Hollow TiO2 spheres with improved visible light photocatalytic activity synergistically enhanced by multi-stimulative: Morphology advantage, carbonate-doping and the induced Ti3

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.

Nano-architectural design of TiO2 for high performance photocatalytic degradation of organic pollutant: A review

In the past several decades, significant efforts have been paid toward photocatalytic degradation of organic pollutants in environmental research. During the past years, titanium dioxide nano-architectures (TiO₂ NAs) have been widely used in water purification applications with photocatalytic degradation processes under Uv/Vis light illumination. Photocatalysis process with nano-architectural design of TiO₂ is viewed as an efficient procedure for directly channeling solar energy into water treatment reactions. The considerable band-gap values and the subsequent short life time of photo-generated charge carriers are showed among the limitations of this approach. One of these effective efforts is the using of oxidation processes with advance semiconductor photocatalyst NAs for degradation the organic pollutants under UV/Vis irradiation. Among them, nano-architectural design of TiO₂ photocatalyst (such as Janus, yolk-shell (Y@S), hollow microspheres (HMSs) and nano-belt) is an effective way to improve oxidation processes for increasing photocatalytic activity in water treatment applications. In the light of the above issues, this study tends to provide a critical overview of the used strategies for preparing TiO₂ photocatalysts with desirable physicochemical properties like enhanced absorption of light, low density, high surface area, photo-stability, and charge-carrier behavior. Among the various nanoarchitectural design of TiO₂, the Y@S and HMSs have created a great appeal given their considerable large surface area, low density, homogeneous catalytic environment, favorable light harvesting properties, and enhanced molecular diffusion kinetics of the particles. In this review was summarized the developments that have been made for nano-architectural design of TiO2 photocatalyst. Additional focus is placed on the realization of interfacial charge and the possibility of achieving charge carriers separation for these NAs as electron migration is the extremely important factor for increasing the photocatalytic activity.

Nanometal Oxides with Special Surface Physicochemical Properties to Promote Electrochemical Detection of Heavy Metal Ions

Heavy metal ions (HMIs) are one of the major environmental pollution problems currently faced. To monitor and control HMIs, rapid and reliable detection is required. Electrochemical analysis is one of the promising methods for on-site detection and monitoring due to high sensitivity, short response time, etc. Recently, nanometal oxides with special surface physicochemical properties have been widely used as electrode modifiers to enhance sensitivity and selectivity for HMIs detection. In this work, recent advances in the electrochemical detection of HMIs using nanometal oxides, which are attributed to specific crystal facets and phases, surficial defects and vacancies, and oxidation state cycle, are comprehensively summarized and discussed in aspects of synthesis, characterization, electroanalysis application, and mechanism. Moreover, the challenges and opportunities for the development and application of nanometal oxides with functional surface physicochemical properties in electrochemical determination of HMIs are presented.

Hollow, Rough, and Nitric Oxide-Releasing Cerium Oxide Nanoparticles for Promoting Multiple Stages of Wound Healing

Wound healing is a complex and sequential biological process that involves multiple stages. Although various nanomaterials are applied to accelerate the wound healing process, only a single stage is promoted during the process, lacking hierarchical stimulation. Herein, hollow CeO₂ nanoparticles (NPs) with rough surface and l-arginine inside (_Ah CeO₂ NPs) are developed as a compact and programmable nanosystem for sequentially promoting the hemostasis, inflammation, and proliferation stages. The rough surface of _Ah CeO₂ NPs works as a nanobridge to rapidly closure the wounds, promoting the hemostasis stage. The hollow structure of _Ah CeO₂ NPs enables the multireflection of light inside particles, significantly enhancing the light harvest efficiency and electron-hole pair abundance. Simultaneously, the porous shell of _Ah CeO₂ NPs facilitates the electron-hole separation and reactive oxygen species production, preventing wound infection and promotion wound healing during the inflammation stage. The enzyme mimicking property of _Ah CeO₂ NPs can alleviate the oxidative injury in the wound, and the released l-arginine can be converted into nitric oxide (NO) under the catalysis of inducible NO synthase, both of which promote the proliferation stage. A series of in vitro and in vitro biological assessments corroborate the effectiveness of _Ah CeO₂ NPs in the wound healing process.

Gas-Phase Photoelectrocatalysis for Breaking Down Nitric Oxide

Photoelectrocatalysis (PEC) produces high-efficiency electron-hole separation by applying a bias voltage between semiconductor-based electrodes to achieve high photocatalytic reaction rates. However, using PEC to treat polluted gas in a gas-phase reaction is difficult because of the lack of a conductive medium. Herein, we report an efficient PEC system to oxidize NO gas by using parallel photoactive composites (TiO₂ nanoribbons-carbon nanotubes) coated on stainless-steel mesh as photoanodes in a gas-phase chamber and Pt foil as the working electrode in a liquid-phase auxiliary cell. Carbon nanotubes (CNTs) were utilized as conductive scaffolds to enhance the interaction between TiO₂ and stainless-steel skeletons for accelerated photogenerated electron transfer. Such a PEC system exhibited super-high performance for the treatment of indoor NO gas (550 ppb) with high selectivity for nitrate under UV-light irradiation owing to the conductive, intertwined network structure of the photoanode, fast photocarrier separation, and longer photogenerated hole lifetime. The photogenerated holes were proven to be the most important active sites for directly driving PEC oxidation of indoor NO gas, even in the absence of water vapor. This work created an efficient PEC air-purification filter for treating indoor polluted air under ambient conditions.