Carbon Vacancy-Enhanced Activity of Fe–N–C Single Atom Catalysts toward Luminol Chemiluminescence in the Absence of H₂O₂

Abstract

The classic luminol−H 2 O 2 chemiluminescence (CL) systems suffer from easy self-decomposition of H 2 O 2 at room temperature, hindering the practical applications of the luminol−H 2 O 2 CL system. In this work, unexpectedly, we found that the carbon vacancy-modified Fe−N−C single atom catalysts (V C -Fe−N-C SACs) can directly trigger a luminol solution to generate strong CL emission in the absence of H 2 O 2 . The Fe-based SACs were prepared through the conventional pyrolysis of zeolitic imidazolate frameworks. The massive carbon vacancies were readily introduced into Fe−N−C SACs through a tannic acid-etching process. Carbon vacancy significantly enhanced the catalytic activity of Fe−N−C SACs on the CL reaction of luminol− dissolved oxygen. The V C -Fe−N−C SACs performed a 13.4-fold CL enhancement compared with the classic luminol−Fe 2+ system. It was found that the introduction of a carbon vacancy could efficiently promote dissolved oxygen to convert to reactive oxygen species. As a proof of concept, the developed CL system was applied to detect alkaline phosphatase with a linear range of 0.005−1 U/L as well as a detection limit of 0.003 U/L. This work demonstrated that V C −Fe−N-C SAC is a highly efficient CL catalyst that can promote the analytic application of the luminol CL system.

Facile Estimation of Surface Oxygen Vacancies in Co3O4 Catalysts with a Colorimetric Method

“…We investigated the oxygen-related radicals in this reaction through analyzing ESR spectra. In ESR measurement, 2,2,6,6-tetramethyl-4-piperidine (TEMP) was used as a trapping agent for 1 O 2 , and DMPO acted as a trapping agent for • OH and O 2 •– . , As shown in Figure A, one obvious 1:2:2:1-type ESR signal (the characteristic pattern of • OH) was observed, and the characteristic ESR signal of 1 O 2 or O 2 •– was not found. In addition, methanol (an effective scavenger of • OH), tryptophan (an effective scavenger of 1 O 2 ), and SOD (an effective scavenger of O 2 •– ) were added into this TMB-H 2 O 2 -Co 3 O 4 system, respectively.…”

“…•− . 32,46 As shown in Figure 4A, one obvious 1:2:2:1-type ESR signal (the characteristic pattern of • OH 32 ) was observed, and the characteristic ESR signal of 1 O 2 or O 2…”