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Abstract The majority of harmful atmospheric CO and NO
x emissions are from vehicle exhausts. Although there has been success addressing NOx emissions at temperatures above 250 °C with selective catalytic reduction technology, emissions during vehicle cold start (when the temperature is below 150 °C), are a major challenge. Herein, we show we can completely eliminate both CO and NOxemissions simultaneously under realistic exhaust flow, using a highly loaded (2 wt %) atomically dispersed palladium in the extra‐framework positions of the small‐pore chabazite material as a CO and passive NOx adsorber. Until now, atomically dispersed highly loaded (>0.3 wt %) transition‐metal/SSZ‐13 materials have not been known. We devised a general, simple, and scalable route to prepare such materials for PtIIand PdII. Through spectroscopy and materials testing we show that both CO and NOx can be simultaneously completely abated with 100 % efficiency by the formation of mixed carbonyl‐nitrosyl palladium complex in chabazite micropore. -
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Abstract Characterizing thermal acclimation is a common goal of eco‐physiological studies and has important implications for models of climate change and environmental adaptation. However, quantifying thermal acclimation in biological rate processes is not straightforward because many rates increase with temperature due to the acute effect of thermodynamics on molecular interactions. Disentangling such passive plastic responses from active acclimation responses is critical for describing patterns of thermal acclimation.
Here, we reviewed published studies and distinguished between different study designs measuring the acute (i.e. passive) and acclimated (i.e. active) effects of temperature on metabolic rate. We then developed a method to quantify and classify acclimation responses by comparing acute and acclimated
Q 10values. Finally, we applied this method using meta‐analysis to characterize thermal acclimation in metabolic rates of ectothermic animals.We reviewed 258 studies measuring thermal effects on metabolic rates, and found that a majority of these studies (74%) did not allow for quantifying the independent effects of acclimation. Such studies were more common when testing aquatic taxa and continue to be published even in recent years.
A meta‐analysis of 96 studies where acclimation could be quantified (using 1,072
Q 10values) revealed that ‘partial compensation’ was the most common acclimation response (i.e. acclimation tended to offset the passive change in metabolic rate due to acute temperature changes). However, ‘no acclimation’ and ‘inverse compensation’, in which acclimation further augmented the acute change in metabolic rate, were also common.Acclimation responses differed among taxa, habitats and with experimental design. Amphibians and other terrestrial taxa tended to show weak acclimation responses, whereas fishes and other aquatic taxa tended to show stronger compensatory responses. Increasing how long the animal was allowed to adjust to a new test temperature increased the acclimation response, but body size did not. Acclimation responses were also stronger with longer acclimation durations.
Collectively, these results highlight the importance of using the appropriate experimental design to investigate and estimate thermal acclimation of biological rates. To facilitate and guide future studies of thermal acclimation, we end with some suggestions for designing and interpreting experiments.
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Abstract The majority of harmful atmospheric CO and NO
x emissions are from vehicle exhausts. Although there has been success addressing NOx emissions at temperatures above 250 °C with selective catalytic reduction technology, emissions during vehicle cold start (when the temperature is below 150 °C), are a major challenge. Herein, we show we can completely eliminate both CO and NOxemissions simultaneously under realistic exhaust flow, using a highly loaded (2 wt %) atomically dispersed palladium in the extra‐framework positions of the small‐pore chabazite material as a CO and passive NOx adsorber. Until now, atomically dispersed highly loaded (>0.3 wt %) transition‐metal/SSZ‐13 materials have not been known. We devised a general, simple, and scalable route to prepare such materials for PtIIand PdII. Through spectroscopy and materials testing we show that both CO and NOx can be simultaneously completely abated with 100 % efficiency by the formation of mixed carbonyl‐nitrosyl palladium complex in chabazite micropore.
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3847/2041-8213/aa7cf2
