All Publications


  • Modulating the optoelectronic properties of hybrid Mo-thiolate thin films JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A Shi, J., Zeng, L., Nikzad, S., Koshy, D. M., Asundi, A. S., MacIsaac, C., Bent, S. F. 2022; 40 (1)

    View details for DOI 10.1116/6.0001378

    View details for Web of Science ID 000727196400002

  • Chemical Modifications of Ag Catalyst Surfaces with Imidazolium Ionomers Modulate H2 Evolution Rates during Electrochemical CO2 Reduction. Journal of the American Chemical Society Koshy, D. M., Akhade, S. A., Shugar, A., Abiose, K., Shi, J., Liang, S., Oakdale, J. S., Weitzner, S. E., Varley, J. B., Duoss, E. B., Baker, S. E., Hahn, C., Bao, Z., Jaramillo, T. F. 2021

    Abstract

    Bridging polymer design with catalyst surface science is a promising direction for tuning and optimizing electrochemical reactors that could impact long-term goals in energy and sustainability. Particularly, the interaction between inorganic catalyst surfaces and organic-based ionomers provides an avenue to both steer reaction selectivity and promote activity. Here, we studied the role of imidazolium-based ionomers for electrocatalytic CO2 reduction to CO (CO2R) on Ag surfaces and found that they produce no effect on CO2R activity yet strongly promote the competing hydrogen evolution reaction (HER). By examining the dependence of HER and CO2R rates on concentrations of CO2 and HCO3-, we developed a kinetic model that attributes HER promotion to intrinsic promotion of HCO3- reduction by imidazolium ionomers. We also show that varying the ionomer structure by changing substituents on the imidazolium ring modulates the HER promotion. This ionomer-structure dependence was analyzed via Taft steric parameters and density functional theory calculations, which suggest that steric bulk from functionalities on the imidazolium ring reduces access of the ionomer to both HCO3- and the Ag surface, thus limiting the promotional effect. Our results help develop design rules for ionomer-catalyst interactions in CO2R and motivate further work into precisely uncovering the interplay between primary and secondary coordination in determining electrocatalytic behavior.

    View details for DOI 10.1021/jacs.1c06212

    View details for PubMedID 34472346

  • Bridging the Synthesis Gap: Ionic Liquids Enable Solvent-Mediated Reaction in Vapor-Phase Deposition. ACS nano Shi, J., Bent, S. F. 2021

    Abstract

    Molecular layer deposition (MLD) is an attractive, vapor-phase deposition method for applications requiring ultrathin organic materials, such as photolithography, lithium batteries, and microelectronics. By using sequential self-limiting surface reactions, MLD offers excellent control over thickness and conformality, but there are also challenges such as a limited range of possible film compositions and long deposition times. In this study, we introduce a modified technique, termed ionic liquid assisted MLD (IL-MLD), that can overcome these barriers. By performing the surface reactions inside of an ultrathin layer of a compatible ionic liquid (IL), solvent effects are replicated inside a vacuum system, broadening the possible reactions to a much wider suite of chemistries. Using this strategy, the MLD of polyetherketoneketone, an industrially and research-relevant, high-performance thermoplastic, is reported. With this proof-of-concept, we demonstrate that IL-MLD can enable the synthesis of polymers via solvent- or catalyst-mediated reactions and establish an approach that may allow solution chemistries to be accessed in other vapor deposition techniques as well.

    View details for DOI 10.1021/acsnano.0c09329

    View details for PubMedID 33523630

  • Modified atomic layer deposition of MoS2 thin films Modified atomic layer deposition of MoS2 thin films Zeng, L., Richey, N. E., Palm, D. W., Oh, I., Shi, J., MacIsaac, C., Jaramillo, T., Bent, S. F. 2020; 38: 060403

    View details for DOI 10.1116/6.0000641