N.R. Khalid

Nanostructured-based WO 3 photocatalysts: recent development, activity enhancement, perspectives and applications for wastewater treatment

The growth of highly ordered architectures of semiconductor metallic oxide photocatalyst has acknowledged great consideration due to natural growth along with exceptional morphology properties and potential application ways to resolve the problem of freshwater shortages in this world. Tungsten trioxide (WO3) is a well-known semiconductor photocatalyst due to its better response in solar spectrum, fine metal interactions, mechanical strength, high efficiency, harmlessness and cost-effectiveness. This review focuses on a precise and overall description of the recent literature relating pure and doped/composite WO3 catalyst, photocatalytic enhancement mechanism. Moreover, it will also elaborate the experimental conditions used photocatalyst synthesis processes, optimization of the parameters affecting the degradation efficiency of various dyes. Furthermore, strategies for improving photocatalytic activity of WO3 like metal doping, semiconductor coupling, metal sulfides and metal nitrides coupling are systematically summarized and highlighted. After this, future perspectives about advancement and applications are reviewed. It is expected that this review article could offer strategies for designing novel WO3-based photocatalysts which can have promising prospects of multifunctional applications to meet the imperative demands of highly efficient solar energy conversion.

TiO 2 -Graphene-Based Composites: Synthesis, Characterization, and Application in Photocatalysis of Organic Pollutants

Semiconductor photocatalysis is an emerging field in materials science due to its applications in solar energy conversion and environment remediation. Currently, most efficiently and conventionally studied semiconductor materials for photocatalysis are TiO2, ZnO, ZnS, CdS, WO3, Fe2O3, and Bi2WO4 [1, 2]. Among all these, titanium dioxide (TiO2) is the most widely used photocatalyst due to its excellent properties, such as high stability in the aqueous media, low cost, relatively low toxicity, and excellent photocatalytic performance for the degradation of organic pollutants. In photocatalysis process, when a semiconductor is irradiated with photons of energy (hν) that is equal to or higher than the semiconductor band gap energy (hν ≥ Eg), these photons are absorbed by the semiconductor and create high energy electron–hole pairs. The photogenerated electrons and holes that migrate to the surface of the semiconductor without recombination can reduce and oxidize the reactants adsorbed on the semiconductor surface, respectively [3]. Therefore, suppressing the recombination of photogenerated electron–hole pairs and the efficient utilization of visible light are some of the main challenges before making these processes economically feasible [4, 5]. In order to overcome these drawbacks, previously, a lot of approaches have been explored to improve the photocatalytic performance of TiO2 under visible light irradiation. These approaches include doping with metal and nonmetal ions, dye sensitizing, compositing of TiO2 with narrow band gap semiconductor, etc. [6–17].

Iron Pyrite (FeS 2 ): Sustainable Photovoltaic Material

Fool’s gold or Iron pyrite (FeS2) is a semiconductor comprised of earth-abundant elements that has the potential to be a low cost photovoltaic material with comparatively low toxicity. Despite its promise, photovoltaic modules containing FeS2 continue to show small photo-voltages which have limited power conversion efficiencies to around 3%. Bandgap engineering of pyrite by doping may help in increasing power conversion efficiency by increasing the portion of the solar spectrum absorbed. This may lead to the prospect of tandem device architectures that utilise pyrite as an intrinsic semiconductor

A Review on Novel Eco-Friendly Green Approach to Synthesis TiO2 Nanoparticles Using Different Extracts

The inspiring applications of the metal oxide nanoparticles are capturing the interest of researchers worldwide. Different physical and chemical methods are being adapted to synthesize these nanoparticles. The green synthesis is a fruitful emerging process that is environment friendly and low-cost as well. During the last decade, a plenty of work on green synthesis of TiO2 nanoparticles had been practiced. In this review, a compact data on the green synthesis of TiO2 nanoparticles from the plant extracts is summarized. This review will also mention the amendable features for the qualitative and quantitative enhancement in the product and the reliable application perspectives.Graphical Abstract