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European Journal of Applied Sciences – Vol. 10, No. 1

Publication Date: February 25, 2022

DOI:10.14738/aivp.101.11821. Jin, J. M. (2022). Heterogeneous Catalysis Mechanism: A Comparison of Two Heterogeneous Catalysis Mechanisms. European

Journal of Applied Sciences, 10(1). 598-607.

Services for Science and Education – United Kingdom

Heterogeneous Catalysis Mechanism: A Comparison of Two

Heterogeneous Catalysis Mechanisms

Jia Min Jin

Shanghai Research Institute of Materials, Shanghai, China

ABSTRACT

In this paper, two heterogeneous catalysis mechanisms are introduced, namely:

Chemical Reaction Mode Cyclic Catalysis Mechanism-CRM and Electron Cyclic

Donate-Accept Catalysis Mechanism-ECDAM or Electron Orbital Deformation- Recovery Cyclic Catalysis Mechanism -EODRM . Some difficulties encountered by

CRM are listed. The author clearly points out that the CRM is not credible. This false

theory has misled us for more than 100 years. About ECDAM, the article also gives a

brief description. The main point of ECDAM is that the catalysis phenomenon are

physical rather than chemical phenomenon. The catalysts do not participate in

chemical reactions, It's just contact,electron cyclic donate-accept or electron

orbital deformation-recovery cycle.. The theory contains three viewpoints: 1, There

is a boundary between the catalyst and the poison. 2, The active of the catalyst or

the degree of toxicity of the poison is closely related to the electronegative value of

the catalyst or poison. 3, The active of catalyst is closely related to the chemical state

of the catalyst. The selectivity of catalyst is also related to electronegative or energy

level. According to ECDAM, The author considers that there are several problems

worth studying in production and scientific research. such as: alumina is a poison

in the Fe ammonia synthesis catalyst. The Cordierite (2MgO·2Al2O3·5SiO2 ) ceramic

honeycomb support is also a poison in automotive exhaust purification catalyst

.The Cordierite ceramic honeycomb is retardant in wall flow filter for diesel

vehicles. Activated carbon is a poison in the Ruthenium catalyst for ammonia

synthesis. Alumina and activated carbon all are a poison to noble metal catalysts,

and so on.

Keywords: Heterogeneous catalysis Catalysis Mechanism CRM EODRM

INTRODUCTION

Because the chemical and physical properties of solid catalysts affect the catalytic active of

catalysts at the same time. The result is that the catalysis phenomena are very complicated and

were regarded as mysterious and not amenable to rational interpretation. For a long time, the

selection study of catalysts is always in the skill stage of the laboratory. The author thinks that

the basic reason is lack of correct theoretical guidance.

At present, it can be seen from literature that there are two heterogeneous catalysis

mechanisms. One is the CRM widely adopted , and it is raised to the height of the “principle” by

the scholars, this CRM is also instilled in high school textbooks. It can be said that CRM is deeply

rooted in catalytic academia. Another catalysis mechanism is the EODRM or ECDAM proposed

by author . The EODRM is completely different from CRM, which consider that catalytic

phenomena are physical rather than chemical phenomena, and that catalysts do not participate

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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 1, February-2022

Services for Science and Education – United Kingdom

on balance “specific oxidation-reduction cycles” have been conspicuously successful in

interpreting the effects of these compounds in the various types of carbon gasification

reactions. But the writer feelings that the "specific" word is nowhere to be seen. Although the

author shows that the complex catalysis remains unclear and needs to be better studied

afterward.

A senior American scholar has studied the catalysis of the noble metal Pt on the C+CO2=2CO

and C+H2O=H2+CO reaction, they also adopted CRM to account for the catalysis mechanism.

They believed that Pt is continuously reduced and oxidized by H2,CO and H2O,CO2 in the catalyze

process. This is also Oxgen Transfer Mechanism-OTM. Even though the paper says " proposed

mechanism"。

In 2016, Chen ping, a young scientist from Chinese Academy of Sciences, and other researchers

published a high-level paper in the international top academic Journal (Nature Chemistry).They

have proposed the design theory of "dual-activation center" ammonia synthesis catalyst. Two

activation centers such as TM (transition group metal) and LiH are continuously decomposed

and regenerated in the catalyzing process of ammonia synthesis. In fact, they also follow the“

S-B principle”or the traditional ancient CRM principle. It can be seen that the younger

generation also inherited the idea of CRM.

Based on the above, CRM has been widely adopted in the catalytic community for more than

100 years and it is deeply rooted in catalystic field.

THREE TIMES EXPERIMENTAL STUDIES

The most main idear of the CRM is that the catalyst must take part in the chemical reaction, and

it has to be a cyclic reaction. In order to explore whether CRM can be trusted,The author has

conducted three times experimental studies.

BaCO3 catalysis in carburizing box (the 1960s)

The BaCO3 is commonly used as catalyst in solid carburizing agent of surface of steel parts. At

the beginning, the mechanism of carbonate decomposition to release CO2 which reacts with

carbon to produce carbon monoxide and thus increasing the rate of carburization was used to

account for the reason for accelerating carburizing rate. Later, it was found that CaCO3, which

can release a large amount of carbon dioxide, but it has no catalytic activity, while barium

carbonate, which does not decompose at the carburizing temperature, has carburizing activity.

Therefore, the mechanism of carbon dioxide release was abandoned and the Oxygen Transfer

Mechanism, namely OTM, was adopted.

Namely:

BaCO3+C=BaO+2CO-------------------(1)

CO=CO2+[C]-----------------------------(2)

CO2+BaO=BaCO3-----------------------(3)

The OTM is also CRM.This is a typical CRM. BaO is an intermediate compound, and the BaCO3 is

constantly decomposed and generated in the carburizing process.

The mechanism was first proposed by R.A.Ragaz & L.O.Kowalke 931[4].