Nickel-Doped Ultrathin K‑Birnessite Manganese Oxide Nanosheet As Pseudocapacitor Electrode with Excellent Cycling Stability for High-Power Pesudocapacitors

We herein report a kind of nickel-doped ultrathin δ-MnO₂ nanosheets prepared using a facile chemical bath deposition method. The obtained δ-MnO₂ materials have 2D ultrathin nanosheet structures with a few atomic layers. Electrochemical measurements indicate that an appropriate amount of nickel doping can remarkably improve the specific capacitance of the δ-MnO₂ and that 1.0 mol % nickel-doped δ-MnO₂ nanosheets display the best specific capacitance of 337.9 F g^–1 at 1 A g^–1. The specific capacitance can maintain at 158 F g^–1 even as the current density increases to 20 A g^–1, demonstrating that the electrode material possesses good rate performance. In addition, the discharge capacity fading from 160.9 to 158.8 F g^–1 is slight after 4000 cycles, and the corresponding capacitance retention is as high as 98.6%. The good rate capacity and stability of the δ-MnO₂ nanosheets can be attributed to the ultrathin structure of a few atomic layers which provides large surface areas and lots of reactive active sites. Moreover, the appropriate amount of nickel ion doping at atomic level improves the conductivity of the δ-MnO₂ material

Regulating the Intermolecular Hydrogen Bond to Realize Directional Dimension Reduction of Lead Iodide Perovskite toward Low-Dimensional Photovoltaics

A low-dimensional organic amine lead halide perovskite is an attractive semiconductor material that has potential application prospects in photovoltaics, light-emitting diodes, detectors, X-ray imaging, and other fields. It has been reported that the photoelectric properties of low-dimensional perovskite can be controlled by adjusting the chain length of organic ammonium, the ratio of precursor components, and van der Waals interaction between amine molecules. Herein, we report the successful synthesis of low-dimensional perovskite (PdEA)­PbI4 (PdEA = piperidine ethylammonium) and (MlEA)­PbI4 (MlEA = morpholine ethylammonium) single crystals by regulating the intermolecular hydrogen bond of organic ammonium ligands. The two-dimensional (2D) layered structure (PdEA)­PbI4 single crystal with a fluorescence reflection peak at 563 nm was produced by the reaction of PdEA with PbO in a concentrated hydroiodic acid aqueous solution. Differently, the (MlEA)­PbI4 single crystal prepared by replacing MlEA with PdEA presents a one-dimensional (1D) rod structure, and its fluorescence reflection peak is located at 531 nm. The optical bandgaps of (PdEA)­PbI4 and (MlEA)­PbI4 perovskite films were about 2.16 and 2.33 eV, respectively. Low-dimensional perovskite solar cells with 2D (PdEA)­PbI4 and 1D (MlEA)­PbI4 of perovskite films yielded efficiencies of 1.18 and 1.52%, respectively

Bioinspired Ultrastable MXene/PEDOT:PSS Layered Membrane for Effective Salinity Gradient Energy Harvesting from Organic Solvents

The waste organic solvents containing inorganic salts have been considered sustainable resources, which can effectively capture salinity gradient energy using ion-selective membranes. However, it still remains a great challenge to fabricate the ion-selective membranes with high conversion efficiency and stability in an organic system. Here, the bioinspired nacre-like layered MXene/poly­(3,4-ethylenedioxythiophene)–poly­(styrenesulfonate) (PEDOT:PSS) (MP) composite membranes for capturing salinity gradient energy from an organic solvent are fabricated via filtration method, in which PEDOT:PSS molecules are introduced into MXene interlayers. Accordingly, the MP membrane exhibits high mechanical property and wonderful stability in common organic solvents. As expected, the power generation of the MP membrane reaches up to 3216 ± 603 nW in a 2/0.001 M methanol (Met)–LiCl solution and a record high power generation of 6926 ± 959 nW after adding NaOH into the Met–LiCl solution, which is superior to the previous report. Both experimental and theoretical studies confirm that the MP membrane has excellent cation selectivity and fast ion transport performance. The results are attributable to an increased interlayer spacing between MXene layers and an improved cation selectivity due to the insertion of PEDOT:PSS chains and the enhanced dissociation of negative charges by NaOH. The ultrastable two-dimensional (2D) nanochannel membrane provides practical application for harvesting energy from waste organic solvents

Supplementary document for Vivid reflective color generation mechanism in Al/AAO/Al configuration - 5806460.pdf

The calculation of the angle-dependent transmissive spectra of PAlpore/AAOthick and the analytical solution of dispersion relation of PAlpore/AAOthic

Photo-controllable Ion-Gated Metal–Organic Framework MIL-53 Sub-nanochannels for Efficient Osmotic Energy Generation

By closing and opening ion channels, electric eels are able to convert ion concentration gradients into electricity. Inspired by electric eels, considerable artificial sub-nanoscale ion channels with high ion selectivity and transportation efficiency have been designed for harvesting the osmotic energy between ionic solutions of different salinities, but constructing smart ion-gated sub-nanochannels for effective ion transport is still a huge challenge. Herein, photo-controllable sub-nanochannels of metal–organic framework (MOF) NH2-MIL-53 encapsulated with spiropyrans (SP-MIL-53) were fabricated by a facile in situ growth strategy. Interestingly, the highly ordered sub-nanochannels of SP-MIL-53 were switched on and off to efficiently regulate the ion flux by the light-driven isomerization of SP, which made it a smart ionic gate with a high on–off ratio of 16.2 in 10 mM KCl aqueous solution via UV irradiation. Moreover, the ion-gated sub-nanochannel membrane yielded a high power density of 8.3 W m–2 under a 50-fold KCl concentration gradient in the open state. Density functional theory calculations revealed that K+ ions in SP-MIL-53 sub-nanochannels had a higher mobility constant (3.61 × 10–2) with UV irradiation than without UV illumination (2.33 × 10–22). This work provides an effective way to develop smart ion-gating sub-nanochannels for capturing salinity gradient power

Engineering a Hierarchical Al Nanocap Array with Tunable Plasmonic Properties for Sensing Applications

In this study, we propose an easy and cost-effective method to improve the refractive index (RI) sensitivity of hierarchical aluminum (Al) nanocap arrays (HAlNAs) that are suitable for RI sensing applications. By adjusting the deposited Al thickness, deposition rate, and period, HAlNAs with tunable plasmonic and sensing properties could be achieved. The optimal sensitivity could reach 631 nm/RIU, and the detection limit of adenine ethanol solution with different concentration was as low as 1 × 10–6 M. The experimental results confirmed that the RI sensitivity of the proposed sensor was primarily related to the period and deposited Al thickness. Moreover, a higher deposition rate could narrow the full width at half-maximum (FWHM) of the reflection spectra, resulting in a higher figure of merit (FOM). The simulated electric field (EF) distribution revealed that the high RI sensitivity could be attributed to the strong coupling between propagating surface plasmon polaritons (PSPPs) and localized surface plasmon resonance (LSPR). In addition, HAlNAs with larger periods could generate a greater hot spot density, resulting in higher sensing sensitivity. The results of this study provide a method to easily fabricate Al-based RI sensors that exhibit great promise for the development of highly sensitive and selective biosensors

Data_Sheet_1_Pomelo Green Production on Acidic Soil: Reduce Traditional Fertilizers, but Do Not Ignore Magnesium.doc

Orchards in acid soils are at risk of magnesium (Mg) deficiency which negatively affects the plant growth, yield, and quality. However, the impacts of Mg supplementation on fruit yield, quality, and environmental and economic benefits have only been rarely addressed. We conducted 15 pomelo (Citrus grandis L.) orchard trials in South China to assess more efficient integrated nutrient management (INM) practices, including local farmer fertilization practices (FP; average application rate of nitrogen, phosphorus, and potassium were 1,075 kg N ha−1, 826 kg P2O5 ha−1, and 948 kg K2O ha−1, respectively), optimum fertilization practice (OPT; average application rate of nitrogen, phosphorus, and potassium were 550 kg N ha−1, 295 kg P2O5 ha−1, and 498 kg K2O ha−1, respectively) and optimum fertilization supplemented with Mg (OPT+Mg; average application rate of Mg was 196 kg MgO ha−1). The results showed that the yield, total soluble solid-to-titratable acidity ratio, and economic benefits under OPT practice were not significantly different from those of FP, while those of OPT+Mg were significantly higher than those of FP, by 8.76, 8.79, and 15.00%, respectively, while titratable acidity contents were significantly lower by 7.35%. In addition, compared with those from FP, the energy inputs and greenhouse gas (GHG) emissions from OPT were 31.00 and 26.48% lower, and those from OPT+Mg were 26.71 and 23.40% lower, respectively. Compared with those of OPT, the marginal efficiency of energy, GHG emissions, and capital of Mg under OPT+Mg were reduced by 62.30, 44.19, and 21.07%, respectively. Overall, adopting OPT+Mg for pomelo production could further enhance yield, fruit quality, and economic benefits while reducing the environmental burdens.</p