Boosting ORR/OER Activity of Graphdiyne by Simple Heteroatom Doping

Nitrogen-doped graphdiynes recently emerged as promising metal-free oxygen reduction reaction (ORR) electrocatalysts. However, which type of N-dopants contributing to the enhanced catalytic performance and the catalytic performances of other heteroatom-doped graphdiynes has not been explored systematically. Herein, ORR and oxygen evolution reaction (OER) catalytic performances of X-doped graphdiynes are examined by means of DFT computations (X = B, N, P, and S). It is revealed that the graphitic S-doped graphdiyne (Model S1), the sp-N-doped graphdiyne (Model N3) and the graphitic P-doped graphdiyne (Model P1) exhibit comparable or even better ORR/OER activities than Pt/C or RuO2, with ORR activity trend as Model S1 > Pt/C > Model N3 and OER trend as Model P1 > RuO2 > Model N3. The carbon atoms near N- and S-dopants and featuring large positive charge are the ORR active sites in Models N3 and S1, whereas the carbon atoms near N- and P-dopants and possessing high spin are the OER active sites in Models N3 and P1. Overall, this study not only gains deep insights into the catalytic activity of N-doped graphdiyne for ORR, but also guides developing of graphdiyne-based ORR/OER catalysts beyond N-doping.