Photocatalysis uses solar energy to convert nitrogen and water directly into ammonia, helping reduce dependence on fossil fuels and offering a way to integrate the nitrogen cycle into a clean energy network. Ohmic junctions between metals and semiconductors have demonstrated significant advantages in enhancing stability and reducing carrier recombination, but their application in photocatalytic nitrogen fixation is limited due to the difficulty of work function matching and the complexity of fabrication processes. In this study, density functional theory (DFT) calculations were used to confirm the work function matching between Bi and Bi2Ti2O7 (BTO), ensuring the formation of an Ohmic junction. A Bi-Bi2Ti2O7 (B-BTO) composite was successfully synthesized via a one-step hydrothermal method, using bismuth nitrate and titanium sulfate as precursors. Compared to pure BTO, the B-BTO heterojunction, driven by dual electron injection from both metal Bi and BTO, significantly increased the ammonia synthesis rate to 686.95 mu mol g(-1) h(-1), making it the most active nitrogen fixation material among similar pyrochlore-based catalysts to date. The differential charge density calculations, photocurrent (i-t) measurements, and photoluminescence (PL) tests further validate the role of Ohmic contacts in enhancing charge transfer and prolonging carrier lifetimes. This research provides valuable insight into the application of Ohmic junctions in photocatalytic nitrogen fixation and contributes to advancements in this field. (c) 2025 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Photocatalysis has been recognized as a viable technology for pollutant degradation in wastewater, owing to its ability to generate reactive radicals under photoirradiation. Among these, sulfate radicals (SO4·-) have been attracting significant attention due to their strong oxidizing properties; yet the specific mechanism of action has remained elusive thus far. In this study, defective NH2-MIL-88B (DNMB) is prepared via a facile hydrothermal procedure in the presence of potassium sodium tartrate and found to facilitate the production of sulfate radicals from sulfate anions under visible light irradiation, due to partial reduction of Fe3+ to Fe2+ in the NMB skeleton by the added tartrate that enriches the Fe3+/Fe2+ redox couples, in addition to other reactive species like superoxide radicals and hydroxy radicals. This effectively improves the degradation efficiency toward a variety of organic pollutants, including antibiotics such as tetracycline (TC), sulfamethoxazole (SMX), and levofloxacin (LEV), as well as common organic contaminants like bisphenol A (BPA) and rhodamine B (RhB), as compared to pristine NMB. Specifically, after 40 minutes of visible light irradiation, the degradation rate increases from 61.5% to 92.1% for TC, from 76.1% to 89.4% for SMX, from 60.5% to 75.2% for LEV, from 61.7% to 91.2% for BPA, and from 78.4% to 94.8% for RhB. The primary active species are identified to be sulfate radicals, with minor contributions from holes, superoxide radicals, and hydroxyl radicals, as demonstrated in quenching experiments and electron spin resonance measurements, and further confirmed by theoretical studies. Degradation pathways for the various pollutants are then proposed based on results from Fukui index calculations and liquid chromatography-mass spectrometry analysis. These results underscore the crucial role of structural engineering in driving the advancement of green and sustainable technologies for environmental engineering.

Single atom catalysts (SACs) supported on metal oxide are usually prepared at high temperature, high pressure, and complex process. Herein, a new strategy is developed to prepare SACs anchored on vacancy-rich TiO2 using Ti2O3 as the support precursor under mild conditions, where Ti3+ on Ti2O3 surface acts as "traps" to capture and then reduce metal ions through electron transfer without using reducing agents. This approach is universally applicable for different single metal atoms supported on diverse phases of TiO2 (anatase, rutile, metastable and mixed counterpart). The as-obtained Pt1/TiO2 with controllable Pt loading and multiple oxygen vacancies (Ov) exhibits excellent activity in photocatalytic H2 evolution. At optimal conditions, the H2 evolution rate is up to 95,180 mu mol g-1 h-1, which is the highest for TiO2 supported SACs reported.

The development of efficient and stable photocatalysts remains a key objective for advancing photocatalytic hydrogen (H2) evolution. This study introduces a rapid one-step synthesis to fabricate amine-functionalized Zn1-xCdxS over ZnS-ethylenediamine (ZC/Z-EDA) inorganic–organic hybrid materials. The incorporation of amine component serves dual functions. It facilitates the formation of Z-EDA nanosheets featuring a tunable band structure while simultaneously enabling the precise anchoring of ZC onto the Z-EDA surfaces. This precise anchoring establishes an intimate contact interface between the hybrid components. Within this engineered architecture, the coexistence of strategically induced defects, optimized interlayer charge transfer channels, and tailored type-II heterojunctions operates synergistically. This combination significantly enhances visible light absorption efficiency, promotes the separation and migration of photogenerated charge carriers, and isolates reactive sites. Consequently, the optimized ZC/Z-EDA hybrid demonstrates a 4338-fold increase in photocatalytic H2 evolution rate under visible light compared to pristine Z-EDA alone. Furthermore, it achieves an apparent quantum efficiency of 43.7

Zero-dimensional NiS cocatalysts were deposited onto ethylenediamine-intercalated two-dimensional ZnS (en)0.5/CdxZn1-xS (ZC) supports via combined solvothermal and precipitation methods, forming NiS/ZC organic-inorganic hybrid photocatalysts. Through integrating morphology control, ionic doping, cocatalyst modification, and heterojunction construction, the photoresponse of ZnS was broadened into the visible region. The multi-strategy synergy enhanced charge carrier separation/migration kinetics and increased active-site accessibility. Consequently, the optimized NiS/ZC catalyst achieved an exceptional hydrogen evolution reaction rate and sustained stability under visible light irradiation, accompanied by an apparent quantum yield (AQY) of 58.6 % at 420 nm.

Bismuth titanate has found widespread applications in photocatalysis for hydrogen production, degradation of organic pollutants, nitrogen oxide removal, and carbon dioxide reduction, among others, due to its unique crystal structure and electronic energy band configuration. In this paper, we summarize the recent progress in the preparation of bismuth titanate, mainly Bi2Ti2O7, which is classified into four categories according to their morphological and structural characteristics, explore the manipulation of the materials morphology, and analyze the influence of the materials structures on the photocatalytic performance. The review is concluded with a perspective highlighting the key challenges and future research directions.

To establish a sterile culture system and protoplast regeneration system for Bryum argenteum, and to establish and apply CRISPR/Cas9 system in Bryum argenteum. Bryum argenteum is a fascinating, cosmopolitan, and versatile moss species that thrives in various disturbed environments. Because of its comprehensive tolerance to the desiccation, high UV and extreme temperatures, it is emerging as a model moss for studying the molecular mechanisms underlying plant responses to abiotic stresses. However, the lack of basic tools such as gene transformation and targeted genome modification has hindered the understanding of the molecular mechanisms underlying the survival of B. argenteum in different environments. Here, we reported the protonema of B. argenteum can survive up to 95.4

Photocatalytic nitrogen reduction represents a viable technology for green ammonia synthesis under mild conditions. However, the performance of the photocatalysts is typically limited by high charge carrier recombination and low adsorption and activation of nitrogen molecules. Herein, Bi/Bi2Sn2O7 (Bi/BSO) heterojunction nanocomposites are prepared via a one-step hydrothermal method, where NaOH etching of oxygen vacancies in the Bi-O bonds of Bi2Sn2O7 (BSO) is exploited for the in situ formation of metallic Bi and hence Schottky junctions with the semiconducting BSO. This leads to a high separation rate of photogenerated charge carriers. Consequently, compared to the pure-phase BSO, the Bi/BSO heterostructures exhibit markedly enhanced ammonia production, reaching an optimum rate of 284.5 mu mol g(-1) h(-1), where the rectifying contact between the semiconducting BSO and metallic Bi facilitates directional BSO to Bi electron transfer, leading to enrichment of photogenerated electrons at the active sites of metallic Bi. First-principles calculations confirm the alteration of active sites and the guided electron flow by the Schottky junctions and surface oxygen vacancies. Results from this study offer an effective paradigm of structural engineering in manipulating the photocatalytic activity of bismuth-based pyrochlore materials toward nitrogen fixation to ammonia.

The effective degradation of organic dye pollutants in water is a research hotspot at present.

Development of effective technologies for artificial nitrogen fixation under mild conditions is of fundamental and technological significance, as the traditional production of NH3 by the Haber-Bosch process entails a high energy consumption and carbon emission. In this study, Bi2Sn2O7 ultrasmall nanoparticles of the pyrochlore phase are synthesized hydrothermally, and the photocatalytic activity towards nitrogen fixation is found to be modulated by the addition of sodium oleate. Among the series, the optimal sample displays a photocatalytic performance with an NH3 production rate of 231 mu mol g- 1 h-1, due to the formation of a high specific surface area, a large number of active sites for N2 adsorption, and extensive lattice oxygen vacancies. In conjunction with results from first principles calculations, the Bi species around the O2-site oxygen vacancies are found to play a key role in the adsorption and activation of N2. Results from this study highlight the significant potential of Bi2Sn2O7 nano-structures as high-performance catalysts for solar ammonia synthesis.Data Availability: Data will be made available upon request from the authors.

构建了银纳米立方体/PE/金膜三明治结构用于拉曼检测,由于这种结构的场增强特性,一般认为它用于荧光增强也能有较好的性能,在实际测试中发现两者并不完全相同,主要是由于物质分子与纳米颗粒靠近时有荧光猝灭现象.为了尽可能消除荧光猝灭现象,探究场增强基底最强荧光增强能力,更改了中间层的厚度和物质分子在中间层的位置,获得最强荧光增强光谱.这种能够使荧光增强的结构对研究下一代纳米光子学器件在荧光检测上的应用有启示意义;同时,也为开发具有更强大检测功能的拉曼-荧光双检测器提供可参照的模板.

Hierarchical CdS nanosheet assembled flowers modified with CuS were synthesized by a simple ion exchange method. The prepared CuS/CdS composites exhibited high visible light photocatalytic hydrogen production activity, and the optimal photocatalytic hydrogen activity of CuS/CdS with 5 wt% loading was 2978 mu mol g(-1) h(-1), which exceeded the pure CdS by more than 6 times. The hierarchical organization of nanosheet and uniform distribution as well as close contact between the components in the multi-component photocatalyst improved the light absorption and charge carrier transfer ability, ultimately enhanced the photocatalytic hydrogen production activity. This work shows a great potential of hierarchical CuS/CdS nanosheet assembled flowers for photocatalytic hydrogen production, and also demonstrates that the ion exchange strategy can be extended to the preparation of other CuS and sulfides with hierarchical nanostructures.

Various morphologies of CdS photocatalysts, including one dimensional nanorods, and three dimensional nanosheet assembled flowers were prepared via a solvothermal process by tailoring the solvothermal temperature. CdS nanosheet assembled flowers prepared with lower temperature displayed excellent photocatalytic hydrogen production rate of 510 mu mol g(-1) h(-1) under visible light, which exceeded the CdS nanorods by more than 2.1 times. The enhanced photocatalytic activity was ascribed to the high purity, unique microstructure and band structure, which was favorable for transfer of photogenerated carriers and thus reduced the recombination of electron hole pairs. The reaction temperature had a significant effect on the hydrogen production of CdS, and the hydrogen production peak area sharply increased to 2.3 times of that at 6 degrees, only when the temperature was raised from 6 degrees to 17 degrees. The apparent hydrogen production rate of 17 degrees was 2.3 times that of the 6 degrees reaction, namely 1183 mu mol g(-1) h(-1). However, the true rate was 657 mu mol g(-1)h(-1), slightly greater than that of 6 degrees. Therefore, the reaction temperature of the system should be strictly controlled, and the fluctuation of the temperature will cause a change in the amount of hydrogen.

Magnesium oxide (MgO) has been used in various reactions such as transesterification, biodiesel production, dry reforming. In the present study, MgO nanosheets were fabricated by the electrical wire explosion process under argon protection with a slow release of oxygen into the reaction chamber after the explosion. The activity of the MgO nanosheets towards transesterification of dimethyl carbonate with phenol to produce diphenyl carbonate was then evaluated. The results showed that the MgO nanosheets possessed enhanced activity and excellent selectivity to target products compared with many conventional ester exchange catalysts. When the reaction was performed at 453 K at a phenol to dimethyl carbonate molar ratio of 2:1, for a reaction time of 13 h, and at a catalyst loading of 0.2% (molar ratio to phenol); the selectivity of the transesterification reaction reached 95.7%. Moreover, the used MgO nanosheets might be easily reactivated by calcination under vacuum, and the regenerated MgO nanosheets showed a catalytic activity almost as high as that of the fresh sample.

表象是物体没有呈现的情况下,头脑中所出现的该物体的形象.历史上,很多的科学发现和创造都归功于人类丰富的表象储存.本文认为表象与感知觉、形象思维、想象力和情感都有着重要的联系,表象的训练对右脑的开发也有促进作用.在小学科学教学中,教师应利用科学课程内容广泛的特点,帮助儿童积累表象,同时在进行科学探究和技术产品制作时,合理地利用表象进行教学可以产生事半功倍的效果.

Magnesium oxide (MgO) nanosheets were prepared by the electrical wire explosion process under argon protection with a slow release of oxygen into the reacting chamber after the explosion. The structures were studied by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) measurements. The average size of the nanosheets was 100 to 110 nm and the thickness 3 to 5 nm. The uptake of CO2 by MgO nanosheets was determined under a flow of 100% dry CO2 at atmospheric pressure, which is about 70-85% of the uptake by pure nanopowders, and the maximum value of CO2 adsorption was 3.64 cm(3) . g(-1).

科学态度是科学素养的一个重要成分，但是科学态度的培养一直是科学教育一项艰巨和复杂的任务。科学态度作为隐性知识，其内涵丰富。角度不同对科学态度内涵的理解也不同，而从态度对象角度看，科学态度应包括对与科学有关的人物、对科学事物和相关事件的态度。如此将科学态度内涵具体化在实际教学中更具有操作性，可以充分挖掘科学史的教育价值，借助其培养学生对待与科学有关的人的态度；开设情感体验课可以帮助学生习得对科学事物的积极态度；通过科学实验和科学探究让学生重历科学认识过程，可以培养学生对事件的多种态度等。

Cellulose diacetate (CDA) had been modified by stearoyl chloride (STC) in homogeneous CDA/pyridine solution. The structure of the CDA and CDA-STC were confirmed via IR and (HNMR)-H-1. The degree of substitution (DS) for the CDA-STC is 2.79 measured in accordance with international standards, and about 77.17% of the residually free hydroxyl of CDA had been substituted with stearoyl group of STC. The thermal properties of them were tested by TGA in the range of room temperature to 950 degrees C. The absorbing properties of CDA and CDA-STC for dust and haze-fog simulated by cigarette smoke were measured with a simple suction device. The acylate of CDA-STC could be used as filter materials to produce surgical mask, smock, mask and other civil or industrial products to absorb dust and haze-fog and some other polluted air.

一、概念转变理论的形成 许多教师在教学中都发现,不同的学生对一个新知识的理解与体验相差很大.有些学生对要学习的知识能够迅速地接受和运用,一点就通,而有的学生对新知识的学习则显得木讷和陌生,需要读两三遍新知识才能熟练.由此可见,学生并不是空着脑袋来学习新知识的,在接触新事物之前,每个学生都有自己的科学前概念.

<正>小学科学课是以实验和活动为基础、实践性和创造性都很强的的学科,三维目标是科学知识、科学探究和情感态度与价值观。而科学知识是科学素养的首要组成部分,其对应的是行为目标的价值取向,宜采