Construction of a Novel Z-Scheme Heterojunction with Molecular Grafted Carbon Nitride Nanosheets and V₂O₅ for Highly Efficient Photocatalysis

Abstract

Molecular grafted carbon nitride (CN) nanosheets coupled with V 2 O 5 to form a novel Z-scheme heterojunction photocatalyst V 2 O 5 /CNX (X is 2-aminobenzonitrile) by a facile in situ growth method was acquired. Its photocatalytic properties were investigated by hydrogen evolution and degradation of rhodamine B under simulated sunlight irradiation. It was found that the assembled heterojunction could remarkably enhance photocatalytic activity in contrast to pure CN, V 2 O 5 , and previous reported heterojunctions. The great improvement of photocatalytic activity can be attributed to molecular grafting and the formation of the Z-scheme heterojunction, resulting in a remarkable red shift of the optical absorption, a rapid separation of charge carriers, an increase of specific surface area, and introduction of defects. Moreover, exfoliation of bulk CNX into ultrathin nanosheets increases mobility of charges and specific surface area. Different wt % ratios of V 2 O 5 -loaded heterojunctions were prepared, and 2% of V 2 O 5 -loaded heterojunctions were found to display optimal catalytic efficiency. The possible activity enhanced mechanism was proposed. This work reveals that the molecular grafted V 2 O 5 /CNX Z-scheme heterojunction can be utilized for highly efficient photocatalysis applied in energy conversion and environmental remediation.

Efficient Solar Light Driven Degradation of Tetracycline by Fe-EDTA Modified g-C3N4 Nanosheets

“…The red-shift of the absorption band edge and the increased absorption in visible light region favor the generation of more charge carriers, resulting in a enhanced photocatalytic activity. The optical band gaps for the semiconductor catalyst can be calculated using the formula in which the α, h , ν, A , and E g represent the absorption coefficient, Planck constant, light frequency, proportionality, and band gap energy, respectively. − The calculated band gaps are about 2.68, 2.715, and 2.69 eV for 2% Fe-EDTA/g-C 3 N 4 , g-C 3 N 4 nanosheets, and bulk g-C 3 N 4 , respectively, corresponding to the diffuse reflectance spectra of the samples. When the bulk g-C 3 N 4 is exfoliated into the g-C 3 N 4 nanosheets, its size and π–π conjugated length are reduced, which leads to increasing of band gap due to the quantum confinement effect. , As the g-C 3 N 4 nanosheets are modified by Fe-EDTA, the Fe ions incorporate into the lattice of g-C 3 N 4 , alter the electronic structures, and form a new impurity band for g-C 3 N 4 which leads to a reduction of the band gap …”

Insight into the Fabrication and Characterization of Novel Heterojunctions of Fe2O3 and V2O5 with TiO2 and Graphene Oxide for Enhanced Photocatalytic Hydrogen Evolution: A Comparison Study

“…Recent studies based on the photocatalytic nature of transition metals (TM), their oxides (TMO), − and their mixed oxides (TMMO) reveal their beneficial properties for the synthesis of photocatalysts during the HER. Among them, TiO 2 is one such material with beneficial properties, such as low cost, consistent stability, nontoxicity, favorable negative reduction band-gap edge potential, and abundant nature, for production of H 2 under light radiation .…”

NiB as a Substitute for the Pt Cocatalyst in CdS with Enhanced Visible-Light Photocatalytic H2 Production

“…As a clean energy source, hydrogen has the potential to replace fossil fuels in the future. − Photocatalytic water splitting has been proved to be the efficient way to sustainably generate H 2 . − For CdS, the bottom level of its conduction band ( E CB ) exhibited a more negative potential than H + /H 2 (0 V), and the top of the valence band ( E VB ) was more positive than the potential of O 2 /H 2 O (1.23 V), thereby meeting the thermodynamic requirement of water splitting . Besides, the band gap of CdS (2.42 eV) was smaller than other catalysts, such as TiO 2 (3.0 eV) and WO 3 (2.8 eV) .…”