Mexican Institute of Petroleum

About: Mexican Institute of Petroleum is a government organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Catalysis & Asphaltene. The organization has 3273 authors who have published 4170 publications receiving 87269 citations.

Chemical, Structural, and Morphological Changes of a MoVTeNb Catalyst during Oxidative Dehydrogenation of Ethane

Abstract: MoVTeNb mixed oxide, a highly active and selective catalyst for the oxidative dehydrogenation of ethane to produce ethylene, exhibits the so-called M1 and M2 crystalline phases. The thermal stability of the MoVTeNb catalytic system was assessed under varying reaction conditions; to this end, the catalyst was exposed to several reaction temperatures spanning from 440 to 550 °C. Both the pristine and spent materials were analyzed by several characterization techniques. The catalyst was stable below 500 °C; a reaction temperature of ≥500 °C brings about the removal of tellurium from the intercalated framework channels of the M1 crystalline phase. Rietveld refinement of X-ray diffraction patterns and microscopy results showed that the tellurium loss causes the progressive partial destruction of the M1 phase, thus decreasing the number of active sites and forming a MoO2 crystalline phase, which is inactive for this reaction. Raman spectroscopy confirmed the MoO2 phase development as a function of reaction temp...

Effect of sulfation on the photoactivity of TiO2 sol–gel derived catalysts

Abstract: Titania and sulfated-titania were prepared by the sol–gel method using titanium alkoxide as titania precursor. BET specific surface areas on samples calcined at 600 °C were 57 and 62 m2/g for titania and sulfated-titania, respectively. FTIR spectra of sulfated samples show the 1360–1370 cm−1 absorption band assigned to SO vibrations. Moreover, by means of FTIR-pyridine absorption the strength of the sulfate bonded on the TiO2 surface was studied. Pyridine absorption bands assigned to Lewis and Bronsted acidic sites were identified on sulfated TiO2. A diminution of the band gap (Eg) by effect of sulfation was observed by UV-Vis spectroscopy. X-ray diffraction patterns show that sulfate ions stabilize the anatase phase. The photoactivity of the samples determined in the 2,4-dinitroaniline decomposition was found to be higher in sulfated samples. A model is proposed, in which the sulfate anchored to the titania surface acts as an electron trap during photo activation leading to an enhancement of activity.

A direct reputation model for VO formation

Abstract: We show that reputation is a basic ingredient in the Virtual Organisation (VO) formation process. Agents can use their experiences gained in direct past interactions to model other's reputation and deciding on either join a VO or determining who is the most suitable set of partners. Reputation values are computed using a reinforcement learning algorithm, so agents can learn and adapt their reputation models of their partners according to their recent behaviour. Our approach is especially powerful if the agent participates in a VO in which the members can change their behaviour to exploit their partners. The reputation model presented in this paper deals with the questions of deception and fraud that have been ignored in current models of VO formation.