Comparative Photocatalytic Activity and Total Organic Carbon Removal Efficiency of TiO₂ And ZnO for Reactive Black 5 Photodegradation

Abstract

The photocatalytic performance of TiO2 and ZnO was comparatively studied for photocatalytic degradation of reactive black 5 (RB5) under artificial UVC irradiation. The effect of initial solution pH, catalyst concentration, initial RB5 concentration, purging oxygen rate, stirring rate, and process temperature on the degradation process by TiO2 and ZnO was investigated. In addition, total organic carbon (TOC) analysis has been employed for each parameter to detect the presence of organic intermediates and the photodegradation performance of catalysts simultaneously with the photocatalytic degradation process. The RB5 photodegradation was more rapid in the aqueous medium by TiO2 under UVC irradiation compared to the catalysis by ZnO. On the other hand, the slower photocatalysis by ZnO resulted in generating more organic intermediates. The structural and morphological analyses of photocatalysts TiO2 and ZnO were performed using XRD and FE‐SEM techniques. The UV‐vis spectroscopy measurements supported that the TiO2 demonstrated evidently better photocatalytic activity than ZnO for RB5 degradation.

Role of pH in the Hydrothermal Synthesis of TiO2 Nanorod Photocatalysts

“…[3,12] Numerous studies have focused on promoting light-harvesting and charge separation/transfer in TiO 2 by modulating the intrinsic and interfacial properties. [12][13][14][15][16] Low electron diffusion in TiO 2 nanoparticles typically limits the photocatalytic activity. Vertically oriented 1-D TiO 2 nanostructures such as nanowires, [17] nanorods [18,19] and nanotubes [20] have also been reported to remarkably enhance electron transport by creating a straight conduction pathway, decreasing intercrystalline contacts and stretching grown structure with the specified directionality.…”

“…While the unique chemical and physical characteristics of titanium dioxide can be controlled through the modulation of the nanocrystal structure, size, shape and organization, the TiO 2 interface properties may be adjusted through its interaction with the surrounding environment including light harvesters, charge transport materials, additives and interfacial modifiers [3,12] . Numerous studies have focused on promoting light‐harvesting and charge separation/transfer in TiO 2 by modulating the intrinsic and interfacial properties [12–16] . Low electron diffusion in TiO 2 nanoparticles typically limits the photocatalytic activity.…”

Photo(electro)catalytic Performance of ZnO‐Based Nanopowders Prepared through Pulse Alternating Current Electrosynthesis in Alkaline Earth Chloride Electrolytes

“…Photocatalytic (PC) technologies can be used for solving the problem of water resource contamination with toxic pollutants including undesirable textile and agricultural effluents. [1] Photoelectrocatalytic (PEC) processes are becoming a powerful sustainable technique for pollutant degradation, microorganism inactivation, hydrogen generation and biomass valorization. [2] Semiconductive metal oxides are promising candidates for diverse photo-and photoelectrocatalytic applications due to their ability to produce the photogenerated electron-hole pairs when illuminated with light of sufficient energy, chemical stability, and availability.…”

“…Photo(electro)catalysis is a key technology that allows abundant and clean solar energy to be harvested as an essential step to achieving sustainable development goals. Photocatalytic (PC) technologies can be used for solving the problem of water resource contamination with toxic pollutants including undesirable textile and agricultural effluents [1] . Photoelectrocatalytic (PEC) processes are becoming a powerful sustainable technique for pollutant degradation, microorganism inactivation, hydrogen generation and biomass valorization [2] …”