- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Electrospun nanostructured Co3O4/BiVO4 composite films for photoelectrochemical applications
摘要： Co3O4/BiVO4 (Co/BiV) based nanostructured photoanode films were fabricated by simple facile electrospinning method and were characterized by a variety of techniques. It was found that the films have web-linked structure, composed of BiVO4 and Co3O4 nanostructures. The photoanode was used for the photoelectrochemical (PEC) degradation of bisphenol-A (BPA) by illumination at 0.25 V vs. SCE assisted by 1 mM peroxymonosulfate (PMS). The removal percentage of BPA was enhanced to 96% for the Co/BiV film that was much better than that of BiVO4 film, which was 48%. The pseudo-first kinetic constants were raised from 0.1126 min?1 to 0.4714 min?1, respectively. The enhanced PEC performance of Co/BiV films can be attributed its p-n heterojunction setup and synergetic contribution of PMS, which efficiently inhibits the recombination of photogenerated electron-hole pairs. The free radicals quenching experiment and electron spin resonance suggested that the major reactive oxygen species were photogenerated holes, superoxide radicals and sulfate radicals. These findings demonstrate that PMS assisted Co/BiV films, are good candidates for PEC application in environmental purification.
关键词： BiVO4,Peroxymonosulfate,Photoelectrochemistry,Electrospinning,Thin films
更新于2025-09-23 15:23:52
-
Oxynitride Thin Films versus Particle-Based Photoanodes: a Comparative Study for Photoelectrochemical Solar Water Splitting
摘要： The solar water splitting process assisted by semiconductor photocatalysts attracts growing research interests worldwide for the production of hydrogen as a clean and sustainable energy carrier. Due to their optical and electrical properties several oxynitride materials show great promise for the fabrication of efficient photocatalysts for solar water splitting. This study reports a comparative investigation of particle- and thin films-based photocatalysts using three different oxynitride materials. The absolute comparison of the photoelectrochemical activities favors the particle-based electrodes due to the better absorption properties and larger electrochemical surface area. However, thin films surpass the particle-based photoelectrodes due to their more suitable morphological features that improve the separation and mobility of the photo-generated charge carriers. Our analysis identifies what specific insights into the properties of materials can be achieved with the two complementary approaches.
关键词： Oxynitride,pulsed laser deposition,photoelectrochemistry,thin films,solar water splitting,photoanode
更新于2025-09-23 15:23:52
-
The role of synthesis conditions for structural defects and lattice strain in β-TaON and their effect on photo- and photoelectrocatalysis
摘要： The importance of the synthesis conditions on the structural and photocatalytic properties of tantalum oxide nitride was investigated by comparing two variants of phase-pure β-TaON obtained from application of two different synthesis routes, leading to one unstrained and one heavily anisotropically microstrained β-TaON as shown by XRD-based Rietveld refinement. HRTEM images reveal the origin of the strain to be lattice defects such as stacking faults. The strained β-TaON was found to be the clearly less active semiconductor in photochemical and photoelectrochemical water oxidation. The lattice defects are assumed to act as charge carrier traps hindering the photo-generated holes to be displaced to the reaction sites at the surface.
关键词： tantalum oxide nitride,photocatalysis,photoelectrochemistry,water splitting,structural defects
更新于2025-09-23 15:22:29
-
Transparent Ta3N5 Photoanodes for Efficient Oxygen Evolution toward the Development of Tandem Cells
摘要： Photoelectrochemical water splitting is regarded as a promising approach to the production of hydrogen, and the development of efficient photoelectrodes is one aspect of realizing practical systems. In this work, transparent Ta3N5 photoanodes were fabricated on n-type GaN/sapphire substrates to promote O2 evolution in tandem with a photocathode, to realize overall water splitting. Following the incorporation of an underlying GaN layer, a photocurrent of 6.3 mA cm-2 was achieved at 1.23 V vs. a reversible hydrogen electrode. The transparency of Ta3N5 to wavelengths longer than 600 nm allowed incoming solar light to be transmitted to a CuInSe2 (CIS), which absorbs up to 1100 nm. A stand-alone tandem cell with a serially-connected dual-CIS unit terminated with a Pt/Ni electrode was thus constructed for H2 evolution. This tandem cell exhibited a solar-to-hydrogen energy conversion efficiency greater than 7% at the initial stage of the reaction.
关键词： solar energy conversion,photoelectrochemistry,water splitting,photoelectrochemical tandem cell,(oxy)nitrides
更新于2025-09-23 15:22:29
-
Decoupling Effects of Surface Recombination and Barrier Height on p-Si(111) Photovoltage in Semiconductor|Liquid Junctions via Molecular Dipoles and Metal Oxides
摘要： This work provides insight into carrier dynamics in a model photoelectrochemical system comprised of a semiconductor, metal oxide, and metal. To isolate carrier dynamics from catalysis, a common catalytic metal (Pt) is used in concert with an outer-sphere redox couple. Silicon (111) substrates were surface-functionalized with electronegative aryl moieties (p-nitrophenyl and m-dinitrophenyl). A mixed monolayer using p-nitrophenyl/methyl exhibited high surface quality as determined by X-ray photoelectron spectroscopy (low surface SiOx content) and low surface recombination velocity. This substrate also exhibited the expected positive surface dipole, as evidenced by rectifying J?V behavior on p-type substrates, and by positive photovoltage measured by surface photovoltage spectroscopy. Its close molecular relative m-dinitrophenyl exhibited poor electronic surface quality as indicated by high SiOx coverage and high surface recombination velocities (S > 3000 cm s?1). Photoelectrochemical J?V measurements of p-type Si-functionalized surfaces in contact with a high concentration (50 mM) of methyl viologen (MV2+) in aqueous media revealed VOC values that are correlated with the measured barrier heights. In contrast, low-concentration (1.5 mM) MV2+ experiments revealed significant contributions from surface recombination. Next, the electronic and (photo)electrochemical properties were studied as a function of ALD metal oxide deposition (TiO2, Al2O3) and Pt deposition. For the m-dinitrophenyl substrate, ALD deposition of both TiO2 and Al2O3 (150 °C, amorphous) decreased the surface recombination velocity. Surprisingly, this TiO2 deposition resulted in negative shifts in VOC for all surfaces (possibly ALD-TiO2 defect band effects). However, Pt deposition recovered the efficiencies beyond those lost in TiO2 deposition, affording the most positive VOC values for each substrate. Overall, this work demonstrates that (1) when carrier collection is kinetically fast, p-Si(111)?R devices are limited by thermal emission of carriers over the barrier, rather than by surface recombination. And (2) although TiO2 |Pt improves the PEC performance of all substrates, the beneficial effects of the underlying (positive) surface dipole are still realized. Lastly (3) Pt deposition is demonstrated to provide beneficial charge separation effects beyond enhancing catalytic rates.
关键词： solar fuels,interfacial dipole,atomic layer deposition (ALD),surface functionalization,band-edge modulation,photoelectrochemistry
更新于2025-09-23 15:22:29
-
Enhanced Photoelectrochemical Performance and Stability of Si Nanowire Photocathode with Deposition of Hematite and Carbon
摘要： Tremendous efforts have been dedicated to the development of transition metal and/or metal oxide surface coating materials to enhance the activity and stability of photoelectrodes. Nanostructured Si photoelectrodes have shown outstanding photoelectrochemical (PEC) performance due to their effective photon absorption and charge generation, separation, and mobility. While the chemical stability and surface reaction efficiency of Si photoelectrodes still need improvement before commercial application. Herein, we report the design and synthesis of a composite Si photoelectrode with a configuration of C/α-Fe2O3/Si nanowires, which presented a stable photoelectrochemical hydrogen production in neutral electrolyte. The p-Si nanowires were prepared by metal-assisted chemical etching for enhanced optical absorption and decorated with a mesoporous α-Fe2O3 thin film (~80 nm) through pyrolysis of ferrocene. A thin carbon passivation layer (~20 nm) was further deposited through ion sputtering further increasing the stability of the composite structure and low bias photocurrent. The role of α-Fe2O3 and carbon layer have been discussed. The composite photoelectrode shows a stable photocurrent of ~ -27 mA/cm2 in 2 h and an anodic onset potential shift of ~0.33 V relative to the bare Si in the neutral solution.
关键词： Si nanowires,photoelectrochemistry,α-Fe2O3,carbon,hydrogen
更新于2025-09-23 15:21:21
-
Modified Nanopillar Arrays for Highly Stable and Efficient Photoelectrochemical Water Splitting
摘要： Atomically modified graphitic carbon nitride quantum dots (QDs), characterized by strongly increased reactivity and stability, are developed. These are deposited on arrays of TiO2 nanopillars used as a photoanode for the photoelectrochemical water splitting. This photoanode shows excellent stability, with 111 h of continuous work without any performance loss, which outperforms the best-reported results by a factor of 10. Remarkably, our photoanode produces hydrogen even at zero bias. The excellent performance is attributed to the enhancement of photoabsorption, as well as to the promotion of charge separation between TiO2 nanopillars and the QDs.
关键词： hydrogen evolution,quantum dots,graphitic carbon nitride,photoelectrochemistry,TiO2 nanopillars
更新于2025-09-23 15:21:21
-
Photoelectrochemical-assisted batch injection analysis (PEC-BIA) of glucose exploiting visible LED light as an excitation source
摘要： This work describes the development of a novel method for glucose determination exploiting a photoelectrochemical-assisted batch injection analysis cell designed and constructed with the aid of 3D printer technology. The PEC-BIA cell was coupled to a LED lamp in order to control the incidence of light on the Cu2O/Ni(OH)2/FTO photoelectroactive platform. The electrochemical characteristics of Cu2O/Ni(OH)2/FTO photoelectroactive platform were evaluated by cyclic voltammetry, amperometry, and electrochemical impedance spectroscopy. The PEC-BIA cell presented linear response range, limit of detection based on a signal-to-noise ratio of three, and sensitivity of 1 – 1000 μmol L-1, 0.76 μmol L-1 and 0.578 μA L μmol-1, respectively. The PEC-BIA method presented a mean value of the recovery values of 97.0 % to 102.0 % when it was applied to glucose determination in artificial blood plasma samples which indicates the promising performance of the proposed system to determine glucose.
关键词： Photoelectrochemistry,Visible LED light,Glucose,Batch injection analysis,3D-Printing,Cu2O/Ni(OH)2
更新于2025-09-23 15:21:01
-
Enhanced Photoelectrochemical Water Oxidation from CdTe Photoanodes Annealed with CdCl2
摘要： CdTe absorbs sunlight up to 830 nm and has the potential to promote efficient photoelectrochemical (PEC) water splitting. However, most CdTe photoanodes and CdTe photocathodes show positive and negative photocurrent onset potentials for water oxidation and reduction, respectively, and are thus unable to drive PEC water splitting without external applied biases. In this work, we enhanced the activity of a CdTe photoanode having an internal p-n junction during PEC water oxidation by applying a CdCl2 annealing treatment together with surface modifications. The resulting CdTe photoanode generated photocurrents of 1.8 and 5.4 mA cm-2 at 0.6 and 1.2 VRHE, respectively, with a photoanodic current onset potential of 0.22 VRHE under simulated sunlight (AM 1.5G). The CdCl2 annealing increased the grain sizes in this material and lowered the density of grain boundaries, allowing for more efficient charge separation. Consequently, a two-electrode tandem PEC cell comprising a CdTe-based photoanode and photocathode split water without any external bias at a solar-to-hydrogen conversion efficiency of 0.51% at the beginning of the reaction.
关键词： Photoanode,Overall water splitting,Photoelectrochemistry,p-n junction,CdCl2 treatment
更新于2025-09-23 15:21:01
-
Untangling Photofaradaic and Photocapacitive Effects in Organic Optoelectronic Stimulation Devices
摘要： Light, as a versatile and non-invasive means to elicit a physiological response, offers solutions to problems in basic research as well as in biomedical technologies. The complexity and limitations of optogenetic methods motivate research and development of optoelectronic alternatives. A recently growing subset of approaches relies on organic semiconductors as the active light absorber. Organic semiconductors stand out due to their high optical absorbance coefficients, mechanical flexibility, ability to operate in a wet environment, and potential biocompatibility. They could enable ultrathin and minimally invasive form factors not accessible with traditional inorganic materials. Organic semiconductors, upon photoexcitation in an aqueous medium, can transduce light into (1) photothermal heating, (2) photochemical/photocatalytic redox reactions, (3) photocapacitive charging of electrolytic double layers, and (4) photofaradaic reactions. In realistic conditions, different effects may coexist, and understanding their role in observed physiological phenomena is an area of critical interest. This article serves to evaluate the emerging picture of photofaradaic vs. photocapacitive effects in the context of our group’s research efforts and that of others over the past few years. We present simple experiments which can be used to benchmark organic optoelectronic stimulation devices.
关键词： neurostimulation,photostimulation,bioelectronics,organic electronics,photoelectrochemistry
更新于2025-09-23 15:21:01