Table 2.

Coating methods and materials for suppressing photocatalytic activity of TiO₂ pigments.

TiO2 Material	Average Diameter (nm)	Coating Method	Coating Material	Coating Thickness (nm)	Deposition Temperature (°C)	Photocat. Reaction	Ref.
P25	21	ALD	Al2O3	6.0	177	Methylene blue	[40]
Anatase Rutile	160 280	ALD	SiO2	2.0	500 for SiO2 177 for Al2O3	IPA to acetone	[14]
			SiO2/Al2O3	1.0/1.0
			SiO2/Al2O3/SiO2/Al2O3	0.5/0.5/0.5/0.5
P25	21	ALD	Al2O3	3.8	150	RhB	[85]
Anatase	160	ALD	SiO2	6.0	175	Methylene blue	[15]
P25	18			9.0
Anatase	160	MLD	Alucone	7–10	100–160	Methylene blue	[86]
Rutile	Not reported	CVD	SiO2	1–2	900–1000	Methylene blue	[13]
Rutile	300	Wet-chemistry	ZrO2	5.0	40	RhB	[19]
			CeO2	1–2	60
Rutile	300	Wet-chemistry	CeO2	1–2	60	RhB	[87]
ST-21	20	Wet-chemistry	SiO2	4.0	40	Methylene blue	[8]
P25	21	Wet-chemistry	Porous SiO2	20.0	Room temperature	RhB	[10]
Anatase Rutile P25	270 300 21	ALD-like	Al2O3	1.0	Room temperature	RhB	This work