Imaging of Formaldehyde Adsorption and Diffusion on TiO2(110)

Journal Article · Sun Mar 01 00:00:00 EST 2015 · Topics in Catalysis, 58(2-3):103-113

DOI:https://doi.org/10.1007/s11244-014-0349-6· OSTI ID:1184296

Zhang, Zhenrong; Tang, Miru; Wang, Zhitao; Ke, Zhu; Xia, Yaobiao; Park, Kenneth T.; Lyubinetsky, Igor; Dohnalek, Zdenek; Ge, Qingfeng

Surface reactions of formaldehyde with reduced TiO2(110) surfaces have been studied using variable-temperature scanning tunneling microscopy (STM) and density functional theory (DFT). STM results show that formaldehyde preferably adsorbs on the bridging bonded oxygen (Ob) vacancy (VO) defect site. Bias-dependent STM images show that both the Ti-bound CH2O and the VO-bound CH2O are positioned between the Ob row and the Ti row. The VO-bound formaldehyde rotates at 95 K. It starts to diffuse along the Ob row as –CH2– at ~170 K and starts to diffuse along the Ti row as a molecule at ~215 K. However, the stabilities and the configurations of the Ti-bound and the VO-bound formaldehyde calculated using DFT are not in line with the experimental results. The values of diffusion barriers determined experimentally and theoretically are also different. The discrepancy between the experiment and theory indicates the presence of a complex charge distribution related to the defects.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1184296
• Report Number(s): PNNL-SA-103383; 48368; KC0302010
• Journal Information: Topics in Catalysis, 58(2-3):103-113, Journal Name: Topics in Catalysis, 58(2-3):103-113
• Country of Publication: United States
• Language: English

Related Subjects

Titanium dioxide
formaldehyde
defects
diffusion
scanning tunneling microscope
density function theory
Environmental Molecular Sciences Laboratory