Catalysts are materials that promote chemical reactions without being consumed themselves. Today, catalysts are used in numerous industrial processes, from fertiliser production to manufacturing plastics. Because of this, catalysts are of huge economic importance. A very well-known example is the catalytic converter installed in the exhaust systems of cars. These contain precious metals such as platinum, rhodium and palladium, which allow highly toxic carbon monoxide (CO) to be converted into carbon dioxide (CO2) and reduce the amount of harmful nitrogen oxides (NOx).