Fabrication of an S-Scheme Heterojunction Photocatalyst MoS2/PANI with Greatly Enhanced Photocatalytic Performance

Synthesis and Photocatalytic Application of Magnetic CoFe2O4/Conjugated Poly(vinyl chloride) Derivative Nanocomposite

CoFe2O4 has potential for application as a magnetically recoverable visible-light photocatalyst, but its photocatalytic activity is encumbered by the high recombination probability of its photogenerated holes (h+) and electrons (e-). This work was undertaken to boost the photocatalysis of CoFe2O4 through coupling with conjugated poly(vinyl chloride) derivative (CPVC). An easily implementable solvothermal-liquid solid mixing-evaporation of the solvent-pyrolysis method was exploited to synthesize CoFe2O4/CPVC nanocomposites. The photocatalytic capabilities of the products were assessed through photocatalyzing the reduction of Cr(VI) under visible-light (λ > 420 nm). The results demonstrate that the optimal CoFe2O4/CPVC nanocomposite (CoFe2O4/CPVC-2) has markedly heightened photocatalytic activity (3.6 times that of CoFe2O4) and competent reusability and is magnetically recoverable. Furthermore, CoFe2O4/CPVC-2 also shows superior performance toward photocatalytic treatment of the diluted Cr(VI)-containing passivation solution of copper alloys. It is deduced based on the photoelectricity measurement results that the increased photocatalysis of CoFe2O4/CPVC-2 is chiefly attributed to its p-n heterojunction structure, which greatly elevates the h+-e- separation and transfer efficiency. When waste PVC plastic films (replacing the new pure PVC powder) were utilized for the synthesis, the obtained CoFe2O4/CPVC nanocomposite exhibited even better photocatalytic activity (4 times that of CoFe2O4). This work not only has made a new magnetically recoverable, efficient visible-light photocatalyst for decontamination of Cr(VI) in water but also is inspirational for recycling PVC plastic waste to produce high-valued visible-light photocatalysts.

Synthesis of the Ag2S/PANI@PES Composite Membrane and Its Antipollution Properties

Membrane separation technology offers a sustainable and efficient solution to wastewater management; however, membrane fouling significantly impedes its application. Photocatalytic membranes, integrating photocatalytic and membrane separation technologies, enhance membrane separation efficacy while effectively mitigating organic and biological contaminations. In this work, Ag2S/PANI@PES composite membranes were prepared via a facile in situ polymerization and successive layer adsorption technique. The modified poly(ether sulfone) (PES) membrane demonstrated improved hydrophilicity and separation performance, and its heterostructure between polyaniline (PANI), Ag0, and Ag2S effectively addressed organic fouling issues. Moreover, Ag2S/PANI@PES exhibited outstanding antimicrobial properties, as well as chemical and mechanical stability.

Oxygen Vacancy-Mediated CuWO4/CuBi2O4 Samples with Efficient Charge Transfer for Enhanced Catalytic Activity toward Photodegradation of Pharmacologically Active Compounds

Photocatalytic degradation is a promising method for controlling the increasing contamination of the water environment due to pharmacologically active compounds (PHACs). Herein, oxygen vacancy (OV)-modulated Z-scheme CuWO4/CuBi2O4 hybrid systems were fabricated via thermal treatment by loading of CuWO4 nanoparticles with OVs on CuBi2O4 surfaces. The synthesized CuWO4/CuBi2O4 hybrid samples exhibited an enhanced photodegradation ability to remove PHACs under visible-light irradiation. More importantly, an optimized sample (10 wt % CuWO4/CuBi2O4) exhibited superior catalytic activity and excellent recycling stability for PHAC photodegradation. In addition, possible degradation paths for PHAC removal over the CuWO4/CuBi2O4 hybrid systems were proposed. The enhanced photocatalytic performance could be attributed to the efficient separation and transfer of photoformed charge pairs via the Z-scheme mechanism. This Z-scheme mechanism was systematically analyzed using trapping experiments of active species, ultraviolet photoelectron spectroscopy, electron spin resonance, and the photodepositions of noble metals. The findings of this study can pave the way for developing highly efficient Z-scheme photocatalytic systems for PHAC photodegradation.