Two-dimensional/three-dimensional hierarchical self-supporting potassium ammonium vanadate@MXene hybrid film for superior performance aqueous zinc ion batteries.

Currently, aqueous zinc ion batteries (AZIBs) have grown to be a good choice for large-scale energy storage systems due to their high theoretical specific capacity, low redox potential, low cost, and non-toxicity of the aqueous electrolyte. However, it is still challenging to obtain high specific capacity and stability suitable cathodes. Herein, hierarchical self-supporting potassium ammonium vanadate@MXene (KNVO@MXene) hybrid films were prepared by vacuum filtration method. Due to the three-dimensional nanoflower structure of KNVO with dual ions intercalation, high conductivity of two-dimensional Ti3C2Tx MXene, and the hierarchical self-supporting structure, the AZIB based on the KNVO@MXene hybrid film cathode possessed superior specific capacity (481 mAh/g at 0.3 A/g) and cycling stability (retaining 125 mAh/g after 1000 cycles at a high current density of 10 A/g). In addition, the storage mechanism was revealed by various ex-situ characterizations. Hence, a new viewpoint for the preparation of AZIB self-supporting cathode materials is presented.

Boosting Hydrogen Production of a MOF-based Multicomponent Photocatalyst with Clean Interface via Facile One-pot Electrosynthesis.

Hydrogen production from photocatalysis via the usage of multicomponent photocatalysts represents a promising pathway for carbon peaking and carbon neutrality, owing to their structural advantages in dealing with the three crucial processes in photocatalysis, namely, light harvesting, charge transfer, and surface redox reactions. We demonstrate the fabrication of a MOF-based multicomponent photocatalyst, denoted as semiconductor/MOF/cocatalyst, by a one-pot electrochemical synthetic route. The as-fabricated multicomponent photocatalyst has a clean interface among the components, leading to close connections that contribute to high-quality heterojunction and facilitate photogenerated charge transfer and separation, thereby the efficient hydrogen evolution. The hydrogen production rate of the resultant ZrO2 /Zr-MOF/Pt is 1327 µmol ⋅ g-1 ⋅ h-1 , which is much higher than that of ZrO2 /Zr-MOF (15 µmol ⋅ g-1 ⋅ h-1 ) and pure Zr-MOF (10.1 µmol ⋅ g-1 ⋅ h-1 ), as well as the photodeposited-Pt products ZrO2 /Zr-MOF/PtPD (287 µmol ⋅ g-1 ⋅ h-1 ) and Zr-MOF/PtPD (192 µmol ⋅ g-1 ⋅ h-1 ) obtained by the step-wise synthetic approach. The work gives a good inspiration for the rational design and construction of MOF-based multicomponent photocatalysts through the one-pot electrosynthesis.

PigBiobank: a valuable resource for understanding genetic and biological mechanisms of diverse complex traits in pigs.

To fully unlock the potential of pigs as both agricultural species for animal-based protein food and biomedical models for human biology and disease, a comprehensive understanding of molecular and cellular mechanisms underlying various complex phenotypes in pigs and how the findings can be translated to other species, especially humans, are urgently needed. Here, within the Farm animal Genotype-Tissue Expression (FarmGTEx) project, we build the PigBiobank (http://pigbiobank.farmgtex.org) to systematically investigate the relationships among genomic variants, regulatory elements, genes, molecular networks, tissues and complex traits in pigs. This first version of the PigBiobank curates 71 885 pigs with both genotypes and phenotypes from over 100 pig breeds worldwide, covering 264 distinct complex traits. The PigBiobank has the following functions: (i) imputed sequence-based genotype-phenotype associations via a standardized and uniform pipeline, (ii) molecular and cellular mechanisms underlying trait-associations via integrating multi-omics data, (iii) cross-species gene mapping of complex traits via transcriptome-wide association studies, and (iv) high-quality results display and visualization. The PigBiobank will be updated timely with the development of the FarmGTEx-PigGTEx project, serving as an open-access and easy-to-use resource for genetically and biologically dissecting complex traits in pigs and translating the findings to other species.

Boosting Oxygen Evolution Performance of Nickel-Iron Layered Double Hydroxides by Controlling Oxygen Vacancies and Structural Disorder via n-Butyllithium Treatment.

Nickel-iron-based layered double hydroxides (NiFe-LDHs) are promising catalysts for the oxygen evolution reaction (OER) because of their high activity, availability, and low cost. Defect engineering, particularly the formation of oxygen vacancies, can improve the catalytic activity of NiFe-LDHs. However, the controllable introduction of uniform oxygen vacancies remains challenging. Herein, an n-butyllithium treatment method is developed to tune oxygen vacancy defects and change the degree of amorphization in NiFe-LDHs via deep reduction, followed by partial oxidization at low temperatures. Interestingly, the Ni in the NiFe-LDHs is selectively reduced to the alloy state by n-butyllithium, whereas Fe is not. The different structural transformations of Ni and Fe during the treatment successfully produce an oxygen-defect-rich amorphous/crystalline electrocatalyst. Under optimal conditions, the treated NiFe-LDHs exhibit high OER activity with an overpotential of 223 mV at 10 mA cm-2 (68 mV lower than that of a commercial IrO2 electrocatalyst) and long-term stability. Notably, the n-butyllithium treatment can be applied to other electrocatalysts, such as CoFe-LDHs and IrO2 (treated IrO2 with an overpotential of 197 mV at 10 mA cm-2). This n-butyllithium reduction/partial oxidization treatment constitutes a novel top-down strategy for the controllable modification of metal oxide structures, with various energy-related applications.

Phase Interface Regulating on Amorphous/Crystalline Bismuth Catalyst for Boosted Electrocatalytic CO2 Reduction to Formate.

Electroreduction of carbon dioxide into readily collectable and high-value carbon-based fuels is greatly significant to overcome the energy and environmental crises yet challenging in the development of robust and highly efficient electrocatalysts. Herein, a bismuth (Bi) heterophase electrode with enriched amorphous/crystalline interfaces was fabricated via cathodically in situ transformation of Bi-based metal-phenolic complexes (Bi-tannic acid, Bi-TA). Compared with amorphous or crystalline Bi catalyst, the amorphous/crystalline structure Bi leads to significantly enhanced performance for CO2 electroreduction. In a liquid-phase H-type cell, the Faraday efficiency (FE) of formate formation is over 90% in a wide potential range from -0.8 to -1.3 V, demonstrating a high selectivity toward formate. Moreover, in a flow cell, a large current density reaching 600 mA cm-2 can further be rendered for formate production. Theoretical calculations indicate that the amorphous/crystalline Bi heterophase interface exhibits a favorable adsorption of CO2 and lower energy barriers for the rate-determining step compared with the crystalline Bi counterparts, thus accelerating the reaction process. This work paves the way for the rational design of advanced heterointerface catalysts for CO2 reduction.

Silicene/poly(N-isopropylacrylamide) smart hydrogels as remote light-controlled switches.

Smart hydrogels with good flexibility and biocompatibility have been widely used. The common near-infrared (NIR) photothermal agents are facing a trade-off between good photothermal-conversion efficiency and high biocompatibility. Therefore, developing new metal-free photothermal agents with low cost, high biocompatibility and excellent phase stability is still in urgent need. In this study, we successfully combined poly(N-isopropylacrylamide) (PNIPAM) with the two-dimensional (2D) silicene nanosheets via the in situ polymerization method. Attributed to the thermal-responsive nature of PNIPAM and the excellent photothermal properties of 2D silicene, the obtained silicene/PNIPAM composite hydrogels exhibited dual thermal and NIR responsive properties. This smart hydrogel showed rapid, reversible and repeatable NIR light-responsive behaviors. The volume of this smart hydrogels can shrink significantly under NIR irradiation and recover to its original size without the NIR irradiation. Remote near-infrared light-controlled microfluidic pipelines and electronic switches based on obtained silicene/PNIPAM composite hydrogels were also demonstrated. This work significantly broadens the application prospects of silicene-based hydrogels in remote light-controlled devices.

Impacts of renewable electricity standard and Renewable Energy Certificates on renewable energy investments and carbon emissions.

Accelerating the development of renewable energy is seen as an effective way for achieving the goals of carbon peak and carbon neutrality. The polices of Renewable Electricity Standard (RES) and Renewable Energy Certificates (REC) play increasing and important roles in developing renewable energy. In this paper, we develop an analytical model to analyze the impacts of the interaction of RES and REC polices on the renewable energy investment levels of an electricity generation firm and the carbon emissions. Our analysis reveals several interesting insights. First, we find that the green tags price under REC policy has a non-monotonic effect on the renewable energy investment, which highly depends on the quota (i.e., the required percentage of renewable electricity consumption on total electricity consumption) under the RES policy. Specifically, when the quota in RES policy is set too high, an increase in the green tags price will increase renewable energy investment; otherwise it will reduce the electricity generation firm's incentive to invest in renewable energy. Second, we show that the green tags price also has a non-monotonic effect on the carbon emissions. Specifically, when the quota in RES policy is set small enough, an increase in the green tags price will decrease the carbon emission. However, when the quota in RES policy is high enough, an increase in the green tags price will increase the carbon emission.

MXene derivatives: synthesis and applications in energy convention and storage.

Transition metal carbides or nitrides (MXene) have shown promising applications in energy convention and storage (ECS), owing to their high conductivity and adjustable surface functional groups. In the past several years, many MXene derivatives with different structures have been successfully prepared and their impressive performance demonstrated in ECS. This review summarizes the progress in the synthesis of MXene and typical Ti3C2T x MXene derivatives with different morphologies, including 0D quantum dots, 1D nanoribbons, 2D nanosheets and 3D nanoflowers. The mechanisms involved and their performance in photocatalysis, electrocatalysis and rechargeable batteries are also discussed. Furthermore, the challenges of MXene derivatives in ECS are also proposed.

Sensory evoked fMRI paradigms in awake mice.

Mouse fMRI has become increasingly popular in the small animal imaging field. However, compared to the more commonly used rat fMRI, it is challenging for mouse fMRI to obtain robust and specific functional imaging results. In the meantime, in other neuroscience modalities such as optical imaging, functional recording in the awake mice is common and becoming standard. Therefore, in the current study we developed comprehensive setups and analysis pipeline for multi-sensory fMRI paradigms in the awake mice. Customized setups of somatosensory (whisker), auditory and olfactory stimulation were developed for use in the cryogenic coil in the awake mouse fMRI setting. After carefully evaluating head motion and motion artefacts, the nuisance regression approach was optimized for reducing the confounding effect of motion. The high temporal resolution data (TR = 0.35 s) revealed fast temporal dynamics (time-to-peak ~2 s) of evoked BOLD responses in most brain regions. Using the derived awake mouse specific hemodynamic response functions, high spatial resolution data revealed robust, specific and consistent cortical and subcortical activations in response to somatosensory, auditory and olfactory stimulations, respectively. Overall, we present comprehensive methods for acquiring and analyzing sensory evoked awake mouse fMRI data. The establishment of multi-sensory paradigms in awake mouse fMRI provides valuable tools for examining spatiotemporal characteristics and neural mechanisms of BOLD signals in the future.

N-Butyllithium-Treated Ti3C2Tx MXene with Excellent Pseudocapacitor Performance.

MXenes, a family of two-dimensional (2D) transition-metal carbide and nitride materials, are supposed to be promising pseudocapacitive materials because of their high electronic conductivity and hydrophilic surfaces. MXenes, prepared by removing the "A" elements of their corresponding MAX phases by hydrofluoric acid (HF) or LiF-HCl etching, possess abundant terminal groups like -F, -OH, and -O groups. It has been proven that the MXenes with fewer -F terminal groups and more -O groups showed a higher pseudocapacitor performance. In organic reactions, -OH and -X (X = halogen) groups could turn to ether groups in strong nucleophilic reagent. Inspired by that, herein, we report an n-butyllithium-treated method to turn the -F and -OH terminal groups to -O groups on the Ti3C2Tx MXenes. Two types of Ti3C2Tx MXenes prepared by either HF or LiF-HCl etching were systematically investigated, and a comparison with the traditional KOH/NaOH/LiOH-treated method was also carried out. It is found that most of the -F terminal groups on the Ti3C2Tx MXenes can be successfully removed by n-butyllithium, and abundant -O terminal groups were formed. The n-butyllithium-treated Ti3C2Tx MXenes show promising applications in high-performance pseudocapacitors. A record high capacitance of 523 F g-1 at 2 mV s-1 was obtained for the n-butyllithium-treated Ti3C2Tx MXenes, and 96% capacity can remain even after 10 000 cycles.

Reversible intercalation and exfoliation of layered covalent triazine frameworks for enhanced lithium ion storage.

We report that layered covalent triazine frameworks (CTF-1) can be rapidly and reversibly intercalated with either an oxidizing or a non-oxidizing acid based on the acid-base driven mechanism. The obtained CTF-1 intercalated compounds can be readily reacted with nitronium ions and spontaneously exfoliated into 1-2 layered functionalized CTF-1 nanosheets (f-CTF-1) with a high yield of 42%. The f-CTF-1 shows a 2.5 to 3.8 times increase in specific capacitance and much better rate performance when used as an LIB anode.

Awake and behaving mouse fMRI during Go/No-Go task.

Functional magnetic imaging (fMRI) has been widely used to examine the functional neural networks in both the evoked and resting states. However, most fMRI studies in rodents are performed under anesthesia, which greatly limits the scope of their application, and behavioral relevance. Efforts have been made to image rodents in the awake condition, either in the resting state or in response to sensory or optogenetic stimulation. However, fMRI in awake behaving rodents has not yet been achieved. In the current study, a novel fMRI paradigm for awake and behaving mice was developed, allowing functional imaging of the mouse brain in an olfaction-based go/no-go task. High resolution functional imaging with limited motion and image distortion were achieved at 9.4T with a cryogenic coil in awake and behaving mice. Distributed whole-brain spatiotemporal patterns were revealed, with drastically different activity profiles for go versus no-go trials. Therefore, we have demonstrated the feasibility of functional imaging of an olfactory behavior in awake mice. This fMRI paradigm in awake behaving mice could lead to novel insights into neural mechanisms underlying behaviors at a whole-brain level.

Partially Etched Ti3 AlC2 as a Promising High-Capacity Lithium-Ion Battery Anode.

MXenes, a family of two-dimensional transition-metal carbide and nitride materials, are thought to be promising materials in energy storage because of their high electronic conductivity, hydrophilic surfaces, and low diffusion barriers. MXenes are generally prepared by removing the "A" elements (A=Al, Si, Sn, etc.) from their corresponding MAX phases by using hydrofluoric acid (HF) and other etching agents, although these "A" elements usually have great volumetric and gravimetric capacities. In a study of the etching progress of Ti3 AlC2 and evaluation of their anode performance in lithium-ion batteries, a partially etched sample (0.5 h-pe Ti3 C2 Tx ) is found to have much higher capacity (160 mAh g-1 , 331.6 mAh cm-3 at 1C) when compared with the fully etched Ti3 C2 Tx (110 mAh g-1 , 190.3 mAh cm-3 at 1C). Moreover, a 99 % capacity retention was observed even after 1000 cycles in the 0.5 h-pe Ti3 C2 Tx anode. This interesting result can be explained, at least in part, by the alloying of the residual Al during lithiation.

Rational Design of Fe/N/S-Doped Nanoporous Carbon Catalysts from Covalent Triazine Frameworks for Efficient Oxygen Reduction.

Porous organic polymers (POPs) are promising precursors for developing high performance transition metal-nitrogen-carbon (M/N/C) catalysts for the oxygen reduction reaction (ORR). The rational design of POP precursors remain a great challenge, because of the elusive structural association between the sacrificial POPs and the final M/N/C catalysts. Based on covalent triazine frameworks (CTFs), we developed a series of S-doped Fe/N/C catalysts by selecting six different aromatic nitriles as building blocks. A new mixed solvent of molten FeCl3 and S was used for CTF polymerization, which benefited the formation of Fe-Nx sites and made the subsequent pyrolysis process more convenient. Comprehensive study of these CTF-derived catalysts showed that their ORR activities are not directly dependent on the theoretical N/C ratio of the building block, but closely correlated to the ratio of the nitrile group to benzene ring (Nnitrile /Nbenzene ) and geometries of the building blocks. The high ratios of Nnitrile /Nbenzene are crucial for ORR activity of the final catalysts owing to the formation of more N-doped micropores and Fe-Nx sites in pyrolysis possess. The optimized catalyst shows high ORR performances in acid and superior ORR activity to the Pt/C catalysts under alkaline conditions.

Super rapid removal of copper, cadmium and lead ions from water by NTA-silica gel.

Copper (Cu2+), cadmium (Cd2+) and lead ions (Pb2+) are toxic to human beings and other organisms. In this study, a silica gel material modified with nitrilotriacetic acid (NTA-silica gel) was sensibly designed and prepared via a simple amidation procedure for the removal of Cu2+, Cd2+ and Pb2+ from water. The NTA-silica gels showed rapid removal performances for the three metal ions (Pb2+ (<2 min), Cu2+ and Cd2+ (<20 min)) with relatively high adsorption capacities (63.5, 53.14 and 76.22 mg g-1 for Cu2+, Cd2+ and Pb2+, respectively). At the same concentration of 20 mg L-1, the removal efficiencies of the three metals by the adsorbent ranged from 96% to 99%. The Freundlich and Langmuir models were utilized to fit the adsorption isotherms. The adsorption kinetics for the three metal ions was pseudo-second-order kinetics. The removal performance of the NTA-silica gels increased in a wide pH range (2-9) and maintained in the presence of competitive metal ions (Na+, Mg2+, Ca2+ and Al3+) with different concentrations. In addition, the NTA-silica gels were easily regenerated (washed with 1% HNO3) and reused for 5 cycles with high adsorption capacity. This study indicates that the NTA-silica gel is a reusable adsorbent for the rapid, convenient, and efficient removal of Cu2+, Cd2+, and Pb2+ from contaminated aquatic environments.