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Heterogeneous Catalysis

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Introduction A catalyst is a substance that accelerates the rate of a chemical reaction and not consumed during the reaction. Traditional catalysis can be classified into homogeneous catalysis and heterogeneous catalysis. In a homogeneous catalytic reaction, the catalyst and reactants are in the same phase, generally occurring in a liquid state. The catalyst can generate intermediate reactant, which make the activation energy lower than originally reactant, so the reaction rate can be enhanced. [1] In heterogeneous catalytic reactions, the catalyst and reactants are in the different phase, generally occurring in a porous solid. One or more of the reactants is adsorbed  on to the surface of the catalyst. The solid catalyst surface is not uniform, only some points of chemical adsorption of reactant molecules, which are known as the active site. Main Section Heterogeneous catalysis is significant to chemical technology. During the catalytic process, the original bonds are broken and new bonds are synthesized. Without the catalysts, the chemical transformation would either slower rates or synthesize with a lower yield. [2] In the early 1800s, the ability of platinum to facilitate oxidation reactions was examined by Faraday. After that, isomerization, dehydrogenation, facilitated hydrogenation and polymerization reactions were developed with the other catalysts which played a important part in the industrial revolution. During 1900s, the development of catalytic processing which convert crude oil to fuels and some other petrochemical products brought about great change on people's lifestyle and society. Nowadays, people rely more on heterogeneous catalysis, It is hard to imagined that our world without the fruits of heterogeneous catalysis. More efficient catalyst is continuously developed to solve the problems on environment and improvement of productive forces. In an effective catalyst, the surface can be moved in the molecules and bonding to different active sites. The reaction can be increased by the adsorption of reac

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