One-step hydrothermal synthesis of SnO2-MoS2 composite heterostructure for improved visible light photocatalytic performance

Photo-Assisted Chemical Self-Rechargeable Zinc Ion Batteries with High Charging and Discharging Efficiency

Chemical self-recharging zinc ion batteries (ZIBs), which are capable of auto-recharging in ambient air, are promising in self-powered battery systems. Nevertheless, the exclusive reliance on chemical energy from oxygen for ZIBs charging often would bring some obstacles in charging efficiency. Herein, we develop photo-assisted chemical self-recharging aqueous ZIBs with a heterojunction of MoS2/SnO2 cathode, which are favorable to enhancing both the charging and discharging efficiency as well as the chemical self-charging capabilities under illumination. The photo-assisted process promotes the electron transfer from MoS2/SnO2 to oxygen, accelerating the occurrence of the oxidation reaction during chemical self-charging. Furthermore, the electrons within the MoS2/SnO2 cathode exhibit a low transfer impedance under illumination, which is beneficial to reducing the migration barrier of Zn2+ within the cathode and thereby facilitating the uniform inserting of Zn2+ into MoS2/SnO2 cathode during discharging. This photo-assisted chemical self-recharging mechanism enables ZIBs to attain a maximum self-charging potential of 0.95 V within 3 hours, a considerable self-charging capacity of 202.5 mAh g-1 and excellent cycling performance in a self-charging mode. This work not only provides a route for optimizing chemical self-charging energy storage, but also broadens the potential application of aqueous ZIBs.

Advanced photocatalysis as a viable and sustainable wastewater treatment process: A comprehensive review

In our era, water pollution not only poses a serious threat to human, animal, and biotic life but also causes serious damage to infrastructure and the ecosystem. A set of physical, chemical, and biological technologies have been exploited to decontaminate and/or disinfect water pollutants, toxins, microbes, and contaminants, but none of these could be ranked as sustainable and scalable wastewater technology. The photocatalytic process can harmonize the sunlight to degrade certain toxins, chemicals, microbes, and antibiotics, present in water. For example, transition metal oxides (ZnO, SnO2, TiO2, etc.), when integrated into an organic framework of graphene or nitrides, can bring about more than 90% removal of dyes, microbial load, pesticides, and antibiotics. Similarly, a modified network of graphitic carbon nitride can completely decontaminate petrochemicals. The present review will primarily highlight the mechanistic aspects for the removal and/or degradation of highly concerned contaminants, factors affecting photocatalysis, engineering designs of photoreactors, and pros and cons of various wastewater treatment technologies already in practice. The photocatalytic reactor can be a more viable and sustainable wastewater treatment opportunity. We hope the researcher will find a handful of information regarding the advanced oxidation process accomplished via photocatalysis and the benefits associated with the photocatalytic-type degradation of water pollutants and contaminants.

Hierarchical Ultrathin Layered GO-ZnO@CeO2 Nanohybrids for Highly Efficient Methylene Blue Dye Degradation

Highly efficient interfacial contact between components in nanohybrids is a key to achieving great photocatalytic activity in photocatalysts and degradation of organic model pollutants under visible light irradiation. Herein, we report the synthesis of nano-assembly of graphene oxide, zinc oxide and cerium oxide (GO-ZnO@CeO₂) nanohybrids constructed by the hydrothermal method and subsequently annealed at 300 °C for 4 h. The unique graphene oxide sheets, which are anchored with semiconducting materials (ZnO and CeO₂ nanoparticles), act with a significant role in realizing sufficient interfacial contact in the new GO-ZnO@CeO₂ nanohybrids. Consequently, the nano-assembled structure of GO-ZnO@CeO₂ exhibits a greater level (96.66%) of MB dye degradation activity than GO-ZnO nanostructures and CeO₂ nanoparticles on their own. This is due to the thin layers of GO-ZnO@CeO₂ nanohybrids with interfacial contact, suitable band-gap matching and high surface area, preferred for the improvement of photocatalytic performance. Furthermore, this work offers a facile building and cost-effective construction strategy to synthesize the GO-ZnO@CeO₂ nanocatalyst for photocatalytic degradation of organic pollutants with long-term stability and higher efficiency.

Crystal facets effect of tin dioxide nanocrystals on photocatalytic degradation and photo-assisted gas sensing properties

Crystal facets effects have been widely concerned in the field of photocatalysis and gas sensing in recent years. However, little attention have been paid to the crystal facets effect of...

Recent insights into SnO2-based engineered nanoparticles for sustainable H2 generation and remediation of pesticides

Due to the ongoing industrial revolution and global health pandemics, solar-driven water splitting and pesticide degradation are highly sought to cope with catastrophes such as depleting fossil reservoirs, global warming, and environmental degradation.

Highly active Z-scheme heterojunction photocatalyst of anatase TiO2 octahedra covered with C-MoS2 nanosheets for efficient degradation of organic pollutants under solar light

The construction of a Z-scheme photocatalyst by coupling semiconductors with conductors is an efficient way to achieve high pollutant degradation efficiency. In this study, a hydrothermal approach was used to fabricate a Z-scheme photocatalyst consisting of C-MoS₂ sheets wrapped around octahedral anatase TiO₂ nanocrystals. The catalyst showed excellent photocatalytic efficiency (99%) for methylene blue degradation with low catalyst loading (0.2 g L^-1) under the simulated solar light within 60 min. High photocatalytic degradation efficiencies were also observed for Rhodamine B, methyl orange, and tetracycline under solar irradiation. The C-MoS₂ acts as an electron mediator and serves as a carrier transmission bridge for the efficient electron-hole separation. The electron-rich (101)-faceted TiO₂ benefits the Z-scheme recombination of electrons from the conduction band of TiO₂ and holes at the valence band of MoS₂. The semiconductor coupling of (101)-exposed octahedral TiO₂ and 2H-MoS₂ as well as the introduction of solid-state electron mediators, 1T-MoS₂ and carbon, resulted in increased light absorption and accelerated charge transfer at the contact interface, which enhanced the photocatalytic activity of the photocatalyst significantly compared to those of P25, MoS₂/TiO₂, and C-MoS₂. The efficient separation of electron-hole pairs prolongs their lifetime for oxidation and reduction reactions in the degradation process.

Recent Advances of Photocatalytic Application in Water Treatment: A Review

Photocatalysis holds great promise as an efficient and sustainable oxidation technology for application in wastewater treatment. Rapid progress developing novel materials has propelled photocatalysis to the forefront of sustainable wastewater treatments. This review presents the latest progress on applications of photocatalytic wastewater treatment. Our focus is on strategies for improving performance. Challenges and outlooks in this promising field are also discussed. We hope this review will help researchers design low-cost and high-efficiency photocatalysts for water treatment.

Hierarchical ultrathin layered MoS2@NiFe2O4 nanohybrids as a bifunctional catalyst for highly efficient oxygen evolution and organic pollutant degradation

Rational design and highly efficient dual-functional catalyst are still difficult to develop for electrocatalytic oxygen evolution reaction and degradation of RhB dye pollutant. Herein, we report a highly efficient "bandgap matching and interfacial coupling" strategy to synthesize nano-assembled ultrathin layered MoS₂@NiFe₂O₄ (MS@NiFeO) bifunctional catalyst constructed by the hydrothermal route and subsequently amine-hydrolysis. The OER performance of the prepared MS@NiFeO catalyst delivers a low overpotential of 290 mV at 10 mA/cm² and Tafel slope is 69.2 mV dec^-1 in an alkaline solution. In addition, the nano-assembled ultrathin layered structure of MS@NiFeO showed a highly efficient (96.37%) RhB dye degradation performance than that of MoS₂ nanosheets and NiFe₂O₄ nanostructures. Unique nanostructure of ultrathin layered MS@NiFeO with suitable band matching, interfacial charge transfer, high surface area and more active sites favored for the enhancement of the catalytic activity. This work presents an unpretentious construction and low-cost production strategy to synthesize bifunctional hybrid catalyst for oxygen evolution reaction as well as degradation of organic pollutant with superior efficiency and longer stability.

Loading SnS2 nanosheets decorated with MoS2 nanoparticles on a flake-shaped g-C3N4 network for enhanced photocatalytic performance

A g-C₃N₄/MoS₂/SnS₂ ternary composite photocatalyst with a unique photo-generated carrier transfer pathway is obtained, which exhibits excellent photocatalytic activity.

One-step synthesis of ZnS@MoS2 core–shell nanostructure for high efficiency photocatalytic degradation of tetracycline

Four kinds of ZnS@MoS₂ nanocomposite photocatalysts were successfully prepared via a facile hydrothermal method.