Carbon/Graphene-Modified Titania with Enhanced Photocatalytic Activity under UV and Vis Irradiation

Abstract

Laser synthesis was used for one-step synthesis of titania/graphene composites (G-TiO 2 (C)) from a suspension of 0.04 wt% commercial reduced graphene oxide (rGO) dispersed in liquid titanium tetraisopropoxide (TTIP). Reference titania sample (TiO 2 (C)) was prepared by the same method without graphene addition. Both samples and commercial titania P25 were characterized by various methods and tested under UV/vis irradiation for oxidative decomposition of acetic acid and dehydrogenation of methanol (with and without Pt co-catalyst addition), and under vis irradiation for phenol degradation and inactivation of Escherichia coli. It was found that both samples (TiO 2 (C) and G-TiO 2 (C)) contained carbon resulting from TTIP and C 2 H 4 (used as a synthesis sensitizer), which activated titania towards vis activity. The photocatalytic activity under UV/vis irradiation was like that by P25. The highest activity of TiO 2 (C) sample for acetic acid oxidation was probably caused by its surface enrichment with hydroxyl groups. G-TiO 2 (C) was the most active for methanol dehydrogenation in the absence of platinum (ca. five times higher activity than that by TiO 2 (C) and P25), suggesting that graphene works as a co-catalyst for hydrogen evolution. High activity under both UV and vis irradiation for decomposition of organic compounds, hydrogen evolution and inactivation of bacteria suggests that laser synthesis allows preparation of cheap (carbon-modified) and efficient photocatalysts for broad environmental applications.

Ultra-Highly Efficient Removal of Methylene Blue Based on Graphene Oxide/TiO2/Bentonite Sponge

“…Owing to the difficulty of dye degradation, it is difficult for normal treatment by biochemical methods to meet the requirements for their treatment. Photocatalytic decomposition of organic compounds has been widely studied to elevate the degradation efficiency of dyes in aqueous solution, wherein TiO 2 has received much attention and has been reported in various studies [5][6][7][8]. TiO 2 is one of the most popular types of photocatalyst, and it is utilized in many fields, such as wastewater degradation and energy fuel, because of its high efficiency, nontoxicity, good chemical stability, and low cost [9,10].…”

Laser pyrolysis in papers and patents

“…Kabashin et al, 2019) • Other fields of application of laser pyrolysis are: the protection and monitoring of the environment, e.g. through the production of catalyst nanopowders for air depollution (Barrault et al, 2009) or its direct application for the study of rocks as a measuring instrument (Al Sandouk-Lincke et al, 2013), precision manufacturing, by replacing of other less performing technologies (Shin et al, 2020), energy production, exploiting the heat generated by the reaction of pyrolysis or producing gas that can be used as fuel (Masyuk et al, 2018), food production and conservation through the chemical action especially of nanopowders and coatings produced by laser pyrolysis (Wang et al, 2019) and aerospace.…”

Novel Structures and Applications of Graphene-Based Semiconductor Photocatalysts: Faceted Particles, Photonic Crystals, Antimicrobial and Magnetic Properties

“…For example, hydrothermally prepared composites have shown to be quite efficient for photocatalytic decomposition of organic compounds, e.g., bisphenol A under both UV and vis irradiation (TiO 2 -rGO) [7], 4-chlorophenol under solar radiation (TiO 2 -G) [8], and butene in the gas phase (TiO 2 -GO) [9]. TiO 2 -rGO, synthesized by ionothermal [10] method and laser synthesis [11], is able to generate hydrogen under UV irradiation, indicating that graphene might work as co-catalyst on titania surface similar to well-known noble metals for hydrogen evolution. ZnO-G, synthesized by combined method of Hummers, Offeman and hydrothermal treatment, is efficient for degradation of cyanide in water under UV, vis, solar and even NIR irradiation due to plasmonic properties of graphene [12].…”