Mutual self-regulation of d electrons of single atoms and adjacent nanoparticles for acetaldehyde manufacture

Metal-support interactions in catalysis impose fundamental limitations on maximum activity. Here, we show that the constraint relationship of local electronic and geometric structures of carbon-supported palladium (Pd) catalysts can be broken through the synergy between the Pd-Pd and the Pd-B coupling interaction, producing a class of densely populated entities with unique negatively charged properties. A volcano-shaped curve that depicts the relationship between Pd Bader charge and neighboring atomic distance is established, thereby optimizing catalytic performance. Acetaldehyde manufacture via acetylene hydration is used as our study case. Outstanding performance can be triggered over the densely populated Pd single-atom and nanoparticle co-catalytic sites compared with individual Pd sites. The effect is attributed to the negative charge and high-density effect of Pd-BN₃ sites, which easily adapt their structures to binding C₂H₂ and H₂O and varying reaction routes. This approach provides practical insights for the design of Pd-based catalysts comprising well-defined electronic and geometric structures.