Photo- and Thermocatalytic CO2 Methanation: A Comparison of Ni/Al2O3 and Ni-Ce Hydrotalcite-Derived Materials under UV and Visible Light.

Catalysts derived from Ni/Al/Mg/Ce hydrotalcite were prepared via a co-precipitation method, varying the Ce/Al atomic ratio. All of the catalytic systems thus prepared were tested for CO2 methanation under dark and photocatalytic conditions (visible and ultraviolet) under continuous flow with the light intensity set to 2.4 W cm-2. The substitution of Al by Ce formed a solid solution, generating oxygen vacancies and Ce3+/Ce4+ ions that helped shift the dissociation of CO2 towards the production of CH4, thus enhancing the activity of methanation, especially at lower temperatures (<523 K) and with visible light at temperatures where other catalysts were inactive. Additionally, for comparison purposes, Ni/Al2O3-based catalysts prepared via wetness impregnation were synthesized with different Ni loadings. Analytical techniques were used for the characterization of the systems. The best results in terms of activity were as follows: Hydrotalcite with Ce promoter > Hydrotalcite without Ce promoter > 25Ni/Al2O3 > 13Ni/Al2O3. Hydrotalcite, with a Ce/Al atomic ratio of 0.22 and a Ni content of 23 wt%, produced 7.74 mmol CH4 min-1·gcat at 473 K under visible light. Moreover, this catalyst exhibited stable photocatalytic activity during a 24 h reaction time with a CO2 conversion rate of 65% and CH4 selectivity of >98% at 523 K. This photocatalytic Sabatier enhancement achieved activity at lower temperatures than those reported in previous publications.

UV- and visible-light photocatalysis using Ni-Co bimetallic and monometallic hydrotalcite-like materials for enhanced CO2 methanation in sabatier reaction.

The CO2 catalytic reduction activities of four different Co-modified Ni-based catalysts derived from hydrotalcite-like materials (HTCs) prepared by co-precipitation method were investigated under thermal and photocatalytic conditions. All catalysts were tested from 473 to 723 K at 10 bar (abs). The light intensity for photocatalytic reactions was 2.4 W cm-2. The samples were characterized to determine the effect of morphological and physicochemical properties of mono-bimetallic active phases on their methanation activity. The activity toward CO2 methanation followed the next order: Ni > Co-Ni > Co. For the monometallic Ni catalyst an increase of a 72% was achieved in the photo-catalytic activity under UV and vis light irradiation at temperatures lower by > 100 K than those in a conventional reaction. Co-modified Ni based hydrotalcite catalysts performed with stability and no deactivation for the 16 h studied under visible light for methanation at 523 K due to the presence of basic sites.

Observations on female bats transporting non-volant juveniles during flight / Observations on female bats transporting non-volant juveniles during flight

We report observations on mother bats of six species transporting their non-volant juveniles during flight. This is the first published record of such behavior for Carollia sowelli and Glossophaga commissarisi. Transportation of non-volant juveniles has been occasionally documented in several species, in most of the cases after roost disturbance. Many explanations have been suggested for this behavior related to the complex patterns of social organization and roost utilization during the breeding season. Nevertheless, for frugivorous species, an alternative explanation has been suggested that transportation of the offspring during foraging flights may serve for training purposes, where the juveniles learn about suitable food, location of resources and flight routes. Here we contribute to the knowledge of parental care in tropical bats presenting data about transportation of juveniles by their mothers. Four of six captured female bats belong to species with obligatory or facultative use of exposed roost. Because of this, it is likely that mothers transferred their juveniles between alternative roosts, as a strategy to increase the offspring survival probability.

We report observations on mother bats of six species transporting their non-volant juveniles during flight. This is the first published record of such behavior for Carollia sowelli and Glossophaga commissarisi. Transportation of non-volant juveniles has been occasionally documented in several species, in most of the cases after roost disturbance. Many explanations have been suggested for this behavior related to the complex patterns of social organization and roost utilization during the breeding season. Nevertheless, for frugivorous species, an alternative explanation has been suggested that transportation of the offspring during foraging flights may serve for training purposes, where the juveniles learn about suitable food, location of resources and flight routes. Here we contribute to the knowledge of parental care in tropical bats presenting data about transportation of juveniles by their mothers. Four of six captured female bats belong to species with obligatory or facultative use of exposed roost. Because of this, it is likely that mothers transferred their juveniles between alternative roosts, as a strategy to increase the offspring survival probability.

Observations on female bats transporting non-volant juveniles during flight / Observations on female bats transporting non-volant juveniles during flight

We report observations on mother bats of six species transporting their non-volant juveniles during flight. This is the first published record of such behavior for Carollia sowelli and Glossophaga commissarisi. Transportation of non-volant juveniles has been occasionally documented in several species, in most of the cases after roost disturbance. Many explanations have been suggested for this behavior related to the complex patterns of social organization and roost utilization during the breeding season. Nevertheless, for frugivorous species, an alternative explanation has been suggested that transportation of the offspring during foraging flights may serve for training purposes, where the juveniles learn about suitable food, location of resources and flight routes. Here we contribute to the knowledge of parental care in tropical bats presenting data about transportation of juveniles by their mothers. Four of six captured female bats belong to species with obligatory or facultative use of exposed roost. Because of this, it is likely that mothers transferred their juveniles between alternative roosts, as a strategy to increase the offspring survival probability.

We report observations on mother bats of six species transporting their non-volant juveniles during flight. This is the first published record of such behavior for Carollia sowelli and Glossophaga commissarisi. Transportation of non-volant juveniles has been occasionally documented in several species, in most of the cases after roost disturbance. Many explanations have been suggested for this behavior related to the complex patterns of social organization and roost utilization during the breeding season. Nevertheless, for frugivorous species, an alternative explanation has been suggested that transportation of the offspring during foraging flights may serve for training purposes, where the juveniles learn about suitable food, location of resources and flight routes. Here we contribute to the knowledge of parental care in tropical bats presenting data about transportation of juveniles by their mothers. Four of six captured female bats belong to species with obligatory or facultative use of exposed roost. Because of this, it is likely that mothers transferred their juveniles between alternative roosts, as a strategy to increase the offspring survival probability.