A5075451221- Advanced Photocatalysis Techniques
- Copper-based nanomaterials and applications
- Electronic and Structural Properties of Oxides
- Gas Sensing Nanomaterials and Sensors
- Electrocatalysts for Energy Conversion
- Transition Metal Oxide Nanomaterials
- Iron oxide chemistry and applications
- Catalytic Processes in Materials Science
- Ga2O3 and related materials
- TiO2 Photocatalysis and Solar Cells
- Semiconductor materials and devices
- ZnO doping and properties
- Chalcogenide Semiconductor Thin Films
- Hybrid Renewable Energy Systems
- Quantum Dots Synthesis And Properties
- Advanced battery technologies research
- Electron and X-Ray Spectroscopy Techniques
- Electrochemical Analysis and Applications
- Perovskite Materials and Applications
- Metal-Organic Frameworks: Synthesis and Applications
- Luminescence Properties of Advanced Materials
- Advancements in Battery Materials
- Solar-Powered Water Purification Methods
- Covalent Organic Framework Applications
- CO2 Reduction Techniques and Catalysts
Helmholtz-Zentrum Berlin für Materialien und Energie
2016-2025
Technische Universität Berlin
2016-2025
Robert Bosch (Germany)
2023
Solar Fuels Institute
2014-2020
Laboratoire de Chimie Moléculaire et Thioorganique
2019
Delft University of Technology
2005-2015
Leiden University
2013-2014
The direct conversion of solar energy into hydrogen represents an attractive but challenging alternative for photo-voltaic cells. Several metal oxide semiconductors are able to split water and oxygen upon illumination, the efficiencies still (too) low. operating principles photo-electrochemical devices splitting, their main bottlenecks, various device concepts will be reviewed. Materials properties play a key role, advantages pitfalls use interfacial layers dopants discussed. Special...
We unravel for the first time origin of poor carrier transport properties BiVO4, a promising metal oxide photoanode solar water splitting. Time-resolved microwave conductivity (TRMC) measurements reveal an (extrapolated) mobility ∼4 × 10–2 cm2 V–1 s–1 undoped BiVO4 under ∼1 sun illumination conditions, which is unusually low material. The compensated by unexpectedly long lifetime 40 ns. This translates to relatively diffusion length 70 nm, consistent with high quantum efficiencies reported...
BiVO4 is considered to be a promising photoanode material for solar water splitting applications. Its performance limited by two main factors: slow oxidation kinetics and poor charge separation. We confirm recent reports that cobalt phosphate (Co-Pi) an efficient catalyst report AM1.5 photocurrent of 1.7 mA/cm2 at 1.23 V vs RHE 100 nm spray-deposited, compact, undoped films with optimized Co-Pi film thickness 30 nm. The separation these depends strongly on light intensity, ranging from 90%...
The main role of a cobalt phosphate catalyst on BiVO<sub>4</sub> is to improve the photocurrent by passivating surface and suppressing recombination.
The development of new energy materials that can be utilized to make renewable and clean fuels from abundant easily accessible resources is among the most challenging demanding tasks in science today. Solar-powered catalytic water-splitting processes exploited as a source electrons protons fuels, such hydrogen, sequestration CO2 its conversion into low-carbon carriers. Recently, there have been tremendous efforts build up stand-alone solar-to-fuel device, "artificial leaf", using light water...
BiVO4 has received much recent interest as a promising photocatalyst for oxygen evolution from water, but little is known about the factors that limit its performance photoanode. In this article, we report on highly efficient and reproducible photoanodes prepared by new spray pyrolysis recipe. For undoped films deposited transparent conducting substrate (F-doped SnO2, FTO), electron transport charge collection at back-contact were found to photoresponse. Electron could be greatly enhanced...
Abstract Bismuth vanadate (BiVO 4 ) thin film photoanodes for light‐induced water oxidation are deposited by a low‐cost and scalable spray pyrolysis method. The resulting films of high quality, as indicated an internal quantum efficiency close to 100 % between 360 450 nm. However, its performance under AM1.5 illumination is limited slow kinetics. This can be addressed using cobalt phosphate (Co‐Pi) co‐catalyst. Electrodeposition 30 nm Co‐Pi catalyst on the surface BiVO increases from ≈30...
CuBi2O4 is a multinary p-type semiconductor that has recently been identified as promising photocathode material for photoelectrochemical (PEC) water splitting. It an optimal bandgap energy (∼1.8 eV) and exceptionally positive photocurrent onset potential (>1 V vs RHE), making it ideal candidate the top absorber in dual PEC device. However, photocathodes made from have not yet demonstrated high photoconversion efficiencies, factors limit efficiency fully identified. In this work we...
Abstract Metal oxide semiconductors are promising photoelectrode materials for solar water splitting due to their robustness in aqueous solutions and low cost. Yet, solar-to-hydrogen conversion efficiencies still not high enough practical applications. Here we present a strategy enhance the efficiency of metal oxides, hetero-type dual photoelectrodes, which two photoanodes different bandgaps connected parallel extended light harvesting. Thus, photoelectrochemical device made modified BiVO 4...
Several application fields can benefit from solar-hydrogen technologies <italic>via</italic> specific short-term and long-term pathways.
Abstract Covalent organic frameworks (COFs) have emerged as an important class of semiconductors and photocatalysts for the hydrogen evolution reaction (HER)from water. To optimize their photocatalytic activity, typically moieties constituting are considered most suitable combinations them searched for. However, effect covalent linkage between these on performance has rarely been studied. Herein, we demonstrate that donor‐acceptor (D‐A) type imine‐linked COFs can produce with a rate high...
Conventional TiO(2)-based photocatalysts oxidize NO(x) to nitrate species, which do not spontaneously desorb and therefore deactivate the catalyst. We show that selectivity of this reaction can be changed by creating a large concentration oxygen vacancies in TiO(2) nanoparticles through thermal reduction reducing atmosphere. This results photoreduction nitric oxide (NO) N(2) O(2), species at room temperature. The activity greatly enhanced doping with Fe(3+), an acceptor-type dopant...
Through examination of the optoelectronic and photoelectrochemical properties BiVO4 Cu2O photoelectrodes, we evaluate feasibility a BiVO4/Cu2O photoanode/photocathode tandem cell for overall unassisted solar water splitting. Using state-of-the-art photoelectrodes identify current-matching conditions by altering photoanode active layer thickness. By further employing oxidation reduction catalysts (Co-Pi RuOx, respectively) together with an operating point analysis, show that photocurrent...
A new strategy of using forward gradient self-doping to improve the charge separation efficiency in metal oxide photoelectrodes is proposed. Gradient self-doped CuBi2O4 photocathodes are prepared with and reverse gradients copper vacancies a two-step, diffusion-assisted spray pyrolysis process. Decreasing Cu/Bi ratio introduces Cu that increase carrier (hole) concentration lowers Fermi level, as evidenced by shift flat band toward more positive potentials. Thus, leads an internal electric...
Abstract Nickel‐molybdenum (NiMo) alloys can be a possible alternative to platinum as hydrogen evolution reaction (HER) catalysts because of the superior HER activity. However, activity and pH‐dependent kinetics are not currently fully understood. Herein, we present study mechanisms NiMo in alkaline, near‐neutral acidic media by combining voltammetry measurements with electrochemical impedance spectroscopy microkinetic model. The results indicate that, compared Ni, has significantly higher...
An "ink" (cyanamide) infiltrated anodic aluminum oxide (AAO) stamp is found capable of printing carbon nitride films featuring regular microstructures the onto substrates via in situ "chemical vapor deposition". A photocurrent density 30.2 μA cm(-2 --) at 1.23 VRHE achieved for a film on conductive substrate, which so far highest value pure based photoelectrochemical devices.
Abstract Addressing the intrinsic charge transport limitation of metal oxides has been significance for pursuing viable PEC water splitting photoelectrodes. Growing a photoelectrode with conductive nanoobjects embedded in matrix is promising enhanced but remains challenge technically. We herein show strategy embedding laser generated nanocrystals BiVO 4 photoanode matrix, which achieves photocurrent densities up to 5.15 mA cm −2 at 1.23 V RHE (from original 4.01 ) single configuration, and...
When new covalent organic frameworks (COFs) are designed, the main efforts typically focused on selecting specific building blocks with certain geometries and properties to control structure function of final COFs. The nature linkage (imine, boroxine, vinyl, etc.) between these naturally also defines their properties. However, besides type, orientation, i.e., constitutional isomerism linkages, has rarely been considered so far as an essential aspect. In this work, three pairs...
Understanding the oxygen evolution reaction (OER) activity and stability of NiFe-based materials is important for achieving low-cost highly efficient electrocatalysts practical water splitting. Here, we report roles Ni Fe on OER metallic NiFe pure thin films in alkaline media. Our results support that Ni(OH)2/NiOOH does not contribute to directly, but it serves as an ideal host incorporation, which essential obtaining high activity. Furthermore, availability electrolyte found be necessary...
Abstract Metal oxides are promising for photoelectrochemical (PEC) water splitting due to their robustness and low cost. However, poor charge carrier transport impedes activity, particularly at low-bias voltage. Here we demonstrate the unusual effectiveness of phosphorus doping into bismuth vanadate (BiVO 4 ) photoanode efficient PEC splitting. The resulting BiVO shows a separation efficiency 80% 99% potentials as 0.6 1.0 V RHE , respectively. Theoretical simulation experimental analysis...
Abstract Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last five decades, significant effort has been dedicated towards increasing performance of solar fuels generating devices. Specifically, to hydrogen efficiency photoelectrochemical cells progressed steadily its fundamental limit, and faradaic valuable products in CO 2 reduction systems increased dramatically. However, there are still numerous scientific engineering challenges that must be...