A Mini Review on Borate Photocatalysts for Water Decomposition: Synthesis, Structure, and Further Challenges.

The development of novel photocatalysts, both visible and UV-responsive, for water decomposition reactions is of great importance. Here we focused on the application of the borates as photocatalysts in water decomposition reactions, including water splitting reaction, hydrogen evolution half-reaction, and oxygen evolution half-reaction. In addition, the rates of photocatalytic hydrogen evolution and oxygen evolution by these borate photocatalysts in different water decomposition reactions were summarized. Further, the review summarized the synthetic chemistry and structural features of existing borate photocatalysts for water decomposition reactions. Synthetic chemistry mainly includes high-temperature solid-state method, sol-gel method, precipitation method, hydrothermal method, boric acid flux method, and high-pressure method. Next, we summarized the crystal structures of the borate photocatalysts, with a particular focus on the form of the B-O unit and metal-oxygen polyhedral in the borates, and used this to classify borate photocatalysts, which are rarely mentioned in the current photocatalysis literature. Finally, we analyzed the relationship between the structural features of the borate photocatalysts and photocatalytic performance to discuss the further challenges faced by the borate photocatalysts for water decomposition reactions.

Au/Ti3C2/g-C3N4 Ternary Composites Boost H2 Evolution Efficiently with Remarkable Long-Term Stability by Synergistic Strategies.

The use of novel two-dimensional MXene materials and conventional g-C3N4 photocatalysts to fabricate the composites for hydrogen evolution reaction (HER) has attracted much attention, for which there is plenty of room for the enhancement of hydrogen evolution rates particularly under visible light and photostability. Herein, g-C3N4 was modified by copolymerization of malonamide and melamine and used to fabricate the ternary composites of Au particles and Ti3C2 MXene, and based on the synergistic effect, the composites enhanced the hydrogen evolution rates by 2.1, 99.8, and ∞ times compared with the unmodified g-C3N4 under UV, simulated sunlight, and visible light illumination, respectively. Moreover, the composite exhibited a sustained hydrogen evolution capacity in the cycle test for up to 120 h. Theoretical calculations and experimental results indicated that the hot electrons of Au are injected into the modified g-C3N4 and transferred to Ti3C2 simultaneously along with the photogenerated electrons of the modified g-C3N4 and then further transferred to Au, forming a photogenerated electron transfer channel of Au and modified g-C3N4 → Ti3C2 → Au within the composite. Ti3C2 acts as a bridge for fast separation of photogenerated electrons and holes on Au and modified g-C3N4, playing a key role in the enhanced photocatalytic performance. In addition, the visible light absorption ability of Au also positively contributed to the enhancement of visible light photocatalytic performance by providing hot electrons. Therefore, the selection of suitable cocatalysts for the design of composites is a crucial research direction to improve the photocatalytic performance and photostability of photocatalysts.

A dual amplification-based CRISPR/Cas12a biosensor for sensitive detection of miRNA in prostate cancer.

MicroRNA (miRNA) has gained significant attention as a potential biomarker for cancer clinics, and there is an urgent need for developing sensing strategies with high selectivity, sensitivity, and low background. In vitro diagnosis based on Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-Associated protein (CRISPR/Cas) technology could simplify the detection procedure, improve sensitivity and selectivity, and has broad application prospects as the next-generation molecular diagnosis technology. We propose a novel dual signal amplification strategy, called CENTER, which integrates the CRISPR/Cas12a system, an entropy-driven DNA signaling network, and strand displacement amplification to achieve ultrasensitive detection of miR-141, a potential marker for prostate cancer. The experimental results demonstrate that CENTER can distinguish single nucleotide mutations, and the strategy exhibits a good linear calibration curve ranging from 100 aM to 1 pM. Due to dual signal amplification, the detection limit is as low as 34 aM. We proposed a method for identifying miR-141 expressed in human serum and successfully distinguished between prostate cancer patients (n = 20) and healthy individuals (n = 15) with an impressive accuracy of 94%. Overall, CENTER shows great promise for the detection of miRNA.

FBL promotes cancer cell resistance to DNA damage and BRCA1 transcription via YBX1.

Fibrillarin (FBL) is a highly conserved nucleolar methyltransferase responsible for methylation of ribosomal RNA and proteins. Here, we reveal a role for FBL in DNA damage response and its impact on cancer proliferation and sensitivity to DNA-damaging agents. FBL is highly expressed in various cancers and correlates with poor survival outcomes in cancer patients. Knockdown of FBL sensitizes tumor cells and xenografts to DNA crosslinking agents, and leads to homologous recombination-mediated DNA repair defects. We identify Y-box-binding protein-1 (YBX1) as a key interacting partner of FBL, and FBL increases the nuclear accumulation of YBX1 in response to DNA damage. We show that FBL promotes the expression of BRCA1 by increasing the binding of YBX1 to the BRCA1 promoter. Our study sheds light on the regulatory mechanism of FBL in tumorigenesis and DNA damage response, providing potential therapeutic targets to overcome chemoresistance in cancer.

The metagenomics of soil bacteria and fungi and the release of mechanical dormancy in hard seeds.

Persistence in the soil is a function of seed physiology, particularly non-germination and inherent lifespan. However, for seeds with mechanical dormancy, non-germination is also a function of the composition and activity of the soil microbiota. We attempted to screen out microorganisms in the soil that can specifically and rapidly decompose the hard fruit pericarps of Tilia miqueliana Maxim., a unique native tree species in China. Using the classical replica plating method, more than 100 different culturable microorganisms that could rapidly erode the pericarp were collected from the surface of pericarps under different culture conditions. At the same time, we successfully extended the concept of metagenomics and applied it to the identification of mixed artificial cultures. The decomposition process of the pericarps in soil was also simulated artificially. The physical and chemical data suggested a potential mechanism of microbial scarification and cracking in pericarp, whilst the embryos inside the eroded fruits retained good viability. Our discoveries could pave the way for the removal of physical and mechanical obstacles that prevent hard coat seeds from germinating. We anticipate that the use of this technology will improve the germination of other hard coat seeds. More research is needed to investigate the impacts on other seeds. The findings of this research can inform the design of experiments on the seed ecology of persistence.

Enzymatic preparation of chondroitin sulfate oligosaccharides and its alleviating effect on ovariectomy-induced osteoporosis in rats.

Postmenopausal osteoporosis is the most common type of osteoporosis. Chondroitin sulfate (CS) has been successfully employed as food supplement against osteoarthritis, while the therapeutic potential on postmenopausal osteoporosis is little explored. In this study, CS oligosaccharides (CSOs) were enzymatically prepared through the lysis of CS by a chondroitinase from Microbacterium sp. Strain. The alleviating effects of CS, CSOs and Caltrate D (a clinically used supplement) on ovariectomy (OVX) - induced rat's osteoporosis were comparatively investigated. Our data showed that the prepared CSOs was basically unsaturated CS disaccharide mixture of ∆Di4S (53.1%), ∆Di6S (27.7%) and ∆Di0S (17.7%). 12 weeks' intragastric administration of Caltrate D (250 mg/kg/d), CS or CSOs (500 mg/kg/d, 250 mg/kg/d, 125 mg/kg/d) could obviously regulate the disorder of serum indices, recover the mechanical strength and mineral content of bone, improve the cortical bones' density and the number and length of trabecular bones in OVX rats. Both CS and CSOs in 500 mg/kg/d and 250 mg/kg/d could restore more efficiently the serum indices, bone fracture deflection and femur Ca than Caltrate D. As compared with CS at the same dosage, CSOs exhibited a more significant alleviating effect. These findings suggested that there was great potential of CSOs as daily interventions for delaying the progression of postmenopausal osteoporosis.

Size controllable single-crystalline Ni-rich cathodes for high-energy lithium-ion batteries.

A single-crystalline Ni-rich (SCNR) cathode with a large particle size can achieve higher energy density, and is safer, than polycrystalline counterparts. However, synthesizing large SCNR cathodes (>5 µm) without compromising electrochemical performance is very challenging due to the incompatibility between Ni-rich cathodes and high temperature calcination. Herein, we introduce Vegard's Slope as a guide for rationally selecting sintering aids, and we successfully synthesize size-controlled SCNR cathodes, the largest of which can be up to 10 µm. Comprehensive theoretical calculation and experimental characterization show that sintering aids continuously migrate to the particle surface, suppress sublattice oxygen release and reduce the surface energy of the typically exposed facets, which promotes grain boundary migration and elevates calcination critical temperature. The dense SCNR cathodes, fabricated by packing of different-sized SCNR cathode particles, achieve a highest electrode press density of 3.9 g cm-3 and a highest volumetric energy density of 3000 Wh L-1. The pouch cell demonstrates a high energy density of 303 Wh kg-1, 730 Wh L-1 and 76% capacity retention after 1200 cycles. SCNR cathodes with an optimized particle size distribution can meet the requirements for both electric vehicles and portable devices. Furthermore, the principle for controlling the growth of SCNR particles can be widely applied when synthesizing other materials for Li-ion, Na-ion and K-ion batteries.

Identification of immune-related signature for the prognosis and benefit of immunotherapy in triple-negative breast cancer.

Background: There is a lack of biomarkers for predicting the efficacy of immunotherapy in triple-negative breast cancer (TNBC). Hence, we constructed an immune risk score (IRS) model to predict the prognosis of patients with TNBC and evaluate those who are sensitive to immunotherapy. Methods: The ribonucleic acid (RNA) sequencing data, mutation data, and clinical information of TNBC patients were obtained from The Cancer Genome Atlas database. Data of immune-related genes were obtained from the Import and InnateDB databases. The IRS model was constructed using univariate, least absolute shrinkage and selection operator, and multivariate Cox regression analyses, and the predictive ability of the prognostic model was evaluated. Further external validation was performed using the Gene Expression Omnibus (GEO) databases GSE58812 and GSE135565. Data on the clinical characteristics, immune landscape, and immune checkpoint inhibitors used in different risk groups were analyzed. Finally, the drug sensitivity of the patients in the high- and low-risk groups was predicted. Results: The prognostic risk score model comprised six genes: HSPA6, LCN1, ARTN, IL36G, BCL2A1, and CASP12. The area under the curve values at 1 year, 3 years, and 5 years were 0.835, 0.852, and 0.843, respectively, indicating that the model has a good potential for predicting the long-term survival of TNBC patients, which is consistent with the results of the GEO cohort. Compared with the high-risk group, the low-risk group had a better prognosis; more abundant immune-activated cell infiltrates, such as CD8+ T cells and CD4 memory-activated T cells, and a higher enrichment of immune-related signaling pathways, such as the cytokine receptor interaction, nucleotide oligomerization domain-like receptor signal pathway, T-cell receptor signal pathway, and B-cell receptor signaling pathway, were observed. In addition, the immune checkpoint encoding genes, such as CD274, CTLA4, PDCD1, and PDCD1LG2 were highly expressed in the low-risk group, which showed that this group was more likely to benefit from immunotherapy. Conclusion: A new IRS gene feature was established to predict the patients' prognosis and guide immunotherapy. Moreover, it was revealed that several potential therapeutic drugs can be used in high-risk patients who are unresponsive to immunotherapy.

Research on Learning Evaluation of College Students Based on AHP and Fuzzy Comprehensive Evaluation.

The aim of this paper is to propose a scientific and practical evaluation method for college students' learning evaluation. The students' learning experience and harvest are the ultimate embodiment of colleges teaching quality. Considering the multilevel and fuzzy characteristics of learning evaluation, a novel college evaluation method is put forward based on the analytic hierarchy process and fuzzy comprehensive evaluation. The flow chart and index system for college students' learning evaluation are designed. Meanwhile, the weight of the evaluation index and the calculation steps of fuzzy evaluation is demonstrated and applied actually. The results show that the method is practical which has advantages over the simple analytic hierarchy process.

Characteristics of the enzyme-induced release of bitter peptides from wheat gluten hydrolysates.

Bitter peptides in the enzymatic hydrolysates were prepared and purified from wheat gluten using aqueous ethanol solutions and macroporous resin, which has opened a new road for the extraction and separation of bitter peptides. This report contains the release regularity of bitter peptides and the factors affecting the change of bitter intensity during enzymatic hydrolysis, providing a scientific basis for the research on debitterizing method. In this study, the effects of different degrees of hydrolysis (DH) and enzyme active sites on the bitter peptide content and bitter taste thresholds were discussed. The relationship between amino acid composition, molecular weight distribution, surface hydrophobicity and bitter taste thresholds was extensively researched. The results showed the exposure of hydrophobic amino acids and the bitterness intensity of the hydrolysates increased as the DH increased, and the bitterness of wheat gluten hydrolysates (WGHs) hydrolyzed by Alcalase was stronger than that of Trypsin. According to correlation analysis, the proportion of total hydrophobic amino acid is the first factor that affects the sensory properties of bitter peptide, and the release content of bitter peptides and the content of total bitter amino acids are the second, following by the content of peptide in the molecular weight range of 500-1,000 Da and the surface hydrophobicity. The amino acid sequence of bitter peptides from WGHs were identified and predicted using high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) and bioinformatics. It was found that the molecular weight of most of the peptides was below 1,500 Da, and the Q value was higher than 5.86 kJ/mol.

Review on the release mechanism and debittering technology of bitter peptides from protein hydrolysates.

Recent scientific evidence indicates that protein hydrolysates contain bioactive peptides that have potential benefits for human health. However, the bitter-tasting hydrophobic peptides in protein hydrolysates negatively affect the sensory quality of resulting products and limit their utilization in food and pharmaceutical industries. The approaches to reduce, mask, and remove bitter taste from protein hydrolysates have been extensively reported. This review paper focuses on the advances in the knowledge regarding the structure-bitterness relationship of peptides, the release mechanism of bitter peptides, and the debittering methods for protein hydrolysates. Bitter tastes generating with enzymatic hydrolysis of protein is influenced by the type, concentration, and bitter taste threshold of bitterness peptides. A "bell-shaped curve" is used to describe the relationship between the bitterness intensity of the hydrolysates and the degree of hydrolysis. The bitter receptor perceives bitter potencies of bitter peptides by the hydrophobicity recognition zone. The intensity of bitterness is influenced by hydrophobic and electronic properties of amino acids and the critical spatial structure of peptides. Compared to physicochemical debittering (i.e., selective separation, masking of bitter taste, encapsulation, Maillard reaction, and encapsulation) and other biological debittering (i.e., enzymatic hydrolysis, enzymatic deamidation, plastein reaction), enzymatic hydrolysis is a promising debittering approach as it combines protein hydrolyzation and debittering into a one-step process, but more work should be done to advance the knowledge on debittering mechanism of enzymatic hydrolysis and screening of suitable proteases. Further study can focus on combining physicochemical and biological approaches to achieve high debittering efficiency and produce high-quality products.

DSA Image Analysis of Clinical Features and Nursing Care of Cerebral Aneurysm Patients Based on the Deep Learning Algorithm.

Objective: A deep learning algorithm was developed for automatic detection and localization of intracranial aneurysms in DSA, and its clinical characteristics were analyzed, and targeted nursing measures were formulated. Methods: Using a retrospective multicenter study method based on radiology reports, DSA images of aneurysms were randomly divided into 75 cases in the training set, 20 cases in the internal test set, and 35 cases in the external test set. Using a computer-aided detection method based on the three-dimensional U-Net (3D U-Net), after preprocessing DSA images, automatic segmentation of intracranial blood vessels is performed to obtain regions of interest, and based on the segmentation results, physicians' annotations are introduced. The 3D U-Net network model is trained and adjusted, and the obtained model is used to automatically detect the cerebral aneurysm area. Results: Fivefold cross-validation was used for the training set and the internal test set, and a sensitivity of (94.4 ± 1.1)% was obtained. Automatic detection of aneurysms was performed on the external test set, and the average false positive rate was 0.86 FPs/case (false positives/case). The resulting sensitivity was 82.9%. The classification comparison of external test sets showed that the sensitivity of the method for detecting aneurysms with sizes of 5.00~<10.00 mm and ≥10.00 mm (88.2% and 100.0%) was higher than that for aneurysms with sizes of <3.00 mm and 3.00~<5.00 mm (50.0% and 72.7%). The sensitivity of patients aged 50-60 years and >60 years (90.0% and 87.5%) was higher than that of patients aged <50 years (66.7%), and there was little difference between different genders (84.6% in males and 81.8% in females). Conclusion: The deep learning algorithm has high diagnostic performance in detecting intracranial aneurysms, which is verified by external datasets.

Metagenomic analysis reveals the different characteristics of microbial communities inside and outside the karst tiankeng.

BACKGROUND: Karst tiankengs serve as a reservoir of biodiversity in the degraded karst landscape areas. However, the microbial diversity of karst tiankengs is poorly understood. Here, we investigated the composition and function of the microbial community in a karst tiankeng. RESULTS: We found that habitat differences inside and outside the karst tiankeng changed the composition and structure of the soil microbial communities, and the dominant phyla were Proteobacteria, Actinobacteria, Chloroflexi and Acidobacteria. The Shannon-Wiener diversity of microbial communities inside and outside the tiankeng was significantly different, and it was higher inside the tiankeng (IT). Venn and LEfSe analysis found that the soil microbial communities inside the tiankeng had 640 more endemic species and 39 more biomarker microbial clades than those identified outside of the tiankeng (OT)..Functional prediction indicated that soil microorganisms in outside the tiankeng had a high potential for carbohydrate metabolism, translation and amino acid metabolism. There were biomarker pathways associated with several of human diseases at both IT and OT sites. Except for auxiliary activities (AA), other CAZy classes had higher abundance at IT sites, which can readily convert litter and fix carbon and nitrogen, thereby supporting the development of underground forests. The differences in microbial communities were mainly related to the soil water content and soil total nitrogen. CONCLUSIONS: Our results provide a metagenomic overview of the karst tiankeng system and provide new insights into habitat conservation and biodiversity restoration in the area.

Fine Identification and Classification of a Novel Beneficial Talaromyces Fungal Species from Masson Pine Rhizosphere Soil.

Rhizosphere fungi have the beneficial functions of promoting plant growth and protecting plants from pests and pathogens. In our preliminary study, rhizosphere fungus JP-NJ4 was obtained from the soil rhizosphere of Pinus massoniana and selected for further analyses to confirm its functions of phosphate solubilization and plant growth promotion. In order to comprehensively investigate the function of this strain, it is necessary to ascertain its taxonomic position. With the help of genealogical concordance phylogenetic species recognition (GCPSR) using five genes/regions (ITS, BenA, CaM, RPB1, and RPB2) as well as macro-morphological and micro-morphological characters, we accurately determined the classification status of strain JP-NJ4. The concatenated phylogenies of five (or four) gene regions and single gene phylogenetic trees (ITS, BenA, CaM, RPB1, and RPB2 genes) all show that strain JP-NJ4 clustered together with Talaromyces brevis and Talaromyces liani, but differ markedly in the genetic distance (in BenA gene) from type strain and multiple collections of T. brevis and T. liani. The morphology of JP-NJ4 largely matches the characteristics of genes Talaromyces, and the rich and specific morphological information provided by its colonies was different from that of T. brevis and T. liani. In addition, strain JP-NJ4 could produce reduced conidiophores consisting of solitary phialides. From molecular and phenotypic data, strain JP-NJ4 was identified as a putative novel Talaromyces fungal species, designated T. nanjingensis.

Screening LiMn2O4 Surface Modification Schemes under Theoretical Guidance.

Mn dissolution is one of the most important factors for the failure of LiMn2O4 batteries. Doping has been widely adopted in the modification of LiMn2O4 cathodes; however, there is still a lack of theoretical guidance on screening the dopants. Here, through first-principles calculations, we systematically investigated the effects of all 3, 4d transition metals as well as Mg, Ca, Sr, Al, Ga, and In on the surface oxygen stability of LiMn2O4 cathodes, which has been proved to be correlated with the stability of the surface Mn atoms. Six competitive dopants, namely Nb, Ru, Mo, V, Tc, and Ti, were screened out. Besides, for three dopants in low valence states (Mg, Cu, and Zn), their Li-site doping can more effectively stabilize the surface oxygen atoms compared with Mn-site doping. Finally, we synthesized LiMn2O4 samples with Mg, Mo, and Nb surface doping to validate the rationality of the computational results. We found that particle morphology should also be considered in addition to surface oxygen stability for controlling Mn dissolution. Moreover, the electrochemical performance of LiMn2O4 batteries is a more complex issue and cannot be solely regulated by Mn dissolution. During the experiments, we have explored novel efficient binary chromogenic reagents for ultraviolet-visible spectroscopy analysis that can be used for rapid and low-cost Mn dissolution detection. This work provides a paradigm for the systematic design of the surface modification of the LiMn2O4 cathode under theoretical guidance.

Identification of Two Fungal Pathogens Responsible for Liriodendron chinense × tulipifera Black Spot and Screening of Trichoderma sp. for Disease Control.

Liriodendron chinense × tulipifera black spot is a newly discovered disease that causes yellowing and early shedding of leaves, affecting the growth of Liriodendron trees, and significantly reducing their ornamental value as a garden species. The pathogen responsible for this disease, and how it can be prevented and controlled, are not clear. In this study, the occurrence of this disease was first investigated according to Koch's postulates, and the primary pathogens causing Liriodendron black spot were determined to be Colletotrichum gloeosporioides and Alternaria alternata. Biocontrol strains antagonistic to these two pathogens were then screened from the leaf microorganisms of L. chinense × tulipifera, and a preliminary investigation of the biological control of Liriodendron black spot was performed. Through the screening of antagonistic microorganisms on the leaf surface of L. chinense × tulipifera, the strain Trichoderma koningiopsis T2, which displayed strong antagonism against C. gloeosporioides and A. alternata, was obtained. The T2 strain could inhibit the growth of the two pathogens via three mechanisms: hyperparasitism, volatile and nonvolatile metabolite production, and environmental acidification. The biocontrol experiments in the greenhouse and field showed that initial spraying with a T. koningiopsis T2 spore suspension followed by the two pathogens resulted in the lowest disease incidence. These results confirmed the black spot pathogens of L. chinense × tulipifera, clarified the antagonistic mechanism of T. koningiopsis T2 against the two pathogens, and provided a theoretical basis and technical support for the biological control of the disease.

Photo-Fenton Process over an Fe-Free 3%-CuO/Sr0.76Ce0.16WO4 Photocatalyst under Simulated Sunlight.

Photo-Fenton is a promising photocatalytic technology that utilizes sunlight. Herein, an Fe-free 3%-CuO/Sr0.76Ce0.16WO4 photocatalyst was synthesized to apply simulated wastewater degradation via a photo-Fenton process under simulated sunlight. The photodegradation efficiency of RhB solution over the 3%-CuO/Sr0.76Ce0.16WO4 photocatalyst is 93.2% in the first 3 h; its photocatalytic efficiency remains at 91.6% even after three cycle experiments. The kinetic constant of the 3%-CuO/Sr0.76Ce0.16WO4 photocatalyst is 0.0127 min-1, which is 2.8-fold that of an intrinsic Sr0.76Ce0.16WO4 sample. The experiment of radical quenching revealed that the photogenerated electrons and holes are transferred to CuO to form hydroxyl radicals. Besides, the photocatalyst was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), diffused reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS) measurements. It has some reference significance for the design of iron-free photocatalysts.

Reaction Mechanisms of Ta-Substituted Cubic Li7La3Zr2O12 with Solvents During Storage.

The reactivity of garnet solid electrolytes toward humid air hinders their practical application despite their attractive, superior properties such as high Li+ conductivity and wide electrochemical window. Sealing garnets with organic solvents can not only prevent them from reacting with humid air but also render them compatible with other processing technologies. Therefore, the chemical and structural stability of garnets in organic solvents must be studied. In this study, we selected several commonly used organic solvents with different representative functional groups to investigate their stability with garnets and reaction mechanisms. The experiments and theoretical calculations revealed that all of the solvents reacted with garnets through Li-H exchange, and solvent acidity determined the reaction strength. Furthermore, the solvent acidity was closely correlated to the functional groups connected to H atoms, which can affect charge distribution. Solvents or the tautomer of the solvents with hydroxyl groups such as alcohol, acetone, and N-methyl pyrrolidone, which are relatively more acidic, can lead to a violent reaction with changes in the lattice parameters of garnets. Ether compounds and saturated aliphatic hydrocarbons with relatively low acidity are highly stable against garnets. The proposed reaction mechanisms and rules may help in selecting appropriate solvents for different applications of garnets.

First-Principles Simulations for the Surface Evolution and Mn Dissolution in the Fully Delithiated Spinel LiMn2O4.

The interfacial stability between the cathode and electrolyte is an essential issue in the development of high-energy-density and long-life lithium-ion batteries. The deterioration of capacity dominated by Mn dissolution makes LiMn2O4 a representative case for studying the evolution of interfaces. Here, we use the ab initio molecular dynamics (AIMD) method to simulate the interface reaction between the ethylene carbonate (EC) molecules and the (110) surface of completely delithiated LiMn2O4 where most severe Mn dissolution is observed in the experiment. It is found that the intrinsic oxygen loss on the surface will drive the initial migration of surface Mn atoms to the electrolyte while reducing them. The EC molecules will decompose after transferring electrons to the surface Mn atoms, and its decomposition products further promote the Mn dissolution. In addition, oxygen loss and EC decomposition are in a competitive relationship when transferring electrons to the surface Mn atoms. This work provides a complete picture of the step-by-step dissolution of Mn atoms along with the interfacial evolution in the spinel LiMn2O4 system and also provides a scope for the study of transition-metal dissolution in other cathode materials and electrolytes.

Photocatalytic Reduction of Cr(VI) on a 3.0% Au/Sr0.70Ce0.20WO4 Photocatalyst.

Herein, a 3.0%-Au/Sr0.70Ce0.20WO4 sample was prepared for the photocatalytic reduction of the Cr2O7 2- ion. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible diffuse reflectance spectra. The Sr0.70Ce0.20WO4 sample presented a photocatalytic reduction activity that is better than those of the Ce-doped sample and the intrinsic sample. Thereafter, different metal elements, Cu, Ag, Au, and Pt, were used as cocatalysts, which were loaded on the Sr0.70Ce0.20WO4 sample. The 3.0%-Au/Sr0.70Ce0.20WO4 photocatalyst showed optimal photocatalytic reduction activity in a 8 vol % methanol solution (pH = 7) under visible light irradiation. The kinetic constant of the optimal one is 0.0039 min-1, which is 1.86 times that of the Sr0.70Ce0.20WO4 sample. The photocatalyst is stable enough after a 24 h photocatalytic experiment.