Nanoscale mapping of strained catalysts

Nanoscale mapping of strained catalysts

Electrochemistry

Nurkhan Nurapin

Prof Patrick R. Unwin

Straining a metal’s crystal lattice is expected to change how well it catalyses reactions such as oxygen evolution, the slow step in making green hydrogen. To test this on real nickel, we pressed a microscopic pyramid into the surface and mapped the electrochemical response around the dent with scanning electrochemical cell microscopy (SECCM), a droplet probe that records a voltammogram at each of 1,640 points. The dent appeared 3–15 times more active than flat nickel. However, the charging current showed that the droplet wetted 6–11 times more surface there, and per unit of wetted area the dent was not measurably more active. The method works in alkaline electrolyte, but wetting must be controlled first.

SECCM, nickel, electrocatalysis