Acceleration effect of thiourea on the oxidation reaction of hypophosphite ion on Ni surface

Masahiro Kunimoto, Kazuaki Endo, Hiromi Nakai, Takayuki Homma*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The acceleration effect of thiourea on an electroless Ni deposition reaction was analyzed through experimental and theoretical approaches. In the experimental approach, the entire deposition process was physically separated into the anodic and the cathodic reactions by preparing two cells connected by a salt bridge. The cells contained either a bath without metal (Ni) ions or a bath without a reducing agent (hypophosphite ions). The current flowing between the two separated baths increased when thiourea was added only to the anodic reaction bath, which indicated that the acceleration effect of thiourea was mainly on the anodic reaction of the hypophosphite ions. Based on this experimental result, in the theoretical calculation approach, a co-adsorption system consisting of thiourea, hypophosphite, and a Ni metal surface was analyzed using density functional theory. Among all the elementary steps of a hypophosphite reaction, thiourea primarily should promote the adsorption step owing to the following two factors. One was the molecular interaction between thiourea and the hypophosphite ion. The other was the restructuring of the electronic states of the Ni surface owing to the adsorption of thiourea, which enhanced the interaction between hypophosphite and its adsorption site on the Ni surface.

Original languageEnglish
Pages (from-to)311-316
Number of pages6
JournalElectrochimica Acta
Publication statusPublished - 2013 Jun 30


  • Density functional theory
  • Electroless Ni deposition
  • Hypophosphite ion
  • Thiourea

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry


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