Molecular Hydrogen Formation from Photocatalysis of Methanol on Anatase-TiO₂(101)

Abstract

Photocatalysis of methanol (CH3OH) on anatase (A)-TiO2(101) has been investigated using temperature programmed desorption (TPD) method with 266 nm light at low surface temperatures. Experimental results show that CH3OH adsorbs on the A-TiO2(101) surface predominantly in molecular form, with only a small amount of CH3OH in dissociated form. Photocatalytic products, formaldehyde (CH2O) and methyl formate (HCOOCH3), have been detected under 266 nm light irradiation. In addition to H2O formation, H2 product is also observed by TPD spectroscopy. Experimental results indicate that H2 product is formed via thermal recombination of H-atoms on the BBO sites from photocatalysis of CH3OH on the A-TiO2(101) surface, and H2 production on the A-TiO2(101) surface is significantly more efficient than that on the rutile (R)-TiO2(110) surface.

Enhanced photocatalytic degradation of methylene blue by reduced graphene-oxide/titanium dioxide/zinc oxide ternary nanocomposites

“…Therefore the photocatalytic technique is undoubtedly the finest method to convert harmful organic contaminants into carbonaceous products [6]. [7]; then it started to revolutionize the scientific world in the field of photocatalysis and hydrogen fuel production, owing to its simple, abundant, strong oxidizing and non-toxic nature [8,9]. Yet there are few drawbacks in TiO 2 , such as recombination effect and its low photoresponse towards visible light.…”

The effect of anatase TiO2 surface structure on the behavior of ethanol adsorption and its initial dissociation step: A DFT study

“…Alcohol chemistry on titanium dioxide (TiO 2 ) surfaces is a classic topic in both catalysis and surface science [17][18][19][20][21][22]. TiO 2 -based has been widely applied as a photocatalyst to produce hydrogen from http://dx.doi.org/10.1016/j.apsusc.2015.06.059 0169-4332/© 2015 Elsevier B.V. All rights reserved.…”

“…ethanol in the last decades [2,[23][24][25][26][27][28]. TiO 2 exists in the form of three polymorphs: rutile, anatase, and brookite; rutile and anatase TiO 2 materials have been widely used [20,[29][30][31], moreover, the commercial TiO 2 powders often used as catalyst support are the mixtures of rutile and anatase [32]. Therefore, it is necessary to probe into ethanol adsorption and dissociation over different types of TiO 2 , which will provide microscopic insight into the effect of TiO 2 surface structure on the behavior of ethanol adsorption and dissociation step [2].…”

“…Meanwhile, the minority (0 0 1) surface played a key role in the reactivity of anatase nanoparticles [43,44], and is more reactive than the majority (1 0 1) surface; up to now, a large percent of (0 0 1) facets (as large as 47%) have been successfully synthesized in anatase TiO 2 crystal [44,45]. Photocatalysis of CH 3 OH on the anatase (1 0 1) has shown that CH 3 OH dominantly exists in the form of molecular adsorption with only very small amount of CH 3 OH in the form of dissociative adsorption [20]. Han et al [46] have investigated methanol adsorption, the co-adsorption of dissociation products via the individual O-H, C-O and C-H bond cleavage over the perfect and defective anatase TiO 2 (1 0 1) surface, respectively, suggesting that on the perfect anatase (1 0 1), although methanol dissociation via the O-H scission is endothermic, it is the most favorable route compared with C-O and C-H bond scission in the view of thermodynamics; however, on the defective surface, methanol dissociation via the O-H scission is exothermic, which is also the most favorable route.…”

Optimizing the preparation parameters of mesoporous nanocrystalline titania and its photocatalytic activity in water: Physical properties and growth mechanisms

“…Nanosizedtitania has attracted increasing attention in the scientific community for its broad applications in photocatalysts (Hoffmann et al 1995, Ohno, 2004, Xu, 2014, Hamad et al 2015, bacterial disinfection (Kashyout et al2006), solar cells (Hong, 2014), gas sensors (Zakrzewska et al 2001), electro coagulation /electrofiltration (Yang & Chaung 2005) and optoelectronic devices (Kalyanasundaram et al 1998) . TiO 2 was intensively investigated for photocatalysis because of insolubility, its biological, and chemical inertness, strong oxidizing power, cost effectiveness, non-toxicity and long-term stability against photo and chemical corrosion under the reaction conditions (Nakataet al .…”