ISSN 0023-1584, Kinetics and Catalysis, 2014, Vol. 55, No. 4, pp. 509–519. © Pleiades Publishing, Ltd., 2014. Original Russian Text © V.V. Kaichev, I.P. Prosvirin, V.I. Bukhtiyarov, 2014, published in Kinetika i Kataliz, 2014, Vol. 55, No. 4, pp. 535–546. 509 INTRODUCTION A search for, and the development of, new energy sources is a problem of considerable current interest because of the rapid decrease in natural hydrocarbon reserves (oil, gas, and coal). Currently, methanol, which can be produced on a large scale, in particular, from renewable plant-based raw materials (so-called biomethanol), can serve as an accessible and inexpen- sive alternative fuel. Methanol can be used either as fuel for gasoline internal combustion engines or as a motor fuel additive for increasing the octane number. In both cases, a noticeable economic effect is achieved and the level of harmful impurities in exhaust gases is decreased. Methanol can also be used in special fuel cells for power generation, or it can serve as a raw material for the production of synthesis gas and hydro- gen [1–3]. This is of special interest because the unique properties of hydrogen make it possible to con- sider it as a multipurpose and ecologically clean chem- ical energy carrier suitable for any heat engines and electric power devices. Hydrogen is characterized by a high heat of combustion (121 MJ/kg), and, what is more important, the product of its combustion is water—an environmentally clean product. In turn, synthesis gas can be used as a raw material for the syn- thesis of valuable chemical compounds or added directly to motor fuel for increasing the efficiency of internal combustion engines and decreasing harmful emission levels [4, 5]. Hydrogen and synthesis gas are obtained from methanol in four different catalytic processes: decom- position, partial oxidation, steam reforming, and autothermal conversion [6]. Catalysts based on transi- tion metals such as Pt, Pd, Rh, and Ru exhibit high activity and stability in these reactions [7]. This work deals with the mechanisms of methanol decomposition and oxidation on the surface of plati- num. Note that the mechanisms of the decomposition and oxidation reactions of methanol are still disput- able, although the studies of the interaction of metha- nol with the surface of platinum using a large number of experimental methods have a prolonged history [8 19]. Researchers have come to the in general agree- ment that the main reaction pathway of the decompo- sition of methanol on Pt(111) and Pt(110) single-crys- tal surfaces is its dehydrogenation with the formation of CO and hydrogen. Sexton [8] used vibrational spec- troscopy and temperature-programmed desorption to demonstrate that the molecular adsorption of metha- nol was observed on the Pt(111) surface at tempera- tures lower than 100 K, whereas its complete dehydro- genation to CO occurred even at 140 K. In accordance Decomposition and Oxidation of Methanol on Platinum: A Study by In Situ X-Ray Photoelectron Spectroscopy and Mass Spectrometry V. V. Kaichev a, b, *, I. P. Prosvirin a , and V. I. Bukhtiyarov a, b a Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia b Novosibirsk State University, Novosibirsk, 630090 Russia * e-mail: vvk@catalysis.ru Received November 8, 2013 Abstract—The reactions of the catalytic oxidation and decomposition of methanol on the atomically smooth and high-defect Pt(111) single-crystal surfaces were studied using in situ temperature-programmed reaction and X-ray photoelectron spectroscopy. It was found that the decomposition of methanol on both of the sur- faces occurred via two reaction pathways: complete dehydrogenation to CO and decomposition with the C– O bond cleavage. Although the rate of reaction via the latter pathway was lower than the rate of dehydroge- nation by three orders of magnitude, the carbon formed as a result of the C–O bond cleavage can be accu- mulated on the surface of platinum to prevent the further course of the reaction. It was shown that oxygen exhibits high activity toward the formed carbon deposits. As a result, the rate of methanol conversion in the presence of oxygen in a gas phase increased by one or two orders of magnitude; in this case, CO 2 and water appeared in the composition of the reaction products as a result of the oxidation of CO and hydrogen, respec- tively. The high-defect surface of platinum was more active in the reactions of methanol decomposition and oxidation than the atomically smooth Pt(111) single-crystal surface. On the former, selectivity for the forma- tion of methanol dehydrogenation products in oxygen deficiency was higher than on the latter. The main reaction pathways of the decomposition and oxidation of methanol on platinum were considered. DOI: 10.1134/S0023158414040065