Boron-Doped and Ketonic Carbonyl Group-Enriched Graphdiyne as a Dual-Site Carbon Nanozyme with Enhanced Peroxidase-Like Activity

We demonstrate the preparation of a dual-site carbon nanozyme, boron-doped and ketonic carbonyl (−C=O) group-enriched graphdiyne (B-GDY), with an enhanced peroxidase-like activity. Taking advantage of acidic oxidation treatment, GDY oxide (GDYO) with abundant surface oxygen-containing groups is obtained from pristine bulk GDY. Upon further thermal annealing of GDYO with H3BO3 under an inert atmosphere, B is introduced into GDY, while the loading of −C=O groups is increased onto B-GDY. We discover that boron-doped and ketonic carbonyl group-enriched graphdiyne as a dual-site carbon nanozyme endows it with an enhanced peroxidase-like activity, which is nearly 4.2-fold higher than that of GDY without B atoms and 6.6-fold higher than that of GDYO without B atoms and with low loading of −C=O groups. The high peroxidase-like activity of B-GDY is ascribed to the dual active sites (−C=O group and B atom) within it, which facilitates the adsorption and decomposition of H2O2 into hydroxyl radicals revealed by experimental and theoretical studies. Moreover, B-GDY is successfully employed to develop a colorimetric method for the detection of glucose with good sensitivity and selectivity. This work probes into the intrinsic peroxidase activity and structure–reactivity correlation, creating effective strategies for the preparation of GDY-based nanozymes.