TY - JOUR
T1 - Ruthenium-alloy electrocatalysts with tunable hydrogen oxidation kinetics in alkaline electrolyte
AU - St. John, Samuel
AU - Atkinson, Robert W.
AU - Unocic, Raymond R.
AU - Zawodzinski, Thomas A.
AU - Papandrew, Alexander B.
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/6/18
Y1 - 2015/6/18
N2 - High-surface-area ruthenium-based RuxMy (M = Pt or Pd) alloy catalysts supported on carbon black were synthesized to investigate the hydrogen oxidation reaction (HOR) in alkaline electrolytes. The exchange current density for hydrogen oxidation on a Pt-rich Ru0.20Pt0.80 catalyst is 1.42 mA/cm2, nearly 3 times that of Pt (0.490 mA/cm2). Furthermore, RuxPty alloy surfaces in 0.1 M KOH yield a Tafel slope of ∼30 mV/dec, in contrast with the ∼125 mV/dec Tafel slope observed for supported Pt, signifying that hydrogen dissociative adsorption is rate-limiting rather than charge-transfer processes. Ru alloying with Pd does not result in modified kinetics. We attribute these disparate results to the interplay of bifunctional and ligand effects. The dependence of the rate-determining step on the choice of alloy element allows for tuning catalyst activity and suggests not only that a low-cost, alkaline anode catalyst is possible but also that it is tantalizingly close to reality.
AB - High-surface-area ruthenium-based RuxMy (M = Pt or Pd) alloy catalysts supported on carbon black were synthesized to investigate the hydrogen oxidation reaction (HOR) in alkaline electrolytes. The exchange current density for hydrogen oxidation on a Pt-rich Ru0.20Pt0.80 catalyst is 1.42 mA/cm2, nearly 3 times that of Pt (0.490 mA/cm2). Furthermore, RuxPty alloy surfaces in 0.1 M KOH yield a Tafel slope of ∼30 mV/dec, in contrast with the ∼125 mV/dec Tafel slope observed for supported Pt, signifying that hydrogen dissociative adsorption is rate-limiting rather than charge-transfer processes. Ru alloying with Pd does not result in modified kinetics. We attribute these disparate results to the interplay of bifunctional and ligand effects. The dependence of the rate-determining step on the choice of alloy element allows for tuning catalyst activity and suggests not only that a low-cost, alkaline anode catalyst is possible but also that it is tantalizingly close to reality.
UR - http://www.scopus.com/inward/record.url?scp=84934940223&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.5b03284
DO - 10.1021/acs.jpcc.5b03284
M3 - Article
AN - SCOPUS:84934940223
SN - 1932-7447
VL - 119
SP - 13481
EP - 13487
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 24
ER -
