Method of making an inorganic platinum compound

A method of making an inorganic platinum compound, comprising steps of:

• Step (A):
• providing a platinum material and a halogen-containing oxidizing agent;
• and
• Step (B):
• treating the platinum material with the halogen-containing oxidizing agent in a hydrochloric acid aqueous solution to obtain an inorganic platinum compound;
• wherein the halogen-containing oxidizing agent excludes chlorine gas, and the halogen-containing oxidizing agent is selected from the group consisting of:
• a halogen oxoacid, a halogen oxoacid salt, a halogen oxide, and any combination thereof;
• wherein the halogen oxoacid comprises hypobromous acid, bromous acid, bromic acid, hypoiodous acid, iodic acid, or periodic acid;
• the halogen oxoacid salt comprises sodium hypobromite, sodium bromite, sodium bromate, sodium hypoiodite, sodium iodate, sodium periodate, potassium hypobromite, potassium bromite, potassium bromate, potassium hypoiodite, potassium iodate, potassium periodate, or ammonium iodate;
• the halogen oxide comprises dichlorine monoxide, dichlorine trioxide, dibromine monoxide, dibromine trioxide, bromine dioxide, dibromine pentoxide, diiodine monoxide, or diiodine pentoxide;
• and
• the inorganic platinum compound comprises chloroplatinic acid or chloroplatinate salt.