Single Layer of Polymeric Cobalt Phthalocyanine: Promising Low-Cost and High-Activity Nanocatalysts for CO Oxidation

The catalytic behavior of transition metals (Sc to Zn) combined in polymeric phthalocyanine (Pc) is investigated systematically by using first-principles calculations. The results indicate that CoPc exhibits the highest catalytic activity for CO oxidation at room temperature with low energy barriers. By exploring the two well-established mechanisms for CO oxidation with O-2, namely, the Langmuir-Hinshelwood (LH) and the Eley-Rideal (ER) mechanisms, it is found that the first step of CO oxidation catalyzed by CoPc is the LH mechanism (CO + O-2 CO2 + O) with energy barrier as low as 0.65 eV. The second step proceeds via both ER and LH mechanisms (CO + O CO2) with small energy barriers of 0.10 and 0.12 eV, respectively. The electronic resonance among Co-3d, CO-2*, and O-2-2* orbitals is responsible for the high activity of CoPc. These results have significant implications for a novel avenue to fabricate organometallic sheet nanocatalysts for CO oxidation with low cost and high activity.