摘要：Hierarchically structured nanomaterials have attracted much attention owing to their unique *** this study,TiO2 nanofibers assembled from nanosheets(TiO2-NFs-NSs)were fabricated through electrospinning technique,which was followed by hydrothermal treatment in NaOH *** effect of hydrothermal reaction time(0-3 h)on the structure and properties of TiO2 nanofibers(TiO2-NFs)was systematically studied,and TiO2-NFs was evaluated in terms of the photocatalytic activity toward photocatalytic oxidation of acetone and the photoelectric conversion efficiency of dye-sensitized solar *** was found that(1)hydrothermal treatment of TiO2-NFs in NaOH solution followed by acid washing and calcination results in the formation of TiO2-NFs-NSs;(2)upon extending the hydrothermal reaction time from 0 h to 3 h,the BET surface area of TiO2-NFs-NSs(T3.0 sample)increases 3.8 times(from 28 to 106 m2 g^-1),while the pore volume increases 6.0 times(from 0.09 to 0.54 cm3 g^-1);(3)when compared with those of pristine TiO2-NFs(T0 sample),the photoreactivity of the optimized TiO2-NFs-NSs toward acetone oxidation increases 3.1 times and the photoelectric conversion efficiency increases 2.3 *** enhanced photoreactivity of TiO2-NFs-NSs is attributed to the enlarged BET surface area and increased pore volume,which facilitate the adsorption of substrate and penetration of gas,and the unique hollow structure of TiO2-NFs-NSs,which facilitates light harvesting through multiple optical reflections between the TiO2 nanosheets.

摘要：在低碳经济背景下,开发以氢能为代表的清洁可再生能源至关重要.利用太阳能驱动半导体进行光催化分解水,是未来可持续制取氢气的有效方法之一.然而,光催化制氢技术产业化受限于半导体表面光生载流子复合效率高和量子效率低.解决上述问题的办法是在半导体中引入双元助催化剂,这不仅可以促使三相界面的形成,促进界面电荷的有效转移,而且不同种类的双助催化剂可以为半导体提供各自的积极作用,协同提高光催化产氢效率和稳定性.因此,需要密切关注双助催化剂的开发,以建立一个集优异的光活性和光稳定性于一体的光催化产氢体系.本文系统地介绍了光催化产氢双助催化剂的类别、优势、合成方法和设计策略.首先,双助催化剂被分为双还原型(Red-Red)和还原-氧化型(Red-Ox)两类,详细概述了在光催化产氢领域中还原型和氧化型助催化剂相互匹配后形成的双助催化剂的实例及其协同效应.总结了在制氢体系中双助催化剂相对于单一助催化剂的五大优势:促进载流子快速迁移、实现电子-空穴空间分离、提高产氢吸附/脱附动力学、提高催化剂光稳定性和阻断可逆反应.随后,概括了双助催化剂-半导体光催化剂的合成策略,基于通常报道的水/溶剂热处理、煅烧、光沉积、自组装和化学沉积等助催化剂的合成方法,可以采用一步法和两步法将两种助催化剂加载到半导体上,获得三元复合材料.探讨了双助催化剂-半导体光催化体系的设计策略,详细总结了如何设计具有优化电子传递路径的Red-Red助催化剂体系和具有空间分离电荷的Red-Ox助催化剂体系.其中,为了优化电子传递路径,两种还原型助催化剂的位置关系可分为三类:核壳包裹结构、分散分布结构和相邻结构;为了实现氧化/还原位点空间分离,氧化-还原型双助催化剂在半导体表面可设计为三种结构:内外结构、晶面相关结构和端侧结构.最后,提出了双助催化剂在光催化制氢领域中的现状、挑战及未来发展方向.在未来,可以继续开发新型无贵金属助催化剂来降低催化剂体系总成本,真正达到经济实用目标;需要继续发展利于规模化生产的双助催化剂三元复合材料的合成策略;需要通过实验表征,结合同位素标记法、分子模拟和密度泛函理论计算,深入研究助催化剂的性质和作用机理.希望本文能够为构建高效实用的双助催化剂三元析氢光催化体系提供借鉴.

摘要：Tailoring the microstructure of pristine TiO2 is essential to narrow its band gap and prolong the charge lifetime. In particular, strategies involving fluorine have been used successfully to tune the surface chemistry, electronic structure, and morphology of TiO2 photocatalysts to improve their photocatalytic activity based on the strong complexation between fluoride ions and TiO2 and the high electronegativity of fluorine. In this review, we summarize the strategies involving fluorine to establish highly efficient TiO2 photocatalytic systems or fabricate highly efficient TiO2 photocatalysts. The main fluorine effects(i.e. the effects of fluorine on photocatalysis) include the following four aspects:(1) Surface effects of fluoride on TiO2 photocatalysis,(2) effects of fluorine doping on TiO2 photocatalysis,(3) fluoride-mediated tailoring of the morphology of TiO2 photocatalysts, and(4) the effects of fluorine on non-TiO2 photocatalysis. Additionally, the unique applications of these fluorine effects in photocatalysis, including selective degradation of pollutants, selective oxidation of chemicals, water-splitting to produce H2, reduction of CO2 to produce solar fuels, and improvement of the thermostability of TiO2 photocatalysts, are reviewed.

摘要：Ti^（3＋） self-doped anatase three-dimensional（3D） TiO_2 hollow nanoboxes were synthesized via a topological transformation process involving template participation by a facile one-pot hydrothermal treatment with an ethanol solution of zinc powder and TiOF_2. It is worth noting that the 3D TiO_2 hollow nanoboxes are assembled from six single-crystal nanosheets and have dominant exposure of the {001} facets. It is found from EPR spectra that adding zinc powder is an environment-friendly and effective strategy to introduce Ti^（3＋） and oxygen vacancy（Ov） into the bulk of 3D hollow nanoboxes rather than the surface, which is responsible for their enhanced visible photocatalytic *** photocatalytic activity was evaluated by measuring the formation rate of hydroxide free radicals using 7-hydroxycoumarin as a probe. The sample prepared with zinc/TiOF_2 mass ratio of0.25 exhibited the highest RhB photodegradation activity under visible-light irradiation with a degradation rate of 96%, which is 4.0-times higher than that of pure TiO_2. The results suggest a novel approach to construct in-situ 3D hierarchical TiO_2 hollow nanoboxes doped with Ti^（3＋） and Ov without introducing any impurity elements for superior visible-light photocatalytic activity.

摘要：精心设计的异质结光催化剂已经被证明能够有效地促进电荷转移,从而实现特定的迁移路径和长的载流子寿命,这在进一步提高性能方面具有巨大的潜力.然而,传统二元异质结光催化剂的光催化性能仍然受到其较低的载流子分离效率的影响.本文报道了一种通过原位面对面生长直接合成双Ⅱ型SnO_(2)@ZnS-ZHS(ZHS=ZnSn(OH)_(6))三元异质结的策略.基于可靠的实验和理论计算,揭示了双Ⅱ型SnO_(2)@ZnSZHS的载流子动力学提升机制.SnO_(2)的光生空穴(h+)能够分别迁移到ZHS和ZnS的价带,确保了SnO_(2)@ZnS-ZHS可以保持双氧化电位来产生足够的羟基自由基(·OH)参与NO氧化反应.这种独特的双Ⅱ型SnO_(2)@ZnS-ZHS三元结构在光照30 min后对NO去除率高达44.5%,活性分别是ZHS的23.5倍、SnO_(2)的29.7倍和ZnS的15.9倍.光催化活性提升与独特的双Ⅱ型反应机理反映了SnO_(2)@ZnS-ZHS异质结构的优势,本工作有望为三元异质结的设计提供可行的思路.

摘要：针对传统的环境工程专业实验课在教学中的局限:水处理工艺系统庞大,设备多且管道错综复杂,工艺运行时间长,在实践教学中可操作性差。构建虚拟仿真实验室和工程中式实训两大平台,通过工程项目的实际训练,培养学生环境工程项目设计与运行调试的能力和解决复杂工程问题的能力。