Chen Yu Chang

Bio: Chen Yu Chang is an academic researcher from National Taitung Junior College. The author has contributed to research in topics: Photocatalysis & Visible spectrum. The author has an hindex of 12, co-authored 40 publications receiving 540 citations. Previous affiliations of Chen Yu Chang include MingDao University.

Fluorescence Silica Nanoprobe as a Biomarker for Rapid Detection of Plant Pathogens

Abstract: Fluorescent silica nanoprobe as a biomarker for detection has attracted much attention in the field of nano-biotechnology recently but no further research applications using fluorescent silica nanoparticles (FSNP) combined with antibody molecules reported to detect pathogen detection. In this study, silica nanoparticles were prepared using the water-in-oil (w/o) microemulsion method. The silica nanoparticles were circular in diameter of 50 ± 4.2 nm. The organic dye, tris-2, 2' -bipyridyl dichlororuthenium (II) hexahydrate (Rubpy), could be incorporated efficiently into the core of silica nanoparticles. The fluorescence of Rubpy-doped silica nanoparticles was photostable using a collisional quenching fluorescence test. The Rubpy-doped silica nanoparticles were conjugated with the secondary antibody of goat anti-rabbit immunoglobulin G (IgG) and successfully detected plant pathogen such as Xanthomonas axonopodis pv. vesicatoria that causes bacterial spot disease in Solanaceae plant. These results demonstrated that the fluorescence silica nanoprobe biomarker will have been potential for rapid diagnosis applications on plant diseases.

Photocatalytic disinfection of phytopathogenic bacteria by dye-sensitized TiO2 thin film activated by visible light

Abstract: Synthetic pesticides have been used to control plant diseases or pests for a long time. The public has been affected by many problems such as environmental pollution and health issues from synthetic pesticide use in agriculture. It has consequently become necessary to develop alternative methods for the control of plant diseases. The TiO2 photocatalyst technique has potential for agricultural application because it will not form dangerous compounds. However, UV is only about 3% of the light existing in the solar spectrum. This limits TiO2 photocatalytic disinfection application under visible light irradiation. Our current research emphasizes the improvement of TiO2 thin film photocatalytic efficiency under visible light (λ > 400 nm) by doping a novel photosensitive dye (5, 10, 15, 20-tetraphenyl-21H, 23H-porphine nickel, TPPN) using the sol–gel method. These results showed that the TiO2 thin film doped with 200 μM of TPPN had high indigo dye photodegrading efficiency. The inhibition rates of TiO2/TPPN thin film illuminated by visible light against phytopathogenic bacteria including Enterobacter cloacae SM1, Erwinia carotovora subsp. carotovora 3 and E. carotovora subsp. carotovora 7 which induced severe soft/basal rot disease in vegetable crops were all more than 90%. These evidence suggest that the TiO2/TPPN thin film under visible light irradiation has the potential for direct application to plant protection in irrigation water systems.

Photocatalytic degradation of 2,4-dichlorophenol wastewater using porphyrin/TiO2 complexes activated by visible light

Abstract: The use of TiO2 as photocatalyst to degrade the organic compounds is an effective method of oxidation process and has been widely studied in environmental engineering. However, TiO2 absorbed the UV light which is only small part of sunlight reaching earth surface to activate photocatalytic procedure effectively is a major disadvantage. Therefore, studies on the development of new TiO2 wherein its photocatalytic activity can be activated by visible light which is the major part of sunlight will be valuable for field application. In this study, we evaluate the photocatalytic degrading efficiency of porphyrins/TiO2 complexes on the organic pollutants under irradiation with visible light (λ = 419 nm). The results showed that the photodecomposition efficiency of 2,4-dichlorophenol (2,4-DCP) wastewater by using porphyrin/TiO2 irradiated under visible light for 4 h was up to 42–81% at pH 10. These evidences reveal that the system of porphyrin/TiO2 complexes has also significantly efficiency of photocatalytic degradation for some hazardous or recalcitrant pollutants under visible light irradiation.

Visible light activated bactericidal effect of TiO2/Fe3O4 magnetic particles on fish pathogens

Abstract: The purpose of this research is to develop a bactericidal photocatalytic TiO 2 that can be activated by visible light and can be conveniently recollected for reusing. This research synthesizes the 22 to 33 nm TiO 2 /Fe 3 O 4 particles with magnetization of 2.9 emu/g using modified sol–gel method followed by 500 °C calcinations. The experiment verifies that both household fluorescent light (HFL, contains minor UV-A) and visible fluorescent light (VFL, contains no UV-A) can activate the photocatalytic activity of TiO 2 /Fe 3 O 4 particles as did ultraviolet A light (UV-A, 360 nm). Regular magnets can be used to separate TiO 2 /Fe 3 O 4 particles from solution. There have not been any significant weight and photocatalytic activity lost during 2 reusings. After 60 min and 120 min VFL irradiation, the bactericidal efficiencies of TiO 2 /Fe 3 O 4 are 35% and 72 % for Streptococcus iniae and 35% and 53% for Edwardsiella tarda , respectively. The results indicate that VFL irradiated TiO 2 /Fe 3 O 4 particles can disinfect fish pathogens in the absence of UV-A and the issue of TiO 2 /Fe 3 O 4 recollection from water for reusing is also resolved.

Semiconductor-based Photocatalytic Hydrogen Generation

Abstract: 2.3. Evaluation of Photocatalytic Water Splitting 6507 2.3.1. Photocatalytic Activity 6507 2.3.2. Photocatalytic Stability 6507 3. UV-Active Photocatalysts for Water Splitting 6507 3.1. d0 Metal Oxide Photocatalyts 6507 3.1.1. Ti-, Zr-Based Oxides 6507 3.1.2. Nb-, Ta-Based Oxides 6514 3.1.3. W-, Mo-Based Oxides 6517 3.1.4. Other d0 Metal Oxides 6518 3.2. d10 Metal Oxide Photocatalyts 6518 3.3. f0 Metal Oxide Photocatalysts 6518 3.4. Nonoxide Photocatalysts 6518 4. Approaches to Modifying the Electronic Band Structure for Visible-Light Harvesting 6519

Photocatalytic disinfection using titanium dioxide: spectrum and mechanism of antimicrobial activity

Abstract: The photocatalytic properties of titanium dioxide are well known and have many applications including the removal of organic contaminants and production of self-cleaning glass. There is an increasing interest in the application of the photocatalytic properties of TiO2 for disinfection of surfaces, air and water. Reviews of the applications of photocatalysis in disinfection (Gamage and Zhang 2010; Chong et al., Wat Res 44(10):2997–3027, 2010) and of modelling of TiO2 action have recently been published (Dalrymple et al. , Appl Catal B 98(1–2):27–38, 2010). In this review, we give an overview of the effects of photoactivated TiO2 on microorganisms. The activity has been shown to be capable of killing a wide range of Gram-negative and Gram-positive bacteria, filamentous and unicellular fungi, algae, protozoa, mammalian viruses and bacteriophage. Resting stages, particularly bacterial endospores, fungal spores and protozoan cysts, are generally more resistant than the vegetative forms, possibly due to the increased cell wall thickness. The killing mechanism involves degradation of the cell wall and cytoplasmic membrane due to the production of reactive oxygen species such as hydroxyl radicals and hydrogen peroxide. This initially leads to leakage of cellular contents then cell lysis and may be followed by complete mineralisation of the organism. Killing is most efficient when there is close contact between the organisms and the TiO2 catalyst. The killing activity is enhanced by the presence of other antimicrobial agents such as Cu and Ag.

Recent developments in heterogeneous photocatalytic water treatment using visible light-responsive photocatalysts: a review

Abstract: Visible light-responsive photocatalytic technology holds great potential in water treatment to enhance purification efficiency, as well as to augment water supply through the safe usage of unconventional water sources. This review summarizes the recent progress in the design and fabrication of visible light-responsive photocatalysts via various synthetic strategies, including the modification of traditional photocatalysts by doping, dye sensitization, or by forming a heterostructure, coupled with π-conjugated architecture, as well as the great efforts made within the exploration of novel visible light-responsive photocatalysts. Background information on the fundamentals of heterogeneous photocatalysis, the pathways of visible light-responsive photocatalysis, and the unique features of visible light-responsive photocatalysts are presented. The photocatalytic properties of the resulting visible light-responsive photocatalysts are also covered in relation to the water treatment, i.e., regarding the photocatalytic degradation of organic compounds and inorganic pollutants, as well as photocatalytic disinfection. Finally, this review concludes with a summary and perspectives on the current challenges faced and new directions in this emerging area of research.