Nucleobase-mediated synthesis of nitrogen-doped carbon nanozymes as efficient peroxidase mimics

Abstract

Carbon nanozymes are catalytic carbon nanomaterials with intrinsic enzyme-like activities. They are advantageous over their natural counterparts in terms of higher stability, lower preparation cost, and better robustness. However, the peroxidase-like activities of the most developed carbon nanozymes were moderate due to the imperfection of active centers and limited tuning strategies. Herein, we designed a novel class of efficient peroxidase-mimicking carbon nanozymes with nitrogen atom doping. The N-doped carbon nanozymes were facilely synthesized by direct pyrolysis of different nucleobases at controlled temperatures without other treatments. A high ratio of nitrogen atoms was doped into the carbon skeleton. For example, 8.77 wt% of N remained in the guanine-derived carbon nanozyme with a pyrolysis temperature of 900 °C. The dominant graphitic N species greatly boosted the peroxidase-like activities of nucleobase-derived carbon nanozymes. Moreover, nucleobases are cheap, abundant, and environmentally friendly. We have demonstrated that nitrogen-rich nucleobases are ideal starting materials for the large-scale and cost-effective synthesis of N-doped carbon nanozymes. The carefully designed N-doped carbon nanozymes with superior activities were further used to construct effective biosensors for bioactive molecules (i.e., H₂O₂ and glucose). Highly sensitive and selective detection of H₂O₂ and glucose was achieved using the N-doped carbon nanozymes as efficient peroxidase mimics. This study offers an economical and sustainable approach for the scalable preparation of N-doped carbon nanozymes and creates a new path for the rational design of efficient peroxidase-mimicking carbon nanozymes by heteroatom doping.