HCOOH decomposition over the pure and Ag-modified Pd nanoclusters: Insight into the effects of cluster size and composition on the activity and selectivity

Abstract

This work is designed to examine the size and composition effects of the pure and Ag-modified Pd nanoclusters on the activity and selectivity of HCOOH decomposition using DFT calculations and microkinetic modeling, Pdn(n = 13,38,55) and Agm@Pdn(m + n = 13,38,55) nanoclusters are considered. The results show that HCOOH decomposition dominantly undergoes COOH intermediate instead of HCOO intermediate, and CO2 formation is more favorable than CO formation. The pure and Ag-modified Pd nanoclusters with the small size exhibit higher activity and selectivity toward CO2 formation; meanwhile, when the nanocluster size is the same, compare to the pure Pd, the Ag composition improves the activity and selectivity toward CO2 formation, and decreases the usage of noble-metal Pd. The better catalytic performance is attributed to that the d-band center is more close to the Fermi level. The results provide a method for improving catalytic performance of Pd-based nanoclusters by adjusting the size and core composition of the nanocluster.