Comparative Study of C₃N- and Graphene-Supported\nSingle-Atom Pt

Abstract

Substrate-supported\nsingle atoms have been of interest in many\nfields, such as magnetism, semiconductors, catalysis, and others.\nAs far as single-atom catalysts (such as Pt, Pd, and Au atoms) are\nconcerned, the substrates play vital roles for the stability and activity\nof single-atom states. A carbon-based two-dimensional material (such\nas graphene) is one sort of potential substrates for single-atom catalysis.\nRecently, C₃N, as a new carbon-based two-dimensional material,\nhas been synthesized and attracted broad attention. We use single-atom\nPt load as a probe to compare the differences of graphene and C₃N substrates. It is found that C₃N substrates have\ninteresting physicochemical properties and significant superiorities.\nOn graphene, the aggregation of Pt atoms easily occurs. However, on\nC₃N, Pt can remain separated from each other with a single-atom\nstate even at a high temperature. On graphene, single-atom Pt is always\npositively charged (Pt⁺). In contrast, both Pt^– and Pt⁺ are observed on perfect and defective C₃N, respectively, which significantly affect molecule adsorption.\nOur calculations suggest that different gas molecules prefer different\ncharge states of Pt. Additionally, Pt-modified defective graphene\nand C₃N are confirmed to have different magnetism. The\nformer is paramagnetic; the latter, conversely, has nonzero magnetic\nmoment. These are instructive to design single-atom nanomaterials\nand nanodevices.