II International Symposium on Carbon for Catalysis ABSTRACTS

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MOLECULAR STRUCTURE EFFECT OF CARBONS ON THEIR CATALYTIC
ACTIVITY IN THE ELECTRON AND PROTON TRANSFER REACTIONS
Strelko V.V.
Institute for Sorption and Problems of Endoecology, NAS of Ukraine, Kiev, Ukraine
e-mail: ispe@ispe.kiev.ua
Molecular structure of carbons depends on a number of factors, namely, precursor’s type,
pyrolysis conditions, presence of heteroatoms in the lattice, etc. In turn, the molecular
structure (the chemical nature of matrix) is influences on catalytic activity of carbons in
various types reactions, all other things being equal.
In this presentation the attempt has been done to propose the phenomenological concept
for explaining the mechanism of the influence of N- and O- heteroatoms on the catalytic
activity of carbons in the electron and proton transfer reactions. We start from the state that N-
and O- heteroatoms influence on the energetic parameters of π-conjugation in graphene-like
system.
For the evaluation of individual and combine influence of N- and O-heteroatoms on
carbons catalytic activity in the reactions of electron transfer, the energetic parameters (the
energies of HOMO and LUMO and the value of forbidden zone) of clusters modeling the
active carbons with various amount of N- and O-heteroatoms in different positions have been
calculated using semi-empirical quantum-chemical method AM 1. π –conjugated systems
containing 37 condensed rings have been computed. We consider that clusters with minimal
values of work function (E HOMO) and gap (ΔE) correspond to carbons with maximal
catalytic activity in the electron transfer reactions. That is N- and O-heteroatoms improve
electron-donor function of carbons and reduce value of E HOMO as well as increase the
mobility of carries and reduce value of ΔE.
In accordance with the prognostic data of quantum-chemical calculations we synthesized
N- and O-containing carbons and studied their catalytic activity in the reactions of peroxides
decomposition and H2S oxidation.
Thus active carbons are known as catalysts of oxidation for not only H 2 S but several
other organic (alcohols, amine acids, aldehydes) and inorganic (SO 2 , Fe 2+, Mn 2+ , cyanides
etc.) compounds, we conclude that less values of electron work function in the case of N- and
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