Photocatalysts with different exposed facets often exhibit different photochemical performances, but the underlying mechanisms are not fully understood. In this study, we synthesized two ...nanosheet-assembled bismuth oxyiodide (BiOI) microspheres with exposed (110) and (001) facets, respectively, to further investigate facet-dependent photocatalytic activity. Our experimental results showed that the BiOI microspheres with exposed (110) facets exhibited much greater catalytic activity than the BiOI microspheres with exposed (001) facets in the degradation of bisphenol A under visible light irradiation. Density functional theory calculation revealed that the (110) facets can adsorb a greater amount of O2 and, thus, form more O2 • – and •OH radicals than the (001) facets. The electron spin resonance spectroscopy and radical scavenging experiments verified that the BiOI microspheres with exposed (110) facets could produce a greater amount of O2 • – radicals than the BiOI microspheres with exposed (001) facets, and more importantly, between the two BiOI products, only the BiOI microspheres with exposed (110) facets could generate •OH radicals directly. The facet-dependent radical formation mechanisms were previously unidentified. The findings of this study may have important implications for the understanding of the facet-dependent photochemical performance of photocatalysts and the design of novel catalytic materials with inorganic nanostructures.
The dopants of sulfur, nitrogen, or both, serving as the active sites, into the graphitic framework of graphene is an efficient strategy to improve the electrochemical performance of electrochemical ...membrane filtration. However, the covalent bonds between the doped atoms and the substrate that form different functional groups have a significant role in the specific activity for pollutant degradation. Herein, we found that the singly doped heteroatom graphene (NG and SG) achieved superior removal efficiency of pollutants as compared with that of the double doped heteroatom graphene (SNG). Mechanism studies showed that the doped N of NG presented as graphitic N and substantially increased electron transfer, whereas the doped S of SG posed as -C-SOx-C- provided more adsorption sites to improve electrochemical performance. However, in the case of SNG, the co-doped S and N cannot form the efficient graphitic N and -C-SOx-C- for electrochemical degradation, resulting in a low degradation efficiency. Through the fundamental insights into the bonding of the doped heteroatom on graphene, this work furnishes further directives for the design of desirable heteroatom graphene for membrane filtration.
Cattleyaks are equally adaptable to harsh environment as yaks, but produce far more milk and meat in terms of quality and quantity. However, male cattleyaks with active secondary sexuality are ...infertile and have restricted productivity and breeding of yaks. Much researches continue to be done in regard to the differences in transcriptome profiling in cattleyak epididymis with respect to yak epididymis. The caput segment of the epididymis is highly specialized for the initiation of spermatozoa maturation, synthesis and secretion. We used RNA-Seq technology to comparatively analyze differentially expressed genes (DEGs) associated with sperm maturation between the caput epididymis of yak and cattleyak. Transcriptomic profiling identified 109 DEGs in which 44 were upregulated and 65 were downregulated. 8 DEGs were validated by quantitative real-time PCR. DEGs were analyzed by GO and KEGG analysis to screen the key genes involved in sperm maturation. The upregulation of PAOX and ATP2C2 may be associated with toxicity and apoptosis resistance in cattleyak with respect to yak. However, downregulated DEFB109, DEFB121, DEFB123, DEFA1, LY6G5C, SLC13A2, CST3, CRYBA4 and ADAM28 were associated with innate immune response, sperm maturation, motility and antimicrobial functions. AMPK and Hedgehog signaling pathways were involved in the top-listed five significantly enriched pathways, and the downregulation of HNF4α and LRP2 may have contributed to infertility in cattleyak. The data provide a powerful resource, contributing to the knowledge on the molecular mechanisms underlying male cattleyak infertility.
•RNA-Seq technology comparative analysis of DEGs in sperm maturation between the caput epididymis of yak and cattleyak.•Transcriptomic profiling identified 109 DEGs, 44 upregulated and 65 downregulated.•Upregulation of PAOX and ATP2C2 may cause toxicity and apoptosis resistance in cattleyak with respect to yak. Downregulation of HNF4α and LRP2 may cause infertility in cattleyak.
The first filial generation of the cattleyaks demonstrates hybrid vigor; however, the male cattleyaks are infertile and restrict productivity and breeding. The discovery of genes in a ...segment‐specific approach offers valuable information and understanding concerning fertility status, yet the biology of cattleyak epididymis is still progressing. Comparative transcriptome analysis was performed on segment pairs of cattleyak epididymis. The caput versus corpus epididymis provided the highest (57.8%) differentially expressed genes (DEGs), corpus versus cauda (25.1%) followed, whereas caput versus cauda pair (17.1%) had the least DEGs. The expression levels of genes coding EPHB6, TLR1, MUC20, MT3, INHBB, TRPV5, EI24, PAOX, KIF12, DEPDC5, and KRT25, which might have the potentials to regulate the homeostasis, innate immunity, differentiation, motility, transport, and sperm maturation‐related function in epididymal cells, were downregulated in the distal segment of epididymis. Top enriched KEGG pathways included mTOR, axon guidance, and taste transduction signaling pathways. EIF4B, EPHB6, and TAS2R42 were enriched in the pathways, respectively. Identifying key, new, and unexplored DEGs among the epididymal segments and further analyzing them could boost cattleyak fertility by maximizing sperm quality from genetically better sires and also facilitate better understanding of the epididymal biology.
Circular RNAs (circRNAs), as endogenous non-coding RNA with unique closed ring structure, is closely related to animal reproduction, and understanding the expression of circRNA in yak and cattleyak ...epididymal tissues is of great significance for understanding cattleyak sterility. Based on this, we screened and identified the differentially expressed circRNA in the epididymis of three yaks and two cattleyak. A total of 1,298 circRNAs were identified in the epididymis of yak and cattleyak, of which 137 differentially expressed (DE) circRNAs and the functions of some of them were elucidated in this research, as well as qPCR verification to 6 circRNAs from the 137 DE circRNAs. Gene Ontology (GO) enrichment analysis suggested that DE circRNAs were mainly related to metabolic process, development process, immune system process, reproductive process, reproduction, biological adhesion and growth. COG classification analysis showed that the DE circRNAs derived genes were mainly related to replication, recombination and repair. KEGG pathway analysis suggested that DE circRNAs were mainly involved in RNA degradation. In addition, we also screened Bta-mir-103, which is a circRNA binding miRNA related to sperm activity.
The need for highly efficient and environmentally friendly catalysts for pollutants removal sustainably has drawn extensive attention. In particular, piezocatalysis is promising for harnessing ...low-frequency vibration (e.g., wind) to enable high-performance degradation of organic pollutants. Herein, we synthesized a sandwich-like piezocatalyst by fabricating MoS2 nanosheets onto S, N-codoped graphene (MoS2@SNG) through a facile hydrothermal strategy. Results indicate that the MoS2@SNG exhibited ultrahigh piezocatalytic activities for both oxidation and reduction degradation of pollutants. Benefiting from the reduced stacking of MoS2 nanosheets and accelerated electron transfer of heterogeneous graphene, MoS2@SNG had a sharply enhanced electric field (i.e., 29.3 mV of MoS2@SNG versus 4.7 mV of MoS2). Moreover, the abundance of active sites of Mo4+ being exposed over MoS2@SNG remarkably promoted the redox reaction. This study provided evidence that layered piezoelectric materials represent an attractive strategy for environmental remediation.
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•Sandwich-like piezocatalyst for high-performance degradation of organic pollutants.•Layer-structured support of graphene improved electron-hole separation efficiency.•More active sites of Mo4+ exposed over MoS2@SNG promoted redox reaction.•MoS2@SNG gave a significantly enhanced electric field.
Strategies for harmonizing the construction of an active site and the building of electron transport for a hybrid MoS2 catalyst are crucial for its application in electrochemical reactions. In this ...work, an accurate and facile hydrothermal strategy was proposed to fabricate the active center of Co–O–Mo on a supported MoS2 catalyst by forming a CoMoSO phase on the edge of MoS2, yielding (Co–O) x -MoS y (x = 0, 0.3, 0.6, 1, 1.5, or 2.1). The results show that the electrochemical performances (hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and electrochemical degradation) of the yielded MoS2-based catalysts were positively correlated with the Co–O bonds, verifying the significant role of Co–O–Mo as the active center. The fabricated (Co–O)-MoS0.9 presented an extremely low overpotential and Tafel slope in both HER and OER, and it also demonstrated excellent BPA removal in the electrochemical degradation reaction. As compared with the Co–Mo–S configuration, the configuration of Co–O–Mo not only serves as the active center but also provides a conducting channel to facilitate electron conductivity with more accessible charge transfer at the electrode/electrolyte interface, which is favorable for electrocatalytic reaction. This work offers a new perspective for the active mechanism of metallic-heteroatom-dopant electrocatalysts and further boosts research on the development of noble/non-noble hybrid electrocatalysts in the future.
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•NC@CMPS was successfully grafted with imine group.•imine group can distinguish protonated phosphate from deprotonated competing anions.•imine group has stronger interaction force ...toward P(V) than that of amine group.•P(V) adsorption on NC@CMPS is slightly exothermic.•NC@CMPS can be repeatedly used for P(V) adsorption.
The development of phosphate-selective adsorbents is essential for addressing eutrophication-associated problems and issues about lack of phosphorus resources. In this study an imine-functionalized adsorbent (NC@CMPS) was synthesized for this purpose; briefly, the commercially available precursor, chloromethylated polystyrene adsorbent (CMPS), was grafted with ethylenediamine (EDA) to yield the intermediate (EDA@CMPS), which was subsequently subjected to synchronous elimination to yield the product with imine functional group (NC@CMPS). Spectroscopic analyses and macroscopic experiments were then employed to evaluate the as-prepared adsorbent. As compared with CMPS, EDA@CMPS, and two commercial amine-based adsorbents, NC@CMPS exhibited much higher adsorption capacity and selectivity toward phosphate P(V); such improvement can be primarily attributed to the imine group of NC@CMPS and their difference in the acid-base property. The imine group, acting as the recognition unit to distinguish P(V) from background anions, can solely serve as H-bond acceptors and exclusively interact with the protonated P(V) species (H2PO4- and HPO42-, H-bond donors) under neutral pH but not with the deprotonated anions such as Cl-, NO3–, and SO42-. the thermodynamic parameters confirm the spontaneous and slightly exothermic nature of P(V) adsorption on NC@CMPS, according with the domination of hydrogen bonding interactions. NC@CMPS also exhibited very broad applicability for P(V) adsorption over a wide range of pH (3 ∼ 10). Furthermore, the exhausted NC@CMPS can be efficiently regenerated with the combination of dilute NaOH solution and dilute HNO3 solution for repeated use.
About 3.93 billion tons of wastewater containing heavy metal complexes are discharged (e.g., from the electroplating industry) every year in China alone. It is challenging to appropriately treat such ...wastewaters. Here, a multifunctional composite nanowires BaTiO3@graphene was designed based on Comsol simulations and made into 3D millimeter-sphere in order to facilitate practical application. Results indicate 100% of Cu-EDTA was decomplexed in situ via piezoelectric potential by BaTiO3@graphene. Notably, the addition of graphene sharply increased the surface potential (from 19.8 ± 0.97 to 96.8 ± 1.48 mV) of BaTiO3@graphene by its flexoelectric effect then effectively promoted piezoelectric electrons to be separated and transferred, which favors the piezoelectric catalysis. Moreover, the released Cu(II) from Cu-EDTA decomplexation were recovered simultaneously via the interaction on graphene groups. This method efficiently recovered Cu(II) to avoid the consumption of massive chemical reagents and the generation of secondary hazardous solid waste containing heavy metal ions, compared with the conventional oxidative decomplexation/precipitation strategy for heavy metal complexes removal. Piezoelectric catalysis paves a new possibility for advanced oxidation in wastewater treatment.
Inefficient mechanical energy capture and inadequate active sites of piezoelectric materials remain the principal impediment for more widespread application in environmental remediation. Herein, a ...strategy was proposed to substantially improve the piezocatalytic performance via hybridizing hollow wurtzite ZnS nanospheres (H-ZnS) onto flexible S,N-codoped graphene (SNG). The resulting piezoelectric composite (H-ZnS@SNG) exhibited faster electrical transport and more superior piezocatalytic properties for dye degradation (~100% in 10 min) under external strain (either ultrasonic or mechanical stirring), compared with bulk H-ZnS (~58.4%) and the piezoelectric composite coupled with solid wurtzite ZnS nanospheres (S-ZnS@SNG, ~89.9%). This improvement is ascribed to the strain-induced piezopolarization charges of H-ZnS@SNG, with the unique hollow structure of the H-ZnS nanosphere accelerating the electron transfer of heterogeneous graphene. H-ZnS@SNG had the optimum crystal phase and morphology of H-ZnS at the annealing treatment temperature of 700 ℃, leading to the highest piezocatalytic performance. Simulations of the wurtzite hollow ZnS piezocatalyst ties the enhanced performance to excellent flexibility, along with more catalytic active sites on both inner and outer surfaces, compared with solid ZnS. This study provides valuable insights into the mechanisms underlying the excellent purification efficiency by hollow structural piezocatalysts, which are expected to be useful in customizing the designs of such materials for practical implementation.
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•Hollow structural H-ZnS@SNG fabricated by in-situ growth of hollow ZnS on graphene.•H-ZnS@SNG gave 100% removal, relative to 58% by H-ZnS and 90% by S-ZnS@SNG.•Hollow H-ZnS nanosphere enhanced electron transfer of heterogeneous graphene.•Optimum crystal phase and morphology of H-ZnS at annealing temperature of 700 ℃.•Simulations show hollow ZnS has excellent flexibility and more active sites.
