Enhanced photocatalytic degradation of tetracycline using NiCo-BiVO4 nanocomposite under visible light irradiation: A noble-metal-free approach for water remediation

The increasing pollution of water bodies with organic contaminants, including antibiotics, has become a significant environmental concern. In this study, a noble-metal-free alternative, NiCo bimetal cocatalyst, was synthesized and applied to enhance the photocatalytic degradation of the antibiotic tetracycline (TC) using BiVO4 as the photocatalyst under the visible spectrum. The NiCo-BiVO4 nanocomposite exhibited improved visible light absorption, reduced recombination rate of charge carriers, and enhanced electrochemical properties. The photocatalytic degradation of TC was significantly enhanced by the NiCo bimetal modification, with the 2 wt% NiCo-BiVO4 nanocomposite achieving an 87.2% degradation of TC and 82% Total Organic Carbon (TOC) removal within 120 min. The degradation kinetics of TC (target compound) followed a first-order reaction, with photogenerated electrons and holes identified as the primary active species responsible for the degradation process. The recyclability of the catalyst was also demonstrated for multiple runs, indicating its stability. Furthermore, the pathway of TC degradation by 2 wt% NiCo-BiVO4 nanocomposite was proposed based on the detected intermediate products using LC-MS analysis. This study provides a promising approach for developing efficient, noble-metal-free photocatalysts to remove organic contaminants from water sources.

Superior visible light antimicrobial performance of facet engineered cobalt doped TiO2 mesocrystals in pathogenic bacterium and fungi

Pristine and Co-doped TiO2 mesocrystals have been synthesized via a simple sol-gel method and their antimicrobial activity has been investigated. The antimicrobial performance was evaluated in terms of zone of inhibition, minimum inhibitory concentration (MIC), antibiofilm activity, and effect of UV illumination in liquid media. The Co-doped TiO2 mesocrystals showed very promising MIC of 0.390 μg/mL and 0.781 μg/mL for P. mirabilis and P. mirabilis, respectively. Additionally, the material showed an MIC of 12.5 μg/mL against C. albicans, suggesting its use as antifungal agent. Upon the addition of 10.0 µg/mL of Co-doped TiO2 mesocrystals, the biofilm inhibition% reaches 84.43% for P. aeruginosa, 78.58% for P. mirabilis, and 77.81% for S. typhi, which can be ascribed to the created active oxygen species that decompose the tested microbial cells upon illumination. Thus the fabricated Co-doped TiO2 mesocrystals exhibit sufficient antimicrobial features under visible light, qualifying them for use as antimicrobial agents against pathogenic bacteria and fungi and subsequently inhibit their hazardous effects.

A nano-surface monocrystalline BiVO4 nanoplate photoanode for enhanced photoelectrochemical performance

A nano-surface monocrystalline BiVO₄ photoanode with a large surface area is prepared by a low-cost and simple etching process.

Solar-enhanced hybrid lithium-oxygen batteries with a low voltage and superior long-life stability

Lithium-oxygen batteries (LOBs) can suffer from large charge overpotentials during the sluggish oxygen evolution reaction (OER). Here, a strategy used in the photo-electrochemical (PEC) water oxidation area is integrated into hybrid LOBs. Coating α-Fe₂O₃ with NiOOH results in enhanced electrochemical properties, and the as-assembled hybrid LOBs deliver a low charge voltage of 3.03 V, high energy efficiency of 88%, and long-term stability for over 350 hours.

Electrodeposited Co-Substituted LaFeO3 for Enhancing the Photoelectrochemical Activity of BiVO4

Co-substituted LaFeO₃ was electrodeposited on the surface of BiVO₄ as a co-catalyst to enhance the water splitting performance. Compared to bare BiVO₄, the BiVO₄/Co-LaFeO₃ composite photoanode shows a water oxidation photocurrent of 3.4 mA/cm² at 1.23 V versus reverse hydrogen electrode, accompanied by a notable cathodic shift in the onset potential for 300 mV. Combined optical and electrochemical characterizations show that the solid/electrolyte charge transfer efficiency of BiVO₄ are dramatically improved by the incorporation of Co-substituted LaFeO₃. From the surface kinetic study of charge carriers by intensity-modulated photocurrent spectroscopy, a suppressed surface recombination rate constant is observed and the enhanced photoelectrochemical water splitting performance observed in the BiVO₄/Co-LaFeO₃ photoanode is attributed to the surface passivation effect of Co-substituted LaFeO₃.

Fabrication of a TiO2 trapped meso/macroporous g-C3N4 heterojunction photocatalyst and understanding its enhanced photocatalytic activity based on optical simulation analysis

The enhanced photocatalytic performance of a TiO₂ nanoparticle trapped meso/macroporous g-C₃N₄ heterojunction photocatalyst is strongly related to its enhanced light absorption as revealed by optical simulation.