Laser-derived porous carbon as a metal-free electrocatalyst for oxygen evolution reaction

Laser‐Patterned Carbon‐Supported Graphitic Carbon Nitride Quantum Dots for Flexible Nanozyme‐Based Fluoride Sensor

“…Five nitrogen‐based species are determined from the N 1s line (Figure 4f), namely, pyridinic (N6) (398.6 ± 0.1) eV, amide (399.6 ± 0.2) eV, pyrrolic (N5) (400.1 ± 0.1) eV, graphitic N (401.2 ± 0.2) eV, and quaternary N species at (401.8 ± 0.2) eV. [ 20 ] The C 1s spectrum of g‐CNQDs/LP‐C has been deconvoluted into five species (Figure 4h): CC (284.60 ± 0.1 eV), CC (285.12 ± 0.1 eV), CNH 2 (286.12 ± 0.2 eV), NCN (288.24 ± 0.2 eV), and OCOH (288.9 ± 0.2 eV). The N 1s spectrum has been deconvoluted into the two coordinated nitrogen species, CNC (398.42 eV), three coordinated nitrogen species, N(C) 3 (399.90 ± 0.2 eV) and NH (401.81 ± 0.2 eV) species (Figure 4i).…”

“…Fabrication of LP‐C was carried out in parallel, which is described in detail elsewhere. [ 20 ] For fabrication of g‐CNQDs/LP‐C nanozyme assembly, g‐CNQDs ink was prepared by mixing 200 µL QDs with 10 µL of Nafion‐117 solution. This suspension was sonicated for 2 h, thereafter 30 µL of the ink was drop‐casted upon LP‐C (5 × 10 mm) and air dried at 80 °C for 60 min.…”

“…Raman spectra and XRD analysis of LP-C are reported elsewhere. [17,20] The optical properties of g-CNQDs were studied using UV-vis and fluorescence spectroscopies and are provided in the Supporting Information (Figure S1). The UV absorbance spectrum of g-CNQDs shows two prominent absorbance peaks at 350 and 245 nm (Figure S1a, Supporting Information) owing to n-𝜋* and 𝜋-𝜋* electronic transitions from C=N-C species and C=C species, respectively.…”

“…Owing to its fascinating physicochemical characteristic, LP-C has been used in various applications such as biomedical sensors, [18] supercapacitors, [19] and electrocatalysis. [16,20] However, its utilization as a catalytic support in flexible devices has not been explored to its full potential. [21,22] One plausible reason is the lack of understanding of the surface chemistry of LP-C, which is influenced by fabrication parameters as well as substrate composition.…”

“…LP‐C contains pyrrolic, pyridinic as well as graphitic‐N in a π ‐electron‐rich carbon network. [ 20 ] Therefore, this material was expected to participate in the electronic transitions during fluoride ion sensing in the nanozyme‐based sensors reported here. To our pleasant surprise, LP‐C not only participated but significantly enhanced the sensitivity of the device rather than being counter‐effective to the g‐CNQDs activity.…”