KSCN-induced Interfacial Dipole in Black TiO2 for Enhanced Photocatalytic CO2 Reduction

• Published in: ACS applied materials & interfaces Vol. 11; no. 28; pp. 25186 - 25194
• Main Authors: Fu, Fang-Yu, Shown, Indrajit, Li, Chia-Shuo, Raghunath, Putikam, Lin, Tsai-Yu, Billo, Tadesse, Wu, Heng-Liang, Wu, Chih-I, Chung, Po-Wen, Lin, Ming-Chang, Chen, Li-Chyong, Chen, Kuei-Hsien
• Format: Journal Article
• Language: English
• Published: American Chemical Society 17.07.2019
• Subjects: artificial photosynthesis; black TiO2; photocatalyst; CO2 reduction; solar fuel; interfacial dipole
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.9b06264

Tuning the electronic band structure of black titania to improve photocatalytic performance through conventional band engineering methods has been challenging because of the defect-induced charge carrier and trapping sites. In this study, KSCN-modified hydrogenated nickel nanocluster-modified black TiO2 (SCN–H–Ni–TiO2) exhibits enhanced photocatalytic CO2 reduction due to the interfacial dipole effect. Upon combining the experimental and theoretical simulation approach, the presence of an electrostatic interfacial dipole associated with chemisorption of SCN has dramatic effects on the photocatalyst band structure in SCN–H–Ni–TiO2. An interfacial dipole possesses a more negative zeta potential shift of the isoelectric point from 5.20 to 3.20, which will accelerate the charge carrier separation and electron transfer process. Thiocyanate ion passivation on black TiO2 demonstrated an increased work function around 0.60 eV, which was induced by the interracial dipole effect. Overall, the SCN–H–Ni–TiO2 photocatalyst showed an enhanced CO2 reduction to solar fuel yield by 2.80 times higher than H–Ni–TiO2 and retained around 88% product formation yield after 40 h.