A New Strategy for Improving the Efficiency of Low-temperature Selective Catalytic Reduction of NOx with CH4via the Combination of Non-thermal Plasma and Ag2O/TiO2 Photocatalyst

Advances in Hybrid Composites for Photocatalytic Applications: A Review

Heterogeneous photocatalysts have garnered extensive attention as a sustainable way for environmental remediation and energy storage process. Water splitting, solar energy conversion, and pollutant degradation are examples of nowadays applications where semiconductor-based photocatalysts represent a potentially disruptive technology. The exploitation of solar radiation for photocatalysis could generate a strong impact by decreasing the energy demand and simultaneously mitigating the impact of anthropogenic pollutants. However, most of the actual photocatalysts work only on energy radiation in the Near-UV region (<400 nm), and the studies and development of new photocatalysts with high efficiency in the visible range of the spectrum are required. In this regard, hybrid organic/inorganic photocatalysts have emerged as highly potential materials to drastically improve visible photocatalytic efficiency. In this review, we will analyze the state-of-art and the developments of hybrid photocatalysts for energy storage and energy conversion process as well as their application in pollutant degradation and water treatments.

Carbon Dioxide Conversion Synergistically Activated by Dielectric Barrier Discharge Plasma and the CsPbBr3@TiO2 Photocatalyst

Carbon dioxide utilization activated by the integration of plasma and photocatalyst is a promising approach to achieve the mitigation of the greenhouse effect. In this paper, for the first time, the dielectric barrier discharge (DBD) plasma and halide perovskite photocatalysts were synergistically used to facilitate the carbon dioxide conversion. After introducing the photocatalyst into the plasma reactor, the plasma discharge characteristics were improved by the photocatalyst while the active photons, electrons, and vibrationally excited molecules in plasma also enhanced the photocatalytic activity of the photocatalyst. Compared with pure CsPbBr₃ and Al₂O₃, the CsPbBr₃@TiO₂ with the best photocatalytic activity also exhibited the best performance in plasma. The carbon dioxide conversion rate of the DBD plasma filled with CsPbBr₃@TiO₂ was found to be 29.6% higher than the sum of sole plasma and photocatalysis, illustrating the achievement of the synergistic effect between the plasma and photocatalyst. This work brings up new opportunities for efficient large-scale conversion and utilization of carbon dioxide by the coupling of nonthermal plasma and photocatalysis.

The Bibliometric Analysis and Review of the Application of Plasma in the Field of VOCs

The application of plasma in the field of volatile organic compounds (VOCs) can be traced back to the 1990s and has gradually developed into an important research field. In this regard, this article primarily sorts and analyzes the literature on the “application of plasma in the field of VOCs” in the Web of Science core collection database from 1992 to 2021 and, subsequently, obtains important data and trends, including the annual number of articles published, country, institution analysis, and journal, as well as discipline analysis, etc. The results show that China is not only in a leading position in the field of research, but also has six top-ten research institutions. This field has more research results in engineering, chemistry, physics, and environmental disciplines. In addition, this article summarizes dielectric barrier discharge (DBD) and titanium-containing catalysts, which represent the discharge characteristics and type of catalyst highlighted through the hot keywords. This review will provide certain guidance for future, related research.

In-plasma-catalysis for NO x degradation by Ti3+ self-doped TiO2-x /γ-Al2O3 catalyst and nonthermal plasma

In an attempt to realize the efficient treatment of NO_x, a mixed catalyst of Ti³⁺ self-doped TiO_2−x and γ-Al₂O₃ was constructed by reducing commercial TiO₂. The degradation effect on NO_x was evaluated by introducing the mixed catalyst into a coaxial dual-dielectric barrier reactor. It was found that the synthesized TiO_2−x could achieve considerable degradation effects (84.84%, SIE = 401.27 J L⁻¹) in a plasma catalytic system under oxygen-rich conditions, which were better than those of TiO₂ (73.99%) or a single plasma degradation process (26.00%). The presence of Ti³⁺ and oxygen vacancies in TiO_2−x resulted in a relatively narrow band gap, which contributed to catalyzing deeply the oxidation of NO_x to NO₂⁻ and NO₃⁻ during the plasma-induced “pseudo-photocatalysis” process. Meanwhile, the TiO_2−x showed an improved discharge current and promoted discharge efficiency, explaining its significant activation effect in the reaction. Reduced TiO_2−x could achieve an impressive degradation effect in a long-time plasma-catalysis process, and still maintained its intrinsic crystal structure and morphology. This work provides a facile synthesis procedure for preparing Ti³⁺ self-doped TiO_2−x with practical and scalable production potential; moreover, the novel combination with plasma also provides new insights into the low-temperature degradation of NO_x.

TiO_2−x has a smaller forbidden band width, more abundant Ti³⁺ and oxygen vacancies, so as to obtain a better and more stable degradation effect of NO_x in plasma-catalysis process.

Steering Hollow Multishelled Structures in Photocatalysis: Optimizing Surface and Mass Transport

Hollow multishelled structures (HoMSs) provide a promising platform for fabricating photocatalysts, because the unique structure optimizes the effective surface and mass transport, showing enhanced light absorption, optimized mass transport and highly effective active sites exposed. Subsequently, the rational design on HoMS photocatalytsts is elaborated to boost the photocatalytic activity with efforts in all dimensions, from nanoscale to microscale. Breakthroughs in synthetic methodology of HoMSs have greatly evoked the prosperous photocatalytic researches for HoMSs since the developing of sequential templating approach in 2009. The dawn of HoMS photocatalyst is coming after revealing the temporal-spatial ordering property, which is also discussed in this paper with pioneer works demonstrating the greatly enhanced energy/mass transfer processes. Some insights into the key challenges and perspectives of HoMSs photocatalysts are also discussed. With the reviewed fate and future of HoMSs photocatalysts, hopefully new concepts and innovative works can be inspired to flourish this sun-rise field.