Search

In order to determine the physiological mechanism of drought resistance of northern wheat in China, six drought resistant wheat and one sensitivity to drought wheat were planted in pots. They were subjected to drought treatment and normal water when the plants grew to the 3-leaf stage. Samples were collected at 10, 20, 30, and 40 days after the drought treatment, respectively. The electrical conductivity, photosynthetic parameters, chlorophyll fluorescence parameters, sugar content, proline content, protein content, and active oxygen scavenging enzyme activity of the plants were detected, and the agronomic traits of the wheat varieties were investigated at maturity. The results indicated that the phenotype and yield-related factors of Darkhan 144 changed little under the drought stress. The relative electrical conductivity of Kefeng 6 and Darkhan 166 was lower under the drought stress, and their cell membrane was less damaged. The Darkhan 144 and Darkhan 166 had higher drought resistance coefficients, and were the wheat varieties with stronger drought resistance. However, the physiological mechanisms of drought resistance of these three wheat were different: Darkhan 144 maintained a higher photosynthetic activity under the drought stress; Darkhan 166 maintained a higher protein content, photosynthetic activity and active oxygen scavenging enzyme activity. In addition, other drought-resistant varieties Kefeng 6, Kefeng 10 and Longmai 26 had a higher content of osmoregulatory substances under the drought stress. [ABSTRACT FROM AUTHOR]

The ultralow turn-on fields, high current density and high emission stability of field emission (FE) cathodes are described as three of the main factors promoting their practical application in electronic devices, despite the fact that integrating all of these elements into a single cathode is a big challenge. In this study, we explored high-performance FE cathodes with numerous pyramid-shaped CoO nanoparticles around single-crystal N-doped SiC nanowires based on a novel and facile gas-phase in situ cation exchange (CA) method. The CoO nanoparticles growing from the wires' surface significantly increased electron emission sites. The strong connection between the wire body and the nanoparticles without interfaces provided emitters with a robust structure to prevent structural damage in long-term FE operation. In addition, the as-constructed CoO/SiC heterojunction and incorporated N dopants offered emitters with low work function (Φ) for electron emission. Accordingly, the obtained CoO/SiC nanowire field emitters presented superior comprehensive performance with ultralow turn-on field (0.40 V μm−1), high current density (18.6 mA cm−2) and high emission stability with just ±2% current fluctuation during 10 h long-term operation. The ultralow turn-on field could be comparable to the state-of-the-art one ever reported. This study offers a new approach to the design and fabrication of improved FE cathodes for additional prospective applications in harsh working environments requiring high performance. [ABSTRACT FROM AUTHOR]

The development of visible‐light‐induced photocatalysts is one of the critically important issues because it offers a green and sustainable route for solar energy conversion. Herein, In‐doped ZnO@In2O3 hybrid photocatalysts are designed and constructed through a one‐pot metal‐organic frameworks (MOFs)‐encapsulation‐derived method. The photocatalytic activity of the sample photocatalysts is systematically investigated by photocatalytic hydrogen evolution under visible light irradiation. The composition of the hybrid photocatalysts is also controlled to find the best photocatalytic activities. Interestingly, using a visible‐light irradiation source, the optimized In‐doped ZnO@In2O3 photocatalyst shows an H2 evolution rate of 417 µmol∙g−1∙h−1, which is nearly 20 times higher than that of the In‐doped ZnO sample and also exceeds most ZnO‐based catalysts ever reported. The enhanced catalytic performance is ascribed to the increased visible‐light response and enhanced charge separation efficiency by the synergistic effects of electron‐trapped In doping and electron‐donated In2O3 coupling. This work presents a promising pathway for fabricating MOFs‐encapsulation derived visible‐light‐driven composites for high photocatalytic performance towards hydrogen evolution. [ABSTRACT FROM AUTHOR]

Photoinduced charge separation and transfer has been recognized as one of the core factors affecting the photoelectrochemical (PEC) performance of BiVO4 based photoanodes. To achieve a higher charge separation efficiency, modulating the surface band edge of BiVO4-based photoanodes could be regarded as the best choice but still a challenge. Herein, first, it was confirmed by density functional theory (DFT) calculations that pristine BiVO4 could form a type-II heterojunction with BiVO4–VBi (replacing Bi sites with V in BiVO4), which could be used to enhance carrier separation. Then we use a gas-phase cation exchange (CA) method to in situ modulate the surface band edge of the BiVO4 photoanode by partially replacing Bi on the surface with V to form a V-rich surface. The charge separation efficiency of the optimized V-rich BiVO4 (V/BVO) photoanode is significantly enhanced from 56.5% to 81.5% compared to pristine BiVO4. As expected, it also displays a higher photocurrent density of 2.87 mA cm−2 at 1.23 V vs. RHE (under AM 1.5G illumination), which is nearly 3.2 times higher compared with pristine BiVO4. Upon further loading the FeOOH cocatalyst, the photocurrent of the V/BVO/FeOOH photoanode reached 4.26 mA cm−2 due to the boosted surface water oxidation properties. This work sheds light on a simple strategy to regulate surface band edges for designing highly efficient photoanodes. [ABSTRACT FROM AUTHOR]

Constructing core/shell nanoarrays with optimal structure and composition can maximize solar light utilization. In the present work, a distinct regular array of SiC/TiO2 core/shell nanoarray photoanodes with improved charge separation is successfully achieved through two sequential steps of electrochemical etching and atomic layer deposition. The suitable band offset between SiC and TiO2 results in forming a type-II heterojunction at the SiC/TiO2 interface, which efficiently promotes electron–hole separation. Under simulated sunlight illumination (100 mW/cm2), the SiC/TiO2 nanoarray composite photoanode exhibits a significantly improved photocurrent of 3.62 mA/cm2 at 1.4 V versus Ag/AgCl, which demonstrates significantly increased photoelectrochemical (PEC) activity compared to the intrinsic SiC photoanode. The significant enhancement of PEC behaviors is mainly assigned to the improved electron–hole separation at the surface of the junction, combined with the synergistic effect of the highly oriented nanochannel array configuration, single-crystal character of the etched entire SiC nanoarray film, as well as the incorporation of N dopants. We explored an N-doped 4H-SiC/TiO2 core–shell heterojunction nanochannel array photoanode for photoelectrochemical water splitting, which presents a high photocurrent density of ~ 3.62 mA/cm2 (1.4 V vs. Ag/AgCl). [ABSTRACT FROM AUTHOR]

The thermodynamically viable halogen vacancy defects in CsPbCl3 perovskite nanocrystals (NCs) are considered the main factor in weakening their optical quality. However, their separate impact on the dopant emission in Mn2+‐doped CsPbCl3 perovskite NCs is still under exploration owing to the absence of comparable samples. Herein, a series of Mn2+‐doped CsPbCl3 samples were synthesized with different oleylamine‐Cl (OAm‐Cl) contents based on a halogen‐hot‐injection strategy. It is found that the Mn2+ concentration of as‐prepared samples fixed at 0.65%, and the Mn2+ photoluminescence (PL) also exhibited an OAm‐Cl content‐independent lifetime of ∼ 1.78 ms, implying the efficient and identical luminescence of isolated Mn2+ ion in all samples. In contrast, the excitonic and Mn2+ PL intensities of the NCs are strong related to the amount of OAm‐Cl, which are attributed to the coordination effect of the suppressed excitonic nonradiative recombination owing to the passivation of chloride vacancies and the enhanced energy transfer from the host exciton to Mn2+ ions in the samples with sufficient OAm‐Cl contents. The temperature‐dependent of Mn2+ PL disclosed an initial increase and was followed by a decrease with increasing temperature for the samples with relatively higher OAm‐Cl contents, while it monotonously decreases for the sample with lower OAm‐Cl content of 0.4 mL. The different PL intensity change trend results from the effective passivation of chloride vacancies by extra OAm‐Cl. Above results present here will help clarify the underlying influence mechanism of halogen vacancy on the PL properties of Mn2+‐doped perovskite NCs, which is essential for targeted modulation of their optical properties. [ABSTRACT FROM AUTHOR]