CO oxidation on Ni and Cu embedded graphdiyne as efficient noble metal-free catalysts: A first-principles density-functional theory investigation

Single atom catalysts (SACs) have become the research hotspot on account of the maximum usage of the metal atom and have exhibited preferable catalytic activity. As a new allotrope of carbon, graphdiyne (GDY) has been proposed to be a potential substrate for SACs. CO oxidation on GDY embedded with Ni and Cu atoms (Ni-GDY and Cu-GDY), as a prototype reaction, has been systematically investigated by first-principles density-functional theory calculations. The calculated results show that both Ni and Cu atoms tend to embed at the corner of the acetylenic ring of GDY and the diffusion barriers of Ni and Cu atoms on GDY are rather high. Furthermore, the CO oxidation via Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms are compared. Since the adsorption of CO on Ni-GDY or co-adsorption of CO and O2 on Cu-GDY is more favorable than the adsorption of O2, the CO oxidation prefers to begin with LH reaction with a lower energy barrier and further proceeds with ER reaction. The calculated results presented here demonstrate that GDY is believed to be a promising SAC substrate for CO oxidation, which also provide deeper insights into the design of novel heterogeneous catalysts based on GDY.