Isolated Cobalt Atoms on N-Doped Carbon as Nanozymes for Hydrogen Peroxide and Dopamine Detection

Abstract

Single-atom catalysts are becoming a hot research topic owing to their unique characteristics of maximum specific activity and atomic utilization. Herein, atomically dispersed Co on a N-doped carbon matrix with an enzyme-like M–N x structure has been developed as a bifunctional biosensor to detect hydrogen peroxide (H2O2) and dopamine (DA). It features 100% atomic utilization, high electrochemical activity and selectivity, and strong stability in various pH environments. The abundance of Co-N x sites can be increased via regulating calcination temperature, and as a result, the sensing performance is significantly improved. This platform could selectively catalyze the oxidation of DA and the reduction of H2O2 at different holding potentials. The optimal Co-N-C-800 affords high sensitivity (H2O2: 943.9 μA mM–1 cm–2 and DA: 979.6 μA mM–1 cm–2), low detection limit (H2O2: 0.13 μM and DA: 0.04 μM), high selectivity, and robust stability. At the same time, H2O2 and DA released by PC12 can be detected, which proved the feasibility of the enzyme-like single-atomic materials in electrochemical biosensing.

Femtosecond Laser One‐Step Direct Writing Electrodes with Ag NPs‐Graphite Carbon Composites for Electrochemical Sensing

“…[5,42] An imbalance in DA concentrations in the body can cause numerous diseases. [43][44][45][46] A good linear relationship between I P and v 1/2 was also obtained from the CV plot of DA(Figure S7, Supporting Information), indicating that the reaction process of DA may also be controlled by the diffusion process. We performed an electrochemical analysis of DA solutions (PBS, pH = 0.72) at different concentrations using DPV between 0 and +0.4 V. The peak of the DPV curve increases proportionally with the increasing DA concentration (Figure 6a,b), indicating that the sensor has an effective response to DA.…”

Prospects of nano-carbons as emerging catalysts for enzyme-mimetic applications

“…87 These electrochemical detection-based tests could be useful for a clinical diagnosis, like diabetes, kidney dysfunctions, fatty liver, biomarkers detection and cancer diagnosis. 158,159 Wang et al synthesized a gold and cobalt co-doped hollow carbon framework (Au/Co@HNCF)-based nanozyme for the electrochemical detection of uric acid. The synergy of both NPs on the carbon framework enhances the efficiency of the electrochemical sensors, and could go up to the low detection limit of 0.023 mM.…”

Homogeneity of Supported Single‐Atom Active Sites Boosting the Selective Catalytic Transformations

“…[362,370] At present, carbon-based SACs have raised great interest to mimic enzymes because of their favorable stability, flexibility with dopants, and good electrical conductivity. [371] N-Doped carbon materials including nanowires, nanotubes, nanosheets, and MOFs [372,373] have been used to prepare carbon-supported SACs with uniform M-N-C sites to mimic natural metalloenzymes. [374] Fe-N-C SAzymes are synthesized by dispersing single Fe atoms in carbon nanowire-derived and nanotube-derived materials.…”