Tracking Site-specific C-C Coupling of Formaldehyde Molecules on Rutile TiO2(110)

Journal Article · Thu Jun 25 04:00:00 EDT 2015 · Journal of Physical Chemistry C, 119(25):14267-14272

DOI:https://doi.org/10.1021/acs.jpcc.5b04781· OSTI ID:1221499

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

Direct imaging of site-specific reactions of individual mole-cules as a function of temperature is a long-sought goal in molecular science. Here, we report the direct visualization of molecular coupling of formaldehyde on reduced rutile TiO2(110) surfaces as we track the same set of molecules when the temperature is increased from 75 to 170 K using scanning tunneling microscope (STM). Our recent study showed that formaldehyde preferably adsorbs on bridging-bonded oxygen (Ob) vacancy (VO) defect site. Herein, images from the same area as the temperature is increased show that VO-bound formaldehyde couples with Ti-bound formaldehyde forming a diolate intermediate. Exposure of formaldehyde at room temperature leads to diolate as the majority species on the surface and no VO-bound formaldehyde is observed. The diolate species are the key reaction intermediates in the formation of ethylene reported in previous ensemble-averaged studies.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1221499
• Report Number(s): PNNL-SA-109861; 48368; KC0302010
• Journal Information: Journal of Physical Chemistry C, 119(25):14267-14272, Journal Name: Journal of Physical Chemistry C, 119(25):14267-14272
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory