Abstract: Provided is a method of making colloidal platinum nanoparticles. The method includes three consecutive steps: dissolving platinum powders by a halogen-containing oxidizing agent in HCl to obtain an inorganic platinum solution containing an inorganic platinum compound; adding a reducing agent into the same reaction vessel to form a mixture solution and heating the mixture solution to undergo a reduction reaction and produce a composition containing platinum nanoparticles, residues and a gas, and guiding the gas out of the reaction vessel, wherein the amount of the residues is less than 15% by volume of the mixture solution; and adding a medium into the same reaction vessel to disperse the platinum nanoparticles to obtain colloidal platinum nanoparticles. The method is simple, safe, time-effective, cost-effective, and has the advantage of high yield.

Abstract: Provided is a method of making an inorganic platinum compound. The method includes the 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 the inorganic platinum compound, including chloroplatinic acid or chloroplatinate salt; wherein the halogen-containing oxidizing agent excludes chlorine gas. The method of making an inorganic platinum compound is simple, safe, time-effective, cost-effective, and environment-friendly, and has the advantage of high yield.

Abstract: Provided is a method of making an inorganic platinum compound. The method includes the 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 the inorganic platinum compound, including chloroplatinic acid or chloroplatinate salt; wherein the halogen-containing oxidizing agent excludes chlorine gas. The method of making an inorganic platinum compound is simple, safe, time-effective, cost-effective, and environment-friendly, and has the advantage of high yield.

Abstract: Provided is a method of making colloidal platinum nanoparticles. The method includes three consecutive steps: dissolving platinum powders by a halogen-containing oxidizing agent in HCl to obtain an inorganic platinum solution containing an inorganic platinum compound; adding a reducing agent into the same reaction vessel to form a mixture solution and heating the mixture solution to undergo a reduction reaction and produce a composition containing platinum nanoparticles, residues and a gas, and guiding the gas out of the reaction vessel, wherein the amount of the residues is less than 15% by volume of the mixture solution; and adding a medium into the same reaction vessel to disperse the platinum nanoparticles to obtain colloidal platinum nanoparticles. The method is simple, safe, time-effective, cost-effective, and has the advantage of high yield.

Abstract: Provided is a method of making colloidal metal nanoparticles. The method includes the steps of: mixing a metal aqueous solution and a reducing agent to form a mixture solution in a reaction tank; heating the mixture solution and undergoing a reduction reaction to produce a composition containing metal nanoparticles, residues and gas, wherein the amount of the residues is less than 20% by volume of the mixture solution, and guiding the gas out of the reaction tank; dispersing the metal nanoparticles with a medium to obtain colloidal metal nanoparticles. By separating the reduction reaction step and the dispersion step, the method of making colloidal metal nanoparticles is simple, safe, time-effective, cost-effective, and has the advantage of high yield.

Abstract: A method of making the inorganic gold compound, such as tetrachloroauric acid, sodium tetrachloroaurate, potassium tetrachloroaurate, sodium tetracyanoaurate, and potassium tetracyanoaurate, includes the step of: treating gold with a halogen-containing oxidizing agent in a hydrochloric acid to obtain the inorganic gold compound, wherein the halogen-containing oxidizing agent excludes chlorine gas. The method of making the inorganic gold compound is simple, safe, time-effective, cost-effective, and environment-friendly, and has the advantage of high yield.

Abstract: A method of making the inorganic gold compound, such as tetrachloroauric acid, sodium tetrachloroaurate, potassium tetrachloroaurate, sodium tetracyanoaurate, and potassium tetracyanoaurate, includes the step of: treating gold with a halogen-containing oxidizing agent in a hydrochloric acid to obtain the inorganic gold compound, wherein the halogen-containing oxidizing agent excludes chlorine gas. The method of making the inorganic gold compound is simple, safe, time-effective, cost-effective, and environment-friendly, and has the advantage of high yield.