Platinum black

Platinum sponge - KFO

Platinum black is a fine powder of platinum with a very high surface area, which makes it extremely effective as a catalyst for chemical reactions. The material is called "black" due to its fine particulate nature and its appearance, which is a stark contrast to the shiny, metallic appearance of bulk platinum. Platinum black is produced through the chemical reduction of platinum salts (such as platinum chloride) into metallic platinum in the presence of a reducing agent. This process results in a highly porous material with a large surface area, which is key to its catalytic properties.

Production

The production of platinum black involves the reduction of a platinum salt solution by a reducing agent. Common reducing agents include hydrogen gas, sodium borohydride, and formaldehyde. The choice of reducing agent and the conditions under which the reduction is carried out (such as temperature and pH) can significantly affect the properties of the resulting platinum black, including its surface area and catalytic activity.

Applications

Platinum black is used in a variety of applications, leveraging its high catalytic activity. These include:

• Fuel cells, where it serves as a catalyst in the oxygen reduction reaction on the cathode side, facilitating the conversion of oxygen and hydrogen into water and electricity.
• Electrochemical sensors, where it is used to catalyze reactions of interest, improving the sensitivity and selectivity of the sensor.
• Catalytic converters in automobiles, where it helps in the oxidation of hydrocarbons and carbon monoxide into carbon dioxide and water, reducing harmful emissions.

Properties

Platinum black's effectiveness as a catalyst is primarily due to its high surface area, which provides more active sites for chemical reactions. However, its physical form as a fine powder can also lead to issues such as poor mechanical stability and a tendency to agglomerate, which can reduce its effective surface area and, consequently, its catalytic activity.

Safety and Handling

Handling platinum black requires caution due to its fine particulate nature. Inhalation of the particles can be harmful, and appropriate personal protective equipment (PPE) such as gloves and masks should be used when handling the material. Additionally, platinum black can catalyze unwanted side reactions if it comes into contact with certain chemicals, so it should be stored and used in conditions that minimize these risks.