Regulating Oxygen Vacancies and Fermi Level of Mesoporous CeO2-x for Intensified Built-In Electric Field and Boosted Charge Separation of Cs3 Bi2 Br9 /CeO2-x S-Scheme Heterojunction.

Regulating the built-in electric field (BEF) in the heterojunction is is a great challenge in developing high-efficiency photocatalysts. Herein, by tailoring the content of oxygen vacancies in the constituent reduction semiconductor (mesoporous CeO2-x ), a precise Fermi level (EF ) regulation of CeO2-x is realized, yielding an amplified EF gap and intensified BEF in the Cs3 Bi2 Br9 perovskite quantum dots/CeO2-x S-scheme heterojunction. Such an enhanced BEF offers a strong driving force for directional electron transfer, boosting charge separation in the S-scheme heterojunction. As a result, the optimized Cs3 Bi2 Br9 /CeO2-x heterojunction delivers a remarkable CO2 conversion efficiency, with an impressive CO production rate of 80.26 µmol g-1  h-1 and a high selectivity of 97.6%. The S-scheme charge transfer mode is corroborated comprehensively by density functional theory (DFT) calculations, in situ X-ray photoelectron spectroscopy (XPS), and photo-irradiated Kelvin probe force microscopy (KPFM). Moreover, diffuse reflectance infrared Fourier transform spectra (DRIFTS) and theoretical calculations are conducted cooperatively to reveal the CO2 photoreduction pathway.

Space-Confined Growth of Cs2CuBr4 Perovskite Nanodots in Mesoporous CeO2 for Photocatalytic CO2 Reduction: Structure Regulation and Built-in Electric Field Construction.

Halide perovskites have shown great promise in photocatalytic CO2 conversion. However, their practical application is seriously hindered by severe charge recombination and inadequate adsorption/activation toward CO2 molecules. Herein, the space-confined growth of lead-free Cs2CuBr4 perovskite nanodots in mesoporous CeO2 was realized by a facile impregnation approach. An outstanding CO2 photoreduction performance is achieved by the optimum Cs2CuBr4/CeO2 heterojunction with CO and CH4 yields of 271.56 and 83.28 µmol g-1, respectively. Experimental characterizations and theoretical calculations cooperatively validate the S-scheme charge transfer mechanism in the Cs2CuBr4/CeO2 heterojunction. The CO2 photoreduction pathway is also revealed by combining in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) and density functional theory (DFT) calculations. This study provides useful guidance for the design of high-performance halide perovskite/mesoporous material heterostructure photocatalysts for artificial photosynthesis.

In Situ Growth of Lead-Free Cs2CuBr4 Perovskite Quantum Dots in KIT-6 Mesoporous Molecular Sieve for CO2 Adsorption, Activation, and Reduction.

Metal halide perovskites (MHPs) are emerging as promising candidates for photocatalytic CO2 conversion. However, their practical application is still restricted by the poor intrinsic stability and weak adsorption/activation toward CO2 molecules. The rational design of MHPs-based heterostructures with high stability and abundant active sites is a potential solution to this obstacle. Herein, we report the in situ growth of lead-free Cs2CuBr4 perovskite quantum dots (PQDs) in KIT-6 mesoporous molecular sieve, obtaining remarkable photocatalytic CO2 reduction activity and durable stability. The optimized Cs2CuBr4@KIT-6 heterostructure exhibits the photocatalytic CO and CH4 evolution rates of 51.6 and 17.2 µmol g-1 h-1, respectively, far exceeding those of pristine Cs2CuBr4. On the basis of in situ diffuse reflectance infrared Fourier transform spectra and theoretical investigations, the detailed CO2 photoreduction pathway is systematically revealed. This work provides a new route for the rational construction of perovskite-based heterostructures with strong CO2 adsorption/activation and good stability for photocatalytic CO2 reduction.

Recent Progress in Halide Perovskite Nanocrystals for Photocatalytic Hydrogen Evolution.

Due to its environmental cleanliness and high energy density, hydrogen has been deemed as a promising alternative to traditional fossil fuels. Photocatalytic water-splitting using semiconductor materials is a good prospect for hydrogen production in terms of renewable solar energy utilization. In recent years, halide perovskite nanocrystals (NCs) are emerging as a new class of fascinating nanomaterial for light harvesting and photocatalytic applications. This is due to their appealing optoelectronic properties, such as optimal band gaps, high absorption coefficient, high carrier mobility, long carrier diffusion length, etc. In this review, recent progress in halide perovskite NCs for photocatalytic hydrogen evolution is summarized. Emphasis is given to the current strategies that enhance the photocatalytic hydrogen production performance of halide perovskite NCs. Some scientific challenges and perspectives for halide perovskite photocatalysts are also proposed and discussed. It is anticipated that this review will provide valuable references for the future development of halide perovskite-based photocatalysts used in highly efficient hydrogen evolution.

[Different expression of histamine H4 receptor in nasal mucosa in allergic rhinitis patients].

OBJECTIVE: To observe expression and distribution of histamine H4 receptor in nasal mucosa in normal people and allergic rhinitis patients,and understand role of histamine H4 receptor in allergic rhinitis. METHOD: Select normal people and allergic rhinitis patients each 10, take the nasal mucosa, detect expression and distribution of histamine H4 receptor at proteins and transcription level respectively by immunohistochemical method and RT-PCR, and compared. RESULT: Histamine H4 receptor at proteins and transcription level were found in normal nasal mucosa (25 509 +/- 6 441, 0.42 +/- 0.08), increased significantly in nasal mucosa of allergic rhinitis patients (49 676 +/- 8 541, 0.69 +/- 0.11, P < 0.05), which in structural cells and immune cells. CONCLUSION: Histamine H4 receptors exist in normal nasal mucosa, its express significantly enhance, flew histamine H4 receptor may be mediated histamine in pathogenesis of allergic rhinitis ,who is one of the ligands of histamine.