Pd-doped C3N monolayer: A promising low-temperature and high-activity single-atom catalyst for CO oxidation

Abstract

Using the first-principles theory, we theoretically investigated the CO/O2 adsorption and CO oxidation on the Pd-doped C3N (Pd-C3N) monolayer which we proposed as a low-temperature and high-activity catalyst for CO oxidation. Pd dopant is stably anchored on the N vacancy of C3N monolayer, forming the large binding energy of −4.00 eV without the cluster possibility. Given the larger adsorption energy of Pd-C3N monolayer upon O2 compared to CO molecule, we assume that Eley-Rideal (ER) mechanism is the preferred pathway for CO oxidation. For comparison, we also implemented the Langmuir-Hinshelwood (LH) mechanism to comprehensive understand the CO oxidation processes. Our calculations indicated that the energy barriers for ER and LH in the first step are 0.64 and 0.72 eV, with quite large energy drop of 2.99 and 2.0 eV to release a CO2 molecule, respectively. That means, the CO oxidation using Pd-C3N monolayer is fully-energetically favorable even at room temperature, which could give a novel insight into developing novel single-atom catalyst (SAC) based on C3N monolayer with high-efficiency and low-temperature.