Metal catalysts are substances that speed up chemical reactions without being consumed in the process. They are often made from transition metals like platinum, palladium, or nickel. These metals provide active sites where reactants can come together more easily, leading to faster reaction rates and improved efficiency in various chemical processes. In industrial applications, metal catalysts are crucial for producing chemicals, fuels, and pharmaceuticals. For example, in the Haber process, iron is used as a catalyst to synthesize ammonia from nitrogen and hydrogen. This process is essential for creating fertilizers that support global agriculture.