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Ferroelectric materials with internal spontaneous polarization are conducive to enhancing photocatalytic performance by promoting photogenerated carriers separation. However, the traditional perovskite-type ferroelectric photocatalysts possess a typical 3D structure that is constrained by few exposed catalytic active sites and low specific surface area when compared to a 2D structure. In our study, the electronic properties of the 2D ferroelectric heterostructure for carbon and oxygen co-doping g-C3N4 (COCN)/In2Se3 with different out-of-plane ferroelectric polarization directions are investigated by first-principle calculations, namely, COCN/DOWN and COCN/UP heterostructures. The results show that when the ferroelectric polarization of the 2D In2Se3 layer in heterostructures is reversed, the heterostructure switches from traditional type-II (COCN/DOWN heterostructure) with an indirect bandgap of 1.58 eV to S-scheme (COCN/UP heterostructure) with a direct bandgap of 1.43 eV, in which the band edge positions of the S-scheme COCN/UP heterostructure satisfy the redox potential of the efficient photocatalytic selective oxidation of toluene to benzaldehyde. Further investigations revealed that the application of an electric field 0 ∼ +0.3 V/Å can reduce the bandgap and enhance the out-of-plane polarization of the COCN/UP heterostructure, which improve the photocatalytic activity of the S-scheme COCN/UP heterostructure. This work highlights the significance of ferroelectric polarization for charge transfer in heterostructures and provides theoretical guidance for the design of high-performance S-scheme photocatalysts. [ABSTRACT FROM AUTHOR]

The photocatalytic oxidation of toluene (TL) to benzaldehyde (BAD) has the advantages of mild reaction conditions, green chemistry, and high selectivity of the target products. However, there is a problem on how to improve the selectivity of the product into BAD while ensuring the efficiency of TL conversion. Therefore, it is of great importance to understand the mechanism of the photocatalytic selective oxidation of TL into BAD. In this study, first-principles calculations were performed to investigate the mechanism of the photocatalytic selective oxidation of TL into BAD on a graphitic carbon nitride (g-C3N4) catalyst under visible-light irradiation. The calculation results showed that the holes (g-C3N4˙+) and the hydroperoxyl radicals (˙OOH) were the major reactive oxygen species (ROS). Moreover, the activation energy of the rate-determining step for the dehydration reaction of the C6H5CH2OOH molecule was 40.2 kcal mol−1, which was lower than that of the step in the free sate of about 4.8 kcal mol−1. Moreover, in order to get the maximum selectivity of BAD, the formation of hydroxyl radicals (˙OH) should be avoided. Our work provides theoretical guidance for improving the photocatalytic selective oxidation of TL into BAD. [ABSTRACT FROM AUTHOR]

The three-dimensional (3D) organic–inorganic halide perovskite MAPbI3 has excellent light-harvesting properties but is unstable. However, the newly synthesized two-dimensional (2D) all-inorganic Ruddlesden–Popper (RP) perovskite Cs2PbI2Cl2 has superior stability but adverse photoelectric properties. Therefore, constructing a 2D Cs2PbI2Cl2/3D MAPbI3 heterostructure is expected to combine the superstability of the 2D material and the high efficiency of the 3D one. The photoelectric properties and charge transfer of 2D Cs2PbI2Cl2/3D MAPbI3 heterostructures are investigated using density functional theory, where MAPbI3 has two kinds of contacting interfaces, i.e., MAI and PbI interfaces. The band gaps of 2D/MAI and 2D/PbI heterostructures are 1.52 eV and 1.40 eV, smaller than those of the free-standing materials (2D ∼ 2.50 eV, MAI ∼ 1.77 eV, and PbI ∼ 1.73 eV), which can broaden the light absorption spectrum. Moreover, the 2D/3D heterostructures are typical type-II heterostructures, which is beneficial to facilitate the separation of carriers for increasing the photoelectric conversion. Interestingly, due to the work function difference (2D ∼ 4.97 eV, MAI ∼ 3.57 eV, and PbI ∼ 5.49 eV), the charge transfer directions of the 2D/MAI and 2D/PbI heterostructures are completely opposite, which shows that interface engineering to impose a consistent interface termination is needed to obtain good performance for solar cells. These results demonstrate that constructing 2D Cs2PbI2Cl2 and 3D MAPbI3 heterostructures by interfacial engineering is a potential strategy to improve the performance of perovskite solar cells (PSCs). [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Houttuynia cordata (HC) has been used as a folk therapy to treat pulmonary infections. This study aimed to determine the role and mechanism of action of polysaccharides isolated from HC (HCP) in lipopolysaccharide (LPS)-induced ALI in the mice. Materials and methods LPS was delivered by the intratracheal route to Balb/c mice 2 h before HCP (40, 80 and 160 mg/kg) administration. Results The number of total cells, protein and tumor necrosis factor-α (TNF-α) concentrations in bronchoalveolar lavage fluid, the wet/dry weight ratio (w/d) of lungs and pulmonary pathology of each mouse were analyzed, it was found that HCP significantly alleviated ALI induced by LPS. Moreover, in lungs of mice, it was found that the infiltration of inflammatory cells, the expression of Toll-like receptor 4 and complement deposition were significantly decreased by HCP treatment. In vitro assays showed that C5a, a complement activation product, induced significant macrophage migration and treatment with HCP prevented it. The in vitro results also proved that LPS increased nitric oxide and pro-inflammatory cytokines (TNF-α, interleukin-6, and interleukin-1β) production, and HCP antagonized these effects of LPS. It was also found that HCP alone augmented secretion of some pro-inflammatory cytokines. Conclusion These results indicate that HCP may alleviate LPS induced lung inflammatory injury, which may be associated with its inhibitory effect on the over activation of complement and macrophages. This suggests a potential role to treat ALI. [ABSTRACT FROM AUTHOR]

Purpose: Yanghe Pingchuan granules (YPG), a hospital preparation developed by The First Affiliated Hospital, Anhui University of Chinese Medicine, has been used for the clinical treatment of bronchial asthma (BA) for several decades. This study aimed to explore the mechanism of action of YPG in the treatment of BA., Materials and Methods: Male Sprague Dawley rats (n=60) were randomly divided into six groups (n=10 per group): control, a BA model, positive drug control (Guilong Kechuanning capsules; a proven effective treatment for BA), and model rats treated with a high, medium, or low dose of YPG. H&E staining was used to detect pathological changes in the bronchial tubes. The mRNA expression levels of PI3K , PKB , PCNA , and AR were determined by real-time PCR, and the protein levels of phospho- (p-)PI3K, p-PKB, p-PCNA, and p-AR were detected by Western blotting. ELISAs were used to detect the expression of PIP2, PIP3 IL-6, IL-8, IL-1β, and epinephrine (EPI)., Results: H&E staining demonstrated that BA can be ameliorated using YPG. Real-time PCR, Western blotting, and ELISA indicated that use of YPG decreased expression of the phosphoinositide 3-kinase (PI3K) signaling pathway and PCNA, and can also ameliorate the condition kidney Yang deficiency, which is associated with BA in Chinese traditional medicine., Conclusion: YPG can attenuate BA therapeutically in a dose-dependent manner. The mechanism underlying its therapeutic effect comprises influences on three features that contribute to BA: the PI3K signaling pathway, cell proliferation, and "kidney-Yang deficiency"., Competing Interests: Disclosure The authors report no conflicts of interest in this work.