C6N3: A novel 2D carbon nitride with sp-N as support for efficient hydrogen production.

Ti, Cr, Zr and Hf embedded novel C 6 N 3 containing sp-N exhibit excellent performance toward hydrogen evolution. [Display omitted] Two-dimensional (2D) carbon nitrides (C x N y) have great potential in advanced fields such as energy harvest and storage. We report a novel 2D C x N y , C 6 N 3 , comprising sp-N and sp2-C atoms. Density functional theory calculations indicate that electronically, thermally, and dynamically stable C 6 N 3 is metallic even when cut into very narrow nanoribbons. C 6 N 3 adsorbed single atoms of 3d, 4d, and 5d transition metals to fabricate single-atom catalysts (SACs) for an electrocatalytic hydrogen evolution reaction (HER). Among all SACs studied, Ti-, Cr-, Zr-, and Hf-embedded C 6 N 3 had excellent overall performance including promising stability, moderate binding strength of H and H 2 , and good electrical conductivity. Our results suggest a novel C 6 N 3 with an sp-N skeleton that has great potential for HER. More investigations are needed to further understand the properties and applications of C 6 N 3 in other fields. [ABSTRACT FROM AUTHOR]