DEPENDENCE OF CATALYTIC RATES ON CATALYST WORK FUNCTION

THE catalytic activity and selectivity of metals can be altered dramatically and reversibly by supplying or removing oxide anions, O2-, at the metal catalyst surface by interfacing the catalyst with an O2- conductor such as zirconia1-6. This effect, termed non-faradaic electrochemical modification of catalytic activity (NEMCA), leads to a steady-state catalytic reaction rate increase up to 3 × 105 times higher than the rate of supply or removal of O2- at the catalyst surface1,3,4. Here we report that β"-Al2O3, which is a Na+ conductor, can also induce the NEMCA effect. Furthermore we show that the origin of the NEMCA effect lies in the controlled variation of catalyst work function on polarization of the metal-solid-electrolyte interface, and demonstrate that the rates of metal-catalysed reactions depend exponentially on the average catalyst work function. Thus the influence of catalyst electronic structure, rather than surface geometry, is here the key factor in catalytic activity. © 1990 Nature Publishing Group.