Mineral-Supported Photocatalysts: A Review of Materials, Mechanisms and Environmental Applications

Abstract

Although they are of significant importance for environmental applications, the industrialization of photocatalytic techniques still faces many difficulties, and the most urgent concern is cost control. Natural minerals possess abundant chemical inertia and cost-efficiency, which is suitable for hybridizing with various effective photocatalysts. The use of natural minerals in photocatalytic systems can not only significantly decrease the pure photocatalyst dosage but can also produce a favorable synergistic effect between photocatalyst and mineral substrate. This review article discusses the current progress regarding the use of various mineral classes in photocatalytic applications. Owing to their unique structures, large surface area, and negatively charged surface, silicate minerals could enhance the adsorption capacity, reduce particle aggregation, and promote photogenerated electron-hole pair separation for hybrid photocatalysts. Moreover, controlling the morphology and structure properties of these materials could have a great influence on their light-harvesting ability and photocatalytic activity. Composed of silica and alumina or magnesia, some silicate minerals possess unique orderly organized porous or layered structures, which are proper templates to modify the photocatalyst framework. The non-silicate minerals (referred to carbonate and carbon-based minerals, sulfate, and sulfide minerals and other special minerals) can function not only as catalyst supports but also as photocatalysts after special modification due to their unique chemical formula and impurities. The dye-sensitized minerals, as another natural mineral application in photocatalysis, are proved to be superior photocatalysts for hydrogen evolution and wastewater treatment. This work aims to provide a complete research overview of the mineral-supported photocatalysts and summarizes the common synergistic effects between different mineral substrates and photocatalysts as well as to inspire more possibilities for natural mineral application in photocatalysis.

Fast and Excellent Enhanced Photocatalytic Degradation of Methylene Blue Using Silver-Doped Zinc Oxide Submicron Structures under Blue Laser Irradiation

“…The metal modifier may indirectly affect the charge transfer mechanisms at the interface. Silver is a noble metal that can capture and efficiently store electrons [40]. To properly define the precise function of metal in semiconductor photocatalysis, a basic understanding of photo-induced interactions and interfacial charge transfer mechanisms in metal-modified semiconductors is required.…”

Basic magnesium sulfate@TiO2 composite for efficient adsorption and photocatalytic degradation of 4-dodecylmorpholine in brine

“…Zhu et al developed an activated carbon composite supported by titanate nanotubes for removing per uoro-2-propoxypropionic acid (GenX) with a photodegradation e ciency of 70% [26]. However, a long-term hydrothermal process [25][26][27] or calcination [28,29] is typically required for the deposition of the photocatalyst onto the adsorbent materials, in which the loading e ciency of the photocatalyst is uncontrollable [30][31][32].…”

Basic magnesium sulfate@TiO2 composite for efficient adsorption and photocatalytic degradation of 4-dodecylmorpholine in brine

“…Zhu et al developed an activated carbon composite supported by titanate nanotubes for removing perfluoro-2-propoxypropionic acid (GenX) with a photodegradation efficiency of 70% 26 . However, a long-term hydrothermal process 25 – 27 or calcination 28 , 29 is typically required for the deposition of the photocatalyst onto the adsorbent materials, in which the loading efficiency of the photocatalyst is uncontrollable 30 – 32 .…”