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PVP lets SECCM map Pt OER in concentrated KOH
A little polyvinylpyrrolidone stops alkaline SECCM droplets from spreading, enabling single-grain OER maps that rank Pt(110)/(111) above (100) at pH 13.8.
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Why is SECCM hard in concentrated alkaline electrolyte?
Low surface tension lets the droplet spread, so landing areas and currents are unstable.
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
How is wetting factor defined?
Spreading droplet diameter divided by the tip-end diameter.
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
How large was the wetted spot versus the capillary without PVP?
About seven times the capillary size.
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
What additive was used to control alkaline wettability?
A small amount of PVP in the capillary electrolyte.
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
What WF values did 0.02%, 0.06% and 0.1% PVP give in 1 M KOH?
About 2.5, 2.3 and 1.2, respectively.
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
Did PVP change the KOH pH?
No—it remained pH 13.8.
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
What OER activity trend was mapped on polycrystalline Pt?
(110) and (111) similar and both higher than (100).
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
How does that alkaline ranking compare with acid literature?
Opposite of HClO4/H2SO4 reports that rank (100) above (110) and (111).
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
What complementary microscopy assigned grain orientation?
EBSD on the same polycrystalline Pt surface.
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
How did PVP change Fc(MeOH)2 diffusion versus polymer-free KOH?
Diffusion coefficient about 5 times lower with PVP.
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified
What scan area and hop distance were used for OER maps?
200 μm × 152 μm with 4 μm hopping.
Source: Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy · DOI · quote verified