Search

[Display omitted] • BPQDs are prepared by a sonication-assisted liquid exfoliation method. • BPQDs sensitized g-C 3 N 4 photocatalyst is used in the degradation of PVA. • Accelerated flow of photoinduced electrons can occur from g-C 3 N 4 to BPQDs. • A Z-scheme charge transfer route is supposed for the photocatalytic process. • Theoretical results for electron transfer agree well with experiment tests. To address the pollution caused by polyvinyl alcohol (PVA) waste, a composite photocatalyst is developed by sensitizing g-C 3 N 4 with black phosphorus quantum dots (BPQDs) using a simple mechanical stirring method. Both g-C 3 N 4 and BPQDs are inorganic nonmetallic semiconductors with well-matched band positions, facilitating efficient photoinduced charge transfer. The periodic table's adjacent relationship between C, N and P elements allows easy formation of P-N or P-C bonds by replacing C or N atoms with P atoms. The resulting composite shows uniform decoration of two-dimensional layered g-C 3 N 4 with BPQDs with an average size of 2.2 nm. Under solar light simulator irradiation for 20 min, the composite photocatalyst exhibits significantly enhanced photocatalytic activity, with PVA degradation efficiency increasing from 27.1% (pure g-C 3 N 4) to 85.9%. Experimental results and density functional theoretical calculations suggest the formation of a Z-scheme route at the g-C 3 N 4 /BPQDs interface. This facilitates photoinduced electron transfer from g-C 3 N 4 to BPQDs, leading to improved carrier production and separation, reduced charge-transfer resistance, and accelerated PVA degradation. The proposed composite photocatalyst holds promise for addressing PVA pollution and improving environmental sustainability. [ABSTRACT FROM AUTHOR]

Copper nanoparticles (NPs) deposited on the surface of self-organized highly ordered TiO 2 nanotube arrays (Cu/TiO 2 NTs) were synthesized by electrochemical anodization and the successive ionic layer adsorption and reaction technique. The morphology, elemental composition, crystallinity, light absorption ability and photoelectrochemical property of the as-prepared Cu/TiO 2 NTs electrode were distinguished based on various characterizations. X-ray photoelectron spectroscopy showed that the Cu NPs existed as Cu(II)O and Cu(I) 2 O on the TiO 2 surface. The current–voltage curve of Cu/TiO 2 NTs electrode indicated a rectifying behavior. The surface sensitization of TiO 2 NTs by CuO and Cu 2 O NPs enhanced the absorption of visible light. Meanwhile, the enhanced charge separation was demonstrated by electrochemical impedance spectroscopy, transient photocurrent response and photovoltage measurements. Besides, Cu/TiO 2 NTs electrode showed more effective photoconversion efficiency and enhanced photoelectrocatalytic activity towards the degradation of diclofenac than pure TiO 2 NTs electrode under simulated solar light irradiation, which was attributed to the synergistic effects between nanotubular structures of TiO 2 and uniformly dispersed copper nanoparticles, as well as the small bias potential. Furthermore, the photoelectrocatalytic mechanism was proposed and the possible radical species involved in the photoelectrocatalytic degradation of diclofenac were analyzed by active species trapping. The Cu/TiO 2 NTs electrode exhibited high reusability. [ABSTRACT FROM AUTHOR]