Small things can have big results

Mintu Sarma

(Research Scholar, Gauhati University.

Can be reached at sarmamintu9@gmail.com)

Nature is full of wonders. Every atom is a standing miracle and endowed with amazing characters that propelled modern science to a new height. Catalyst also has extraordinary potential which can regulate a chemical reaction without absorbing itself. It accomplishes the reaction by changing the activation energy required to start a chemicalprocess. The use of catalysts technology is well known from very ancient days, although the concept of catalyst was incomprehensible at that time. The preparation of alcohols by fermentation, synthesis of soap by hydrolysis of animal fat using caustic potash, are some catalytic activities that have been using from the days of yore. In the modern scientific era, catalysis occupies an important place in the field of academic research as well as in the industrial sector. Catalysts have been using in the field of oil refining, Pharmaceuticals, electronics besides it has the potential to act as an environmental purifier. Surprisingly, the human body also runs by catalysts. The enzymes in the human body are such catalysts that create signals to move limbs and also help in digesting food.

Catalysts are prepared in different forms like powder, fine particles, granules, and plasma-enhanced thin films etc. These catalysts may be deposited in solid support (supported catalysts) or used in bulk form (unsupported catalysts). The homogeneous (phase of product and reactant are same) catalysts show better performance in industrial and raw material reactions compared to their heterogeneous (phase of product and reactant are different) counterparts but it produces toxic wastes. Hence homogeneous catalysts are converted into heterogeneous via solid support to reduce their toxicity to make eco-friendly catalysts. On the other hand, photo-catalysts are eco-friendly catalysts that convert light energy into a chemical reaction. The performance of the photo-catalyst depends on the bandgap, surface area, and defect concentration of the catalyst. Extended surface area (ESA) catalysts have gained a lot of interest in recent years; the surface area is an important parameter for catalysis enhancement.

The working mechanism of heterogeneous catalysts can be summarized as 1) Diffusion of reactant molecules towards the surface of the catalysts. 2) Adsorption of the reactant molecules on the surface of the catalysts. 3) Occurrence of the chemical reaction/reactions on the surface of catalysts. 4) Desorption of the product molecules from the surface of the catalysts. 5) Diffusion of product molecules away from the surface of the catalysts. It depicts that catalysts even in small quantities without losing mass and chemical composition could continue the catalysis process invariably. The basic characteristic of the photocatalytic reaction is that it acquires three major active groups: h+, •OH and O2• - radical species, where •OH is the main oxidant in the removal of the dye (pollutant) in water. The light energy equal to or above the bandgap of semiconductor-based photo-catalysts create holes and free electrons. Free electrons and holes interact with Pollutants that produce reduction and oxidation products respectively. On the contrary interaction between •OH radical and pollutant produces degradation products. This mechanism can be used in dye degradation in industrial effluent to impede water pollution.

Using catalysts one can save energy and time during the chemical reaction that to in an eco-friendly method. A very small quantity of catalysts can have a big result. It is also the key to unlocking bio-fuels. The cellulose present in various biomasses such as corn, switchgrass, and trees need to be broken down to make fuel. Catalysts take an important role in disintegrating cellulose to make bio-fuels which could be more viable as a renewable energy source. After the ground breaking result of lithium-ion batteries, a promising idea of the lithium-air battery was instilled into the scientists. To convert this idea into tangible reality requires to revamping of internal chemistry that needs powerful new catalysts to make it workable. Better catalysts are needed to cope up with such new challenges. The miraculous nature of catalysts had admired many scientists and moved their research direction towards it .consequently, the demand for the catalysts are increasing. According to the recently published report "Catalyst Market" – the catalysts global market value was USD 35 billion in 2020 and is expected to be USD 48 billion in 2027 at a growth rate of 4.4%. This figure augurs well the rapid growth of the catalysts market. The shifting energy trend towards alternative fuels like biofuels and shale gas fuel has also propelled the demand for the catalyst rapidly. The catalysts have the hidden potential to bring conspicuous change in the research and industrial sectors, only need to unveil it through experiment.