Various materials are employed as catalysts, including metals, oxides, zeolites, and organometallic complexes. Transition metals like platinum, palladium, and rhodium are especially valued for their catalytic properties. However, these metals are often rare and expensive. Other materials, such as metal oxides (e.g., titanium dioxide) and zeolites, offer more abundant and cost-effective alternatives but may have limitations in terms of activity and selectivity.
