CO Adsorption on Pd Nanoparticles:  Density Functional and Vibrational Spectroscopy Studies

Using the high-entropy alloys (HEAs) CoCuGaNiZn and AgAuCuPdPt as starting points we provide a framework for tuning the composition of disordered multi-metallic alloys to control the selectivity and activity of the reduction of carbon dioxide (CO2) to highly reduced compounds. By combining density functional theory (DFT) with supervised machine learning we predicted the CO and hydrogen (H) adsorption energies of all surface sites on the (111) surface of the two HEAs. This allowed an optimization for the HEA compositions with increased likelihood for sites with weak hydrogen adsorption{to suppress the formation of molecular hydrogen (H2) and with strong CO adsorption to favor the reduction of CO. This led to the discovery of several disordered alloy catalyst candidates for which selectivity towards highly reduced carbon compounds is expected, as well as insights into the rational design of disordered alloy catalysts for the CO2 and CO reduction reaction.

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Chiroptical Sensing of Amino Acid Derivatives by Host–Guest Complexation with Cyclo[6]aramide

Molecules ◽

10.3390/molecules26134064 ◽

2021 ◽

Vol 26 (13) ◽

pp. 4064

Author(s):

Xuebin Wang ◽

Jiecheng Ji ◽

Zejiang Liu ◽

Yimin Cai ◽

Jialiang Tang ◽

...

Keyword(s):

Amino Acid ◽

Density Functional ◽

Cd Spectroscopy ◽

Functional Theory ◽

Chirality Transfer ◽

Supramolecular Chirality ◽

New Strategy ◽

Spectroscopy Studies ◽

Effective Component ◽

Acid Esters

A hydrogen-bonded (H-bonded) amide macrocycle was found to serve as an effective component in the host–guest assembly for a supramolecular chirality transfer process. Circular dichroism (CD) spectroscopy studies showed that the near-planar macrocycle could produce a CD response when combined with three of the twelve L-α-amino acid esters (all cryptochiral molecules) tested as possible guests. The host–guest complexation between the macrocycle and cationic guests was explored using NMR, revealing the presence of a strong affinity involving the multi-point recognition of guests. This was further corroborated by density functional theory (DFT) calculations. The present work proposes a new strategy for amplifying the CD signals of cryptochiral molecules by means of H-bonded macrocycle-based host–guest association, and is expected to be useful in designing supramolecular chiroptical sensing materials.

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Unique structure of active platinum-bismuth site for oxidation of carbon monoxide

Nature Communications ◽

10.1038/s41467-021-23696-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Bing Nan ◽

Qiang Fu ◽

Jing Yu ◽

Miao Shu ◽

Lu-Lu Zhou ◽

...

Keyword(s):

Carbon Monoxide ◽

Low Temperature ◽

Co Oxidation ◽

Density Functional ◽

Technology Development ◽

Co Adsorption ◽

Combustion Engines ◽

Advanced Combustion ◽

Surface Metal ◽

Bismuth Cluster

AbstractAs the technology development, the future advanced combustion engines must be designed to perform at a low temperature. Thus, it is a great challenge to synthesize high active and stable catalysts to resolve exhaust below 100 °C. Here, we report that bismuth as a dopant is added to form platinum-bismuth cluster on silica for CO oxidation. The highly reducible oxygen species provided by surface metal-oxide (M-O) interface could be activated by CO at low temperature (~50 °C) with a high CO2 production rate of 487 μmolCO2·gPt−1·s−1 at 110 °C. Experiment data combined with density functional calculation (DFT) results demonstrate that Pt cluster with surface Pt−O−Bi structure is the active site for CO oxidation via providing moderate CO adsorption and activating CO molecules with electron transformation between platinum atom and carbon monoxide. These findings provide a unique and general approach towards design of potential excellent performance catalysts for redox reaction.

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