“…7C), the applied potential for amperometric sensing of H 2 O 2 should be more positive to decrease the background current and minimize the response of common interference species. 26,27 We studied the influence of the applied potential on the amperometric response of the sensor to H 2 O 2 . As shown in Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The limit of detection (3S/N) was estimated to be 7.2 × 10 −8 mol · L −1 , which was lower than previously reported results. 1,[27][28][29] For comparison, the amperometric responses of pure TiO 2 and hemin modified electrodes to H 2 O 2 were also studied under the same experimental conditions. As shown in Fig.…”
Hemin-functionalized TiO 2 nanoparticles were prepared and assembled on glassy carbon electrode through the electrostatic attraction between positively charged poly(diallyldimethylammonium chloride) and negatively charged hemin and TiO 2 . The scanning electron microscopy and X-ray diffraction characterization showed that the assembled hemin-TiO 2 film displayed a mesoporous structure comprising plenty of TiO 2 nanoparticles in rutile phase. The Fourier transform infrared spectra and UV-visible diffuse reflectance spectra indicated that hemin was successfully incorporated into TiO 2 film and significantly enhanced the absorption of TiO 2 film to visible light. The hemin-TiO 2 film exhibited a pair of well-defined redox peaks of hemin by cyclic voltammetry, which could effectively catalyze the electroreduction of H 2 O 2 . Thus, the hemin-TiO 2 modified electrode was employed as an electrochemical sensor for H 2 O 2 determination, showing a sensitive response linearly proportional to the concentration of H 2 O 2 from 3.0 × 10 −7 to 4.7 × 10 −4 mol · L −1 . At the same time, the photoelectrocatalytic activity of TiO 2 under visible light illumination was dramatically promoted by hemin. The hemin-TiO 2 modified electrode produced a photoelectrochemical response linearly proportional to hydroquinone in the concentration range from 4. Hemin is an iron-containing porphyrin, namely protoporphyrin IX Fe(III) complex, which is well-known as the active center of the hemeprotein family. Because of the reversible reaction of Fe(III)/Fe(II) redox couple, hemin has been extensively demonstrated as an efficient electrocatalyst for many small molecules such as hydrogen peroxide, 1-3 oxygen, 4 nitrite, 5 L-tyrosine 6 and artemisinin. 7 Generally, hemin is loaded on some supporting materials to avoid the molecular aggregation of hemin molecules in aqueous solution and improve the stability and activity of catalyst.8 On the other hand, hemin is a structural analogue of chlorophyll, which can serve as a promising photosensitizer for TiO 2 photocatalyst to harvest visible light. 9,10 Moreover, the presence of Fe(III) porphyrin ring on the surface of TiO 2 can reduce the electron-hole recombination rate and act as a mediator for continuous production of enriched concentration of hydroxyl radicals to enhance the photocatalytic activity of TiO 2 .
11TiO 2 is the most intensively studied photocatalyst for degradation of various organic pollutants.12 In recent years, TiO 2 nanomaterials have been widely utilized for fabrication of sensing devices because of their fascinating properties such as large surface area, good biocompatibility, high stability, and unique electronic and photocatalytic performances.13 When catalytic materials including metal nanoparticles, small molecules and biological macromolecules are immobilized on nanostructured TiO 2 , the obtained nanocomposites can act as bifunctional catalysts which not only possess the catalytic activity of introduced materials but also preserve the intrinsic photocatalytic capacity of T...
“…7C), the applied potential for amperometric sensing of H 2 O 2 should be more positive to decrease the background current and minimize the response of common interference species. 26,27 We studied the influence of the applied potential on the amperometric response of the sensor to H 2 O 2 . As shown in Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The limit of detection (3S/N) was estimated to be 7.2 × 10 −8 mol · L −1 , which was lower than previously reported results. 1,[27][28][29] For comparison, the amperometric responses of pure TiO 2 and hemin modified electrodes to H 2 O 2 were also studied under the same experimental conditions. As shown in Fig.…”
Hemin-functionalized TiO 2 nanoparticles were prepared and assembled on glassy carbon electrode through the electrostatic attraction between positively charged poly(diallyldimethylammonium chloride) and negatively charged hemin and TiO 2 . The scanning electron microscopy and X-ray diffraction characterization showed that the assembled hemin-TiO 2 film displayed a mesoporous structure comprising plenty of TiO 2 nanoparticles in rutile phase. The Fourier transform infrared spectra and UV-visible diffuse reflectance spectra indicated that hemin was successfully incorporated into TiO 2 film and significantly enhanced the absorption of TiO 2 film to visible light. The hemin-TiO 2 film exhibited a pair of well-defined redox peaks of hemin by cyclic voltammetry, which could effectively catalyze the electroreduction of H 2 O 2 . Thus, the hemin-TiO 2 modified electrode was employed as an electrochemical sensor for H 2 O 2 determination, showing a sensitive response linearly proportional to the concentration of H 2 O 2 from 3.0 × 10 −7 to 4.7 × 10 −4 mol · L −1 . At the same time, the photoelectrocatalytic activity of TiO 2 under visible light illumination was dramatically promoted by hemin. The hemin-TiO 2 modified electrode produced a photoelectrochemical response linearly proportional to hydroquinone in the concentration range from 4. Hemin is an iron-containing porphyrin, namely protoporphyrin IX Fe(III) complex, which is well-known as the active center of the hemeprotein family. Because of the reversible reaction of Fe(III)/Fe(II) redox couple, hemin has been extensively demonstrated as an efficient electrocatalyst for many small molecules such as hydrogen peroxide, 1-3 oxygen, 4 nitrite, 5 L-tyrosine 6 and artemisinin. 7 Generally, hemin is loaded on some supporting materials to avoid the molecular aggregation of hemin molecules in aqueous solution and improve the stability and activity of catalyst.8 On the other hand, hemin is a structural analogue of chlorophyll, which can serve as a promising photosensitizer for TiO 2 photocatalyst to harvest visible light. 9,10 Moreover, the presence of Fe(III) porphyrin ring on the surface of TiO 2 can reduce the electron-hole recombination rate and act as a mediator for continuous production of enriched concentration of hydroxyl radicals to enhance the photocatalytic activity of TiO 2 .
11TiO 2 is the most intensively studied photocatalyst for degradation of various organic pollutants.12 In recent years, TiO 2 nanomaterials have been widely utilized for fabrication of sensing devices because of their fascinating properties such as large surface area, good biocompatibility, high stability, and unique electronic and photocatalytic performances.13 When catalytic materials including metal nanoparticles, small molecules and biological macromolecules are immobilized on nanostructured TiO 2 , the obtained nanocomposites can act as bifunctional catalysts which not only possess the catalytic activity of introduced materials but also preserve the intrinsic photocatalytic capacity of T...
“…Recently, various materials, such as Pd nanoparticles plated on a Si substrate, [5] carbon nanotubes/Ag nanohybrids [6] and MnO 2 nanoparticles [7] have been reported to work effectively in the non-enzymatic detection of H 2 O 2 . Although these materials exhibit a good performance as a biosensor, some of them are toxic or harmful to biological systems so that they are not suitable for application in vivo.…”
A flower‐like Au microstructure with a dominantly exposed active (110) plane has been prepared by a simple, facile method at room temperature. Various experimental factors that can control the shape of the Au microflowers have been investigated and optimized. Furthermore, the glassy carbon electrode modified with these Au microflowers exhibits high electrochemical activity towards H2O2 reduction. The sensor shows a linear range from 10 μM to 5.53 mM with a detection limit of 2 μM, which can be attributed to the exposed (110) planes and 3D hierarchical structure of the Au microflowers.
“…1 Various analytical methods for detection of H 2 O 2 have been studied including fluorescence, 2 chemiluminescence, 3,4 electrochemical, [5][6][7][8][9][10][11][12][13][14][15] and chemiresistive 16 detection in addition to titrimetry 17 and spectrophotometry. 18 All these methods, except electrochemical detection, suffer from some technical downsides such as time-consuming procedure, low selectivity, low sensitivity, and complicated instrumentation.…”
mentioning
confidence: 99%
“…6,7,11,13,15 Besides, Li et al reported that incorporating carbon nanotubes in electrode structure would improve the response current to the reduction of hydrogen peroxide. 20 Recently, it is great interest to develop paper-based chemical sensors due to their simple fabrication process, low cost, and scalable manufacturing via the various type of printing.…”
This paper reports a novel disposable non-enzymatic hydrogen peroxide sensor fabricated using an inkjet printing method on paper. An electrochemical cell based on carbon nanotubes was patterned and printed on a paper substrate. Silver nanoparticles have been used as the catalyst for electrochemical reduction of H 2 O 2 . Moreover, a handheld multichannel potentiostat was developed in order to on-site determination of hydrogen peroxide. The device was characterized by performing simultaneous cyclic voltammetry measurements utilizing separate working electrodes at various scan rates. Using the presented system, we successfully measured the hydrogen peroxide concentration in an alkaline solution with the linear range of 1 μM-700 μM. Incorporating the paper-based enzyme-free sensor and portable readout system will result in accurate, reliable, cost effective, and on-site measurement of hydrogen peroxide in concentration as low as 1 μM.
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