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The reductive amination of 1,6‐hexanediol with ammonia is one of the most promising green routes for synthesis of 1,6‐hexanediamine. Herein, we developed a phosphorous modified Ni catalyst of Ni−P/Al2O3. It presented satisfactory improved selectivity to 1,6‐hexanediamine in the reductive amination of 1,6‐hexanediol compared to the Ni/Al2O3 catalyst. The phosphorous tended to interact with Al2O3 to form AlPOx species, induced Ni nanoparticle to be flatter, and the decrease of strong acid sites, the new‐formed Ni−AlPOx−Al2O3 interface and the flatter Ni nanoparticle were the key to switch the dominating product from hexamethyleneimine to 1,6‐hexanediamine. This work develops an efficient catalyst for production of 1,6‐hexanediamine from the reductive amination of 1,6‐hexanediol, and provides a point of view about designing selective non‐noble metal catalysts for producing primary diamines via reductive amination of diols. [ABSTRACT FROM AUTHOR]

Triple‐cation mixed perovskites have attracted much attention recently owing to their prominent optoelectronic properties and good stability for perovskite solar cells. However, the introduction of those cations with different sizes in the perovskite materials will drive the perovskite lattice away from ideal cubic structure and lead to microstrain in the resultant films. Herein,a small amount of KBF4 as an additive to elevate the quality of triple‐cation mixed perovskite thin films is introduced. It is found that KBF4 can enhance the crystallinity and alleviate microstrain of the perovskite thin films. Moreover, KBF4 can passivate defects in perovskite grains, leading to much longer carrier lifetimes. Consequently, the resultant devices show improved fill factor, enhanced device efficiency, and better device stability. Under optimum fabrication conditions, triple‐cation mixed perovskite solar cells with an inverted structure show power conversion efficiency over 23% as well as excellent stability under different conditions. [ABSTRACT FROM AUTHOR]

The utilization of CO2 as a renewable and cheap carbon resource to produce fuels, chemicals and polymers has attracted more attention. This review will summarize the developments in the production of polymers like polyureas and polyurea hybrids with CO2 as a monomer directly or indirectly. The influences of catalyst and the structure of diamine monomer on the molecular weight, thermal stability and mechanical properties of polyureas are discussed. In addition, the general properties and applications of functional CO2‐based polyureas are also described. A few examples of CO2‐based polyurea hybrids are also introduced. Finally, the future research priorities as well as the development trend of polyurea materials are depicted. [ABSTRACT FROM AUTHOR]

2D–3D mixed tin halide perovskites are outstanding candidate materials for lead‐free perovskite solar cells (PSCs) due to their improved stability and decreased trap density in comparison with their pure 3D counterparts. However, the mixture of multiple phases may lead to poor charge transfer across the films and limit the device efficiency. Here, a stacked quasi‐2D (down)–3D (top) double‐layered structure in perovskite films prepared via vacuum treatment is demonstrated, which can result in a planar bilayer heterojunction. In addition, it is found that the introduction of guanidinium thiocyanate (GuaSCN) additive can improve the crystallinity and carrier mobility in the 2D perovskite layer and passivate defects in the whole film, leading to a long carrier lifetime (>140 ns) in photoluminescence measurements. As a result, the PSCs show a high open circuit voltage (VOC) up to 1.01 V with a voltage loss of only 0.39 V, which represents the record values ever reported for tin‐based PSCs. The champion device exhibits a power conversion efficiency (PCE) of 13.79% with decent stability, retaining 90% of the initial PCE for 1200 h storage in N2‐filled glovebox. [ABSTRACT FROM AUTHOR]

Drought stress adversely impacts crop development and yield. Maize frequently encounters drought stress during its life cycle. Improvement of drought tolerance is a priority of maize breeding programs. Here, we identified a novel transcription factor encoding gene, APETALA2 (AP2)/Ethylene response factor (ERF), which is tightly associated with drought tolerance in maize seedlings. ZmERF21 is mainly expressed in the root and leaf and it can be highly induced by polyethylene glycol treatment. Genetic analysis showed that the zmerf21 mutant plants displayed a reduced drought tolerance phenotype, accompanied by phenotypical and physiological changes that are commonly observed in drought conditions. Overexpression of ZmERF21 in maize significantly increased the chlorophyll content and activities of antioxidant enzymes under drought conditions. RNA‐Seq and DNA affinity purification sequencing analysis further revealed that ZmERF21 may directly regulate the expression of genes related to hormone (ethylene, abscisic acid) and Ca signaling as well as other stress‐response genes through binding to the promoters of potential target genes. Our results thereby provided molecular evidence of ZmERF21 is involved in the drought stress response of maize. Summary Statement: Drought stress adversely destroys maize development during the whole life cycle, finally reducing its yield and quality. Thus, improving the performance of maize against drought tolerance is a priority of breeding programs. Here, we identified a novel transcription factor ZmERF21 that is tightly associated with drought tolerance in maize seedlings. ZmERF21 is mainly expressed in root and leaf. Mechanistic analysis demonstrated that ZmERF21 could directly bind to the genes involved in hormone (ethylene, abscisic acid) and Ca signaling pathways. Furthermore, overexpression of ZmERF21 in maize significantly increased drought tolerance, evidenced by chlorophyll content and the activities of antioxidant enzymes. Taken together, our results revealed that ZmERF21 is a positive regulator in response to drought stress in maize. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of six‐membered P,O‐heterocycles from dialkynylphosphine oxides. By using gold(I) complexes, the chemoselectivity of the reaction was switched from literature‐reported double hydration to a hydration/intramolecular cyclization cascade. Control experiments indicated that the first alkyne hydration product is an intermediate of the reaction. In addition, a density functional theory (DFT) calculation allowed to rationalize the observed chemoselectivity. [ABSTRACT FROM AUTHOR]

A non‐noble heterogeneous catalyst of Cu/TiO2 was prepared for N‐methylation of N‐methylaniline (MA) with CO2 and H2. 5 wt.–% Cu loaded TiO2 (P25) catalyst exhibited a high performance, with 82 % MA conversion and 98 % N,N‐dimethylaniline (DMA) selectivity under the reaction conditions used (4 MPa H2, 2 MPa CO2, 180 °C, 36 h). The Cu/TiO2 catalyst was more effective with respective to the total conversion and the DMA selectivity as compared to 5 wt.–% Cu loaded catalysts on CeO2, ZnO and activated carbon materials. The possible active species of Cu/TiO2 catalyst should be both Cu+ and Cu0 which contributed to the high activity as the reaction conversion increased linearly with them exposed on the surface of catalyst. Moreover, the reaction pathways involved were studied; it was likely that the reaction took place via an intermediate of formaldehyde that was formed from CO2 and H2, as confirmed by in situ diffuse reflectance Fourier‐transform infrared spectroscopy, then it reacted with MA to give N‐methylformanilide (MFA), and finally MFA was hydrogenated to DMA. [ABSTRACT FROM AUTHOR]

The relationship between catalyst structure and catalytic activity is an important and challenging topic for researchers in the field of catalysis. In this work, the effect of oxygen vacancies on the activity of ZnPd/ZnO-Al catalysts was studied in an important reaction-glycerol hydrogenolysis. Interestingly, the catalytic activity improved significantly with the addition of a small amount of Al, and high selectivity to 1,2-propanediol (>90 %) was achieved in glycerol hydrogenolysis over ZnPd/ZnO-Al catalysts. Importantly, the formation of oxygen vacancies benefits from the substitution of Al atoms, and the Al content in the ZnO lattice is related to the oxygen vacancies density and catalytic activity. Moreover, the important role played by oxygen vacancies in glycerol hydrogenolysis has been discussed in detail. [ABSTRACT FROM AUTHOR]