15
© Springer Nature Switzerland AG 2020
R. Adzic, N. Marinkovic, Platinum Monolayer Electrocatalysts,
https://doi.org/10.1007/978-3-030-49566-4_2
Chapter 2
Electrocatalytic Reactions
2.1 Effect of Electrode Material: Volcano Plots
Electrocatalysis is the science exploring the rates of electrochemical reactions as a
function of the electrode surface properties. In these heterogeneous reactions, the
electrode does not only accept or supplies electrons (electron transfer), as in simple
redox reactions, but affects the reaction rates interacting with reactants, intermediates, and reaction products. Catalyst remains unchanged upon completion of reaction. The term electrocatalysis, an extension to electrochemistry of the term catalysis
(Greek kata (down) and lyein (to let)), was apparently first used in 1934 [1]. The
beginning of intensive research in this area can be traced back to the early 1960s in
connection with the broadening fuel cell research motivated by high efficiency of
direct energy conversion in those power sources. These include hydrogen, oxygen,
and chlorine evolution, oxygen reduction, oxidation of small organic molecules
suitable for energy conversion (methanol, ethanol, formic acid), and reactions of
organic syntheses.
The role of the electrode material in determining the kinetics of electrode reactions has been the subject of electrocatalysis from the beginning of its definition as
a science. Many electrode reaction rates are a function of the nature of the electrode
surface (see, for example, Ref. [2–6]). A notable example is hydrogen evolution, for
which the exchange current density varies by 11 orders of magnitude. Most studies
of the correlation of kinetics with the nature of the electrode material have been
devoted to the hydrogen evolution reaction (h.e.r.).
Several correlations of the kinetics of the h.e.r. with some factors reflecting the
nature of the electrode materials resulted in the so-called volcano plots, one displaying the linear dependence of exchange current density on work function [6] electrodes with changes in the standard free energy of adsorption of hydrogen. Yeager
[7] analyzed the effects of symmetry factor. A correlation with the work function,
Φ, shows a clear separation between transition and sp metals.
© Springer Nature Switzerland AG 2020
R. Adzic, N. Marinkovic, Platinum Monolayer Electrocatalysts,
https://doi.org/10.1007/978-3-030-49566-4_2
Chapter 2
Electrocatalytic Reactions
2.1 Effect of Electrode Material: Volcano Plots
Electrocatalysis is the science exploring the rates of electrochemical reactions as a
function of the electrode surface properties. In these heterogeneous reactions, the
electrode does not only accept or supplies electrons (electron transfer), as in simple
redox reactions, but affects the reaction rates interacting with reactants, intermediates, and reaction products. Catalyst remains unchanged upon completion of reaction. The term electrocatalysis, an extension to electrochemistry of the term catalysis
(Greek kata (down) and lyein (to let)), was apparently first used in 1934 [1]. The
beginning of intensive research in this area can be traced back to the early 1960s in
connection with the broadening fuel cell research motivated by high efficiency of
direct energy conversion in those power sources. These include hydrogen, oxygen,
and chlorine evolution, oxygen reduction, oxidation of small organic molecules
suitable for energy conversion (methanol, ethanol, formic acid), and reactions of
organic syntheses.
The role of the electrode material in determining the kinetics of electrode reactions has been the subject of electrocatalysis from the beginning of its definition as
a science. Many electrode reaction rates are a function of the nature of the electrode
surface (see, for example, Ref. [2–6]). A notable example is hydrogen evolution, for
which the exchange current density varies by 11 orders of magnitude. Most studies
of the correlation of kinetics with the nature of the electrode material have been
devoted to the hydrogen evolution reaction (h.e.r.).
Several correlations of the kinetics of the h.e.r. with some factors reflecting the
nature of the electrode materials resulted in the so-called volcano plots, one displaying the linear dependence of exchange current density on work function [6] electrodes with changes in the standard free energy of adsorption of hydrogen. Yeager
[7] analyzed the effects of symmetry factor. A correlation with the work function,
Φ, shows a clear separation between transition and sp metals.