Polymeric tungsten carbide nanoclusters as potential non-noble metal catalysts for CO oxidation

Abstract

The discovery of tungsten carbide (WC) as an analog of the noble metal Pt atom is of great significance toward designing novel highly-active catalysts from the viewpoint of the superatom concept. The potential of such a superatom to serve as building blocks of replacement catalysts for Pt has been evaluated in this work. The electronic properties, adsorption behaviors, and catalytic mechanisms towards the CO oxidation of (WC)_n and Pt_n (n = 1, 2, 4, and 6) were compared. Counterintuitively, these studied (WC)_n clusters exhibit quite different electronic properties and adsorption behaviours from the corresponding Pt_n species. For instance, (WC)_n preferentially adsorbs O₂, whereas Pt_n tends to first combine with CO. Even so, it is interesting to find that the catalytic performances of (WC)_n are always superior to the corresponding Pt_n, and especially, the largest (WC)₆ cluster exhibits the best catalytic ability towards CO oxidation. Therefore, assembling superatomic WC clusters into larger polymeric clusters can be regarded as a novel strategy to develop efficient superatom-assembled catalysts for CO oxidation. It is highly expected to see the realization of non-noble metal catalysts for various reactions in the near future experiments by using superatoms as building blocks.