Water oxidation kinetics of nanoporous BiVO4 photoanodes functionalised with nickel/iron oxyhydroxide electrocatalysts

Operando spectroelectrochemical analysis is used to determine the water oxidation reaction kinetics for hematite photoanodes prepared using four different synthetic procedures. Whilst these photoanodes exhibit very different current / voltage performance, their underlying water oxidation kinetics are found to be almost invariant. Lower photoanode performance was found to correlate with the observation of optical signals indicative of charge accumulation in mid-gap oxygen vacancy states, indicating these states do not contribute directly to water oxidation.

Download Full-text

Impact Of Synthesis Route on the Water Oxidation Kinetics of Hematite Photoanodes

10.26434/chemrxiv.12505742 ◽

2020 ◽

Author(s):

Camilo A. Mesa ◽

Ludmilla Steier ◽

Benjamin Moss ◽

Laia Francàs ◽

James E. Thorne ◽

...

Keyword(s):

Oxygen Vacancy ◽

Reaction Kinetics ◽

Water Oxidation ◽

Oxidation Kinetics ◽

Oxidation Reaction ◽

Charge Accumulation ◽

Optical Signals ◽

Current Voltage ◽

Voltage Performance ◽

Kinetics Of

Operando spectroelectrochemical analysis is used to determine the water oxidation reaction kinetics for hematite photoanodes prepared using four different synthetic procedures. Whilst these photoanodes exhibit very different current / voltage performance, their underlying water oxidation kinetics are found to be almost invariant. Lower photoanode performance was found to correlate with the observation of optical signals indicative of charge accumulation in mid-gap oxygen vacancy states, indicating these states do not contribute directly to water oxidation.

Download Full-text

Spectroelectrochemical study of water oxidation on nickel and iron oxyhydroxide electrocatalysts

Nature Communications ◽

10.1038/s41467-019-13061-0 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 20

Author(s):

Laia Francàs ◽

Sacha Corby ◽

Shababa Selim ◽

Dongho Lee ◽

Camilo A. Mesa ◽

...

Keyword(s):

Water Oxidation ◽

Reactive Intermediates ◽

Reaction Rates ◽

Iron Oxyhydroxide ◽

Rate Limiting Step ◽

Limiting Step ◽

Earth Abundant ◽

Fe Oxyhydroxides ◽

Rate Limiting ◽

Kinetics Of

AbstractNi/Fe oxyhydroxides are the best performing Earth-abundant electrocatalysts for water oxidation. However, the origin of their remarkable performance is not well understood. Herein, we employ spectroelectrochemical techniques to analyse the kinetics of water oxidation on a series of Ni/Fe oxyhydroxide films: FeOOH, FeOOHNiOOH, and Ni(Fe)OOH (5% Fe). The concentrations and reaction rates of the oxidised states accumulated during catalysis are determined. Ni(Fe)OOH is found to exhibit the fastest reaction kinetics but accumulates fewer states, resulting in a similar performance to FeOOHNiOOH. The later catalytic onset in FeOOH is attributed to an anodic shift in the accumulation of oxidised states. Rate law analyses reveal that the rate limiting step for each catalyst involves the accumulation of four oxidised states, Ni-centred for Ni(Fe)OOH but Fe-centred for FeOOH and FeOOHNiOOH. We conclude by highlighting the importance of equilibria between these accumulated species and reactive intermediates in determining the activity of these materials.

Download Full-text

Water Oxidation Kinetics of Nanoporous BiVO4 Photoanodes Functionalised with Nickel/iron Oxyhydroxide Electrocatalysts

10.26434/chemrxiv.13295987.v1 ◽

2020 ◽

Author(s):

Laia Francàs ◽

Shababa Selim ◽

Sacha Corby ◽

Dongho Lee ◽

Camilo Mesa ◽

...

Keyword(s):

Water Oxidation ◽

Transient Absorption ◽

Spectroscopic Techniques ◽

Charge Accumulation ◽

Iron Oxyhydroxide ◽

Photoelectrochemical Performance ◽

Absorption Data ◽

Hole Transfer ◽

Nickel Iron ◽

Oxidation Performance

In this work, spectroelectrochemical techniques are employed to analyse the catalytic water oxidation performance of a series of three nickel/iron oxyhydroxide electrocatalysts deposited on FTO and BiVO4, at neutral pH. Similar electrochemical water oxidation performance is observed for each of the FeOOH, Ni(Fe)OOH and FeOOHNiOOH electrocatalysts studied, which is found to result from a balance between degree of charge accumulation and rate of water oxidation. Once added onto BiVO4 photoanodes, a large enhancement in the water oxidation photoelectrochemical performance is observed in comparison to the un-modified BiVO4. To understand the origin of this enhancement, the films were evaluated through time-resolved optical spectroscopic techniques, allowing comparisons between electrochemical and photoelectrochemical water oxidation. For all three catalysts, fast hole transfer from BiVO4 to the catalyst is observed in the transient absorption data. Using operando photoinduced absorption measurements, we find that water oxidation is driven by oxidised states within the catalyst layer, following hole transfer from BiVO4. This charge transfer is correlated with a suppression of recombination losses which result in remarkably enhanced water oxidation performance relative to un-modified BiVO4. Moreover, despite similar electrocatalytic performance of all three electrocatalysts, we show that variations in water oxidation performance observed among the BiVO4/MOOH photoanodes stem from differences in photoelectrochemical and electrochemical charge accumulation in the catalyst layers. Under illumination, the amount of accumulated charge in the catalyst is driven by the injection of photogenerated holes from BiVO4, which is further affected by the recombination loss at the BiVO4/MOOH interface, and thus leads to deviations from their behaviour as standalone electrocatalysts.

Download Full-text

Understanding the role of nickel–iron (oxy)hydroxide (NiFeOOH) electrocatalysts on hematite photoanodes

Sustainable Energy & Fuels ◽

10.1039/d0se01500h ◽

2021 ◽

Author(s):

Jihye Lee ◽

Daye Seo ◽

Sunghwan Won ◽

Taek Dong Chung

Keyword(s):

Surface Charge ◽

Water Oxidation ◽

Oxidation Kinetics ◽

Charge Recombination ◽

Dual Function ◽

Nickel Iron ◽

Anodic Deposition

A NiFeOOH electrocatalyst prepared by photo-assisted anodic deposition on hematite performs a dual function: increasing the water oxidation kinetics and suppressing surface charge recombination.

Download Full-text

Water Oxidation Kinetics of Nanoporous BiVO4 Photoanodes Functionalised with Nickel/iron Oxyhydroxide Electrocatalysts

10.26434/chemrxiv.13295987 ◽

2020 ◽

Author(s):

Laia Francàs ◽

Shababa Selim ◽

Sacha Corby ◽

Dongho Lee ◽

Camilo Mesa ◽

...

Keyword(s):

Water Oxidation ◽

Transient Absorption ◽

Spectroscopic Techniques ◽

Charge Accumulation ◽

Iron Oxyhydroxide ◽

Photoelectrochemical Performance ◽

Absorption Data ◽

Hole Transfer ◽

Nickel Iron ◽

Oxidation Performance

In this work, spectroelectrochemical techniques are employed to analyse the catalytic water oxidation performance of a series of three nickel/iron oxyhydroxide electrocatalysts deposited on FTO and BiVO4, at neutral pH. Similar electrochemical water oxidation performance is observed for each of the FeOOH, Ni(Fe)OOH and FeOOHNiOOH electrocatalysts studied, which is found to result from a balance between degree of charge accumulation and rate of water oxidation. Once added onto BiVO4 photoanodes, a large enhancement in the water oxidation photoelectrochemical performance is observed in comparison to the un-modified BiVO4. To understand the origin of this enhancement, the films were evaluated through time-resolved optical spectroscopic techniques, allowing comparisons between electrochemical and photoelectrochemical water oxidation. For all three catalysts, fast hole transfer from BiVO4 to the catalyst is observed in the transient absorption data. Using operando photoinduced absorption measurements, we find that water oxidation is driven by oxidised states within the catalyst layer, following hole transfer from BiVO4. This charge transfer is correlated with a suppression of recombination losses which result in remarkably enhanced water oxidation performance relative to un-modified BiVO4. Moreover, despite similar electrocatalytic performance of all three electrocatalysts, we show that variations in water oxidation performance observed among the BiVO4/MOOH photoanodes stem from differences in photoelectrochemical and electrochemical charge accumulation in the catalyst layers. Under illumination, the amount of accumulated charge in the catalyst is driven by the injection of photogenerated holes from BiVO4, which is further affected by the recombination loss at the BiVO4/MOOH interface, and thus leads to deviations from their behaviour as standalone electrocatalysts.

Download Full-text

A new method for studying activity and reaction kinetics of photocatalytic water oxidation systems using a bubbling reactor

Chemical Engineering Journal ◽

10.1016/j.cej.2013.08.094 ◽

2014 ◽

Vol 238 ◽

pp. 17-26 ◽

Cited By ~ 15

Author(s):

Simelys Hernández ◽

Samir Bensaid ◽

Marco Armandi ◽

Adriano Sacco ◽

Angelica Chiodoni ◽

...

Keyword(s):

Reaction Kinetics ◽

Water Oxidation ◽

New Method ◽

Kinetics Of

Download Full-text

An exceptionally stable octacobalt-cluster-based metal–organic framework for enhanced water oxidation catalysis

Chemical Science ◽

10.1039/c9sc03224j ◽

2019 ◽

Vol 10 (42) ◽

pp. 9859-9864 ◽

Cited By ~ 6

Author(s):

Ning-Yu Huang ◽

Jian-Qiang Shen ◽

Zi-Ming Ye ◽

Wei-Xiong Zhang ◽

Pei-Qin Liao ◽

...

Keyword(s):

Reaction Kinetics ◽

Adsorption Energy ◽

Water Oxidation ◽

Metal Organic Framework ◽

Oxidation Catalysis ◽

Cobalt Ions ◽

Water Oxidation Catalysis ◽

Metal Organic ◽

Kinetics Of ◽

Organic Framework

The site, capping four coplanar cobalt ions, has a near-optimal OH− adsorption energy, which is beneficial to accelerate the reaction kinetics of water oxidation catalysis.

Download Full-text