以氮掺杂为代表的非金属掺杂型TiO2光催化剂被誉为"第二代光催化材料"。本文首先系统评述了氮掺杂二氧化钛的制备方法,然后详细阐述了在N掺杂TiO2研究中关于其可见光活性机制以及掺杂N在TiO2晶格中的存在状态等方面的争议。N...以氮掺杂为代表的非金属掺杂型TiO2光催化剂被誉为"第二代光催化材料"。本文首先系统评述了氮掺杂二氧化钛的制备方法,然后详细阐述了在N掺杂TiO2研究中关于其可见光活性机制以及掺杂N在TiO2晶格中的存在状态等方面的争议。N掺杂TiO2粉末的制备方法主要有氨气气氛下的热处理工艺、水解沉淀法、溶胶-凝胶法以及机械化学法等;N掺杂TiO2薄膜的制备方法主要包括磁控溅射法、脉冲激光沉积法以及金属有机化学气相沉积法等。已提出的关于N掺杂TiO2可见光活性机制的观点有N2p与O2p能级相杂化、形成N 2p孤立能态、氧空位的作用以及具顺磁性特征的杂质敏化。关于掺杂N在TiO2晶格中存在状态的分歧在于XPS N 1s谱中特征峰的位置及其归属的解析。文章最后指出了氮掺杂TiO2催化剂研究中有待解决的问题及今后的发展方向。展开更多
Visible-light responsive TiO2-V2O5 catalyst was prepared using a binary sol-gel and in-situ intercalation method. The TiO2 sol and V2O5 sol were mixed to disperse the V2O5 species in the TiO2 phase at molecular level....Visible-light responsive TiO2-V2O5 catalyst was prepared using a binary sol-gel and in-situ intercalation method. The TiO2 sol and V2O5 sol were mixed to disperse the V2O5 species in the TiO2 phase at molecular level. The binary sol was then intercalated into interspaces of polyaniline （PANI） by means of in-situ polymerization of aniline. Conglomeration of the TiO2-V2O5 dusters during the calcination process was avoided because of the wrap of polyaniline. The surface mor- phology, the crystal phases, the structure, and the absorption spectra of （PANI）,/TiO2-V2O5 and the composite catalyst were studied using SEM, XRD, FT-IR, and UV-Vis. The photoactivity of the prepared catalyst under UV and visible light irradiation were evaluated by decolorization of methylene blue （MB） solution. The results showed that the composite catalyst displayed a homogeneous anatase phase, and the vanadium pentoxide species was highly dispersed in the TiO2 phase. The composite catalyst responded to visible light because of the narrowed band gap. In this study, the catalyst with the sol volume ratio of TiO2： V2O5 = 10：1 presented the best photocatalytic activity.展开更多
We report, for the first time, binary ZnO/MnW04 nanocomposites with p-n heterojunction fabricated by a simple ultrasonic-calcination route. The phase structure, morphology, and optical along with tex- tural properties...We report, for the first time, binary ZnO/MnW04 nanocomposites with p-n heterojunction fabricated by a simple ultrasonic-calcination route. The phase structure, morphology, and optical along with tex- tural properties were comprehensively characterized. The photocatalytic performance was studied via degradations of rhodamine B, methyl blue and methyl orange （RhB, MB, MO）, and fuchsine pollutants under visible-light illumination. The ZnO/MnW04 nanocomposites exhibited better photocatalytic per-formance than their single components and the nanocomposite with 30 wt% MnW04 showed the highest activity. Photocatalytic performance of this nanocomposite is 22.5, 17.7, 26.8, and 23.9 times higher than that of the ZnO sample in degradations of RhB, MB, MO, and fuchsine dyes, respectively. The improved photocatalytic performance was ascribed to the formation ofp-n heterojunction between ZnO and MnW04 with high charge separation efficiency as well as strong visible-light absorption ability. The possible mechanism for the improved photocatalytic performance was proposed. This study revealed that the novel ZnO/MnW04 p-n heterojunction can act as a promising visible-light-active photocatalyst for environmental applications.展开更多
TiO2 doped with C, N and S (TCNS photocatalyst) was prepared by hydrolysis process using titanium iso-propoxide and thiourea. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron micro...TiO2 doped with C, N and S (TCNS photocatalyst) was prepared by hydrolysis process using titanium iso-propoxide and thiourea. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photo electron spectroscopy (XPS), BET surface area, FTIR and diffuse reflectance spectra (DRS). The results showed that the prepared catalysts are anatase type and nanosized par-ticles. The catalysts exhibited stronger absorption in the visible light region with a red shift in the adsorption edge. The photocatalytic activity of TCNS photocatalysts was evaluated by the photocatalytic degradation of isoproturon pesticide in aqueous solution. In the present study the maximum activity was achieved for TCNS5 catalyst at neutral pH with 1 g L-1 catalyst amount and at 1.14 x 10-4 M concentration of the pesticide solution. The TCNS photocatalysts showed higher phtocatalytic activity under solar light irradiation. This is attributed to the synergetic effects of red shift in the absorption edge, higher surface area and the inhibition of charge carrier recombination process.展开更多
This paper reports on new applications of water-dispersible graphene quantum dots(GQDs) that we recently developed. The prepared GQDs not only show broad absorption in the visible spectrum from 400 to 700 nm, but can ...This paper reports on new applications of water-dispersible graphene quantum dots(GQDs) that we recently developed. The prepared GQDs not only show broad absorption in the visible spectrum from 400 to 700 nm, but can also serve as smart photosensitizers with high singlet oxygen(1O2) production under visible-light irradiation(≥420 nm). We showed that the prepared GQDs can potentially be used as a metal-free, visible-light-active, sensitized photocatalyst via energy transfer mechanism, in which the light energy was converted by GQDs to produce 1O2, which can kill nearby microorganisms and degrade organic dyes.展开更多
The sanitary and environmental challenges posed by an ever growing economically and geographically diverse human population include the need for sustainable, inexpensive, scalable, and decentralized water treatment te...The sanitary and environmental challenges posed by an ever growing economically and geographically diverse human population include the need for sustainable, inexpensive, scalable, and decentralized water treatment technologies that can supplement or replace conventional treatment methods. These challenges can be met by semiconductor photocatalysis, especially if the process is driven by visible light energy. Visible-light active (VLA) photocatalysis, as opposed to traditional energy-intensive and chemically driven disinfection methods such as ozonation, UV irradiation and chlorination, has the potential for achieving high disinfection efficiency with low energy consumption and no harmful by-products. This technology generates in-situ reactive oxygen species (ROS) such as H2O2, and?, without the need for chemicals addition. In turn, ROS are capable of penetrating cell walls and membranes of microorganisms, effectively inactivating them. Although multiple types of VLA photocatalysts have been used experimentally for disinfection of water, noble-metal-based photocatalysts have gained the most interest due to their surface plasma resonance (SPR) effect, which acts synergistically to increase the disinfection potential of the photocatalytic process. This paper is a review of the different types of noble-metal-based VLA photocatalysts used for water disinfection in different experimental settings, their synthesis procedures and disinfection mechanisms. It also discusses innovative approaches to overcome a major hurdle in photocatalysis, that is, the rapid recombination of the electron and hole pair, by including specific dopants into the structure of the photocatalyst.展开更多
Here, PbCrO4 nanorods, a commonly used and low-cost yellow pigment, was synthesized via a simple pre-cipitation reaction and can serve as a highly efficient oxygen production and photodegradation photocatalyst. The ob...Here, PbCrO4 nanorods, a commonly used and low-cost yellow pigment, was synthesized via a simple pre-cipitation reaction and can serve as a highly efficient oxygen production and photodegradation photocatalyst. The obtained PbCrO4 nanorods exhibit excellent stability and pho-tocatalytic performance for O2 evolution from water. The production rate is approximately 314.0μmol h^-1 g^-1 under visible light, and the quantum efficiency is approximately 2.16% at 420±10 nm and 0.05% at 600±10 nm. In addition, the PhCrO4 shows good degradation performance for methylene blue, methyl blue, methyl orange and phenol under visible-light irradiation. These results indicate that it is potential to fabricate an effective, robust PbCrO4 photocatalyst by trans-forming heavy-metal pollutants Pb（II） and Cr（VI） into a highly efficient O2 evolution and photodegradation material. This strategy which uses pollutant to produce clean energy and degrade contaminants is completely green and environmentally benign, and thus could be a promising way for practical environmental applications. Keywords： 02 evolution, pollutant, PbCrO4 nanorods, visible-light-active, photocatalyst展开更多
文摘以氮掺杂为代表的非金属掺杂型TiO2光催化剂被誉为"第二代光催化材料"。本文首先系统评述了氮掺杂二氧化钛的制备方法,然后详细阐述了在N掺杂TiO2研究中关于其可见光活性机制以及掺杂N在TiO2晶格中的存在状态等方面的争议。N掺杂TiO2粉末的制备方法主要有氨气气氛下的热处理工艺、水解沉淀法、溶胶-凝胶法以及机械化学法等;N掺杂TiO2薄膜的制备方法主要包括磁控溅射法、脉冲激光沉积法以及金属有机化学气相沉积法等。已提出的关于N掺杂TiO2可见光活性机制的观点有N2p与O2p能级相杂化、形成N 2p孤立能态、氧空位的作用以及具顺磁性特征的杂质敏化。关于掺杂N在TiO2晶格中存在状态的分歧在于XPS N 1s谱中特征峰的位置及其归属的解析。文章最后指出了氮掺杂TiO2催化剂研究中有待解决的问题及今后的发展方向。
文摘Visible-light responsive TiO2-V2O5 catalyst was prepared using a binary sol-gel and in-situ intercalation method. The TiO2 sol and V2O5 sol were mixed to disperse the V2O5 species in the TiO2 phase at molecular level. The binary sol was then intercalated into interspaces of polyaniline （PANI） by means of in-situ polymerization of aniline. Conglomeration of the TiO2-V2O5 dusters during the calcination process was avoided because of the wrap of polyaniline. The surface mor- phology, the crystal phases, the structure, and the absorption spectra of （PANI）,/TiO2-V2O5 and the composite catalyst were studied using SEM, XRD, FT-IR, and UV-Vis. The photoactivity of the prepared catalyst under UV and visible light irradiation were evaluated by decolorization of methylene blue （MB） solution. The results showed that the composite catalyst displayed a homogeneous anatase phase, and the vanadium pentoxide species was highly dispersed in the TiO2 phase. The composite catalyst responded to visible light because of the narrowed band gap. In this study, the catalyst with the sol volume ratio of TiO2： V2O5 = 10：1 presented the best photocatalytic activity.
文摘We report, for the first time, binary ZnO/MnW04 nanocomposites with p-n heterojunction fabricated by a simple ultrasonic-calcination route. The phase structure, morphology, and optical along with tex- tural properties were comprehensively characterized. The photocatalytic performance was studied via degradations of rhodamine B, methyl blue and methyl orange （RhB, MB, MO）, and fuchsine pollutants under visible-light illumination. The ZnO/MnW04 nanocomposites exhibited better photocatalytic per-formance than their single components and the nanocomposite with 30 wt% MnW04 showed the highest activity. Photocatalytic performance of this nanocomposite is 22.5, 17.7, 26.8, and 23.9 times higher than that of the ZnO sample in degradations of RhB, MB, MO, and fuchsine dyes, respectively. The improved photocatalytic performance was ascribed to the formation ofp-n heterojunction between ZnO and MnW04 with high charge separation efficiency as well as strong visible-light absorption ability. The possible mechanism for the improved photocatalytic performance was proposed. This study revealed that the novel ZnO/MnW04 p-n heterojunction can act as a promising visible-light-active photocatalyst for environmental applications.
文摘TiO2 doped with C, N and S (TCNS photocatalyst) was prepared by hydrolysis process using titanium iso-propoxide and thiourea. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photo electron spectroscopy (XPS), BET surface area, FTIR and diffuse reflectance spectra (DRS). The results showed that the prepared catalysts are anatase type and nanosized par-ticles. The catalysts exhibited stronger absorption in the visible light region with a red shift in the adsorption edge. The photocatalytic activity of TCNS photocatalysts was evaluated by the photocatalytic degradation of isoproturon pesticide in aqueous solution. In the present study the maximum activity was achieved for TCNS5 catalyst at neutral pH with 1 g L-1 catalyst amount and at 1.14 x 10-4 M concentration of the pesticide solution. The TCNS photocatalysts showed higher phtocatalytic activity under solar light irradiation. This is attributed to the synergetic effects of red shift in the absorption edge, higher surface area and the inhibition of charge carrier recombination process.
基金supported by the National Natural Science Foundation of China(6122700851472252+2 种基金51172244and 11179006)the Key Research Program of the Chinese Academy of Sciences(KGZD-EW-T02)
文摘This paper reports on new applications of water-dispersible graphene quantum dots(GQDs) that we recently developed. The prepared GQDs not only show broad absorption in the visible spectrum from 400 to 700 nm, but can also serve as smart photosensitizers with high singlet oxygen(1O2) production under visible-light irradiation(≥420 nm). We showed that the prepared GQDs can potentially be used as a metal-free, visible-light-active, sensitized photocatalyst via energy transfer mechanism, in which the light energy was converted by GQDs to produce 1O2, which can kill nearby microorganisms and degrade organic dyes.
文摘The sanitary and environmental challenges posed by an ever growing economically and geographically diverse human population include the need for sustainable, inexpensive, scalable, and decentralized water treatment technologies that can supplement or replace conventional treatment methods. These challenges can be met by semiconductor photocatalysis, especially if the process is driven by visible light energy. Visible-light active (VLA) photocatalysis, as opposed to traditional energy-intensive and chemically driven disinfection methods such as ozonation, UV irradiation and chlorination, has the potential for achieving high disinfection efficiency with low energy consumption and no harmful by-products. This technology generates in-situ reactive oxygen species (ROS) such as H2O2, and?, without the need for chemicals addition. In turn, ROS are capable of penetrating cell walls and membranes of microorganisms, effectively inactivating them. Although multiple types of VLA photocatalysts have been used experimentally for disinfection of water, noble-metal-based photocatalysts have gained the most interest due to their surface plasma resonance (SPR) effect, which acts synergistically to increase the disinfection potential of the photocatalytic process. This paper is a review of the different types of noble-metal-based VLA photocatalysts used for water disinfection in different experimental settings, their synthesis procedures and disinfection mechanisms. It also discusses innovative approaches to overcome a major hurdle in photocatalysis, that is, the rapid recombination of the electron and hole pair, by including specific dopants into the structure of the photocatalyst.
基金jointly supported by the National Natural Science Foundation of China(21401190)the Science and Technology Project of Research Foundation of China Postdoctoral Science(2017M612710 and 2016M592519)+2 种基金Shenzhen Peacock Plan(827-000059,827-000113 and KQTD2016053112042971)the Science and Technology Planning Project of Guangdong Province(2016B050501005)the Educational Commission of Guangdong Province(2016KCXTD006 and 2016KSTCX126)
文摘Here, PbCrO4 nanorods, a commonly used and low-cost yellow pigment, was synthesized via a simple pre-cipitation reaction and can serve as a highly efficient oxygen production and photodegradation photocatalyst. The obtained PbCrO4 nanorods exhibit excellent stability and pho-tocatalytic performance for O2 evolution from water. The production rate is approximately 314.0μmol h^-1 g^-1 under visible light, and the quantum efficiency is approximately 2.16% at 420±10 nm and 0.05% at 600±10 nm. In addition, the PhCrO4 shows good degradation performance for methylene blue, methyl blue, methyl orange and phenol under visible-light irradiation. These results indicate that it is potential to fabricate an effective, robust PbCrO4 photocatalyst by trans-forming heavy-metal pollutants Pb（II） and Cr（VI） into a highly efficient O2 evolution and photodegradation material. This strategy which uses pollutant to produce clean energy and degrade contaminants is completely green and environmentally benign, and thus could be a promising way for practical environmental applications. Keywords： 02 evolution, pollutant, PbCrO4 nanorods, visible-light-active, photocatalyst
