Indoor air quality has a great effect on human health. Above 50% of all illnesses are caused by polluted indoor air. The effect of indoor air quality on health has received increasing concern in recent years. Therefore, it is of great interest to effectively control indoor air pollution. We developed a novel Pt/TiO₂ catalyst for ambient HCHO oxidation, and subsequently we found that the addition of alkali metal ions could significantly promote the activity of the Pt/TiO₂ catalyst by inducing atomically dispersed Pt species and opening a new low-temperature reaction pathway. New Air Cleaners equipped with the novel catalyst have been developed and put into the Chinese market. BTX (Benzene, Toluene, and Xylene), pathogenic microbes, ammonia, and ozone are also major contaminants in indoor air, thus removal of these pollutants from indoor air is also very important. We developed a series of efficient catalysts for BTX oxidation based on adsorption-catalysis, nonthermal plasma-catalysis, and electro-catalysis technologies. Photocatalytic or non-photocatalytic oxidation of ammonia has been investigated. The structure-activity relationships have been also elucidated. We have developed a series of Mn-based catalysts with high moisture resistance for ozone decomposition at room temperature at high space velocity. Catalytic sterilization was also studied in detail.