Effect of surface defects on the interaction of the oxygen molecule with the ZnO(101̄0) surface

Saputro, Adhitya Gandaryus; Akbar, Fiki T.; Setyagar, Nikita Pradnya Paramita; Agusta, Mohammad Kemal; Pramudya, Aditya Dimas; Dipojono, Hermawan Kresno

doi:10.1039/c9nj06338b

Cited by 17 publications

(20 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Realizing that the introduction of defects into a semiconductor may significantly tailor the surface physicochemical properties, here, HCHO can be considered as an effective reductant to react with ZnO. The created variety of surface and subsurface defects in ZnO may play decisive roles in heterogeneous catalytic reactions. − Of course, the proposed reaction mechanism cannot be fully confirmed at the current moment since necessary analyses of the reaction products are lacking. Additionally, the formation of Zn or O vacancies may be realized by finely tuning the reaction temperature of HCHO.…”

Section: Resultsmentioning

confidence: 99%

Adsorption of Formaldehyde on the ZnO(101̅0) Surface: A Low-Temperature STM Study

Zhou

Yuan

et al. 2021

J. Phys. Chem. C

View full text Add to dashboard Cite

The details of interaction of formaldehyde (HCHO) with the ZnO surface are important for understanding a number of reaction mechanisms such as degradation of organic pollutes as well as methanol synthesis/combustion over an oxide catalyst. In this work, low-temperature scanning tunneling microscopy (LT-STM) has been applied to investigate the adsorption of HCHO on a ZnO(101̅0) surface. At 77 K, through in situ exposure technique and high-resolution STM imaging, we demonstrate that HCHO adsorbs at the surface trough positions between consecutive surface Zn–O pairs and diffuses preferentially along the [12̅10] direction. At room temperature, HCHO was found to assemble into one-dimensional chains orienting along the [0001] direction. Increasing the coverage gradually leads to the stepwise gathering of HCHO chains in the perpendicular direction to form (3 × 1) and finally saturate as (2 × 1) superstructure. Desorption of HCHO at 700 K was found to create regular line defects, indicating the gentle reduction of the ZnO surface. These results are believed to provide important insights for understanding the reaction mechanisms of aldehyde molecules on typical metal oxides such as ZnO.

show abstract

Section: Resultsmentioning

confidence: 99%

Adsorption of Formaldehyde on the ZnO(101̅0) Surface: A Low-Temperature STM Study

Zhou

Yuan

et al. 2021

J. Phys. Chem. C

View full text Add to dashboard Cite

show abstract

“…The higher probability of the dissociative adsorption of oxygen molecules on the c (+) plane surface than other low‐index planes has been indicated by several studies 12,13,17,31 . It has been attributed to the larger quantities of oxygen vacancies on the surface.…”

Section: Resultsmentioning

confidence: 93%

Crystal plane‐dependent ethanol gas sensing of ZnO studied by low‐energy He⁺ ion scattering combined with pulsed jet technique

Suzuki

Adachi

Ohgaki

et al. 2021

Surface & Interface Analysis

View full text Add to dashboard Cite

Although a semiconductor gas sensor is promising in the future gas sensing technology, the material design for highly sensitive and selective gas sensing is quite challenging. The crystal plane dependence of gas sensing has been studied using various nano‐crystal samples with a controlled crystal facet to obtain a clue for designing the sensing material, but the contact effect between nano‐crystal particles has often hindered the straightforward analysis. In the present study, the crystal plane dependence of ethanol (EtOH) sensing by ZnO, one of the most widely studied target gas‐sensing material combinations, was investigated from an analytical approach. We applied a newly developed low‐energy He+ ion scattering spectroscopy (He+ LEIS) combined with the pulsed jet technique for analyzing the surface structure of ZnO during the EtOH sensing. In this novel technique, the free gas jet is periodically blown onto the sample surface to simulate the gas‐sensing surface in a vacuum as one under the realistic working condition, while the background pressure is maintained low enough for operating He+ LEIS. It was found that the divalent oxygen adatom on the outermost surface is consumed during the EtOH sensing while no change occurs in the concentration of the lattice oxygen on the Zn‐terminated (0001) surface. The availability of this oxygen adsorbate determines the dissociative EtOH adsorption probability on the surface; hence it determines the EtOH sensing sensitivity, which is substantially higher on Zn‐terminated (0001) than other dominant low‐index surfaces, such as O‐terminated (000 true1‾), (10 true1‾ 0), and (11 true2‾ 0).

show abstract

“…This cluster size was selected as it is small enough to accommodate the coadsorption of SO 2 molecule and O adatom. The presence of an O adatom is required to model the sensing mechanism of a chemiresistive gas sensor. ,− The CNT is modeled by using an armchair (8,8) CNT with a diameter of 10.860 Å and a length of 14.677 Å. This particular size of CNT is selected because it is large enough to accommodate the Zn 6 O 6 nanocluster.…”

Section: Methodsmentioning

confidence: 99%

Hollow Zinc Oxide Microsphere–Multiwalled Carbon Nanotube Composites for Selective Detection of Sulfur Dioxide

Septiani

Saputro

Kaneti

et al. 2020

ACS Appl. Nano Mater.

Self Cite

View full text Add to dashboard Cite

This work reports the first utilization of anthocyanin extracted from black rice (Oryza sativa L.) grains as a structure-directing agent for the synthesis of hollow zinc oxide (ZnO) spheres via a simple solvothermal reaction and their subsequent modifications with various amounts of multiwalled carbon nanotubes (MWCNTs). Following hybridization with MWCNTs, some MWCNTs are observed to penetrate into the inner cavities of the spheres, while ZnO nanoparticles are formed on the surface of some MWCNTs. When employed as a sulfur dioxide (SO 2 ) sensor, the ZnO−MWCNT (15:1) composite displays a high response of 156 to 70 ppm of SO 2 at an optimum temperature of 300 °C as well as good selectivity to SO 2 with the response to 50 ppm of SO 2 gas being 3 times higher than those to other gases, such as CO, CO 2 , methanol, toluene, hexane, and xylene. Interestingly, the sensing behavior of this composite is strongly influenced by the proportion of MWCNTs. Specifically, n-type sensing behavior is observed for both ZnO−MWCNT (10:1) and (15:1) composites, while p-type behavior is observed for the ZnO−MWCNT (5:1) composite. The switch in sensing behavior suggests the major contribution of p-type MWCNTs to the electronic and sensing properties of the ZnO/MWCNT composites. The density functional theory (DFT) simulations on the adsorption of SO 2 on the ZnO/CNT system reveal that the SO 2 molecule only chemically interacts with the O adatom of ZnO (i.e., oxygen atom adsorbed on the surface of ZnO) to form sulfur trioxide (SO 3 ), and charge transfer is observed from ZnO to CNT, which enhances the change in resistance of the composite sensor upon exposure to SO 2 gas.

show abstract

Effect of surface defects on the interaction of the oxygen molecule with the ZnO(101̄0) surface

Abstract: Strong O2–ZnO(101̄0) interactions can only occur when the ZnO(101̄0) surface has either an O vacancy or a Zn–O dimer vacancy.

Cited by 17 publications

References 44 publications

Adsorption of Formaldehyde on the ZnO(101̅0) Surface: A Low-Temperature STM Study

Adsorption of Formaldehyde on the ZnO(101̅0) Surface: A Low-Temperature STM Study

Crystal plane‐dependent ethanol gas sensing of ZnO studied by low‐energy He⁺ ion scattering combined with pulsed jet technique

Hollow Zinc Oxide Microsphere–Multiwalled Carbon Nanotube Composites for Selective Detection of Sulfur Dioxide

Contact Info

Product

Resources

About

Effect of surface defects on the interaction of the oxygen molecule with the ZnO(101̄0) surface

Abstract: Strong O2–ZnO(101̄0) interactions can only occur when the ZnO(101̄0) surface has either an O vacancy or a Zn–O dimer vacancy.

Cited by 17 publications

References 44 publications

Adsorption of Formaldehyde on the ZnO(101̅0) Surface: A Low-Temperature STM Study

Adsorption of Formaldehyde on the ZnO(101̅0) Surface: A Low-Temperature STM Study

Crystal plane‐dependent ethanol gas sensing of ZnO studied by low‐energy He+ ion scattering combined with pulsed jet technique

Hollow Zinc Oxide Microsphere–Multiwalled Carbon Nanotube Composites for Selective Detection of Sulfur Dioxide

Contact Info

Product

Resources

About

Crystal plane‐dependent ethanol gas sensing of ZnO studied by low‐energy He⁺ ion scattering combined with pulsed jet technique