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Developing metal-free electrocatalysts is vitally significant for oxygen molecule dissociation. Graphdiynes (GDY) doped with nonmetal atoms are designed and optimized as metal-free electrocatalysts, and their oxygen molecule dissociation catalytic performances are evaluated by density functional theory. The results of formation energies and cohesive energies reveal that the most favorable site for B, Si, P, S, As, Se and Te doping is the sp 2-C atom at benzene ring (X-b), the most preferred sites for N and O doping is the sp -C atom nearest benzene ring at the chain (X-1 GDY). The O 2 molecules are chemisorbed on B, N, O, Si, P, S-doped GDYs, the O O bonds increase from 1.23 Å to 1.39–1.57 Å. But, the O 2 dissociation activation barrier on B, O, Si, P, S-doped GDY monolayers is up to 1.31–4.01 eV, indicating that this reaction is difficult to occur at room temperature. The O 2 is physisorbed on As, Se and Te-doped GDY monolayers with a distance between O 2 and GDY planes of 2.40–2.77 Å. The N-doped GDY has a small dissociation activation barrier of 0.90 eV, which may be a metal-free catalyst. The calculations promote further application of heteroatom doped GDYs on oxygen reduction reaction and other reactions. Unlabelled Image • Si-b GDY is semiconducting, B-b GDY exhibits p-type doping, while other doped GDYs exhibit n-type doping. • B-b, N-1, O-1, Si-b, P-b, S-b doped GDYs GDYs and pristine GDY could increase the O-O bond from 1.23 to 1.39~1.57 Å. • The O 2 is physisorbed on As, Se and Te-doped GDY monolayers with a distance between the O 2 and GDY planes of 2.40~ 2.77 Å. • O 2 →O+O reaction is difficult to occur on doped GDY monolayers with the activation barrier is more than 0.90 eV. [ABSTRACT FROM AUTHOR]

Density functional theory calculations are carried out to study the electronic structures and magnetic properties of single X (X = B, N, O, P, S) atom doped graphdiyne (GDY) monolayers. It is found that there are three distinct doped models (one benzene ring site X-b, two acetylene linkage sites X-1, X-2), and the heteroatom (B, N, O, P, S) doping site has a serious effect on the electronic structure and magnetic properties of GDYs. The results of cohesive energies reveal that the B and S atoms prefer to substitute the sp 2-hybridized C atom at benzene ring, while N, O, P atoms prefer to substitute the sp -hybridized C atom at acetylene linkage. For B, N, O, S-doped GDYs exhibit metallic character, while P-1, P-2 doped GDYs present semiconductor character. The X-1, X-2 (X = B, O, P, S) GDYs with heteroatom at chain site introduce spin polarization, and are magnetic, whereas the X-b (X = B, O, P, S) doped GDYs are nonmagnetic. The N doping site has no impact on its magnetic properties, and all the N doped GDYs are nonmagnetic. The research results offer a theoretical support that heteroatom doping plays an important role in tuning the electronic structures and magnetic properties of GDYs. Image 1 • B-doped GDYs exhibit p-type doping character. • N, O, P and S-doped GDYs exhibit electron doping properties and n-type doping character. • X-1, X-2 (X = B, O, P, S) doped GDYs with heteroatom at acetylene linkage are magnetic. • X-b (X = B, O, P, S) doped GDYs with heteroatom at benzene ring are nonmagnetic. [ABSTRACT FROM AUTHOR]