Electrocatalysis cathodic hydrogen evolution

Trasatti, S. (1992) Electrocatalysis of hydrogen evolution progress in cathode activation, in Advances in Electrochemical Science and Engineering (eds H. Gerischer and C.W. Tobias), VCH Verlag GmbH, Weinheim. 

The chemistry of electrochemical reaction mechanisms is the most hampered and therefore most in need of catalytic acceleration. Therefore, we understand that electrochemical catalysis does not, in principle, differ much fundamentally and mechanistically from chemical catalysis. In addition, apart from the fact that charge-transfer rates and electrosorption equilibria do depend exponentially on electrode potential—a fact that has no comparable counterpart in chemical heterogeneous catalysis—in many cases electrocatalysis and catalysis of electrochemical and chemical oxidation or reduction processes follow very similar if not the same pathways. For instance as electrochemical hydrogen oxidation and generation is coupled to the chemical splitting of the H2 molecule or its formation from adsorbed hydrogen atoms, respectively, electrocatalysts for cathodic hydrogen evolution—... 

Saturating the electrolyte with iron(lll) hydroxide (e.g., by addition of aqueous solutions of ferric nitrate) and simultaneously adding cobaltous salts leads to in situ formation of a mixed Fe(llI)/Co(ll)/Co(IIl) deposit, which exhibits catalytic activity comparable to that of Fe304 shown by the current voltage curve in Fig. 11. Such mixed oxidic catalyst coatings are composed of very small oxide crystals, which evidently are dissolved upon current interruption due to dissociative oxide dissolution. The transfer of dissolved metal ions to the cathode followed by cathodic deposition of the metal, however, can be completely prohibited, if the potential of the cathode due to optimal electrocatalysis of cathodic hydrogen evolution proceeds with an over-... 

Electrocatalysis of Hydrogen Evolution Progress in Cathode Activation... 

Trasatti, Electrocatalysis of Hydrogen Evolution Progress in Cathode Activation A. Hammou, Solid Oxide Fuel Cells... 

XII. Electrocatalysis in Cathodic Hydrogen Evolution and Nature of Electrode Metal... 

Conway BE, Bai L (1986) Determination of adsorption of OPD H species in the cathodic hydrogen evolution reaction at Pt in relation to electrocatalysis. J Electroanal Chem (Lausanne Switz) 198 149... 

Electrocatalysts for cathodic hydrogen evolution or its oxidation and catalysts for chemical hydrogenation are essentially the same platinum and the transition metals of group 10 of the periodic table. Hence, for catalysis and electrocatalysis the same correlation of catal5dic activity in terms of exchange current density (mA/cm ) and... 

Wendt, H. and Plzak, V. (1990) Electrode kinetics and electrocatalysis of hydrogen and oxygen electrode reactions. 2. Electrocatalysis and electrocatalysts for cathodic evolution and anodic oxidation of hydrogen, in Electrochemical Hydrogen Technologies (ed. H. Wendt), Elsevier, Amsterdam, Chapter 1. 2. 

Only two general reviews [38, 39] entirely devoted to the hydrogen evolution reaction have appeared after the start of the development of cathode activation [40]. In several other cases, hydrogen evolution has been discussed within the general frame of electrocatalysis [4, 41-47] or kinetics of electrode reactions [48, 49]. However, only one of the two reviews mentioned above discusses electrocatalytic aspects with literature coverage up to the late 70 s, when the field of cathode activation was at the beginning of its development. 

Electrocatalysis at metal electrodes in aqueous (1.2) and non-aqueous ( ) solvents, phthalocyanine ( ) and ruthenium ( ) coated carbon, n-type semiconductors (6.7.8),and photocathodes (9,10) have been explored in an effort to develop effective catalysts for the synthesis of reduced products from carbon dioxide. The electrocatalytic and photocatalytic approaches have high faradaic efficiency of carbon dioxide reduction (1,6). but very low current densities. Hence the rate of product formation is low. Increasing current densities to provide meaningful amounts of product, substantially reduces carbon dioxide reduction in favor of hydrogen evolution. This reduction in current efficiency is a difficult problem to surmount in light of the probable electrostatic repulsion of carbon dioxide, or the aqueous bicarbonate ion, from a negatively charged cathode (11,12). 

Research in electrocatalysis was strongly stimulated in the early 1960s by efforts toward the development of various types of fuel cells. Studies were initiated on the various factors influencing the rates not only of hydrogen evolution but also of other reactions, particularly cathodic oxygen reduction and the complete oxidation of simple organic substances ( fuels ) to carbon dioxide. The... 

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