Hydrogen electrochemical production from water

Tien HT, Chen JW (1990) Hydrogen production from water by semiconductor septum electrochemical photovoltaic cell using visible light. Int J Hydrogen Energy 15 563-568... 

COORDINATION COMPLEXES AS CATALYSTS FOR THE ELECTROCHEMICAL PRODUCTION OF HYDROGEN OR OXYGEN FROM WATER... 

A recent screening of several hundred possible reactions (Besenbruch et al 2001) has identified two candidate thermochemical cycles for hydrogen production from water (i.e., cycles that enable chemical reactions to take place at high temperatures) with high potential for efficiency and practical applicability to nuclear heat sources. These are the sulfur-iodine (S-I) and calcium-bromine-iron (Ca-Br) cycles. Also, Argonne National Laboratory (ANL) has identified the copper-chlorine (Cu-Cl) thermochemical cycle for this purpose (Doctor et al 2002). A hybrid sulfur-based process that does not require iodine but has a single electrochemical... 

Earlandite structure, 849 Electrical conductivity metal complexes, 133 tetracyanoplatinates anion-deficient salts, 136 Electrical properties metal complexes, 133-154 Electrocatalysis, 28 Electrochemical cells, 1 Electrochemistry, 1-33 hydrogen or oxygen production from water coordination complex catalysts, 532 mineral processing, 831 reduction, 831 Electrodeposi (ion of metals, 1-15 mineral processing difficulty, 831 Electrodes clay modified, 23 ferrocene modified, 20 nation coated, 15 polymers on, 16 polyvinylferrocene coated, 19 poly(4-vinylpyridine) coated, 17 redox centres, 17 Prussian blue modified, 21 surface modified, 15-31 Electrolysis... 

Souza, R. F., PadiUia, J. C., Goncalves, R. S., Souza, M. O., Berthelot, J. R. (2007). Electrochemical hydrogen production from water electrolysis using ionic liquid as electrolytes towards the best device. Journal of Power Sources, 164, 792—798. 

Hydrogen is considered a useful potential fuel for a future hydrogen economy but difficult problems of H2 production and storage need to be solved. Classical electrochemical H2 production from water requires Pt electrodes, so efforts have been made to replace these with cheap metal catalysts. A number of very active Ni catalysts, such as 12.18, have been reported that on electroreduction can undergo protonation to give a nickel hydride 12.18 also incorporates pendant bases that in the protonated form can deliver to a metal-bound hydride to generate H2. ... 

Small amounts of propionitrile and bis(cyanoethyl) ether are formed as by-products. The hydrogen ions are formed from water at the anode and pass to the cathode through a membrane. The catholyte that is continuously recirculated in the cell consists of a mixture of acrylonitrile, water, and a tetraalkylammonium salt the anolyte is recirculated aqueous sulfuric acid. A quantity of catholyte is continuously removed for recovery of adiponitrile and unreacted acrylonitrile the latter is fed back to the catholyte with fresh acrylonitrile. Oxygen that is produced at the anodes is vented and water is added to the circulating anolyte to replace the water that is lost through electrolysis. The operating temperature of the cell is ca 50—60°C. Current densities are 0.25-1.5 A/cm (see Electrochemical processing). 

A photoelectrochemical cell is an electrochemical cell that uses light to carry out a chemical reaction. This type of cell is being considered for the production of hydrogen from water. The silicon electrodes in a photoelectrochemical cell react with water ... 

Adiponitrile is readily hydrogenated catalytically to hexamethylenediamine, which is an important starting material for the prodnction of nylons and other plastics. The electrochemical production of adiponitrile was started in the United States in 1965 at present its volume is about 200 kilotons per year. The reaction occurs at lead or cadmium cathodes with current densities of np to 200 mA/cm in phosphate buffer solutions of pH 8.5 to 9. Salts of tetrabntylammonium [N(C4H9)4] are added to the solution this cation is specihcally adsorbed on the cathode and displaces water molecules from the first solution layer at the snrface. Therefore, the concentration of proton donors is drastically rednced in the reaction zone, and the reaction follows the scheme of (15.36) rather than that of (15.35), which wonld yield propi-onitrile. 

---