Reaction Mechanism of Electroless Metal Deposition Using ZnO Thin Film (I): Process of Catalyst Formation

Abstract

The reaction mechanism of electroless metal deposition proceeding selectively on a ZnO thin film coated on a glass substrate was investigated by x-ray diffraction, x-ray photoelectron spectroscopy, and inductively coupled plasma measurements. The ZnO thin film was activated for e]ectroless metal deposition just by immersion in i.I mM PdC]2 solution adjusted to pH 2.5. In this process, Pd(II) was selectively adsorbed on the ZnO thin film while simultaneously the ZnO underwent dissolution. The dissolution of ZnO thin film easily occurred on the (002) face with polarity. The strongly adsorbed Pd(II) was reduced to Pd(0) by a reducing agent in the electroless plating bath and this served as a catalyst center. As a result, metal layers were obtained selectively on the ZnO thin film in the electroless plating bath.

Improvement in CO sensing characteristics by decorating ZnO nanorod arrays with Pd nanoparticles and the related mechanisms

“…The ZnO nanorod arrays rooted in the substrate were washed with distilled water several times, and dried at 60 uC. The synthesis of Pd/ZnO NRs was performed through immersion of ZnO NRs into the palladium chloride-ethanol solution at room temperature under an ultraviolet lamp (365 nm, around 5.3 mW cm 22 ) irradiation for 30 min. A palladium precursor solution with a light yellow color was obtained by dissolving 0.75 mM PdCl 2 in anhydrous ethanol with vigorous stirring for 30 min.…”

“…21 Accordingly, the zinc atoms become quite easy to dissociate from the ZnO lattice, which causes the dissolution seen in the present system. 22 The remaining surface oxygen atoms attract the palladium ions in bulk solution by electrostatic interaction, and the Pd(II) ions are then adsorbed on the ZnO surface and subsequently reduced to metallic palladium by photochemical reduction. Actually, the photocatalytic activities of ZnO-based materials are well known, and which have also been used to reduce Pd(II) ions acting as active sites for the electroless plating of copper on patterned areas.…”

“…Accordingly, ZnO nanorod/nanowire arrays have been extensively used for research in sensing many gas analytes, including O 2 , H 2 , C 2 H 5 OH, CO, NH 3 , and so on. 1,[3][4] In recent years, considerable efforts have been devoted to improve the gassensing performance of such devices by facilitating the chemical reaction between the analyte gas and the adsorbed oxygen species (O 2 ,O 22 or O {…”

Communication—Reaction Processes in Electroless Pd Deposition on Ni-P Surfaces Utilizing Formic Acid as Reducing Agent

“…due to its high catalytic activity for a breadth of chemical reactions, such as hydrogen evolution reaction 2 and methane oxidation. 3 In addition, Pd is capable of activating the non-active surface prior to the autocatalytic electroless deposition of Ni, Cu, 4 Co and Pd.…”

New Chemical Solution Process for Fabricating Copper Layer on Zinc Oxide Film

“…Preparation of Cu layer in aqueous solutions showed several advantages over the above mentioned techniques. Yoshiki et al 1 and Sun et al 2 reported a chemical method for preparing Cu layer on ZnO film. The method consisted of three steps; (i) adsorption of Pd 2+ ions on the ZnO surface by immersing the film in an acidic PdCl 2 solution, (ii) formation of Pd (0) layer by photoreduction of the Pd 2+ ions using UV irradiation, and (iii) electroless Cu plating on the Pd (0) layer.…”