Insight into the Universal Descriptor for Heterogeneous Catalysis

초록

Theoretical calculations are increasingly playing an important role for initial catalysts screening; however, large scale catalysts screening efforts have been stymied by computationally expensive thermodynamics and kinetics calculations. We are in search of some universal descriptors which will be fast and easy to calculate, and can correctly correlate the catalyst activity and selectivity. A promising Pt3V5 sub nanometer size cluster was screened from a pool of bimetallic clusters by using Sabatier’s principle with Bronsted?Evans?Polanyi (BEP) relation for ultra-low-temperature CO oxidation in hydrogen rich environment by simultaneously tuning of CO and H2 adsorption strength and water activation over the Pt3V5 surface, which could make the hydrogen fuel ultra-pure. The kinetic study confirmed the superiority of Pt3V5 over Pt. Using the Sabatier's principle with BEP relations, promising surfaces can be screened but performing all these needs reasonable computational efforts. In this study, we have tried to correlate the adsorption energies with a degree of chemical softness (a descriptor for catalytic activity and selectivity), which is fast and easy to calculate by using the density functional calculations. Finally, we conclude that further insight is needed for the procedure to calculate chemical softness because of poor estimations of energies of so-called virtual orbitals particular for very stable molecules.