Publications by authors named "D Bethell"
Article Synopsis
- Bimetallic catalysts, like Au-Pd, show higher reaction rates than single-metal catalysts, but the reasons for this improvement are not fully understood.
- Recent research reveals that cooperative redox enhancement in these bimetallic systems boosts catalysis in thermochemical oxidation and connects thermocatalysis with electrocatalysis.
- We found that the increased activity stems from the electrochemical polarization of different catalytic sites, creating a new operating potential that enhances reaction efficiency, and identified factors that affect this enhancement across various bimetal combinations.
The aerobic oxidation of alcohols and aldehydes over supported heterogeneous catalysts can be considered as comprising two complementary and linked processes: dehydrogenation and oxygen reduction. Significant rate enhancements can be observed when these processes are catalyzed by independent active sites, coupled by electron transport between the two catalysts. This effect, termed cooperative redox enhancement (CORE), could significantly influence how researchers approach catalyst design, but a greater understanding of the factors which influence it is required.
View Article and Find Full Text PDFThe direct transformation of methane to methanol remains a significant challenge for operation at a larger scale. Central to this challenge is the low reactivity of methane at conditions that can facilitate product recovery. This review discusses the issue through examination of several promising routes to methanol and an evaluation of performance targets that are required to develop the process at scale.
View Article and Find Full Text PDFArticle Synopsis
- Oxidation reactions with supported metal nanoparticles often have oxygen reduction as a limiting factor, particularly in processes like the oxidative dehydrogenation of alcohols.
- Supported gold nanoparticles are effective for converting alcohols to aldehydes but struggle with oxygen reduction, whereas palladium nanoparticles excel in that area.
- By physically separating gold and palladium in catalysts rather than alloying them, researchers found that this arrangement significantly improves reaction rates due to enhanced cooperative redox reactions between the two metals.
Cinnamic acid was chosen as an exemplar molecule to study the effect of potential contaminants on the kinetics and mechanism of the photocatalytic destruction of hydrocarbons in aqueous solutions. We identify the principal intermediates in the photocatalytic reaction of the acid and corresponding alcohol, and propose a mechanism that explains the presence of these species. The impact of two likely contaminants of aqueous systems, sulfate and chloride ions were also studied.
View Article and Find Full Text PDF