Composite catalyst, air purification device including the same, and method of preparing composite catalyst

A method of preparing a composite catalyst, the method comprising:

• providing an aluminosilicate;
• contacting the aluminosilicate and an alkaline solution to prepare an alkali-treated aluminosilicate;
• performing a first heat-treatment on the alkali-treated aluminosilicate to prepare a heat-treated porous aluminosilicate;
• contacting the heat-treated porous aluminosilicate and a strong acid to prepare an acid-treated aluminosilicate;
• contacting the acid-treated aluminosilicate and a precursor solution of a first particle to prepare an aluminosilicate having a precursor of the first particle supported thereon;
• and
• performing a second heat-treatment on the aluminosilicate having the precursor of the first particle supported thereon to prepare the composite catalyst.