Spectroscopic analyses on ROS generation catalyzed by TiO2, CeO2/TiO2 and Fe2O3/TiO2 under ultrasonic and visible-light irradiation

Author(s):  
Mingming Zou ◽  
Yumei Kong ◽  
Jun Wang ◽  
Qi Wang ◽  
Zhiqiu Wang ◽  
...  
2019 ◽  
Vol 10 (36) ◽  
pp. 8455-8460 ◽  
Author(s):  
Yingmu Zhang ◽  
Jiandong Pang ◽  
Jialuo Li ◽  
Xinyu Yang ◽  
Mingbao Feng ◽  
...  

K-region substituted pyrene-based MOFs for ROS generation upon direct visible-light irradiation.


2006 ◽  
Vol 20 (25n27) ◽  
pp. 3854-3859
Author(s):  
MASAHIRO KATOH ◽  
TOSHIHIDE HORIKAWA ◽  
TAHEI TOMIDA

Cr -containing mesoporous silicates ( Cr -FSM-16) were prepared and characterized by several spectroscopic analyses. Their photocatalytic reactivity for acetone under UV- and visible-light irradiations has been investigated and the effect of adsorption on the reactivity was discussed. XPS spectra showed the Cr -oxide moieties were in the mesoporous framework of FSM-16. The UV-VIS spectra of the Cr -FSM-16 exhibited three distinct absorption bands, which could be assigned to charge transfer from O 2- to Cr 6+ of the tetrahedrally coordinated moieties. In particular, the band at 460 nm was assigned to the symmetry-forbidden nature of the 1 A 1 → 1 T 1 transition of tetrahedral Cr -oxide. The absorption showed Cr -FSM-16 has the photocatalytic reactivity under visible light irradiation. Acetone was adsorbed strongly on Cr -FSM-16, and then adsorbed acetone was decomposed to CO 2 and H 2 O on Cr -FSM-16 under visible light irradiation. But the amount of CO 2 produced was much less than the stoichiometric amount of CO 2 calculated from adsorbed acetone. This may be due to adsorption of acetone, and/or CO 2 on Cr -FSM-16.


Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  

Indoor surface contamination by microbes is a major public health concern. A damp environment is one potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO<sub>2</sub>) can effectively curb this growing threat.<b> </b>Metal-doped titania in anatase phase has been proved as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu) doped TiO<sub>2 </sub>(Cu-TiO<sub>2</sub>) was evaluated against <i>Escherichia coli</i> (Gram-negative) and <i>Staphylococcus aureus</i> (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO<sub>2 </sub>was carried out <i>via</i> sol-gel technique. Cu-TiO<sub>2</sub> further calcined at various temperatures (in the range of 500 °C – 700 °C) to evaluate the thermal stability of TiO<sub>2</sub> anatase phase. The physico-chemical properties of the samples were characterised through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV-visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO<sub>2</sub> was maintained well, up to 650 °C, by the Cu dopant. UV-DRS results suggested that the visible light absorption property of Cu-TiO<sub>2 </sub>was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasises the introduction of Cu<sup>+</sup> and Cu<sup>2+</sup> ions by replacing Ti<sup>4+</sup> ions in the TiO<sub>2</sub> lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9%) was attained in 30 mins of visible light irradiation by Cu-TiO<sub>2</sub>.


2020 ◽  
Vol 16 ◽  
Author(s):  
Yuxue Wei ◽  
Honglin Qin ◽  
Jinxin Deng ◽  
Xiaomeng Cheng ◽  
Mengdie Cai ◽  
...  

Introduction: Solar-driven photocatalytic hydrogen production from water splitting is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. In this review, recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. In particular, the factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Background: Photocatalytic hydrogen evolution from water splitting using photocatalyst semiconductors is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. Methods: This review summarizes the recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation. Results: Recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. The factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Conclusion: The state-of-the-art CdS for producing hydrogen from photocatalytic water splitting under visible light is discussed. The future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are also described.


2018 ◽  
Vol 8 (23) ◽  
pp. 6173-6179 ◽  
Author(s):  
Xu Jin ◽  
Rengui Li ◽  
Yue Zhao ◽  
Xiaodan Liu ◽  
Xiaoqi Wang ◽  
...  

Efficient converting of alcohols to aldehydes under visible light can be achieved on BiVO4 crystals with spatial separation of dual-cocatalysts.


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