Search for: All records

Metal–organic frameworks (MOFs), along with other novel adsorbents, are frequently proposed as candidate materials to selectively adsorb CO 2 for carbon capture processes. However, adsorbents designed to strongly bind CO 2 nearly always bind H 2 O strongly (sometimes even more so). Given that water is present in significant quantities in the inlet streams of most carbon capture processes, a method that avoids H 2 O competition for the CO 2 binding sites would be technologically valuable. In this paper, we consider a novel core–shell MOF design strategy, where a high-CO 2 -capacity MOF “core” is protected from competitive H 2 O-binding via a MOF “shell” that has very slow water diffusion. We consider a high-frequency adsorption/desorption cycle that regenerates the adsorbents before water can pass through the shell and enter the core. To identify optimal core–shell MOF pairs, we use a combination of experimental measurements, computational modeling, and multiphysics modeling. Our library of MOFs is created from two starting MOFs-UiO-66 and UiO-67-augmented with 30 possible functional group variations, yielding 1740 possible core–shell MOF pairs. After defining a performance score to rank these pairs, we identified 10 core–shell MOF candidates that significantly outperform any of the MOFs functioning alone. 

Peptide conjugate molecules comprising a gold-binding peptide (e.g., AYSSGAPPMPPF) attached to an aliphatic tail have proven to be powerful agents for directing the synthesis and assembly of gold nanoparticle superstructures, in particular chiral helices having interesting plasmonic chiroptical properties. The composition and structure of these molecular agents can be tailored to carefully tune the structure and properties of gold nanoparticle single and double helices. To date, modifications to the β-sheet region (AYSSGA) of the peptide sequence have not been exploited to control the metrics and assembly of such superstructures. We report here that systematic peptide sequence variation in a series of gold-binding peptide conjugate molecules can be leveraged not only to affect the assembly of peptide conjugates but also to control the synthesis, assembly, and optical properties of gold nanoparticle superstructures. Depending upon the hydrophobicity of a single-amino acid variant, the conjugates yield either dispersed gold nanoparticles or helical superstructures. These results provide evidence that subtle changes to peptide sequence, via single-amino acid variation in the β-sheet region, can be leveraged to program structural control in chiral gold nanoparticle superstructures.