Electrochemical reduction of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. However, the development of electrocatalysts with high activity and selectivity in a wide potential window is challenging. Herein, atomically thin bismuthene (Bi‐ene) is pioneeringly obtained by an in situ electrochemical transformation from ultrathin bismuth‐based metal–organic layers. The few‐layer Bi‐ene, which possesses a great mass of exposed active sites with high intrinsic activity, has a high selectivity (ca. 100 %), large partial current density, and quite good stability in a potential window exceeding 0.35 V toward formate production. It even deliver current densities that exceed 300.0 mA cm−2 without compromising selectivity in a flow‐cell reactor. Using in situ ATR‐IR spectra and DFT analysis, a reaction mechanism involving HCO3− for formate generation was unveiled, which brings new fundamental understanding of CO2 reduction.
The
detection of hypochlorite (ClO–) content
in tap water is extremely important because excess amounts of hypochlorite
can convert into highly toxic species and inadequate amounts of hypochlorite
cannot fully kill bacteria and viruses. Although several metal–organic
frameworks (MOFs) have been successfully employed as fluorescent sensors
for hypochlorite detection, all these sensors are based on single
emission that responds to the dose of hypochlorite. Ratiometric sensors
are highly desirable, which can improve the sensitivity, accuracy,
and reliability via self-calibration. Herein, a nanoscale dual-emission
multivariate 5-5-Eu/BPyDC@MOF-253-NH2 was synthesized by
sequential mixed-ligand self-assembly and postsynthesis method. Among
the two emission bands of 5-5-Eu/BPyDC@MOF-253-NH2, the
strong blue emitting derived from ligands is sensitive to hypochlorite,
while the red emitting derived from Eu(III) almost keeps invariable.
Therefore, 5-5-Eu/BPyDC@MOF-253-NH2 was exploited as a
fluorescent ratiometric nanosensor for “on–off”
sensing of hypochlorite. Notably, the proposed sensing system showed
an excellent performance including fast response (within 15 s), relative
high specificity, wide linear range (0.1–30 μM), and
low detection limit (0.094 μM). Besides, the suppressed blue
emitting was recovered after the addition of ascorbic acid (AA) that
consumes ClO– via the redox reaction. Therefore,
5-5-Eu/BPyDC@MOF-253-NH2 was further employed as a fluorescent
ratiometric nanosensor for the “on–off–on”
sensing of AA. This work represents the first MOF-based fluorescent
“switch” for the ratiometric sensing of hypochlorite
and the second for ratiometric sensing of AA.
Electrochemical reduction of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. However, the development of electrocatalysts with high activity and selectivity in a wide potential window is challenging. Herein, atomically thin bismuthene (Bi‐ene) is pioneeringly obtained by an in situ electrochemical transformation from ultrathin bismuth‐based metal–organic layers. The few‐layer Bi‐ene, which possesses a great mass of exposed active sites with high intrinsic activity, has a high selectivity (ca. 100 %), large partial current density, and quite good stability in a potential window exceeding 0.35 V toward formate production. It even deliver current densities that exceed 300.0 mA cm−2 without compromising selectivity in a flow‐cell reactor. Using in situ ATR‐IR spectra and DFT analysis, a reaction mechanism involving HCO3− for formate generation was unveiled, which brings new fundamental understanding of CO2 reduction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.