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Title: Inhibition of tafel kinetics for electrolytic hydrogen evolution on isolated micron scale electrocatalysts on semiconductor interfaces

Semiconductor-liquid junctions are ubiquitous in photoelectrochemical approaches for solar-to-fuels energy conversion. Electrocatalysts are added to the interface to improve catalytic efficiency, but they can also impair the photovoltage-generating energetics of the electrode without appropriate microscopic organization of catalytically active area on the surface. This balance is more complicated when gas products are evolved, like hydrogen on water splitting electrodes. Discrete catalysts can be blocked by the gas liquid-solid boundary of a bubble stuck to the surface. Here, we study the kinetics of hydrogen evolution on semiconductor electrodes fabricated with an isolated, micronscale platinum electrocatalyst pad. Movies of in operando bubble evolution were recorded with synchrotron-based high-speed x-ray phase-contrast imaging in a compatible electrochemical cell. The self-limited growth of a bubble residing on the isolated electrocatalyst was measured by tracking the evolution of the gas-liquid boundary through the sequence of images in the movie. As a result, the effect of pad size on the catalytic currents and the issues with reactant transport can be inferred from these dynamics.
 [1] ;  [1] ;  [2] ;  [2]
  1. Univ. of Arkansas, Fayetteville, AR (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 8; Journal Issue: 37; Journal ID: ISSN 1944-8244
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; electrochemistry; catalysis; x-ray phase-contrast microscopy; solar fuels; bubbles; bubble evolution; hydrogen evolution reaction
OSTI Identifier: