
Generic potential energy diagram showing the effect of a catalyst in a hypothetical exergonic chemical reaction X + Y to give Z. The presence of the catalyst opens a different reaction pathway (shown in red) with a lower activation energy. The final result and the overall thermodynamics ΔG are the same.

Generic potential energy diagram showing the effect of a catalyst in a hypothetical exergonic chemical reaction X + Y to give Z. The presence of the catalyst opens a different reaction pathway (shown in red) with a lower activation energy. The final result and the overall thermodynamics ΔG are the same.

In chemistry, catalyst is a molecular substance that increases the rate of a chemical reaction without itself undergoing any permanent change. [1] Catalysts that speed the reaction are called positive catalysts. Catalysts that slow down the reaction are called negative catalysts or inhibitors.

Catalysis
The term "catalysis" is the action, process or result that occurs when a thing comes in contact with a catalyst.

Residence time
A related term is residence time, symbol τ (tau), being the average length of time a particle of reactant spends within a process vessel or in contact with a catalyst. [2]

Overview
The earliest use of catalysts occurred in the first millennium BC, where it was noted in the making of wine, cheese, and bread that it was necessary to add small amounts of the previous batch to make the current batch. [7]

In 1794, Elizabeth Fulhame (c.1750-c.1820), supposedly (Ѻ), was the first to describe catalysis in detail.

In 1831, Alexander Mitscherlich referred to ‘contact processes’ and Johann Döbereiner who spoke of ‘contact action’. [6]

In 1835, the phrase ‘catalysis’ was coined by the Swedish chemist Jacob Berzelius who was the first to note that certain chemicals speed up a reaction. The following year, Berzelius postulated the idea of the “catalytic force”.

In c.1890, German physical chemist Wilhelm Ostwald was the first to realize that a catalyst acts without altering the energy relations of the reaction, and that it usually speeds up a reaction by lowering the activation energy. [5]


Steps of the Haber process, showing an iron surface (embedded with oxides) acting as a catalyst to the reaction of hydrogen with nitrogen to form ammonia. [4]

Steps of the Haber process, showing an iron surface (embedded with oxides) acting as a catalyst to the reaction of hydrogen with nitrogen to form ammonia. [4]

In c.1900, German chemist Fritz Haber developed the "Haber process" in which he was able to synthesize ammonia NH3 from tightly bound oxygen molecules O2 and hydrogen molecule H2 via adding a catalyst surface of iron embedded with oxides in addition to higher temperatures.

In 1928, in a landmark contribution to catalytic theory, English chemist Hugh Taylor suggested that a catalyzed chemical reaction is not catalyzed over the entire solid surface of the catalyst but only at certain ‘active sites’ or centers. [8] Taylor visualized active sites as unsaturated atoms or available binding regions in the solid that resulted from topological features such as surface irregularities, dislocations, edges of crystals, or cracks along grain boundaries, etc. Thus, an active site or binding site is a point on a catalytic reactive surface that can form strong chemical bonds with an absorbent molecule. [9]

Life origin | CHNOPS+ existence
In 1948, biochemist Jerome Alexander, in his chapter “Catalysis as the Efficient Cause of Evolution”, as cited by Judson Herrick (1956), speculated on the role catalysis played in the origin of life in the fabrication of what Ralph Lillie referred to as “novel emergents”, akin to the concept of “emergent evolution” (Ѻ) of Lloyd Morgan (1922). [11]

In 1949, Lancelot Whyte touched on mechanism and autocatalysis in the context of biology. [12]

Human chemistry

See main: Human catalyst; Gavrilo Princip

The identification of what constitutes a “catalyst” in the process of a human chemical reaction is an advanced subject. The basic model, however, divides the matter of the biosphere into divisional categories: of reactive matter (e.g. human molecules), nutritive matter (e.g. an apple), substrate matter (e.g. the plot of land to a house), and catalytic matter (e.g. a television). [3] These tentative divisions, to note, serve only as crude guidelines, and where correctly each specific reaction must be studied in detail to determine the energy components effecting the human interactions.

In the study of the human chemical bond, for instance, the subject of secondary field particles, e.g. gold, as a type matter particle that transmits the force comes into play.

Quotes
The following are related quotes:

“Ostwald talks of the possible new catalytic action of some new mind”
— Henry Adams (1910), “Letter to Barrett Wendell”, May 18

“Speculators on the market play the same role as catalysts in chemistry. By buying when there is a tendency toward a rise in process, they hasten the change in the price. This bring the market into that state of equilibrium corresponding to the new conditions. Thy thus prevent the formation of false equilibria.”
— Jacques Rueff (1922), From the Physical to the Social Science [10]

References
1. Daintith, John. (2004). Oxford Dictionary of Chemistry. Oxford University Press.
2. Licker, Mark D. (2003). Dictionary of Engineering, 2nd ed. New York: McGraw-Hill.
3. (a) Thims, Libb. (2007). Human Chemistry (Volume One) (Catalyst, pgs. 23, 33, 93, 95, 274, 312; Contact action, pg. 95; contact processes, pg. 95; human catalyst, pg. 23; negative catalyst, pg. 94; positive catalyst, pg. 94; catalytic closure, pg. 132; Definition: substrate, pg. 33; Section: substrate and catalysts, pgs. 93-98; Keyword: substrate, pgs. 18, 32, 38, 40, 73, 92-93, 96-99, 101, 107, 129, 140-41, 186, 259, 280, 304) (preview), (Google books). Morrisville, NC: LuLu.
(b) Thims, Libb. (2007). Human Chemistry (Volume Two), (preview), (Google books). Morrisville, NC: LuLu.
4. Chang, Raymond. (1998). Chemistry, (pgs. 540-41, 585). McGraw-Hill.
5. Laidler, Keith J. (1993). The World of Physical Chemistry (pg. 212). Oxford University Press.
6. Catalyst – Wikipedia.
7. Oyana, S.T. & Somorjai, G.A. (1986). J. Chem. Edu. 65 p. 765.
8. Taylor, H.S. (1928). Proc. R. Soc. (London). A108, 105.
9. (a) Fogler, S. (1992). Elements of Chemical Reaction Engineering, 2nd Ed. New Jersey: Prentice Hall, P.T.R.
(b) Active site – Wikipedia.
(c) Binding site – Wikipedia.
10. Rueff, Jacques. (1922). From the Physical to the Social Sciences: Introduction to a Study of Economic and Ethical Theory (Des Sciences Physiques Aux Sciences Morales) (translator: Herman Green) (Introduction: Herman Oliphant and Abram Hewitt) (pg. 105). Johns Hopkins Press, 1929.
11. (a) Alexander, Jerome. (1948). Life, its Nature and Origin (§: “Catalysis as the Efficient Cause of Evolution”). Reinhold.
(b) Herrick, C. Judson. (1956). The Evolution of Human Nature (abs) (pg. 53). University of Texas Press.
12. (a) Whyte, Lancelot. (1949). The Unitary Principle in Physics and Biology (pg. 60). Holt.
(b) Herrick, C. Judson. (1956). The Evolution of Human Nature (abs) (pg. 53). University of Texas Press.

Further reading
● Laidler, Keith J. (1986). “The Development of the Theories of Catalysis” (abs), Archive for Historical Exact Sciences, 35(4): 345-74.

External links
● Catalysis – Wikipedia.