Hydrogen peroxide‐assisted photocatalysis under solar light irradiation: Interpretation of interaction effects between an active photocatalyst and H₂O₂

Abstract

In this work, the combination of H 2 O 2 and an active visible-light-driven photocatalyst (Ag-S/PEG/TiO 2 ) was utilized under natural solar radiation for the degradation of 2-nitrophenol (2-NP), and interaction effects between the photocatalyst and hydrogen peroxide were analyzed. For this purpose, experiments were designed using the response surface methodology based on the central composite design. The resulting data was utilized to obtain a model for the prediction of response (the degradation efficiency) as a function of two independent factors (H 2 O 2 concentration and the photocatalyst loading). The statistical analysis indicated that optimum values of each of the two independent factors decreased by increasing the other one and vice versa. Moreover, it was found that adding the optimal amount of H 2 O 2 to the solution, which contained just the photocatalyst, can enhance the degradation significantly (up to 45 %). However, using higher concentrations of H 2 O 2 may decrease the efficiency. The global optimum condition was found to be 545 ppm and 316 mM for Ag-S/PEG/TiO 2 loading and H 2 O 2 concentration, respectively. In this condition, the degradation efficiency of 2-NP reached 92.4 % after only 45 min of solar light irradiation.

Optimal H2O2 concentration in advanced oxidation over titanium dioxide photocatalyst

“…Moreover, small residual concentration of hydrogen peroxide promotes processes of aerobic biological treatment. For that reason, H2O2 is the promising oxidizer for use in Advanced Oxidation Processes (AOPs) [13,14]. The efficiency of hydrogen peroxide in AOPs is determined by concentration of radicals formed.…”

“…In the case of anatase, the overall photodegradation rate is slightly lesser [22]. Optimal amounts of H2O2 and photocatalyst depend on titania type and specific surface, photoreactor geometry, light intensity as well as pollutant type and concentration [6,14,[23][24][25][26][27][28][29].…”

An intrinsic kinetic model for liquid‐phase photocatalytic hydrogen production

“…Photocatalytic reactions have been considered as a promising alternative for future chemical conversion, since the discovery of water photolysis on a TiO 2 electrode by Fujishima and Honda . Titanium‐based photocatalysts are the most recognized and alternative photocatalysts are not still reliable due to issues such as their stability, cost, toxicity, availability, and activity under full solar spectrum . Deposition of cocatalysts on semiconductor is one of the best‐known approaches to increase the efficiency of photocatalysts and platinum is the most common cocatalyst for hydrogen production .…”

“…8 Photocatalytic reactions have been considered as a promising alternative for future chemical conversion, since the discovery of water photolysis on a TiO 2 electrode by Fujishima and Honda. 9 Titanium-based photocatalysts are the most recognized [10][11][12][13] and alternative photocatalysts are not still reliable due to issues such as their stability, cost, toxicity, availability, and activity under full solar spectrum. 14…”

Issue Highlights

“…The addition of an external electron acceptor such as hydrogen peroxide can hinder the recombination of photo‐generated electrons and holes. In this work, the combination of H 2 O 2 and an active visible‐light‐driven photocatalyst (Ag‐S/PEG/TiO 2 ) was utilized under the natural solar radiation for the degradation of 2‐nitrophenol, and interaction effects between the photocatalyst and hydrogen peroxide were analyzed using the response surface methodology …”