Publications de Florian Le Formal

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

Kevin Sivula, Florian Le Formal, Nestor Guijarro Carratala, 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

Establishing Stability in Organic Semiconductor Photocathodes for Solar Hydrogen Production

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

Insights into the interfacial carrier behaviour of copper ferrite ( CuFe2O4) photoanodes for solar water oxidation

Kevin Sivula, Florian Le Formal, Nestor Guijarro Carratala, Liang Yao, Yongpeng Liu, Florent Alexandre Boudoire

Designing efficient yet robust photoanodes for water oxidation stands out as a major bottleneck in the realization of a feasible photoelectrochemical tandem cell for solar water splitting. Spinel copper ferrite (CuFe2O4) has been recently reported as a pot ...

Royal Society of Chemistry2019

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

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

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

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

Florian Le Formal, Nestor Guijarro Carratala, 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

Spinel Structural Disorder Influences Solar-Water-Splitting Performance of ZnFe2 O4 Nanorod Photoanodes

Kevin Sivula, Florian Le Formal, Nestor Guijarro Carratala, Yongpeng Liu, Rebekah Anne Wells, Xiaodi Zhu, Chen Gao

Wiley2018

Iron-Rich Natural Mineral Gibeon Meteorite Catalyzed N -formylation of Amines using CO2 as the C1 Source

Paul Joseph Dyson, Arnaud Magrez, Kevin Sivula, Florian Le Formal, Ismail Akçok, Aswin Gopakumar

2018

Evaluating spinel ferrites MFe2O4 (M = Cu, Mg, Zn) as photoanodes for solar water oxidation: prospects and limitations

Kevin Sivula, Florian Le Formal, Pauline Bornoz, Xavier Adrian Jeanbourquin, Xiaoyun Yu, Mathieu Steven Prévot, Nestor Guijarro Carratala

2018

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

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

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

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

Florian Le Formal, Min Ling, Yimeng Ma

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

Spectroelectrochemical analysis of the mechanism of (photo)electrochemical hydrogen evolution at a catalytic interface

Michael Graetzel, Florian Le Formal, Stanley David Tilley, Matthew Thomas Mayer

Multi-electron heterogeneous catalysis is a pivotal element in the ( photo) electrochemical generation of solar fuels. However, mechanistic studies of these systems are difficult to elucidate by means of electrochemical methods alone. Here we report a spec ...

Springer Nature2017

Kinetics of Photoelectrochemical Oxidation of Methanol on Hematite Photoanodes

Michael Graetzel, Florian Le Formal, Matthew Thomas Mayer, Yimeng Ma

The kinetics of photoelectrochemical (PEC) oxidation of methanol, as a model organic substrate, on alpha-Fe2O3 photoanodes are studied using photoinduced absorption spectroscopy and transient photocurrent measurements. Methanol is oxidized on alpha-Fe2O3 t ...

American Chemical Society2017

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

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

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

Evaluating Charge Carrier Transport and Surface States in CuFeO

Kevin Sivula, Florian Le Formal, Xavier Adrian Jeanbourquin, Wiktor Stefan Bourée, Mathieu Steven Prévot, Nestor Guijarro Carratala

Interest in delafossite (CuFeO2) as a candidate p-type photocathode for photoelectrochemical (PEC) solar fuel production has recently been increasing, mainly due to its excellent stability in aqueous environments and favorable light absorption properties. ...

American Chemical Society2017

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

Florian Le Formal, Yimeng Ma

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

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

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

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

A Gibeon meteorite yields a high-performance water oxidation electrocatalyst

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

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

Robust Hierarchically Structured Biphasic Ambipolar Oxide Photoelectrodes for Light-Driven Chemical Regulation and Switchable Logic Applications

Kevin Sivula, Florian Le Formal, Xavier Adrian Jeanbourquin, Wiktor Stefan Bourée, Mathieu Steven Prévot, Nestor Guijarro Carratala

Tunable ambipolar photoelectrochemical behavior emerges from microdomains of nanostructured p-type CuFeO2 and n-type Fe2O3 that arise from a single facile solution-processed thin fi lm. The switchable operation of this system is controlled by chemical, opt ...

Wiley-Blackwell2016

Artificial Photosynthesis with Semiconductor-Liquid Junctions

Kevin Sivula, Florian Le Formal, Nestor Guijarro Carratala

Given the urgent need to develop a sustainable, carbon neutral energy storage system on a global scale, intense efforts are currently underway to advance the field of artificial photosynthesis: i.e. solar fuel engineering. In this review we give an overvie ...

Schweizerische Chemische Gesellschaft2015

Efficient suppression of back electron/hole recombination in cobalt phosphate surface-modified undoped bismuth vanadate photoanodes

Florian Le Formal, Yimeng Ma

In this paper, we compared for the first time the dynamics of photogenerated holes in BiVO4 photoanodes with and without CoPi surface modification, employing transient absorption and photocurrent measurements on microsecond to second timescales. CoPi surfa ...

Royal Society of Chemistry2015