Steering and tailoring the chemistry of carbon oxides in heterogeneous catalytic synthesis reactions

In the perspective of a sustainable energy economy, the reduction of CO₂ and CO is attracting increasing attention as a key step towards the synthesis of fuels and valuable chemicals. A possible strategy to develop novel conversion catalysts consists in mimicking reaction centers available in nature, like those in enzymes where Fe, Ni, and Cu play a major role as active metals. The identification of useful descriptors to engineer and tune the reactivity of a surface in the desired way is one of the main objectives of the science of catalysis, with evident applicative interest. To this purpose, a crucial issue is the determination of the relevant active sites and rate limiting steps. This approach can be exploited to design the catalytic activity and selectivity of a NiCu surface, yielding a tailored, continuous tuning of the CO and CO₂ binding energies and reactivity. The results obtained on a model system and interpreted on the basis of ab-initio calculations definitely explain the behavior observed under realistic reaction conditions, yielding general conclusions that may be extended to other bimetallic phases.