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1.
A photochemical system utilising a modular approach characterised through interpretation of photoelectrochemical measurements is discussed. A photoanode was prepared by the chemisorption of a photosensitiser, cis-bis-(2,2'-bipyridine)-(4,4'-bis-(methyl)phosphonato-2,2'-bipyridine)ruthenium(II) dichloride (RuL2L'2+), to a mixed nanoporous nanocrystalline RuO2:TiO2 thin film, calcined on a fluorine doped SnO2 conducting glass substrate. Similarly, an electron relay molecule, 1-ethyl-1'-(2-phosphonoethyl)-4,4'-bipyridinium dichloride (EVP), was covalently bound to a platinum electroplated nanoporous nanocrystalline TiO2 thin film, and the electrodes connected in a photoelectrocatalytic cell (PCC). Irradiation with lamda > 420 nm gave a measurable photocurrent. Interpretation of the photocurrents obtained from this assembly provides a means for understanding photochemical reactions under low light intensities. Optimised conditions of the electrolyte solution were determined to be pH = 5 and illumination yielded eta = 0.0036% with an apparent quantum yield (AQY)= 1.6%. 相似文献
2.
The “Midas Touch” Transformation of TiO2 Nanowire Arrays during Visible Light Photoelectrochemical Performance by Carbon/Nitrogen Coimplantation
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Xianyin Song Wenqing Li Dong He Hengyi Wu Zunjian Ke Changzhong Jiang Gongming Wang Xiangheng Xiao 《Liver Transplantation》2018,8(20)
Titanium dioxide is a promising photoanode material for water oxidation, but it is substantially limited by its poor efficiency in the visible light range. Herein, an innovative carbon/nitrogen coimplantation method is utilized to realize the “Midas touch” transformation of TiO2 nanowire (NW) arrays for photoelectrochemical (PEC) water splitting in visible light. These modified golden–yellow rutile TiO2 NW arrays (C/N‐TiO2) exhibit remarkably enhanced absorption in visible light regions and more efficient charge separation and transfer. As a result, the photocurrent density of carbon/nitrogen co‐implanted TiO2 under visible light (>420 nm) can reach 0.76 mA cm?2, which far exceeds the value of 3 µA cm?2 seen for pristine TiO2 nanowire arrays at 0.8 V versus Ag/AgCl. An incident photon to electron conversion efficiency of ≈14.8% is achieved at 450 nm on C/N‐TiO2 without any other cocatalysts. The ion implantation doping approach, combined with codoping strategies, is proved to be an effective strategy for enhancing the photoelectrochemical conversion and can enable further improvement of the PEC water‐splitting performance of many other semiconductor photoelectrodes. 相似文献
3.
Overcoming Charge Collection Limitation at Solid/Liquid Interface by a Controllable Crystal Deficient Overlayer
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Kan Zhang Sandheep Ravishankar Ming Ma Ganapathy Veerappan Juan Bisquert Francisco Fabregat‐Santiago Jong Hyeok Park 《Liver Transplantation》2017,7(3)
Bulk and surface charge recombination of photoelectrode are two key processes that significantly hinder solar‐to‐fuel conversion of photoelectrochemical cell (PEC). In this study, the function of a “crystal‐deficient” overlayer is unveiled, which outperforms a traditionally used amorphous or crystalline overlayer in PEC water splitting by exhibiting a high conductivity and large electron diffusion length to enable unlimited electron collection. The optimized ≈2.5 nm thickness of the “crystal‐deficient” shell results in a depletion layer with a width of 3 nm, which overcomes the flat band limitation of the photovoltage and increases the light absorptivity in the wavelength range from 300 to 420 nm. In addition, a 50‐fold increase in the conductivity yields a one‐order‐of‐magnitude increase in the diffusion length of an electron (Ln )(≈20 μm), allowing for unlimited electron collection in the 1.9 μm TiO2 nanowire array with the “crystal‐deficient” shell. The controllable “crystal‐deficient” overlayer in rutile TiO2 nanowires photoanode achieves a photocurrent density greater than 2.0 mA cm?2 at 1.23 V versus reversible hydrogen electrode (RHE), a 1.18% applied bias photon‐to‐current efficiency at 0.49 V versus RHE, a faradaic efficiency greater than 93.5% at 0.6 V versus Pt under air mass 1.5G simulated solar light illumination (100 mW cm?2). 相似文献
4.
Multifunctional Coatings from Scalable Single Source Precursor Chemistry in Tandem Photoelectrochemical Water Splitting
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The straightforward and inexpensive fabrication of stabilized and activated photoelectrodes for application to tandem photoelectrochemical (PEC) water splitting is reported. Semiconductors such as Si, WO3, and BiVO4 can be coated with a composite layer formed upon hydrolytic decomposition of heterobimetallic single source precursors (SSPs) based on Ti and Ni, or Ti and Co in a simple single‐step process under ambient conditions. The resulting 3d‐transition metal oxide composite films are multifunctional, as they protect the semiconductor electrode from corrosion with an amorphous TiO2 coating and act as bifunctional electrocatalysts for H2 and O2 evolution based on catalytic Ni or Co species. Thus, this approach enables the use of the same precursors for both photoelectrodes in tandem PEC water splitting, and SSP chemistry is thereby established as a highly versatile low‐cost approach to protect and activate photoelectrodes. In an optimized system, SSP coating of a Si photocathode and a BiVO4 photoanode resulted in a benchmark noble metal‐free dual‐photoelectrode tandem PEC cell for overall solar water splitting with an applied bias solar‐to‐hydrogen conversion efficiency of 0.59% and a half‐life photostability of 5 h. 相似文献
5.
Nanoporous Au Thin Films on Si Photoelectrodes for Selective and Efficient Photoelectrochemical CO2 Reduction
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Jun Tae Song Hyewon Ryoo Minhyung Cho Jaehoon Kim Jin‐Gyu Kim Sung‐Yoon Chung Jihun Oh 《Liver Transplantation》2017,7(3)
An Si photoelectrode with a nanoporous Au thin film for highly selective and efficient photoelectrochemical (PEC) CO2 reduction reaction (CO2RR) is presented. The nanoporous Au thin film is formed by electrochemical reduction of an anodized Au thin film. The electrochemical treatments of the Au thin film critically improve CO2 reduction catalytic activity of Au catalysts and exhibit CO Faradaic efficiency of 96% at 480 mV of overpotential. To apply the electrochemical pretreatment of Au films for PEC CO2RR, a new Si photoelectrode design with mesh‐type co‐catalysts independently wired at the front and the back of the photoelectrode is demonstrated. Due to the superior CO2RR activity of the nanoporous Au mesh and high photovoltage from Si, the Si photoelectrode with the nanoporous Au thin film mesh shows conversion of CO2 to CO with 91% Faradaic efficiency at positive potential than the CO2/CO equilibrium potential. 相似文献
6.
A photoelectrochemical method was proposed to detect DNA hybridization using Au nanoparticle modified DNA as one probe on TiO2 substrate, in which the TiO2 substrate was used not only as DNA anchors but also as the signal transducers. Hybridization between the probe and the target DNA oligonucleotides was confirmed by the decreased photocurrent of the TiO2 electrode. Compared with non-label probe, Au nanoparticles enhanced the photocurrent shifts after the hybridization. The photocurrent decreased with increasing the concentration of target DNA, indicating that this method could be used for quantitative measurements, and the discrimination of the complementary from mismatched DNA. Furthermore, the hybridization binding constant was obtained and photocurrent generation mechanism was discussed. The major advantages of this photochemical method are speed, simplicity and excellent specificity. This method provides a platform for studying a wide variety of biological processes using photoelectrochemical method. 相似文献
7.
The need for cost‐effective and sustainable power supplies has spurred a growing interest in hybrid energy harvesting systems, and the most elementary energy production process relies on intermittent solar power. Here, it is shown how the ambient mechanical energy leads to water splitting in a photoelectrochemical (PEC) cell boosted by a triboelectric nanogenerator (TENG). In this strategy, a flexible TENG collects and transforms mechanical energy into electric current, which boosts the PEC water splitting via the charged Li‐ion battery. Au nanoparticles are deposited on TiO2 nanoarrays for extending the available light spectrum to visible part by surface plasmon resonance effect, which yields a photocurrent density of 1.32 mA cm?2 under AM 1.5 G illumination and 0.12 mA cm?2 under visible light with a bias of 0.5 V. The TENG‐charged battery boosts the water splitting performance through coupling electrolysis and enhanced electron–hole separation efficiency. The hybrid cell exhibits an instantaneous current more than 9 mA with a working electrode area of 0.3 cm2, suggesting a simple but efficient route for simultaneously converting solar radiation and mechanical energy into hydrogen. 相似文献
8.
Removal and degradation of pentachlorophenol (PCP) by Phanerochaete chrysosporium in static flask cultures was studied using ammonium lignosulphonates (LS), a waste product of the papermill industry, as a carbon and nitrogen source. After 3 days, cultures of P. chrysosporium grown in either a 2% LS (nitrogen-sufficient) medium or a 0.23% LS and 2% glucose (nitrogen-deficient) medium removed 72 to 75% of PCP, slightly less than the 95% removal seen using nitrogen-deficient glucose and ammonia medium. PCP dehalogenation occurred despite the fact that extracellular enzyme (LiP) activity, measured by a veratryl alcohol oxidation assay and by PCP disappearance in cell-free extracts, was inhibited by LS. This inactivation of LiP likely contributed to the lower percent of PCP dehalogenation observed using the LS media. In order to better understand the relationship between PCP disappearance and dehalogenation, we measured the fate of the chlorine in PCP. After 13 days, only 1.8% of the initial PCP added was recoverable as PCP. The remainder of the PCP was either mineralized or transformed to breakdown intermediates collectively identified as organic halides. The largest fraction of the original chlorine (58%) was recovered as organic (non-PCP) halide, most of which (73%) was associated with the cell mass. Of the remaining chlorine, 40% was released as chloride ion, indicating a level of dehalogenation in agreement with previously reported values. 相似文献
9.
Removal and degradation of pentachlorophenol (PCP) by Phanerochaete chrysosporium in static flask cultures was studied using ammonium lignosulphonates (LS), a waste product of the papermill industry, as a carbon and nitrogen source. After 3 days, cultures of P. chrysosporium grown in either a 2% LS (nitrogen-sufficient) medium or a 0.23% LS and 2% glucose (nitrogen-deficient) medium removed 72 to 75% of PCP, slightly less than the 95% removal seen using nitrogen-deficient glucose and ammonia medium. PCP dehalogenation occurred despite the fact that extracellular enzyme (LiP) activity, measured by a veratryl alcohol oxidation assay and by PCP disappearance in cell-free extracts, was inhibited by LS. This inactivation of LiP likely contributed to the lower percent of PCP dehalogenation observed using the LS media. In order to better understand the relationship between PCP disappearance and dehalogenation, we measured the fate of the chlorine in PCP. After 13 days, only 1.8% of the initial PCP added was recoverable as PCP. The remainder of the PCP was either mineralized or transformed to breakdown intermediates collectively identified as organic halides. The largest fraction of the original chlorine (58%) was recovered as organic (non-PCP) halide, most of which (73%) was associated with the cell mass. Of the remaining chlorine, 40% was released as chloride ion, indicating a level of dehalogenation in agreement with previously reported values. 相似文献
10.
Wouter J. C. Vijselaar Paula Perez‐Rodriguez Pieter J. Westerik Roald M. Tiggelaar Arno H. M. Smets Han Gardeniers Jurriaan Huskens 《Liver Transplantation》2019,9(19)
Wireless photoelectrochemical (PEC) devices promise easy device fabrication as well as reduced losses. Here, the design and fabrication of a stand‐alone ion exchange material‐embedded, Si membrane‐based, photoelectrochemical cell architecture with micron‐sized pores is shown, to overcome the i) pH gradient formation due to long‐distance ion transport, ii) product crossover, and iii) parasitic light absorption by application of a patterned catalyst. The membrane‐embedded PEC cell with micropores utilizes a triple Si junction cell as the light absorber, and Pt and IrOx as electrocatalysts for the hydrogen evolution reactions and oxygen evolution reactions, respectively. The solar‐to‐hydrogen efficiency of 7% at steady‐state operation, as compared to an unpatterned ηPV of 10.8%, is mainly attributed to absorption losses by the incorporation of the micropores and catalyst microdots. The introduction of the Nafion ion exchange material ensures an intrinsically safe PEC cell, by reducing the total gas crossover to <0.1%, while without a cation exchange membrane, a crossover of >6% is observed. Only in a pure electrolyte of 1 m H2SO4, a pH gradient‐free system is observed thus completely avoiding the build‐up of a counteracting potential. 相似文献
11.
An immobilized chloroplast film, prepared by immobilizing spinach chloroplasts in 2 wt% agar gel, was attached to a SnO2 optically transparent electrode to obtain the immobilized chloroplast film electrode. The immobilized chloroplast film electrode worked as a photoanode under illumination in the presence of methyl viologen, which was an electron carrier from chloroplasts to the SnO2 optically transparent electrode. Water photolysis for producing hydrogen by a photoelectrochemical cell using the immobilized chloroplasts film electrode was successfully achieved. A smooth platinum electrode was used as a cathode to produce hydrogen. The pH and temperature of the anolyte were kept at 7.8 and 25°C. Optimizations of the concentrations of methyl viologen and chlorophyll in the immobilized chloroplast film were studied. The optimum thickness for the immobilized chloroplast film was about 0.8 mm. The immobilized chloroplasts had higher storage stability than that of isolated chloroplasts and they retained more than 50% of the initial activities of photosystem I and photosystem II after 10 days when they were stored at 4°C in the dark. It was conceived from the relationship between the photocurrent and the photosystem I and II activities that the main cause for the decrease in the photocurrent was the photochemical inactivation of photosystem II. 相似文献
12.
Over 17% Efficiency Stand‐Alone Solar Water Splitting Enabled by Perovskite‐Silicon Tandem Absorbers
Siva Krishna Karuturi Heping Shen Astha Sharma Fiona J. Beck Purushothaman Varadhan The Duong Parvathala Reddy Narangari Doudou Zhang Yimao Wan Jr‐Hau He Hark Hoe Tan Chennupati Jagadish Kylie Catchpole 《Liver Transplantation》2020,10(28)
Realizing solar‐to‐hydrogen (STH) efficiencies close to 20% using low‐cost semiconductors remains a major step toward accomplishing the practical viability of photoelectrochemical (PEC) hydrogen generation technologies. Dual‐absorber tandem cells combining inexpensive semiconductors are a promising strategy to achieve high STH efficiencies at a reasonable cost. Here, a perovskite photovoltaic biased silicon (Si) photoelectrode is demonstrated for highly efficient stand‐alone solar water splitting. A p+nn+ ‐Si/Ti/Pt photocathode is shown to present a remarkable photon‐to‐current efficiency of 14.1% under biased condition and stability over three days under continuous illumination. Upon pairing with a semitransparent mixed perovskite solar cell of an appropriate bandgap with state‐of‐the‐art performance, an unprecedented 17.6% STH efficiency is achieved for self‐driven solar water splitting. Modeling and analysis of the dual‐absorber PEC system reveal that further work into replacing the noble‐metal catalyst materials with earth‐abundant elements and improvement of perovskite fill factor will pave the way for the realization of a low‐cost high‐efficiency PEC system. 相似文献
13.
A novel thin film ethanol sensor using sputtered Ni/Pt/Ti on an Al2O3 substrate as the working electrode in an alkaline solution was developed. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to characterize the nanostructure of nickel films. Sputtering deposition conditions for maximum catalytic efficiency, electrode selectivity, and reproducibility were discussed. The results showed that ethanol oxidation was more efficient on the sputtered Ni/Pt/Ti on an Al2O3 substrate electrode than that on the conventional nickel electrode. The optimal operating conditions to generate the sputtered Ni/Pt/Ti on the Al2O3 substrate electrode were: 45 min of Ni sputtering deposition time, and 50 W of Ni sputtering power. The results also indicated that the response time of the prepared ethanol sensor is 27 s and the best sensitivity is 3.08 microA microM(-1) cm(-2). 相似文献
14.
M. B. Cassidy K. W. Shaw H. Lee J. T. Trevors 《Applied microbiology and biotechnology》1997,47(2):108-113
A pentachlorophenol(PCP)-degrading Pseudomonas sp. strain UG30 was encapsulated in κ-carrageenan for use in PCP degradation. Free and encapsulated cells were compared for
their ability to dechlorinate and mineralize 100–800 μg/ml sodium pentachlorophenate in broth. Dechlorination was measured
with a chloride ion electrode, and mineralization was measured by 14CO2 evolution from radiolabelled [U-14C]PCP. Free and encapsulated Pseudomonas sp. UG30 cells mineralized up to 200 μg/ml and 600 μg/ml PCP, respectively, after 21 days. Encapsulation of UG30 cells provided
a protective effect, allowing dechlorination and mineralization of high levels of PCP to occur.
Received: 3 May 1996 / Received revision: 4 September 1996 / Accepted: 13 September 1996 相似文献
15.
A pentachlorophenol (PCP) degrading bacterium was isolated and characterized from sludge of pulp and paper mill. This isolate
used PCP as its sole source of carbon and energy and was capable of degrading this compound, as indicated by stoichiometric
release of chloride and biomass formation. Based on morphology, biochemical tests, and 16S rRNA gene sequence analysis this
strain was identified as Kocuria sp. CL2. High Performance Liquid Chromatography (HPLC) analysis revealed that this strain was able to degrade PCP up to a
concentration of 600 mg/l. This is first time we are reporting the degradation of PCP by the Kocuria species. This isolate was also able to remove 58.64% of PCP from the sludge within two weeks. This study showed that the
removal efficiency of PCP by CL2 was found to be very effective and can be used in degradation of PCP containing pulp paper
mill waste in the environment. 相似文献
16.
Photoelectrocatalytic water splitting offers a promising approach to convert sunlight into sustainable hydrogen energy. A thorough understanding of the relationships between the properties and functions of photoelectrocatalytic materials plays a crucial role in the design and fabrication of efficient photoelectrochemical systems for water splitting. This review presents the advances in the development of efficient photoelectrocatalytic materials. First, the fundamentals involved in the photoelectrocatalytic water splitting are elaborated. Then, the critical properties of photoelectrocatalytic materials are classified and discussed according to the associated photoelectrochemical processes, including light absorption, charge separation, charge transportation, and photoelectrocatalytic reactions. The importance of heterointerfaces in photoelectrodes is also mentioned in conjunction with the illustration of some functional interlayer materials. Finally, some strategies that can be employed in material screening and optimization for the construction of highly efficient photoelectrochemical devices for water splitting are also discussed. 相似文献
17.
A bio-photovoltaic conversion device based on dye-sensitised solar cell (DSSC) using the visible light sensitisation of chlorine-e6 (Chl-e6) derived from chlorophyll from Spirulina adsorbed on a nanocrystalline TiO2 film was developed. Form fluorescence spectrum of Chl-e6 adsorbed on a nanocrystalline TiO2 film, the emission of Chl-e6 was effectively quenched by TiO2 nanocrystalline indicating that the effective electron injection from the excited singlet state of Chl-e6 into the conduction band of TiO2 particles occurred. The short-circuit photocurrent density (Isc). the open-circuit photovoltage (Voc). and the fill factor (FF) of solar cell using Chl-e6 adsorbed on a nanocrystalline TiO2 film electrode were estimated to be 0.305 +/- 0.012 mA cm(-2), 426 +/- 10 mV, and 45.0%, respectively. IPCE values were reached a maximum around the wavelength of absorption maximum (7.40% at 400 nm; 1.44% at 514 nm and 2.91% at 670 nm), indicating that the DSSC using visible light sensitisation of nanocrystalline TiO2 film by Chl-e6 was developed. 相似文献
18.
利用表面修饰的方法制备了5-ALA表面修饰的TiO2(5-ALA/TiO2),并利用傅里叶红外光谱,拉曼光谱以及紫外-可见光吸收光谱(uV—Vis)对样品进行了表征。利用CellCountingKit-8(CCK-8)法检测研究5-ALA/TiO2对HL60细胞的灭活效应。结果显示,5-ALA/TiO2能够显著地抑制HL60细胞的生长,5-ALA/TiO2对HL60细胞的灭活效率要明显高于5-ALA以及TiO2,实验中5-ALA/TiO2的灭活效率达到77.9%,相衬显微镜细胞形态学无损观察表明,细胞凋亡开始于细胞膜的破裂。同时,激光显微拉曼光谱检测显示,TiO2纳米粒子能够进入细胞内部,与细胞发生相互作用。 相似文献
19.
Anodization and sol-gel treatments of titanium (Ti) were evaluated as biofilm control measures on surfaces exposed to seawater exposed to ultraviolet light. Anodized and sol-gel treated specimens were characterized using Raman spectroscopy to confirm the presence of TiO(2). The single anatase phase was observed at the anodized surfaces whereas the anatase/rutile mixed phase was detected on the sol-gel coated surfaces. After exposure of the specimens to seawater, biofilms were characterized by total viable counts, and epifluorescence and Raman microscopy. These techniques confirmed the reduction in biofilm formation on both the anodized and sol-gel coated Ti specimens compared to the untreated specimens. Biofilm control by anodization was found to be more effective than by sol-gel treatment of the specimens. The higher particle size and the inhomogeneity at the sol-gel coated surfaces produced less effective biofilm control. 相似文献
20.
Mixed culture of two bacterial strains Bacillus sp. and Serratia marcescens showed potential pentachlorophenol (PCP) degradation and decolorisation of pulp paper mill effluent. The physico-chemical quality of pulp paper mill effluent has been analyzed after 168 h incubation period degraded by mixed culture. The study revealed that it has decreased high load of BOD, COD, TS, TDS, TSS, sulphate, phosphate, total nitrogen, total phenols, metals and different salts (i.e. chloride, sodium, nitrate, potassium) at 168 h incubation period. PCP degradation in pulp paper mill effluent was confirmed by HPLC analysis. Mixed culture was found to degrade PCP up to (94%) present in pulp paper mill effluent with 1% glucose and 0.5% peptone (w/v) at 30 ± 1 °C, pH 8.0 ± 0.2 at 120 rpm in 168 h incubation period. The simultaneous release of chloride ion up to 1200 mg/l at 168 h emphasized the bacterial dechlorination in the medium. The pulp paper mill effluent degradation was also supported by decline in pH, AOX (absorbable organic halides), color, D.O., BOD, COD and PCP. The analysis of pulp paper mill effluent degradation products by GC–MS analysis revealed the formation of low molecular weight compound like 2-chlorophenol (RT = 3.8 min) and tetrachlorohydroquinone (RT = 11.86 min) from PCP extracted degraded sample. Further, mixed culture may be used for bioremediation of PCP containing pulp paper mill waste in the environment. 相似文献