Related Experiment Video
Updated: May 31, 2026

Aerosol-assisted Chemical Vapor Deposition of Metal Oxide Structures: Zinc Oxide Rods
Published on: September 14, 2017
Modification of the ZnO(0001)-Zn surface under reducing conditions
Erdni D Batyrev1, Johannes C van den Heuvel
1van't Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, 1090 GD Amsterdam, The Netherlands. erdni.batyrev@tatasteel.com
Abstract:
The ZnO(0001)-Zn terminated crystal face was studied after reduction at high temperatures by combination of STM, STS, XPS and TDS. The clean ZnO(0001)-Zn surface exhibits triangular reconstruction in UHV, while after exposure to 10(-5) mbar H(2) at RT this reconstruction is lifted and a rough surface has formed. The roughness as well as the metallic character of the surface increased with the applied low-pressure reduction temperature up to 800 K. XPS revealed that exposure to 1 bar H(2) at RT led to the formation of OH groups; at higher temperatures progressive metallization of the ZnO surface was found to occur. Analysis of the thermal desorption results showed that huge amounts of H(2) dissolved into the ZnO crystal. The results obtained under these conditions were in good accordance with thermodynamic calculations. The experimental ratio between the absorbed amount of H(2) at RT and 800 K amounts to 1000. The ratio calculated from increasing diffusion coefficients with temperature only amounts to 6. This emphasizes the importance of ZnO as a H supplier by spillover, and proves that metallic Zn boosts dissociative adsorption of H(2). This surface modification of the ZnO structure during the reduction promotes an enhanced activity of the Cu/ZnO catalyst at elevated temperatures.
Related Concept Videos
Nitriles to Amines: LiAlH4 Reduction
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
Preparation of Amines: Reduction of Oximes and Nitro Compounds
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
Phase I Reactions: Reductive Reactions
Aldehydes and Ketones to Alkanes: Wolff–Kishner Reduction
Reduction of Alkynes to trans-Alkenes: Sodium in Liquid Ammonia
When dissolved in liquid ammonia, an alkali metal, such as sodium, dissociates into a...
Preparation of Amines: Reduction of Amides and Nitriles
Amides can be reduced to primary, secondary, and tertiary amines using catalytic hydrogenation, active metals like Fe,...
