Catalysis provides powerful tools for efficiently and selectively making/breaking chemical bonds, which is essential for converting raw materials (basic chemicals) into useful products for society in an eco-friendly fashion. Despite the huge developments of catalysis in the past few decades, there are still many challenges ahead.
Many chemical transformations rely on valuable metals like palladium, platinum, ruthenium or rhodium as catalysts. But such metals are rare, expensive and sometimes toxic. This is why, for years, scientists have dedicated many efforts to develop methods of catalysis using cheap, earth-abundant and non-polluting metals like iron, copper or cobalt. It is not easy, especially if we consider that catalysts based on precious metals have enabled highly selective synthesis of a wide range of chemicals.
In the recent years separate teams of researchers have developed catalysts based on cheap metals that can perform impressive reactions traditionally based on earth-scarce and precious metals. For example, in one study, University of Girona researchers showed that common, environmentally benign iron complexes catalyse water oxidation to give O2 and H2. Water oxidation catalysis is crucial for the development of clean and abundant energy vectors such as hydrogen fuel cells based on sunlight. In another investigation, University of Toronto researchers developed an iron catalyst that efficiently mediates the production of alcohols and amines. These chemical compounds are ubiquitous in perfumes and medications.
The highly effective catalysis by nature’s enzymes has inspired scientists to imitate it. A proper understanding of how enzymes (nature’s catalysts) work holds out the promise of artificial catalysts for virtually any organic reaction of interest. Enzymes are more than just highly evolved catalysts: They display extremely high selectivity and are capable of increasing reaction velocities up to 1010 times. Moreover, biocatalytic reactions are usually carried out under physiological conditions, that is, at a temperature not higher than 36ºC, neutral pH and atmospheric pressure. Last but not least, enzyme catalysed transformations are less toxic, polluting and energy consuming than conventional human-designed methodologies (mainly those using valuable metals). Therefore it is not surprise that enzymes have served as a dominant source of inspiration in the pursuit of the “perfect” catalyst.
There are countless different approaches to the perfect catalyst, and there is no exclusive single “recipe” for success.