Crystallization Regulation Engineering in the Carbon Nitride Nanoflower for Strong and Stable Electrochemiluminescence

Abstract

Cathode electrochemiluminescence (ECL) of C 3 N 4 material has suffered from weak and unstable ECL emission for a long time, which greatly limits its practical application. Herein, a novel approach was developed to improve the ECL performance by regulating the crystallinity of the C 3 N 4 nanoflower for the first time. The high-crystalline C 3 N 4 nanoflower achieved a pretty strong ECL signal as well as excellent long-term stability compared to low-crystalline C 3 N 4 when K 2 S 2 O 8 was used as a co-reactant. Through the investigation, it is found that the enhanced ECL signal is attributed to the simultaneous inhibition of K 2 S 2 O 8 catalytic reduction and enhancement of C 3 N 4 reduction in the high-crystalline C 3 N 4 nanoflower, which can provide more opportunities for SO 4• − to react with electro-reduced C 3 N 4 • − , and a new "activity passivation ECL mechanism" was proposed, while the improvement of the stability is mainly ascribed to the long-range ordered atomic arrangements caused by structure stability in the high-crystalline C 3 N 4 nanoflower. As a benefit from the excellent ECL emission and stability of high-crystalline C 3 N 4 , the C 3 N 4 nanoflower/K 2 S 2 O 8 system was employed as a Cu 2+ detection sensing platform, which exhibited high sensitivity, excellent stability, and good selectivity with a wide linear range from 6 nM to 10 μM and a low detection limit of 1.8 nM.

Electron Transfer Efficiency-Regulated Electrochemiluminescence for Rapid Crystallinity Analysis in Layered Materials

“…It was seen that the maximum emission appeared around 470 nm (Figure b), which is consistent with the ECL emission spectra of the sole CN-modified electrode (Figure S4, Supporting Information). Therefore, the ECL luminophor should be the excited-state CN. − The ECL signals of three repeats of all cases under −1.5–0 V potential were shown in Figure c. The similar ECL intensities of the three repeats indicate the high stability of the ECL probe.…”

Nickel Single-Atom Catalyst Boosts Electrochemiluminescence of Graphitic Carbon Nitride for Sensitive Detection of HBV DNA

“…The unique luminescence mechanism enables ECL technology to exhibit high sensitivity and near-zero background signal, thus being extensively applied in the biosensing field. − ECL luminophore is an essential player in the construction of ECL biosensors. Among the various ECL luminophores that have been developed, graphitic carbon nitride (g-C 3 N 4 ) has aroused considerable attention because of its low toxicity, good biocompatibility, and adjustable luminescence characteristics. − Since Cheng et al first reported the ECL property of g-C 3 N 4 , various g-C 3 N 4 -based nanocomposites and vacancy-modified g-C 3 N 4 have sprung up and been successfully used to construct ECL sensors. − These g-C 3 N 4 -based ECL sensing platforms mainly relied on their cathode ECL emission with peroxydisulfate (S 2 O 8 2– ) as coreactant. As the strong background interference of S 2 O 8 2– cannot be ignored, dissolved oxygen (O 2 ) and H 2 O 2 have been considered as alternative coreactants for enhancing cathodic ECL of g-C 3 N 4 .…”