The dry reforming of methane is a promising technology for the abatement of CH₄ and CO₂. Solid solution Ni–La oxide catalysts are characterized by their long–term stability (100h) when tested at full conversion. The kinetics of dry reforming over this type of catalysts has been studied using both power law and Langmuir–Hinshelwood based approaches. However, these studies typically deal with fitting the net CH₄ rate hence disregarding competing and parallel surface processes and the different possible configurations of the active surface. In this work, we synthesized a solid solution Ni–La oxide catalyst and tested six Langmuir–Hinshelwood mechanisms considering both single and dual active sites for assessing the kinetics of dry reforming and the competing reverse water gas shift reaction and investigated the performance of the derived kinetic models. In doing this, it was found that: (1) all the net rates were better fitted by a single–site model that considered that the first C–H bond cleavage in methane occurred over a <a>metal−oxygen </a>pair site; (2) this model predicted the existence of a nearly saturated nickel surface with chemisorbed oxygen adatoms derived from the dissociation of CO₂; (3) the dissociation of CO₂ can either be an inhibitory or an irrelevant step, and it can also modify the apparent activation energy for CH₄ activation. These findings contribute to a better understanding of the dry reforming reaction's kinetics and provide a robust kinetic model for the design and scale–up of the process.

<p>The accuracy of the online quantification of gaseous effluents from catalytic reactors by mass spectrometry (MS) is rarely addressed by researchers, despite the extensive use of the technique. MS results are strongly sensitive to both the operation conditions of the reactor and to the state of the instrument. Therefore, most studies use them as qualitative descriptors of the performance of catalytic reaction systems. The purpose of this work was to develop an accurate method for the quantification of gaseous effluents from catalytic reactors. For this purpose, the mathematical expressions from the so-called external and internal standard calibration methods for MS were coupled to the typical metrics used for studying catalytic reactions; namely, conversion, selectivity, and carbon mass balances. The catalytic combustion of methane was selected as a model reaction to test the developed approach. The accuracy of the developed method was validated by comparison with results obtained in a separated reaction system coupled online to a gas chromatograph. The closure of the carbon mass balance was used as a control metrics allowing for the assessment of the physical meaning of the method. In general, the internal standard method of calibration was found to be best for the accurate quantification of gaseous streams by on-line mass spectrometry. In general, the results of this investigation may be of use to researchers in the field of catalysis as well as to research workers using mass spectrometry for various purposes.</p>

The dry reforming of methane is a promising technology for the abatement of CH₄ and CO₂. Solid solution Ni–La oxide catalysts are characterized by their long–term stability (100h) when tested at full conversion. The kinetics of dry reforming over this type of catalysts has been studied using both power law and Langmuir–Hinshelwood based approaches. However, these studies typically deal with fitting the net CH₄ rate hence disregarding competing and parallel surface processes and the different possible configurations of the active surface. In this work, we synthesized a solid solution Ni–La oxide catalyst and tested six Langmuir–Hinshelwood mechanisms considering both single and dual active sites for assessing the kinetics of dry reforming and the competing reverse water gas shift reaction and investigated the performance of the derived kinetic models. In doing this, it was found that: (1) all the net rates were better fitted by a single–site model that considered that the first C–H bond cleavage in methane occurred over a <a>metal−oxygen </a>pair site; (2) this model predicted the existence of a nearly saturated nickel surface with chemisorbed oxygen adatoms derived from the dissociation of CO₂; (3) the dissociation of CO₂ can either be an inhibitory or an irrelevant step, and it can also modify the apparent activation energy for CH₄ activation. These findings contribute to a better understanding of the dry reforming reaction's kinetics and provide a robust kinetic model for the design and scale–up of the process.

<p>The accuracy of the online quantification of gaseous effluents from catalytic reactors by mass spectrometry (MS) is rarely addressed by researchers, despite the extensive use of the technique. MS results are strongly sensitive to both the operation conditions of the reactor and to the state of the instrument. Therefore, most studies use them as qualitative descriptors of the performance of catalytic reaction systems. The purpose of this work was to develop an accurate method for the quantification of gaseous effluents from catalytic reactors. For this purpose, the mathematical expressions from the so-called external and internal standard calibration methods for MS were coupled to the typical metrics used for studying catalytic reactions; namely, conversion, selectivity, and carbon mass balances. The catalytic combustion of methane was selected as a model reaction to test the developed approach. The accuracy of the developed method was validated by comparison with results obtained in a separated reaction system coupled online to a gas chromatograph. The closure of the carbon mass balance was used as a control metrics allowing for the assessment of the physical meaning of the method. In general, the internal standard method of calibration was found to be best for the accurate quantification of gaseous streams by on-line mass spectrometry. In general, the results of this investigation may be of use to researchers in the field of catalysis as well as to research workers using mass spectrometry for various purposes.</p>