G-C₃N₄ has drawn lots of attention due to its photocatalytic activity, low-cost and facile synthesis, and interesting layered structure. However, to improve some of the properties of g-C₃N₄, such as photochemical stability, electrical band structure, and to decrease charge recombination rate, and towards effective light-harvesting, g-C₃N₄–metal oxide-based heterojunctions have been introduced. In this review, we initially discussed the preparation, modification, and physical properties of the g-C₃N₄ and then, we discussed the combination of g-C₃N₄ with various metal oxides such as TiO₂, ZnO, FeO, Fe₂O₃, Fe₃O₄, WO₃, SnO, SnO₂, etc. We summarized some of their characteristic properties of these heterojunctions, their optical features, photocatalytic performance, and electrical band edge positions. This review covers recent advances, including applications in water splitting, CO₂ reduction, and photodegradation of organic pollutants, sensors, bacterial disinfection, and supercapacitors. We show that metal oxides can improve the efficiency of the bare g-C₃N₄ to make the composites suitable for a wide range of applications. Finally, this review provides some perspectives, limitations, and challenges in investigation of g-C₃N₄–metal-oxide-based heterojunctions.

Valorization of lignocellulosic biomass and food residues to obtain valuable chemicals is essential to the establishment of a sustainable and biobased economy in the modern world. The latest and greenest generation of ionic liquids (ILs) are deep eutectic solvents (DESs) and natural deep eutectic solvents (NADESs); these have shown great promise for various applications and have attracted considerable attention from researchers who seek versatile solvents with pretreatment, extraction, and catalysis capabilities in biomass- and biowaste-to-bioenergy conversion processes. The present work aimed to review the use of DESs and NADESs in the valorization of biomass and biowaste as pretreatment or extraction solvents or catalysis agents.

This paper describes the synthesis of 2-substituted and 2,3-disubstituted 4(3H)-quinazolinones via a tandem reaction involving anthranilamides and aromatic aldehydes catalyzed by 3 mol% CuO powder under air atmosphere. This new method has several advantages: it uses recyclable and cheap CuO powder as the catalyst and air as the green oxidant, water is the only byproduct, and the solvent is recycled. It is easy to run, has a high atom economy and good to excellent yields. A mechanism for the CuO-catalyzed synthesis of the 4(3H)-quinazolinones is proposed.

Deep eutectic solvents (DESs) have emerged as promising green solvents, due to their versatility and properties such as high biodegradability, inexpensiveness, ease of preparation and negligible vapor pressure. Thus, DESs have been used as sustainable media and green catalysts in many chemical processes. On the other hand, lignocellulosic biomass as an abundant source of renewable carbon has received ample interest for the production of biobased chemicals. In this review, the state of the art of the catalytic use of DESs in upgrading the biomass-related substances towards biofuels and value-added chemicals is presented, and the gap in the knowledge is indicated to direct the future research.

This review provides a background on the structure and properties of ZnO nanostructures. ZnO nanostructures are advantageous for many applications in sensing, photocatalysis, functional textiles, and cosmetic industries, which are described in this review. Previous work using UV Visible (UV–vis) spectroscopy and scanning electron microscopy (SEM) for ZnO nanorod growth analysis in‐solution and on a substrate for determination of optical properties and morphology is discussed, as well as their results in determining the kinetics and growth mechanisms. From this literature review, it is understood that the synthesis process greatly affects nanostructures and properties; and hence, their applications. In addition, in this review, the mechanism of ZnO nanostructure growth is unveiled, and it is shown that by having greater control over their morphology and size through such mechanistic understanding, the above‐mentioned applications can be affected. The contradictions and gaps in knowledge are summarized in order to highlight the variations in results, followed by suggestions for how to answer these gaps and future outlooks for ZnO nanostructure research.