Abstract:
Electrochemical promotion of catalysis (EP or EPOC) or non-faradaic electrochemical modification of catalytic activity (NEMCA) corresponds to the induced reversible modification of the catalytic behavior of metal or metal oxide catalyst-electrodes deposited on solid electrolytes or mixed ionic-electronic conductors (MIEC), resulting from polarization of the electrode/electrolyte interface [1-3]. This electrochemically induced catalytic effect has been attributed to electrochemical pumping of mobile promoter ionic species (e.g. O2-, H+, Na+, depending on the solid electrolyte or MIEC) to or from the gas exposed electrode surface under reaction conditions. This results in modification of the electronic properties of the electrode and, concomitantly, to the alteration of its catalytic properties [1-3]. Electrochemical promotion has been demonstrated for a very large number of combinations of solid electrolytes or MIEC, electrodes and catalytic reactions [1-7]. It is an effect of fundamental importance, bridging electrochemistry and heterogeneous catalysis [3], whereas, as it allows for in situ reversible tuning of catalyst performance, it opens up new possibilities for practical application in the fields of heterogeneous catalysis and applied electrochemistry [3-7]. This work highlights key landmarks in electrochemical promotion over the past three decades, with emphasis on the origin and mechanistic understanding of this effect, on the rules of electrochemical promotion and on its functional equivalence to metal support interactions. Moreover, current activities and trends in electrochemical promotion, as well as obstacles to overcome for commercial applications, are also discussed.
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