A hydrogen-evolving Ni(P2N2)2 electrocatalyst covalently attached to a glassy carbon electrode: Preparation, characterization, and catalysis. Comparisons with the homogeneous analogue

Atanu K. Das, Mark H. Engelhard, R. Morris Bullock, John A.S. Roberts

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

A hydrogen-evolving homogeneous Ni(P2N2)2 electrocatalyst with peripheral ester groups has been covalently attached to a 1,2,3-triazolyllithium-terminated planar glassy carbon electrode surface. Coupling proceeds with both the Ni(0) and the Ni(II) complexes. X-ray photoemission spectra show excellent agreement between the Ni(0) coupling product and its parent complex, and voltammetry of the surface-confined system shows that a single species predominates with a surface density of 1.3 × 10-10 mol cm-2, approaching the value estimated for a densely packed monolayer. With the Ni(II) system, both photoemission and voltammetric data show speciation to unidentified products on coupling, and the surface density is 6.7 × 10-11 mol cm-2. The surface-confined Ni(0) complex is an electroctalyst for hydrogen evolution, showing the onset of catalytic current at the same potential as the soluble parent complex. Decomposition of the surface-confined species is observed in acidic acetonitrile. This is interpreted to reflect the lability of the Ni(II)-phosphine interaction and the basicity of the free phosphine and bears on concurrent efforts to implement surface-confined Ni(P2N 2)2 complexes in electrochemical or photoelectrochemical devices.

Original languageEnglish
Pages (from-to)6875-6885
Number of pages11
JournalInorganic Chemistry
Volume53
Issue number13
DOIs
Publication statusPublished - Jul 7 2014

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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