Synergistic catalysis of N vacancies and ∼5 nm Au nanoparticles promoted the highly sensitive electrochemical determination of lead(ii) using an Au/N-deficient-C3N4 nanocomposite†
Most nanomaterials with good adsorption properties are restricted from being applied in electrochemical detection due to the lack of active sites and poor electrocatalytic reactivity. Here, we found a synergistic catalysis effect of N vacancies and ∼5 nm Au nanoparticles in Au/N-deficient-C3N4 for highly sensitive electrochemical detection of Pb(II) with anti-interference via a defect-engineering strategy. N vacancy defects were introduced into g-C3N4 to prepare N-deficient-C3N4, which showed a significantly enhanced electrochemical sensitivity toward Pb(II) (689.0 μA μM−1 cm−2). The sensitivity of Au/N-deficient-C3N4 dramatically rose to 1223.0 μA μM−1 cm−2 because of the synergistic catalysis effect, which was approximately 4 times as large as that of pure g-C3N4. The N vacancies in g-C3N4 could greatly improve the selective adsorption of Pb(II), and ∼5 nm Au nanoparticles enhanced the catalysis of materials. High concentration of other common ions (Hg(II), Cu(II), or Cd(II)) did not interfere in the electrochemical detection of Pb(II). A strong chemical interaction between Pb(II) and Au/N-deficient-C3N4 was confirmed by X-ray photoelectron spectroscopy results, which was possibly responsible for the anti-inference properties. This work provides a new method to make semiconductors with intrinsically poor electrochemical activity potential materials in the electrochemical analysis field by defect-engineering and synergistic catalysis.