Rhenium-Based Electrocatalysts for Water Splitting.

Due to the contamination and global warming problems, it is necessary to search for alternative environmentally friendly energy sources. In this area, hydrogen is a promising alternative. Hydrogen is even more promising, when it is obtained through water electrolysis operated with renewable energy sources.

Electrochemical water oxidation by simple manganese salts.

Recently, it has been great efforts to synthesize an efficient water-oxidizing catalyst. However, to find the true catalyst in the harsh conditions of the water-oxidation reaction is an open area in science. Herein, we showed that corrosion of some simple manganese salts, MnCO, MnWO, Mn(PO) · 3HO, and Mn(VO) · xHO, under the water-electrolysis conditions at pH = 6.

Water oxidation by simple manganese salts in the presence of cerium(iv) ammonium nitrate: towards a complete picture.

For the first time, using scanning electron microscopy, transmission electron microscopy, X-ray absorption near edge structure and extended X-ray absorption fine structure X-ray diffraction, it is showed that MnCO, MnWO, Mn(PO)·3HO, MnS and Mn(VO)·xHO under the water-oxidation conditions and in the presence of cerium(iv) ammonium nitrate, are converted to Mn oxide without a high-range order. A mechanism is proposed for such conversion and as Mn oxide is an efficient water-oxidizing catalyst, it is thus a candidate as a contributor to the observed catalytic activity.

Proposed mechanisms for water oxidation by Photosystem II and nanosized manganese oxides.

Plants, algae and cyanobacteria capture sunlight, extracting electrons from HO to reduce CO into sugars while releasing O in the oxygenic photosynthetic process. Because of the important role of water oxidation in artificial photosynthesis and many solar fuel systems, understanding the structure and function of this unique biological catalyst forms a requisite research field. Herein the structure of the water-oxidizing complex and its ligand environment are described with reference to the 1.

Nano-sized layered Mn oxides as promising and biomimetic water oxidizing catalysts for water splitting in artificial photosynthetic systems.

One challenge in artificial photosynthetic systems is the development of artificial model compounds to oxidize water. The water-oxidizing complex of Photosystem II which is responsible for biological water oxidation contains a cluster of four Mn ions bridged by five oxygen atoms. Layered Mn oxides as efficient, stable, low cost, environmentally friendly and easy to use, synthesize, and manufacture compounds could be considered as functional and structural models for the site.