Bimetallic
Pd based catalysts have received tremendous research
interests for many important reactions in fields of important petrochemical
industrial process, fine chemical synthesis, environment protection,
renewable energy conversion, as their specific activity and selectivity
are usually higher than that of pure Pd. With a well-defined composition,
Pd–M bimetallic catalysts are also the ideal platform for the
investigation of the reaction mechanism, which provides a bridge for
the construction of high-performance catalyst. This Review intends
to give an overview of the recent advances on the design principles
of bimetallic Pd based catalyst in term of active sites’ structure
and number, and provide insights into the synergy effects between
Pd and M as well as the supports to understand the elementary mechanisms
of reactions. The Review starts with how the intrinsic activity and
selectivity of different structures (alloy, core–shell, and
Pd/metal compound interface) would be controlled by ligand effect,
strain effect, ensemble effect, and support effect; followed by a
discussion of the structure determined mechanism investigation in
reactions of selective hydrogenation, CO oxidation, methane combustion,
electrocatalytic energy conversion (HER, ORR, MOR), CO2 reduction, H2 production, biomass upgrading, and fine
chemical synthesis; and then introduces the strategies for how to
maximize the active sites’ number in a finite metal load. Finally,
the operando insight into the active sites’ reconstruction
under reaction condition will be discussed. On the basis of this Review,
the experience and generic rules acquired from the design thoughts,
synthetic disciplines, and the functionalities of bimetallic Pd based
catalysts in a given reaction could have an important referential
significance for revealing catalytic mechanisms at the molecular scales
as well as building up other high-efficiency bimetallic catalysts.
