basis of which a variable coefficient model is tested and a constant coefficient model is established for comparison. The results show that: (1) there is a co-integration relationship between the level of national education and economic development, i.e. the two are in equilibrium in the long run. (2) In some provinces and cities in China, economic development is positively correlated with the level of national education, and some provinces and cities are negatively correlated. (3) Economic development has different effects on the level of national education in the east, middle and west. (4) Economic development and national education level are positively correlated in the average sense in China.

Highly efficient electro-oxidation of benzylamine to generate value-added chemicals coupled with the hydrogen evolution reaction (HER) is crucial but challenging. Herein, targeted regulation of the electronic states of Ni sites was realized via simple yet precise nitridation engineering. Benefiting from the insertion of N atoms into the Ni lattice, the Ni3N electrode exhibits superior activity, selectivity, and stability for the benzylamine oxidation reaction (BOR). Especially, under the industrially relevant current (∼250 mA), the Ni3N catalyst remains ∼95% selective for benzonitrile production, reaching 1.43 mmol h-1 cm-2. Experimental and theoretical findings reveal that the formation of Ni-N bonds upshifts the Ni d-band center and optimizes the electrophilic properties of Ni sites, which contributes to the adsorption and dehydrogenations process of benzylamine. Furthermore, due to the work function difference between Ni and Ni3N, a strong mutual interaction occurs at the heterogeneous interface for Ni-Ni3N, which endows it with the appropriate H* adsorption energy and thus excellent HER performance. Impressively, the integrated solar-energy-driven BOR coupled with the HER electrolyzer affords 10 mA cm-2 at an ultralow voltage of 1.4 V and exhibits a promising practical application (ηsolar-to-hydrogen = 13.8%). This work offers a new perspective for the bifunctional design of nitrides in the field of electrosynthesis.

Although MXene shows amazing application potential, it has always been subject to its own ambient instability, and preparation of MXene with excellent stability remains a persistent challenge because of oxidative degradation mechanism was not fully understood. Herein, we report a oxidative degradation mechanism hypothesis of Ti3C2Tx-MXene and point out the key factors affecting its stability are strong reduc ing Ti atoms inherent in Ti3C2Tx and the exposure of reducing Ti atoms caused by desorption of surface adsorbed HF acid. Based on the mechanism understanding, ambient ultrastable Ti3C2Tx (US-Ti3C2Tx) was successfully obtained and can be durably stored without being oxidatively degraded even if dispersed in water, while the conventional Ti3C2Tx aqueous dispersion can only be stored for a few days. Furthermore, the US-Ti3C2Tx membrane showed better seawater desalination ability than conventional Ti3C2Tx, and more importantly, it can avoid the mixing of harmful elements into desalinated water caused by instability of conventional Ti3C2Tx.

Recently, bismuth-based hybrid organic-inorganic halide perovskite-like materials have attracted great attention due to their friendly and safely processing, chemical stability, and photoconductive properties. Here, we report a simple method to prepare a new lead-free hybrid material of hydrazine iodobismuthate (HyBI) with semiconductor properties, adopting zero-dimensional (0D) perovskite-like structure, and its crystal, thermal, bandgap, and optoelectronic properties were explored. It is noteworthy that HyBI has a direct bandgap of 1.99 eV, carries mobility as high as 64.2 cm2V−1s−1, charge-trap density of 2.32 × 1010 cm−3. Moreover, self-powered photodetector devices were fabricated using HyBI, which showed the responsivity under 470 nm was 7.63 mA/W. This work highlights the material as a promising candidate for lead-free optoelectronic applications.

Most Bi-based semiconductors are incapable of photocatalytic reduction reaction from a thermodynamic view, owing to relatively positive conduction band potentials (ECB ). Here, a novel Bi-based metal-organic framework (Bi-MBA, MBA=4-mercaptobenzoic acid) with excellent photocatalytic reduction activities is developed. The ECB of Bi-MBA locates at -1.38 eV, which is able to efficiently reduce O2 , CrVI and CO2 . Theoretical calculations reveal the significant contribution of organic ligand (MBA) to the conduction band. Our results provide an effective route to improve the photocatalytic reduction activities of Bi-based photocatalysts.

One-dimension (1D) or two-dimension (2D) iodobismuthates are promising perovskite-like photoactive materials for electronic devices. Many researchers focused on how to qualitatively build frameworks to increase the dimension of charge transformation due to the construction of connectivity between bismuth halide ions as the key to achieve ideal properties. In this context, two kinds of organic amine compounds, benzylamine and N-methylaniline, were well-designed and corresponding iodobismuthates single crystals: BA3Bi2I9 and NMA3Bi2I9 (BA = C6H5CH2NH3+, NMA = C6H5(CH3)NH2+) were prepared by solvent evaporation process. Their crystals characterized by S-XRD, SEM, etc. After thoroughly investigated their structures, optical and electronic properties, the results show that the space group changed from C2/c (BABI) to P21/c (NMABI) due to the π-stacking type shifted from I-type to Z-type. So as to the reconstruction of their band structures and the C 2p of BABI is more closed to the band edge than that of NMABI revealed by density functional theory (DFT). Although BABI has higher electrical resistivity, higher trap-state density and lower carrier mobility, its optoelectronic property is superior to NMABI as a result of the I-type π-stacking increased the electronic dimensionality.

Tungsten oxide monohydrate (WO3·H2O) films on glass substrates were prepared by hydrothermal deposition without using any additives. The resulting crystals were single crystalline and possessed microplate-like shape with preferred growth in the two dimensions perpendicular to [010] direction. Many of the WO3·H2O microplates were found to embed into each other, forming interesting interlocking configuration. The initial distance among the nuclei was considered to play decisive role in the formation of the interlocking structure. Gas sensing tests showed that at room temperature the WO3·H2O films could detect 20 ppm of NO2 gas. The room temperature-based measurements guaranteed that the collected data really came from the WO3·H2O itself rather than from the dehydrated product that would be easily formed if elevated measurement temperature was applied. Such an additive-free method to prepare WO3·H2O films is promising to provide good candidate materials for applications like gas sensing, solar energy conversion, and so on.

Indium oxide octahedrons were prepared on glass substrates through a mild route based on sol–gel technique. The preparation possesses characteristics including low temperature, catalyst-free and large production, which is much distinguished from the chemical-vapor-deposition based methods that usually applied to prepare indium oxide octahedrons. Detailed characterization revealed that the indium oxide octahedrons were single crystalline, with {1 1 1} crystal facets exposed. It was found that the spin-coating technique was key for achieving the indium oxide crystals with octahedron morphology. The probable formation mechanism of the indium oxide octahedrons was proposed based on the experiment results. Room temperature NO 2 gas sensing measurements exhibited that the indium oxide octahedrons could significantly enhance the sensing performance in comparison with the plate-like indium oxide particles that prepared from the dip-coated gel films, which was attributed to the abundant sharp edges and tips as well as the special {1 1 1} crystal facets exposed that the former possessed. Such a simple wet-chemical based method to prepare indium oxide octahedrons with large-scale production is promising to provide the advanced materials that can be applied in wide fields like gas sensing, solar energy conversion, field emission, and so on.