Publications by Artur Braun | EPFL Graph Search

Electronic structure of pristine and Ni-substituted LaFeO3 from near edge x-ray absorption fine structure experiments and first-principles simulations

Xinyu Zhang, Nicola Marzari, Piyush Agrawal, Matteo Cococcioni, Artur Braun, Iurii Timrov, Daniele Passerone

We present a joint theoretical and experimental study of the oxygen K-edge spectra for LaFeO3 and homovalent Ni-substituted LaFeO3 (LaFe0.75Ni0.25O3), using first-principles simulations based on density-functional theory with extended Hubbard functionals a ...

AMER PHYSICAL SOC2020

Molecular Origin and Electrochemical Influence of Capacitive Surface States on Iron Oxide Photoanodes

Michael Graetzel, Yelin Hu, Artur Braun, Florent Alexandre Boudoire

The origin, the nature, and the electronic structure of surface defects causing surface states on metal oxides and their role in solar water splitting have been under scrutiny for several decades. In the present study, the surface of hematite films is trea ...

American Chemical Society2016

The electronic, chemical and electrocatalytic processes and intermediates on iron oxide surfaces during photoelectrochemical water splitting

Michael Graetzel, Yelin Hu, Artur Braun, Florent Alexandre Boudoire

We re-assess experimental soft X-ray absorption spectra of the oxygen K-shell which we recorded operando from iron oxide during photoelectrochemical water splitting in KOH electrolyte. In particular, we refer to recently reported transitional electron hole ...

Elsevier2016

Morphology, structural and optical properties of iron oxide thin film photoanodes in photoelectrochemical cell: Effect of electrochemical oxidation

Yelin Hu, Artur Braun

Hematite (alpha-Fe2O3) is a promising semiconductor as photoanode in solar hydrogen production from photoelectrolysis of water due to its appropriate band gap, low cost and high electrochemical stability in aqueous caustic electrolytes. Operation of such p ...

Elsevier Science Bv2016

Influence of anodization time on the surface modifications on alpha-Fe2O3 photoanode upon anodization

Yelin Hu, Artur Braun

In searching for a suitable semiconductor material for hydrogen production via photoelectrochemical water splitting, alpha-Fe2O3 received significant attention as a promising photoanode due to its band gap (similar to 2.1 eV), good stability, low cost, and ...

Materials Research Society2016

A facile nonpolar organic solution process of a nanostructured hematite photoanode with high efficiency and stability for water splitting

Yelin Hu, Artur Braun

We present a facile nonpolar organic solution synthesis and processing method for water splitting photoanodes based on iron oxide with a relatively low sintering temperature (550 degrees C). The photocurrent of these photoanodes can reach 3.3 mA cm(-2) at ...

Royal Society of Chemistry2016

Biological Components and Bioelectronic Interfaces of Water Splitting Photoelectrodes for Solar Hydrogen Production

Yelin Hu, Artur Braun, Florent Alexandre Boudoire

Artificial photosynthesis (AP) is inspired by photosynthesis in nature. In AP, solar hydrogen can be produced by water splitting in photoelectrochemical cells (PEC). The necessary photoelectrodes are inorganic semiconductors. Light-harvesting proteins and ...

Wiley-V C H Verlag Gmbh2015

Between photocatalysis and photosynthesis: Synchrotron spectroscopy methods on molecules and materials for solar hydrogen generation

Michael Graetzel, Yelin Hu, Artur Braun, Jin Guo

Energy research is to a large extent materials research, encompassing the physics and chemistry of materials, including their synthesis, processing toward components and design toward architectures, allowing for their functionality as energy devices, exten ...

Elsevier2013

Formation of an electron hole doped film in the alpha-Fe2O3 photoanode upon electrochemical oxidation

Michael Graetzel, Artur Braun, Florent Alexandre Boudoire

Solar hydrogen generation by water splitting in photoelectrochemical cells (PEC) is an appealing technology for a future hydrogen economy. Hematite is a prospective photoanode material in this respect because of its visible light conjugated band gap, its c ...

Royal Society of Chemistry2013

A dip coating process for large area silicon-doped high performance hematite photoanodes

Michael Graetzel, Yelin Hu, Artur Braun, Florent Alexandre Boudoire

A facile and low-cost dip-coating process for the deposition of silicon doped hematite films (Si:alpha-Fe2O3) for hydrogen production by solar water splitting in photo-electrochemical cells (PEC) is presented. The precursors include iron nitrate, oleic aci ...

Amer Inst Physics2013

Direct Observation of Two Electron Holes in a Hematite Photoanode during Photoelectrochemical Water Splitting

Michael Graetzel, Kevin Sivula, Artur Braun, Li Zhang, Jin Guo

Visible light active photoelectrodes for hydrogen generation by solar photoelectrochemical water splitting have been under scrutiny for many decades. In particular, the role of electron holes and charge transfer remains controversial. We have investigated ...

American Chemical Society2012

Iron Resonant Photoemission Spectroscopy on Anodized Hematite Points to Electron Hole Doping during Anodization

Michael Graetzel, Philippe Wyss, Kevin Sivula, Qianli Chen, Artur Braun, Li Zhang, Jin Guo

Anodization of a-Fe2O3 (hematite) electrodes in alkaline electrolyte under constant potential conditions the electrode surface in a way that an additional current wave occurs in the cyclic voltammogram. The energy position of this current wave is closely b ...

Wiley-Blackwell2012

Evolution of an Oxygen Near-Edge X-ray Absorption Fine Structure Transition in the Upper Hubbard Band in alpha-Fe2O3 upon Electrochemical Oxidation

Michael Graetzel, Kevin Sivula, Artur Braun

Electrochemical oxidation of hematite (alpha-Fe2O3) nanoparticulate films at 600 mV vs Ag+/AgCl in KOH electrolyte forms a species at the hematite surface which causes a new transition in the upper Hubbard band between the Fe(3d)-O(2p) state region and the ...

American Chemical Society2011