A light-enhanced α-FeOOH nanowires/polyaniline anode for improved electricity generation performance in microbial fuel cells

Low power density and poor anode performance seriously limit the potential of practical application of microbial fuel cell (MFC). Utilizing solar energy by developing photoanode is one of the effective pathways to improve the performance of MFC. Here solar energy harvesting was integrated into MFC to achieved the comprehensive utilization of multiple energy sources. A hybrid MFC photoanode (α-FeOOH-NWs/PANI anode) was constructed by loading polyaniline (PANI) and α-FeOOH nanowires (α-FeOOH-NWs) on carbon paper through electro-polymerization synthesis method. Compared with clean carbon paper, nanowires and PANI increased the surface roughness of the electrode, which facilitated the biofilm formation. The electrochemical and photoelectric analysis demonstrated that PANI introduced new electroactive groups and reduced the charge transfer resistance, exhibiting excellent electrochemical and photoelectric activites. The MFC with the α-FeOOH-NWs/PANI photoanode had higher voltage output and power density under light illumination, with the power density of 1.95 W/m² under light, which was 1.4 times higher than that without light. The hybrid α-FeOOH-NWs/PANI photoanode enhanced the separation efficiency of photogenerated electron-hole pairs, thereby improving the photoelectric response capability and generating a high photocurrent. Our research provided a new concept for the combination of solar energy harvesting and MFCs, yielding an overall enhancement of electricity eneration performance in MFC.

A novel polyaniline/NiO nanocomposite as a UV and visible-light photocatalyst for complete degradation of the model dyes and the real textile wastewater

The textile processing industry utilizes enormous amounts of water. After the dying process, the wastewater discharged to the environment contains carcinogens, non-biodegradable, toxic, and colored organic materials. This study aimed to develop a nanocomposite material with improved photocatalytic activity to degrade textile dyes and without a need for a post-separation process after the use. For this, nickel oxide nanoparticles (NiO NPs) were synthesized by a simple method in aqueous media. Then, NiO-doped polyaniline (PANI/NiO) with efficient absorption in the visible region (optical band gap of 2.08 eV) synthesized on a stainless steel substrate with electropolymerization of aniline in the aqueous media. The photocatalytic activity of PANI/NiO film was also investigated by the degradation of model dyes. Under UV and visible light irradiation, the PANI/NiO film degraded methylene blue and rhodamine B dyes entirely in 30 min. Moreover, the PANI/NiO film was also utilized to degrade real textile wastewater (RTW) without applying any pre-process; it was entirely decomposed by the nanocomposite film in only 45 min under UV light irradiation. The photocatalytic reaction rate of the pure PANI film is increased as 2.5 and 1.5 times with the addition of NiO NPs under UV and visible light irradiations for degradation RTW, respectively. The photocatalytic efficiency was attributed to reduced electron-hole pair recombination on the photocatalyst surface. Furthermore, the photocatalytic stability is discussed based on re-use experiments. The photocatalytic performance remains nearly unchanged, and the degradation of dyes is kept 94% after five cycles.

Non-enzymatic sensors based on a glassy carbon electrode modified with Au nanoparticles/polyaniline/SnO2 fibrous nanocomposites for nitrite sensing

A non-enzymatic sensor based on Au nanoparticles (AuNPs)/polyaniline (PANI)/tin oxide (SnO₂) nanocomposites (Au/PANI/SnO₂) was prepared for enhanced electrochemical sensing of nitrite (NO₂⁻).

Immobilization of TiO₂ Nanoparticles on Chlorella pyrenoidosa Cells for Enhanced Visible-Light-Driven Photocatalysis

TiO₂ nanoparticles are immobilized on chlorella cells using the hydrothermal method. The morphology, structure, and the visible-light-driven photocatalytic activity of the prepared chlorella/TiO₂ composite are investigated by various methods. The chlorella/TiO₂ composite is found to exhibit larger average sizes and higher visible-light intensities. The sensitization of the photosynthesis pigment originating from chlorella cells provides the anatase TiO₂ with higher photocatalytic activities under the visible-light irradiation. The latter is linked to the highly efficient charge separation of the electron/hole pairs. The results also suggest that the photocatalytic activity of the composite remains substantial after four cycles, suggesting a good stability.

Stable plasmonic Ag/AgCl–polyaniline photoactive composite for degradation of organic contaminants under solar light

A series of novel plasmonic photocatalysts of Ag/AgCl–polyaniline (Ag/AgCl–PANI) were successfully synthesized by deposition–precipitation reaction followed by a photo-reduction method.