CO2 Hydrogenation at Atmospheric Pressure and Low Temperature Using Plasma-Enhanced Catalysis over Supported Cobalt Oxide Catalysts

CO2 is a promising renewable, cheap, and abundant C1 feedstock for producing valuable chemicals, such as CO and methanol. In conventional reactors, because of thermodynamic constraints, converting CO2 to methanol requires high temperature and pressure, typically 250 °C and 20 bar. Nonthermal plasma is a better option, as it can convert CO2 at near-ambient temperature and pressure. Adding a catalyst to such plasma setups can enhance conversion and selectivity. However, we know little about the effects of catalysts in such systems. Here, we study CO2 hydrogenation in a dielectric barrier discharge plasma-catalysis setup under ambient conditions using MgO, γ-Al2O3, and a series of CoxOy/MgO catalysts. While all three catalyst types enhanced CO2 conversion, CoxOy/MgO gave the best results, converting up to 35% of CO2 and reaching the highest methanol yield (10%). Control experiments showed that the basic MgO support is more active than the acidic γ-Al2O3, and that MgO-supported cobalt oxide catalysts improve the selectivity toward methanol. The methanol yield can be tuned by changing the metal loading. Overall, our study shows the utility of plasma catalysis for CO2 conversion under mild conditions, with the potential to reduce the energy footprint of CO2-recycling processes

Rúbrica de evaluación en un laboratorio de Ingeniería Química

Congreso Universitario de Innovación Educativa En las Enseñanzas Técnicas, CUIEET (26º. 2018. Gijón

Mechanical durability and combustion characteristics of pellets from biomass blends

Biofuel pellets were prepared from biomass (pine, chestnut and eucalyptus sawdust, cellulose residue, coffee husks and grape waste) and from blends of biomass with two coals (bituminous and semianthracite). Their mechanical properties and combustion behaviour were studied by means of an abrasion index and thermogravimetric analysis (TGA), respectively, in order to select the best raw materials available in the area of study for pellet production. Chestnut and pine sawdust pellets exhibited the highest durability, whereas grape waste and coffee husks pellets were the least durable. Blends of pine sawdust with 10–30% chestnut sawdust were the best for pellet production. Blends of cellulose residue and coals (<20%) with chestnut and pine sawdusts did not decrease pellet durability. The biomass/biomass blends presented combustion profiles similar to those of the individual raw materials. The addition of coal to the biomass in low amounts did not affect the thermal characteristics of the blends.Work carried out with financial support from the Spanish MICINN (Project PS- 120000-2006-3, ECOCOMBOS), and co-financed by the European Regional Development Fund, ERDF.Peer reviewe

Selective Aerobic Oxidation of Lactate to Pyruvate Catalyzed by Vanadium-Nitrogen-Doped Carbon Nanosheets

The catalytic oxidative dehydrogenation of lactates with molecular oxygen is a promising yet challenging route for producing high-value pyruvates from biomass. Here we report a simple synthetic strategy for preparing nitrogen-doped carbon nanosheets (NCNs) starting from two abundant precursors, cheap melamine and glucose, and using a simple thermal-annealing process. The resulting NCNs feature numerous edges and holes for anchoring vanadium oxides (V-NCNs). This creates cooperative catalytic sites that boost the catalytic oxidation of ethyl lactate to ethyl pyruvate. Additionally, we systematically studied the surface nitrogen species of NCNs by varying the pyrolysis temperature, and found that the active pyridinic N-oxide species formed in a high thermal-annealing treatment, acting synergistically with vanadium active sites in converting ethyl lactate with oxygen into ethyl pyruvate under mild conditions