Use of the Bubbling Reactor with the $${\mathbf{Ru(bpy)}}_{\mathbf{3}}^{\mathbf{2+}} {\mathbf{/S}}_{\mathbf{2}} {\mathbf{O}}_{\mathbf{8}} ^{\mathbf{2 - }}$$ Photosystem for Measuring the Rate of Water Oxidation as Promoted by Different Manganese Oxides

Author(s):  
Carminna Ottone ◽  
Simelys Hernández ◽  
Marco Armandi ◽  
Barbara Bonelli
2013 ◽  
Vol 110 (22) ◽  
pp. 8801-8806 ◽  
Author(s):  
N. Birkner ◽  
S. Nayeri ◽  
B. Pashaei ◽  
M. M. Najafpour ◽  
W. H. Casey ◽  
...  

ChemSusChem ◽  
2014 ◽  
Vol 7 (8) ◽  
pp. 2202-2211 ◽  
Author(s):  
Prashanth W. Menezes ◽  
Arindam Indra ◽  
Patrick Littlewood ◽  
Michael Schwarze ◽  
Caren Göbel ◽  
...  

2012 ◽  
Vol 9 (75) ◽  
pp. 2383-2395 ◽  
Author(s):  
Mohammad Mahdi Najafpour ◽  
Fahimeh Rahimi ◽  
Eva-Mari Aro ◽  
Choon-Hwan Lee ◽  
Suleyman I. Allakhverdiev

There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese–calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups.


2014 ◽  
Vol 7 (7) ◽  
pp. 2203 ◽  
Author(s):  
M. Wiechen ◽  
M. M. Najafpour ◽  
S. I. Allakhverdiev ◽  
L. Spiccia

2020 ◽  
Vol 234 (5) ◽  
pp. 925-978 ◽  
Author(s):  
Jens Melder ◽  
Peter Bogdanoff ◽  
Ivelina Zaharieva ◽  
Sebastian Fiechter ◽  
Holger Dau ◽  
...  

AbstractThe efficient catalysis of the four-electron oxidation of water to molecular oxygen is a central challenge for the development of devices for the production of solar fuels. This is equally true for artificial leaf-type structures and electrolyzer systems. Inspired by the oxygen evolving complex of Photosystem II, the biological catalyst for this reaction, scientists around the globe have investigated the possibility to use manganese oxides (“MnOx”) for this task. This perspective article will look at selected examples from the last about 10 years of research in this field. At first, three aspects are addressed in detail which have emerged as crucial for the development of efficient electrocatalysts for the anodic oxygen evolution reaction (OER): (1) the structure and composition of the “MnOx” is of central importance for catalytic performance and it seems that amorphous, MnIII/IV oxides with layered or tunnelled structures are especially good choices; (2) the type of support material (e.g. conducting oxides or nanostructured carbon) as well as the methods used to immobilize the MnOx catalysts on them greatly influence OER overpotentials, current densities and long-term stabilities of the electrodes and (3) when operating MnOx-based water-oxidizing anodes in electrolyzers, it has often been observed that the electrocatalytic performance is also largely dependent on the electrolyte’s composition and pH and that a number of equilibria accompany the catalytic process, resulting in “adaptive changes” of the MnOx material over time. Overall, it thus has become clear over the last years that efficient and stable water-oxidation electrolysis by manganese oxides can only be achieved if at least four parameters are optimized in combination: the oxide catalyst itself, the immobilization method, the catalyst support and last but not least the composition of the electrolyte. Furthermore, these parameters are not only important for the electrode optimization process alone but must also be considered if different electrode types are to be compared with each other or with literature values from literature. Because, as without their consideration it is almost impossible to draw the right scientific conclusions. On the other hand, it currently seems unlikely that even carefully optimized MnOx anodes will ever reach the superb OER rates observed for iridium, ruthenium or nickel-iron oxide anodes in acidic or alkaline solutions, respectively. So at the end of the article, two fundamental questions will be addressed: (1) are there technical applications where MnOx materials could actually be the first choice as OER electrocatalysts? and (2) do the results from the last decade of intensive research in this field help to solve a puzzle already formulated in 2008: “Why did nature choose manganese to make oxygen?”.


2017 ◽  
Vol 1 (4) ◽  
pp. 780-788 ◽  
Author(s):  
Suoyuan Lian ◽  
Michelle P. Browne ◽  
Carlota Domínguez ◽  
Serban N. Stamatin ◽  
Hugo Nolan ◽  
...  

Solvothermally synthesised MnCO3 leads to template-free formation of highly porous, defect-rich MnO2 with high activity in water oxidation.


2015 ◽  
Vol 39 (4) ◽  
pp. 2547-2550 ◽  
Author(s):  
Mohammad Mahdi Najafpour ◽  
Maryam Khoshkam ◽  
Davood Jafarian Sedigh ◽  
Ali Zahraei ◽  
Mohsen Kompany-Zareh

We used multivariate chemometrics methods to analyze the concentration profiles of cerium(iv) ammonium nitrate and MnO4−during the water oxidation reaction.


2017 ◽  
Vol 1858 (2) ◽  
pp. 156-174 ◽  
Author(s):  
Mohamad Mahdi Najafpour ◽  
Sima Heidari ◽  
S. Esmael Balaghi ◽  
Małgorzata Hołyńska ◽  
Moayad Hossaini Sadr ◽  
...  

2015 ◽  
Vol 137 (26) ◽  
pp. 8384-8387 ◽  
Author(s):  
Ravi Pokhrel ◽  
McKenna K. Goetz ◽  
Sarah E. Shaner ◽  
Xiaoxia Wu ◽  
Shannon S. Stahl

2014 ◽  
Vol 16 (24) ◽  
pp. 11965 ◽  
Author(s):  
Denys Shevchenko ◽  
Magnus F. Anderlund ◽  
Stenbjörn Styring ◽  
Holger Dau ◽  
Ivelina Zaharieva ◽  
...  

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