Platinum is a silvery-white element with exceptional chemical properties. It is a member of the Platinum Group Metals (PGMs). With an atomic number of 78 and the symbol Pt, platinum is one of the rarest elements in the Earth’s crust, found in concentrations significantly lower than gold.
The metal is prized for its high density. Platinum exhibits outstanding stability, resisting corrosion and oxidation even at extremely high temperatures, classifying it as a noble metal. Its high melting point, around 1768 degrees Celsius, makes it indispensable for applications requiring reliability in harsh environments.
Platinum in Automotive and Industrial Catalysis
The single largest use of platinum globally is in catalytic converters for vehicles powered by internal combustion engines. Platinum acts as a heterogeneous catalyst, accelerating chemical reactions without being consumed in the process. Within the ceramic honeycomb structure, a thin layer of platinum facilitates the transformation of harmful exhaust gases into less damaging substances.
The metal enables the oxidation of carbon monoxide (CO) and unburned hydrocarbons into carbon dioxide and water vapor. Simultaneously, it assists in the reduction of nitrogen oxides (\(\text{NO}_{\text{x}}\)) into inert nitrogen gas and oxygen. By providing an active surface for these chemical conversions, platinum directly contributes to reducing atmospheric pollution from gasoline and diesel engines.
Beyond the automotive sector, platinum is used in industrial chemical processing. It is used as a catalyst in the production of nitric acid, a compound essential for manufacturing fertilizers and explosives. Platinum is also a component in the cracking process within petroleum refining, helping to break down heavy crude oil fractions into lighter, more valuable products like gasoline. The metal’s stability and high efficiency in controlling reaction pathways make it difficult to replace in these large-scale manufacturing applications.
Medical Applications and Biocompatibility
Platinum’s chemical inertness and stability within the human body make it highly valued for medical applications. This characteristic, known as biocompatibility, prevents the metal from reacting with tissues or releasing toxic ions, allowing for long-term implantation. It is frequently alloyed with iridium to enhance mechanical strength for use in devices like pacemaker electrodes, implantable defibrillators, and neurostimulator components.
The metal’s radiopacity, meaning it is opaque to X-rays, also makes it useful in medical devices such as stents and guide wires, allowing surgeons to precisely track their position during minimally invasive procedures. Platinum-iridium alloys are machined into fine wires and components that maintain their integrity and electrical conductivity over decades inside the body.
Furthermore, platinum compounds are foundational to some of the most effective cancer chemotherapy treatments. Drugs like Cisplatin, Carboplatin, and Oxaliplatin—referred to as platinum-based drugs—function by forming cross-links with the DNA of cancer cells. This binding disrupts the cell’s ability to repair and replicate its genetic material, ultimately triggering programmed cell death. The development of these compounds has made platinum a central element in modern oncology.
Electronics and High-Temperature Instruments
The combination of electrical conductivity, corrosion resistance, and thermal stability makes platinum valuable for specialized electronic and high-temperature instruments. Platinum is used in electrical contacts in sensitive equipment where reliability is paramount, as its surfaces do not oxidize or tarnish over time. Its stability extends to fiber optic components and coatings for hard disk drives, where precision and durability are essential.
In temperature measurement, platinum is the industry standard for Resistance Temperature Detectors (RTDs), such as the widely used Pt100 sensor. The metal’s electrical resistance changes predictably and linearly with temperature, offering high accuracy and long-term stability across a wide temperature range. Platinum is also combined with rhodium to create thermocouples used to monitor extreme temperatures in furnaces and kilns. Because platinum does not contaminate or corrode when exposed to molten glass or aggressive chemicals, it is used to manufacture specialized laboratory crucibles and equipment for high-purity chemical analysis.
Jewelry and Investment Asset
Platinum has established a place in the luxury market, primarily for fine jewelry. Unlike gold, which is often mixed with other metals to increase its strength, platinum jewelry is typically 90–95% pure, resulting in its natural, brilliant white sheen. This high purity also makes it hypoallergenic, appealing to individuals with sensitive skin.
The metal is extremely dense and durable, which contributes to the substantial feel of platinum pieces and its ability to securely hold precious gemstones. Platinum’s natural resistance to wear and tarnish means it retains its luster without the need for frequent re-plating.
As an investment asset, platinum is traded as a commodity in the form of bullion bars and coins. Its value is often tied more closely to industrial demand, particularly from the automotive sector, than to investor sentiment, which typically drives the price of gold. Platinum’s rarity and high density mean a significant amount of value can be held in a small, easily storable physical form, providing investors with a tangible asset for portfolio diversification.