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Florian Le Formal

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Related publications (38)

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Nanocrystalline Boron-Doped Diamond as a Corrosion-Resistant Anode for Water Oxidation via Si Photoelectrodes

Kevin Sivula, Jun Ho Yum, Ladislav Kavan, Florian Le Formal

Due to its high sensitivity to corrosion, the use of Si in direct photoelectrochemical (PEC) water-splitting systems that convert solar energy into chemical fuels has been greatly limited. Therefore, the development of low-cost materials resistant to corro ...

AMER CHEMICAL SOC2018

On the Morphology and Interfaces of Nanostructured Hematite Photoanodes for Solar-Driven Water Splitting

Florian Le Formal

A sustainable route to store the energy provided by the Sun, is to directly convert sunlight into molecular hydrogen using a semiconductor performing water photolysis. Hematite (α-Fe2O3) is promising for this application due to its ample abundance, chemica ...

EPFL2011

Photoelectrochemical Water Splitting with Mesoporous Hematite Prepared by a Solution-Based Colloidal Approach

Michael Graetzel, Kevin Sivula, Florian Le Formal

Sustainable hydrogen production through photoelectrochemical water splitting using hematite (alpha-Fe2O3) is a promising approach for the chemical storage of solar energy, but is complicated by the material's nonoptimal optoelectronic properties. Nanostruc ...

American Chemical Society2010

Back Electron-Hole Recombination in Hematite Photoanodes for Water Splitting

Michael Graetzel, Florian Le Formal, Stanley David Tilley, Maurin Cornuz

The kinetic competition between electron-hole recombination and water oxidation is a key consideration for the development of efficient photoanodes for solar driven water splitting. In this study, we employed three complementary techniques, transient absor ...

American Chemical Society2014

Controlling Photoactivity in Ultrathin Hematite Films for Solar Water-Splitting

Michael Graetzel, Kevin Sivula, Florian Le Formal

A promising route to increase the performance of hematite (alpha-Fe2O3) photoelectrodes for solar hydrogen production through water-splitting is to use an extremely thin layer of this visible light absorber on a nanostructured scaffold. However, the typica ...

Wiley-Blackwell2010

WO3-Fe2O3 Photoanodes for Water Splitting: A Host Scaffold, Guest Absorber Approach

Michael Graetzel, Kevin Sivula, Florian Le Formal

Solar hydrogen production via watersplitting with hematite (Fe2O3) has been limited by poor light absorption and a small hole diffusion length. These drawbacks can be overcome by using a high-surface-area host to support a thin layer of hematite-allowing p ...

2009

Hematite Photoanodes for Solar Water Splitting: A Detailed Spectroelectrochemical Analysis on the pH-Dependent Performance

Nestor Guijarro Carratala, Florian Le Formal, Yongpeng Liu, Florent Alexandre Boudoire

The effect of the electrolyte pH on the performance of metal oxide photoanodes for solar water oxidation has not been fully resolved, and contrasting views have been presented in recent reports. Herein, a comprehensive set of spectroelectrochemical techniq ...

AMER CHEMICAL SOC2019

Challenges towards Economic Fuel Generation from Renewable Ellectricity: The Heed for Efficient Electro-Catalysis

Kevin Sivula, Florian Le Formal, Mathieu Steven Prévot, Wiktor Stefan Bourée

Utilizing renewable sources of energy is very attractive to provide the growing population on earth in the future but demands the development of efficient storage to mitigate their intermittent nature. Chemical storage, with energy stored in the bonds of c ...

Swiss Chemical Soc2015

Multi-walled carbon nanotubes functionalized by carboxylic groups: Activation of TiO2 (anatase) and phosphate olivines (LiMnPO4; LiFePO4) for electrochemical Li-storage

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ladislav Kavan, Florian Le Formal

Multi-walled carbon nanotubes functionalized by carboxylic groups, exhibit better affinity towards TiO2 (P90, Degussa) as compared to that of pristine nanotubes. Also the electrochemical performance of TiO2 is improved by nanotube networking, but the Li-st ...

Elsevier2010

Water Oxidation Kinetics of Accumulated Holes on the Surface of a TiO2 Photoanode: A Rate Law Analysis

Florian Le Formal

It has been more than 40 years since Fujishima and Honda demonstrated water splitting using TiO2, yet there is still no clear mechanism by which surface holes on TiO2 oxidize water. In this paper, we use a range of complementary techniques to study this re ...

Amer Chemical Soc2017

A Gibeon meteorite yields a high-performance water oxidation electrocatalyst

Paul Joseph Dyson, Arnaud Magrez, Kevin Sivula, Nestor Guijarro Carratala, Florian Le Formal, Mathieu Steven Prévot, Aswin Gopakumar, Wiktor Stefan Bourée

Examining the electrocatalytic performance of naturally-occurring metallic minerals is of interest for energy conversion applications given their unique atomic composition and formation history. Herein, we report the electrocatalytic function of an iron-ba ...

2016

Photoinduced Absorption Spectroscopy of CoPi on BiVO4: The Function of CoPi during Water Oxidation

Florian Le Formal

This paper employs photoinduced absorption and electrochemical techniques to analyze the charge carrier dynamics that drive photoelectrochemical water oxidation on bismuth vanadate (BiVO4), both with and without cobalt phosphate (CoPi) co-catalyst. These r ...

Wiley-V C H Verlag Gmbh2016

CuInGaS2 photocathodes treated with SbX3 (X = Cl, I): the effect of the halide on solar water splitting performance

Kevin Sivula, Nestor Guijarro Carratala, Florian Le Formal, Xavier Adrian Jeanbourquin, Xiaoyun Yu, Mathieu Steven Prévot, Melissa Catherine Olson, Pauline Bornoz, Wiktor Stefan Bourée

The realization of photoelectrochemical tandem cells for efficient solar-to-hydrogen energy conversion is currently impeded by the lack of inexpensive, stable, and efficient photocathodes. The family of sulfide chalcopyrites (CuInxGa1-xS2) has recently dem ...

Iop Publishing Ltd2017

Rate Law Analysis of Water Oxidation on a Hematite Surface

Michael Graetzel, Florian Le Formal, Stanley David Tilley

Water oxidation is a key chemical reaction, central to both biological photosynthesis and artificial solar fuel synthesis strategies. Despite recent progress on the structure of the natural catalytic site, and on inorganic catalyst function, determining th ...

American Chemical Society2015

Examining architectures of photoanode-photovoltaic tandem cells for solar water splitting

Michael Graetzel, Kevin Sivula, Jun Ho Yum, Florian Le Formal, Maurin Cornuz, Jérémie Minh-Châu Brillet

Given the limitations of the materials available for photoelectrochemical water splitting, a multiphoton (tandem) approach is required to convert solar energy into hydrogen efficiently and durably. Here we investigate a promising system consisting of a hem ...

Cambridge University Press2010

Establishing Stability in Organic Semiconductor Photocathodes for Solar Hydrogen Production

Kevin Sivula, Jun Ho Yum, Liang Yao, Nestor Guijarro Carratala, Florian Le Formal, Yongpeng Liu, Florent Alexandre Boudoire, Muhammad Aiman Bin Rahmanudin Hamdan, Arvindh Sekar, Rebekah Anne Wells, Han-Hee Cho

As organic semiconductors attract increasing attention to application in the fields of bioelectronics and artificial photosynthesis, understanding the factors that determine their robust operation in direct contact with aqueous electrolytes becomes a criti ...

AMER CHEMICAL SOC2020

A Bottom-Up Approach toward All-Solution-Processed High-Efficiency Cu(In,Ga)S

Kevin Sivula, Nestor Guijarro Carratala, Florian Le Formal, Xavier Adrian Jeanbourquin, Xiaoyun Yu, Mathieu Steven Prévot, Melissa Catherine Olson, Pauline Bornoz, Wiktor Stefan Bourée

The development of solution-processable routes to prepare efficient photoelectrodes for water splitting is highly desirable to reduce manufacturing costs. Recently, sulfide chalcopyrites (Cu(In,Ga)S-2) have attracted attention as photocathodes for hydrogen ...

Wiley-VCH Verlag Berlin2016

Spray Synthesis of CuFeO2 Photocathodes and In-Operando Assessment of Charge Carrier Recombination

Kevin Sivula, Nestor Guijarro Carratala, Florian Le Formal, Yongpeng Liu, Florent Alexandre Boudoire, Charles Roger Jean Lhermitte

Semiconducting delafossite-phase CuFeO2 is a promising photocathode material for solar-driven hydrogen production given its suitable energy levels and established robustness for photoelectrochemical water reduction. Nevertheless, reported methods for prepa ...

AMER CHEMICAL SOC2021

Passivating surface states on water splitting hematite photoanodes with alumina overlayers

Michael Graetzel, Kevin Sivula, Thomas Moehl, Florian Le Formal, Nicolas Tétreault, Maurin Cornuz

Hematite is a promising material for inexpensive solar energy conversion via water splitting but has been limited by the large overpotential (0.5-0.6 V) that must be applied to afford high water oxidation photocurrent. This has conventionally been addresse ...

2011

Lead Halide Perovskite Quantum Dots to Enhance the Power Conversion Efficiency of Organic Solar Cells

Kevin Sivula, Jun Ho Yum, Liang Yao, Nestor Guijarro Carratala, Florian Le Formal, Yongpeng Liu, Rebekah Anne Wells, Han-Hee Cho, Barbara Alexandra Primera Darwich, Lucie Navratilova

The facile synthesis, solution-processability, and outstanding optoelectronic properties of emerging colloidal lead halide perovskite quantum dots (LHP QDs) makes them ideal candidates for scalable and inexpensive optoelectronic applications, including pho ...

Wiley-VCH Verlag GmbH2019