Energetics and efficiency analysis of a cobaloxime-modified semiconductor under simulated air mass 1.5 illumination

Alexandra Krawicz, Diana Cedeno, Gary Moore

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

We report on the energetics and efficiency of a p-type (100) gallium phosphide (GaP) semiconductor functionalized with molecular hydrogen production catalysts via polymer grafting. The catalysts belong to the cobaloxime class of compounds that have recently shown promise in electrocatalysis and solar-to-fuel applications. Attachment of the complex to a semiconductor surface allows direct photoelectrochemical (PEC) measurements of performance. Under simulated air mass 1.5 illumination, the catalyst-modified photocathode yields a 0.92 mA cm-2 current density when operating at the equilibrium potential for the hydrogen production half reaction. The open circuit photovoltage (V OC) is 0.72 V vs. a reversible hydrogen electrode (RHE) and the fill factor (FF) is 0.33 (a 258% increase compared to polymer-modified electrodes, without cobaloxime treatment). The external quantum efficiency (EQE), measured under a reverse bias of +0.17 vs. RHE, shows a maximum of 67% under 310 nm illumination. Product analysis of the head-space gas yields a lower limit on the Faradaic efficiency of 88%. In addition, the near linear photoresponse of the current density upon increasing illumination indicates that photocarrier transport to the interface can limit performance. These results give insights into the design of improved photocatalytic constructs with additional performance gains. This journal is

Original languageEnglish (US)
Pages (from-to)15818-15824
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume16
Issue number30
DOIs
StatePublished - Aug 14 2014
Externally publishedYes

Fingerprint

air masses
Lighting
illumination
hydrogen production
Semiconductor materials
Hydrogen production
catalysts
Electrodes
Catalysts
electrodes
Hydrogen
Polymers
Current density
Air
current density
gallium phosphides
Electrocatalysis
Photocathodes
photovoltages
polymers

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Physics and Astronomy(all)

Cite this

Energetics and efficiency analysis of a cobaloxime-modified semiconductor under simulated air mass 1.5 illumination. / Krawicz, Alexandra; Cedeno, Diana; Moore, Gary.

In: Physical Chemistry Chemical Physics, Vol. 16, No. 30, 14.08.2014, p. 15818-15824.

Research output: Contribution to journalArticle

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