Photocatalytic production of methanol and hydrogen from methane and water

Taylor, Charles; Noceti, Richard P.; D'Este, Joseph R.; Martello, Donald V.

doi:10.1016/s0167-2991(96)80251-5

Cited by 4 publications

(2 citation statements)

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“…Several metals in the form of nanoparticles loaded on metal oxides exhibit activity for photocatalytic production of hydrogen from water (1)(2)(3)(4). Among them, gold has received attention recently in pollution control and fuel cell applications (5,6), but has received very little attention with regard to photocatalysis.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic methanol reforming on Au/TiO2 for hydrogen production

et al. 2006

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Several metals in the form of nanoparticles loaded on metal oxides exhibit activity for photocatalytic production of hydrogen from water (1-4). Among them, gold has received attention recently in pollution control and fuel cell applications (5,6), but has received very little attention with regard to photocatalysis.The activity of gold loaded on metal oxides depends on many factors such the type of support material, the preparation method and the calcination temperature. This group has carried out a number of investigations concerning the activity of Pd/TiO 2 (7-13) and Au/TiO 2 to produce hydrogen gas (11)(12)(13)(14). We have found that Au/TiO 2 was slightly more reactive than Pd/TiO 2 and mixed metal catalysts of gold and palladium on titania have greater activity than sums of the reaction using the single metal catalysts (14).In this paper, we show the activity of Au/TiO 2 in the liquid phase and, for the first time, in the gas phase, and a mechanism for the photocatalytic reforming of methanol is presented. ExperimentalExperiments were carried out in a Pyrex reaction flask which contains two arms, one for purging the reaction by argon and the other for sampling through a rubber septum. For liquid phase reactions, the reaction mixture is 0.2 g of the catalyst, 100 ml of deionized water and 100 l methanol. Note that we have previously found that the reaction is close to zero order in the concentration of methanol in solution (7,8). For gas phase reactions, 0.05 g of the catalyst was mounted on a slide which is supported in a modified reactor without direct contact with the reaction mixture (15 ml of deionized water and 100 l methanol). There is no forced circulation of the gas phase.In both cases, the mixture was stirred with a magnetic stirrer and was illuminated with light from a 400 W xenon arc lamp (Oriel model) from the side. Every 30 minutes, 0.2 ml samples were taken from the gas phase and analysed by GC (Varian 3900).The catalyst was prepared by the incipient wetness method as follows. The appropriate mass of metal salt (HAuCl 4 ) was dissolved in water and a volume of this solution was added to P25 titania (Degussa) which was just sufficient to fill the pores of the support. The sample was then dried in an oven at 110°C for 2 h, ground in a pestle and mortar, calcined at 500°C for 2 h and finally sieved to less than 53 m aggregate size. Results and discussion a) Liquid phaseIt was found that the gold was active for photocatalysis, as shown in Figure 1, and had very good activity compared with AbstractMethanol can be reformed with water, at ambient temperature, using photocatalysis, and this reaction represents a possible low energy, more sustainable pathway to hydrogen production than (for instance) steam reforming. The requirements for the catalysts are rather strict since titania itself is almost inactive for anaerobic photocatalysis, whereas the addition of a very limited range of metals to the surface renders it active. Surprisingly, this includes gold, which shows one of the highest reactivitie...

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Section: Introductionmentioning

confidence: 99%

Photocatalytic methanol reforming on Au/TiO2 for hydrogen production

et al. 2006

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“…Several efforts have been performed to examine the effect of dopants on photocatalyst performance in absorbing light irradiation, visible light in particular. The former study by Taylor [ 73 ] used four dopants, including copper, lanthanum, platinum, and a mixture of copper and lanthanum in a WO 3 -based photocatalyst. The structure of the doped WO 3 photocatalyst showed to be more crystalline with a larger crystal and smoother edge.…”

Section: Selection Of Materials For Photocatalytic Methane To Methano...mentioning

confidence: 99%

Recent Advances in Photocatalytic Oxidation of Methane to Methanol

et al. 2022

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Methane is one of the promising alternatives to non-renewable petroleum resources since it can be transformed into added-value hydrocarbon feedstocks through suitable reactions. The conversion of methane to methanol with a higher chemical value has recently attracted much attention. The selective oxidation of methane to methanol is often considered a “holy grail” reaction in catalysis. However, methanol production through the thermal catalytic process is thermodynamically and economically unfavorable due to its high energy consumption, low catalyst stability, and complex reactor maintenance. Photocatalytic technology offers great potential to carry out unfavorable reactions under mild conditions. Many in-depth studies have been carried out on the photocatalytic conversion of methane to methanol. This review will comprehensively provide recent progress in the photocatalytic oxidation of methane to methanol based on materials and engineering perspectives. Several aspects are considered, such as the type of semiconductor-based photocatalyst (tungsten, titania, zinc, etc.), structure modification of photocatalyst (doping, heterojunction, surface modification, crystal facet re-arrangement, and electron scavenger), factors affecting the reaction process (physiochemical characteristic of photocatalyst, operational condition, and reactor configuration), and briefly proposed reaction mechanism. Analysis of existing challenges and recommendations for the future development of photocatalytic technology for methane to methanol conversion is also highlighted.

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Recent Developments in Photocatalysis

Howe

1998

Dev. Chem. Eng. Mineral Process.

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Photocatalytic production of methanol and hydrogen from methane and water

Cited by 4 publications

References 5 publications

Photocatalytic methanol reforming on Au/TiO2 for hydrogen production

Photocatalytic methanol reforming on Au/TiO2 for hydrogen production

Recent Advances in Photocatalytic Oxidation of Methane to Methanol

Recent Developments in Photocatalysis

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