. 2022 Aug 15;14(33):38255–38269. doi: 10.1021/acsami.2c06404

Table 3. Results of XPS Analysis of TiO₂ and TiO₂@2%Fe₂O₃ Nanocrystals—Assignment of Ti2p, O1s, and Fe2p peaks to Certain Types of Bonding.

	binding energy (eV)
symbol	TiO₂	TiO₂@2%Fe₂O₃	type of bonding	refs
Ti2p
Ti_I	458.2(3)	458.4(3)	Ti 2p_3/2, O–Ti–O	[⁴⁵]
Ti_II	463.8(3)	464.0(3)	Ti 2p_1/2, O–Ti–O	[⁴⁵]
Ti_I′	472.1(3)	472.2(3)	satellite of Ti2p_3/2, O–Ti–O	[⁴⁵]
TiI_I′	477.3(3)	477.6(3)	satellite of Ti2p_1/2, O–Ti–O	[⁴⁵]
O1s
O_I	529.3(4)	529.3(4)	Ti–O–Ti	[⁴⁶]
O_II	530.6(4)	530.6(4)	oxygen vacancies or defects	[⁴⁶]
O_III	532.7(4)	532.7(4)	chemisorbed species, e.g., OH^–, H₂O, O^2–	[⁴⁶]
Fe2p
Fe_I		710.6(7)	Fe 2p_3/2, Fe³⁺ in Fe₂O₃	[^{47, 49}]
Fe_II		715.2(8)	satellite of Fe 2p_3/2, Fe³⁺ in Fe₂O₃	[^{47, 49}]
Fe_III		723.5(7)	Fe 2p_1/2, Fe³⁺ in Fe₂O₃	[^{47, 49}]
Fe_IV		728.4(7)	satellite of Fe 2p_1/2, Fe³⁺ in Fe₂O₃	[^47, 49]

Table 3. Results of XPS Analysis of TiO2 and TiO2@2%Fe2O3 Nanocrystals—Assignment of Ti2p, O1s, and Fe2p peaks to Certain Types of Bonding.