construction of the Schottky-junction is considered to be a valid route to boost the spatial charge separation and transfer of the photocatalytic system. Herein, two-dimensional (2D) O-doped g-C 3 N 4 nanosheets were prepared by an annealing route, and then a 2D/2D Ti 3 C 2 MXene/O-doped g-C 3 N 4 Schottky-junction was fabricated using an in-situ electrostatic assembly of negatively charged Ti 3 C 2 MXene and positively charged O-doped g-C 3 N 4 nanosheets. The as-prepared Ti 3 C 2 MXene/O-doped g-C 3 N 4 Schottky-junction exhibited almost two times enhanced hydrogen evolution (25124 μmol/g/h) in comparison to pristine O-doped g-C 3 N 4 (13745 μmol/g/h) and Ti 3 C 2 MXene/pristine C 3 N 4 (15573 μmol/g/h). Based on fully characterizations and theory calculation, the enhanced photocatalytic performance could be attributed to the synergy effect of intimate 2D/2D interfacial contact and the construction of Schottky-junction, which result in the short charge transport distance from HCN to Ti 3 C 2 MXene and efficient separation of the photo-generated charge. This study will provide new insight into developing 2D/2D Schottky-junction photocatalysts for the solution of the energy crisis.
Yao Jie,Chen Hongfang,Yang Xiaohua,Iqbal Muzaffar,Bian Wei
Mercury ions (Hg 2+ ) are categorized as environmental pollutants, which distributed in water, soil, and food systems due to environmental contamination. Hence, designing a sensitive assay for the convenient determination of Hg 2+ is of great importance. Herein, S and O-doped graphite phase nitrogenized carbon quantum dots (S, O-C 3 N 4 QDs) was encapsulated within a europium -based metal-organic framework (Eu-MOF) to construct a novel ratiometric fluorescent nanoprobe for the quantitative detection of Hg 2+ . The native emission of S, O-C 3 N 4 QDs at 445 nm is used as a response signal, while Eu-MOF with fluorescence offers a reference signal at 619 nm. Hg 2+ exhibits high affinity for the surface functional groups of S/O-C 3 N 4 QDs, forming non-fluorescent chelation complexes that induce static quenching. This results in significant attenuation of the fluorescence intensity at 445 nm, while the emission at 619 nm remains invariant. A ratiometric fluorescence sensing platform was established based on the intensity ratio (F 445 /F 619 ) for the selective detection of Hg 2+ . The linear range of S, O-C 3 N 4 QDs/Eu-MOF of Hg 2+ was 0.25–35 µM and with a detection limit of 4.3 nM. The satisfying results demonstrate the effectiveness of the developed S, O-C 3 N 4 QDs/Eu-MOF-based fluorescence probe for Hg 2+ detection, highlighting its promising potential for environmental monitoring applications.
The effective construction of electron transport channels has essential significance for electron-transfer rate enhancement in REDOX processes during peroxymonosulfate (PMS) activation. This study focuses on the establishment of Cu-involved covalent bonds due to the unique electron configuration of Cu ions. The strategy was achieved by anchoring Cu atoms to an O-doped g-C3N4 (Cu–O–CN) matrix. The C–O–Cu linkage was successfully constructed, derived from the precise incorporation of oxygen. From XAFS, H2-TPR, and solid-ESR characteristic observations, the desired REDOX performance was verified. The constructed C–O–Cu linkages were treated as electron transport channels for electron transfer while reacting with PMS, effectively accelerating the REDOX circulation of the Cu(II)/Cu(I) redox couple and promoting the consecutive generation of active species. Consequently, nearly 100% bisphenol A (BPA) was degraded in the Cu–O–CN/PMS reaction system within 30 min. This demonstrates the effectiveness of Cu–O–CN for PMS activation. The prepared Cu–O–CN exhibited definite stability and potential reusability. This research not only highlights the tailored design of heterogeneous catalysts for PMS activation but also broadens its application in water purification.
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