NiGa Unsupported Catalyst for CO2 Hydrogenation at Atmospheric Pressure. Tentative Reaction Pathways

The hydrogenation of CO2 is presented as a catalytic strategy for CO2 utilization and an approach to the development of sustainable processes to obtain products with high added value, such as CO, CH4, and CH3OH. An unsupported NixGay model catalyst with high surface area was synthesized by an ultrasonic-assisted coprecipitation method. The in situ H2-treatment and the activation temperature (600, 700, and 800 °C) are key in the phases present in the catalyst and, therefore, in the reactivity in the CO2 hydrogenation reaction at atmospheric pressure. Operating conditions have been selected that maximize the selectivity to be able to correlate phases, surface, and reactivity. Independently of the H2/CO2 feed ratio, after treatment in hydrogen at 600 °C, CO selectivity values are higher than 97%, via a reverse water gas shift reaction, with Ni13Ga9 and Ni metallic being the main phases detected. The H2-treatment at 700 °C increases the proportion of Ni0 and Ni13Ga9 phases, and even with the use of a H2/CO2 feeding ratio of 3, methanation is the only reaction that occurs. At 800 °C, Ni5Ga3 is the main phase detected, and methanol is formed at 150 °C, through the intervention of a necessary formate species; when the reaction temperature is higher than 400 °C, the rWGS is the only observable reaction, with complete CO formation.Funding for open access charge: Universidad de Málaga / CBU

Eliminación de carbonilla en gases de escape con catalizadores DeNOx. Determinación de parámetros cinéticos

Los catalizadores DeNOx se emplean en la eliminación de los óxidos de nitrógeno en vehículos diésel y, también, puede que entren en contacto con carbonilla o incluso sean utilizados como sistemas de reducción de NOx y soot simultáneamente (DPNR-Diesel Particulate NOx Reduction); por ello, es importante profundizar en el mecanismo de interacción entre el soot y el catalizador. Se ha utilizado un soot Printex U modelo y un catalizador Pt-K/Al2O3, con el potasio en forma de óxido e hidroxicarbonato hidratado. Se ha estudiado mediante TG-MS el proceso de eliminación en diferentes atmósferas oxidantes. Los procesos han sido desacoplados mediante el establecimiento de la función de distribución de energía de activación. En ausencia de catalizador, se produce la combustión del soot con el oxígeno molecular en fase gas a temperaturas alrededor de los 1100 K. En presencia de NO, la reducción tiene lugar a menor temperatura debido a su carácter más oxidante y a las especies de óxidos de nitrógeno retenidas y en fase gas. Si la carbonilla se encuentra en contacto con el catalizador Pt-K/Al2O3, los centros Pt-OH-K son los responsables de la eliminación vía gasificación a 780 K con una energía de activación alrededor de 85 kJ·mol-1.Os catalisadores do tipo DeNOx eliminam óxidos de nitrogênio em veículos a diesel e, também, podem entrar em contato com partículas ou até mesmo serem usados como sistemas de redução de NOx e carvão simultaneamente (DPNR-Diesel Particulate NOx Reduction); portanto, é importante aprofundar o mecanismo de interação entre a carvão e o catalisador. Carvão modelo Printex U e um catalisador Pt-K/Al2O3 foram utilizados, com potássio na forma de óxido e idroxicarbonato hidratado. O processo de eliminação em diferentes atmosferas oxidantes foi estudado mediante TG-MS. Os processos foram dissociados, estabelecendo a função de distribuição de energia de ativação. Na ausência de um catalisador, a combustão do carvão com o oxigênio molecular na fase gasosa ocorre a temperaturas em torno de 1100K. Na presença de NO, a redução ocorre a uma temperatura inferior devido ao seu caráter mais oxidante e às espécies de óxidos de nitrogênio retidos e na fase gasosa. Se o carbono estiver em contato com o catalisador Pt-K/Al2O3, os centros de Pt-OH-K são responsáveis pela eliminação via gaseificação a 780K com uma energia de ativação em torno de 85 kJ·mol-1.DeNOx catalysts eliminate nitrogen oxides in diesel vehicles and, in addition, can come in contact with soot or, even, be used as Diesel Particulate NOx Reduction (DPNR) material. Therefore, the understanding of the interaction mechanism between soot and catalyst is of high interest. The Printex U model soot and a Pt-K/Al2O3 catalyst have been used, with potassium in the form of oxide and hydrated hydroxycarbonate. The process of elimination in different oxidizing atmospheres has been studied by TG-MS. The processes have been decoupled by establishing the distribution function of activation energy. In the absence of catalyst, the combustion of the soot with the molecular oxygen in the gas phase occurs at temperatures around 1100K. In the presence of NO, the reduction takes place at a lower temperature due to its more oxidizing character and the species of nitrogen oxides retained and in the gas phase. If the carbon is in contact with the Pt-K/Al2O3 catalyst, the Pt-OH-K centers are responsible for the elimination via gasification at 780K with an activation energy around 85 kJ·mol-1

Isotopic study of the influence of oxygen interaction and surface species over different catalysts on the soot removal mechanism

In order to improve the catalytic formulations for soot removal in after-treatment emission control technologies for gasoline and diesel engine vehicle, an isotopic study was approached using transitory labeled oxygen response method over model catalysts that allows the unraveling of soot oxidation mechanism. Ce-based materials promote oxygen exchange associated with the high population of lattice oxygen species (O2-) denoted as OI type. The incorporation of praseodymium produces a Pr3+ enrichment that decrease the energy for oxygen release and increase oxygen mobility through surface and subsurface oxygen centers (OII type) depending on the synthesis procedure. For PtBaK catalyst, OIII species are responsible for oxygen exchange. Gas-solid reaction between soot and gas phase molecular oxygen is responsible for direct uncatalyzed soot oxidation. For ceria containing catalysts, low-temperature soot removal takes place through the intervention of lattice atomic species and superoxide species. For DPNR model catalyst, PtBaK/Al2O3, the soot elimination occurs with the intervention OIII type centers. In the presence NO, the assisted and cooperative mechanism due to NO2 and the intervention of the adsorbed nitrate species on the trimetallic catalyst enhances soot removal capacity.MCR acknowledges the postdoctoral fellowship obtained from the University of Malaga. MCR, CH, MAL and LJA want to thank the financial support of CTQ 2017-87909R project. MCR also want to thank the University of Alicante for the financial support for the internship (INV19-07). JCMM and AGG gratefully acknowledge the financial support of Generalitat Valenciana (PROMETEO/2018/076 project) and the Spanish Ministry of Science, Innovation and Universities (PID2019-105542RB-I00 project) and the UE-FEDER funding. JCMM also acknowledges Spanish Ministry of Science, Innovation and Universities for the financial support through a FPU grant (FPU17/00603)

Estudio DRIFTs-MS in situ de la oxidación de CO en condiciones subestequiométricas de oxígeno con un catalizador bimetálico Ni-Ce

El interés en la reducción de uno de los principales contaminantes atmosféricos como el monóxido de carbono hace que se hayan propuesto diversas técnicas para su eliminación. Actualmente, la oxidación catalítica a baja temperatura presenta gran interés, siendo los catalizadores soportados que contienen metales nobles, como Pt o Pd, los más estudiados. Los catalizadores bimetálicos Ni-Ce no soportados con alta área superficial han mostrado una importante población de vacantes de oxígeno, en comparación con sus equivalentes materiales soportados; mostrando un rendimiento considerable en la reacción de oxidación de CO, con prácticamente conversión completa por encima de los 460K. La actividad catalítica mejorada está relacionada con la presencia de la solución Ni-Ce-Ox que favorece las dos rutas involucradas en el mecanismo de oxidación de CO.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Distribution of comorbidities in spondyloarthritis with regard to the phenotype and psoriasis: data from the ASAS-COMOSPA study

Introduction: The aim of the study was to compare the prevalence of comorbidities between patients with axial and peripheral phenotypes and to evaluate the role of psoriasis in such comorbidities. Methods: Patients from the cross-sectional Assessment in SpondyloArthritis Inter-national Society (ASAS)-COMOSPA study were classified as having either the axial (presence of sacroiliitis on X-ray or MRI) or peripheral phenotype (absence of sacroiliitis AND presence of peripheral involvement). Patients with each phenotype were divided into two groups depending on the presence or history of psoriasis. Pair-wise comparisons among the four groups (axial/peripheral phenotype with/without psoriasis) were conducted through univariate logistic regressions and generalized linear mixed models using disease duration and sex as fixed effects and country as random effect.Results: A total of 3291 patients were included in this analysis. The peripheral involvement with psoriasis phenotype showed the highest prevalence of hypertension (44.9%), dyslipidaemia (34%) and diabetes (8.8%), while the axial involvement without psoriasis phenotype exhibited the lowest prevalence of dyslipidaemia (14.2%), diabetes (4.1%) and stroke (0.9%). Among patients with psoriasis, the axial phenotype showed a significantly lower prevalence of hypertension (OR: 0.51, 95% CI: 0.35–0.75) and lower prevalence pof Framingham score ⩾15 (OR: 0.57, 95% CI: 0.38–0.85) than patients with peripheral involvement after adjusting for disease duration, sex and country. Among patients with the axial phenotype, patients with psoriasis showed a higher prevalence of hypertension (OR 1.76, 1.40–2.20), dyslipidaemia (OR: 1.99, 95% CI: 1.56–2.53), diabetes (OR: 2.05, 95% CI: 1.39–3.02) and Framingham score ⩾15 (OR: 2.00, 95% CI: 1.57–2.55) than non-psoriatic patients. No differences were found across groups concerning bone metabolism disorders.Conclusion: Both the peripheral phenotype and psoriasis are independently associated with an increased prevalence of cardiovascular risk factors. No differences were found for bone metabolism disorders.This study was conducted with the financial support of Abbvie, Pfizer and UCB, who provided an unrestricted grant.” with this one “The ASAS-COMOSPA study was conducted with the financial support of Abbvie, Pfizer and UCB, who provided an unre stricted grant.Ye

Achilles enthesitis on physical examination leads to worse outcomes after 2 years of follow up in patients with ankylosing spondylitis from REGISPONSER-AS registry

Abstract Background Enthesitis represents one of the most important peripheral musculoskeletal manifestations in patients with axial spondyloarthritis (axSpA). However, studies specifically evaluating Achilles tendon enthesitis and its impact over time are scarce. The objectives of this study were to evaluate the impact of Achilles’ tendon enthesitis found at baseline during physical examination on the outcome measures after 2 years of follow-up in patients with ankylosing spondylitis (AS). Methods This was an observational and prospective study conducted during 2 years of follow-up in the REGISPONSER-AS registry. Linear regression models adjusted for age, body mass index (BMI), and anti-TNF intake were conducted to evaluate the association between the presence of Achilles enthesitis at baseline and the patient-reported outcome (PRO) scores at baseline. The impact of this feature on PROs over 2 years of follow-up was evaluated using mixed models for repeated measures adjusted for age, BMI, and anti-TNF intake. Results Among the 749 patients included, 46 patients (6.1%) showed Achilles’ tendon enthesitis during physical examination at the baseline study visit. Patients with Achilles enthesitis had an increase in the global VAS score, BASDAI, mBASDAI, ASDAS-CRP, and BASFI scores in comparison with patients without this feature. In addition, the mean global VAS, BASDAI, and ASDAS-CRP scores were significantly higher among patients with Achilles enthesitis over the 2 years of follow-up after adjusting for age, BMI, and current anti-TNF intake. The percentage of patients achieving ASDAS low disease activity (ASDAS < 2.1) after 2 years of follow-up was 15.9% and 31.5% for patients with and without Achilles enthesitis, respectively (p = 0.030). Conclusions In patients with AS, the presence of Achilles’ tendon enthesitis was associated with worse scores on the outcome measures after 2 years of follow-up, leading to a lower probability of achieving low disease activity