Platinum is the foremost of the platinum-group metals: silvery-white, extremely ductile, strongly chemically inert and catalytically outstanding, carrying a dual identity of industry and luxury. Its largest industrial use is as a catalyst: in automotive three-way catalytic converters, platinum works together with palladium and rhodium to convert carbon monoxide, hydrocarbons and nitrogen oxides into harmless gases - the single largest outlet for platinum worldwide. In chemicals, platinum catalysts are used in nitric-acid manufacture (the ammonia-oxidation process), petroleum reforming, silicone-rubber crosslinking and the hydrogen-oxidation reaction in fuel cells. In new energy, platinum is the core catalyst in proton-exchange-membrane fuel-cell electrode assemblies, and the growth of the green-hydrogen industry has directly pulled on platinum demand. In jewelry, platinum has long been favored by the high-end market for its pure white color and resistance to tarnishing. In electronics and medicine, platinum is used in high-temperature electrical contacts, thermocouples, getters, prosthetic electrodes and pacemaker leads; in the lab, platinum crucibles, electrodes and resistance thermometers are standard equipment for precision analysis, and platinum is also an international reserve asset. It is precisely this dual identity of 'king of catalysis' and 'king of inertness' that keeps its position solid in automotive, energy and high-end manufacturing.
Elemental platinum (Pt) is itself one of the most important application forms, used directly as platinum black, platinum gauze, platinum sponge and platinum targets in catalysts, electrodes and coatings. Platinum tetrachloride (PtCl4) is a basic halide of platinum, used to prepare other platinum compounds and platinum-plating baths. Cisplatin (cis-diamminedichloroplatinum, Pt(NH3)2Cl2) is one of the most successful chemotherapy drugs in history, with marked efficacy against testicular, ovarian, lung and bladder cancers and other solid tumors; it remains a cornerstone of oncological chemotherapy regimens, and its discovery is regarded as a milestone in metallopharmaceutics. Platinum dioxide (PtO2, Adams' catalyst) is a versatile catalyst commonly used in organic hydrogenation, reducing unsaturated bonds, nitro groups and carbonyl groups under mild conditions, and is widely used in pharmaceuticals and fine synthesis. In addition, chloroplatinic acid is a key intermediate for platinum plating and platinum refining, and platinum complexes are also used in certain next-generation anticancer drugs and OLED emissive materials.
