GB/T 39952-2021 "Titanium Dioxide-Based Photocatalytic Dispersions" applies to ultraviolet light and visible light responsive titanium dioxide-based photocatalytic dispersions that are miscible with water. It specifies core content such as product classification and labeling, technical requirements, and test methods. Key indicators include a total solid content and titanium mass fraction not less than 90% of the nominal value, with pH controlled within the nominal value ±0.3. After standing for 24 hours, there should be no obvious stratification. The phenol degradation rate under ultraviolet light within 2 hours should be ≥60%. The standard clearly defines inspection rules as well as storage and transportation requirements to ensure the product's photocatalytic performance and stability.