My research is interdisciplinary in nature and at the crossroads of chemistry, material science, and engineering. I develop novel nanoporous materials for energy and environmental applications that address societal problems of the impending climate change, depletion of current fuel sources, and increasing need for on-the-go energy supply. Examples include: (i) adsorbents for carbon capture and storage, (ii) thermally insulating materials to improve energy efficiency of buildings and devices, (iii) photocatalysts for hydrogen production by water splitting and conversion of CO2 into fuels, and (iv) electrode materials for energy storage in batteries and supercapacitors.
Transparent mesoporous silica thermal barriers
To date, the main contender for window insulation have been silica aerogels due to their high porosity (> 95%) and exceptionally low effective thermal conductivity (< 0.02 W m–1 K–1). However, silica aerogels have some limitations that preclude them from practical application such as poor optical clarity and poor mechanical stability.
To address this issue, as a part of a UCLA team, I designed, synthesized, and characterized mesoporous (pore width = 2–50 nm) silica slabs that were both thermally insulating and transparent. Together we developed a patented method to synthesize monolithic mesoporous silica slabs with the effective thermal conductivity comparable to silica aerogels and the optical transparency comparable to glass. These slabs will be used as optically clear thermal insulation for windows and in solar-thermal energy conversion systems.
My Ph.D. research focused on synthesis methods of mesoporous titania for photocatalytic applications. Titania is a photocatalyst that can reduce or oxidize chemicals when illuminated with light. Specifically, titania can (a) split H2O into H2 and O2, (b) reduce CO2 producing CH4, CH3OH and other useful hydrocarbons and fuels, and (c) decompose organic pollutants. A good titania photocatalyst must have a large surface area, large pore volume, high crystallinity, and bandgap Eg < 3 eV. Typical titania, however, lacks all these elements.
To address this issue, I proposed and executed three syntheses of mesoporous titania: (i) block copolymer-assisted synthesis, (ii) scaffold-assisted synthesis, and (iii) modified precursor synthesis. In the last work, I accomplished my goal by synthesizing mesoporous titania with a large surface area, large porosity, high crystallinity, and bandgap Eg = 2.3 eV.
Image source: Marszewski et al., Mater. Horiz., 2015, 2, 261 DOI: 10.1039/C4MH00176A. Reproduced by permission of The Royal Society of Chemistry.
In collaboration with Professor Jerzy Choma’s research group from the Military University of Technology (Warsaw, Poland) we synthesized, characterized, and test mesoporous and microporous (pore width < 2 nm) carbons. We were interested in adsorption and storage of CO2, H2, C6H6, and CH4 in these materials. Together, we synthesized and characterized (a) microporous and mesoporous carbon spheres using Stöber synthesis, (b) polymer-templated mesoporous carbons containing nanoparticles of Ni or NiO2, (c) carbon–gold core–shell structures and gold nanoparticles-containing mesoporous carbons, (d) ordered mesoporous carbons by organic acid-assisted soft-templating synthesis, (e) micro-mesoporous carbons from polypyrrole, polyvinylidene fluoride, sulfonated styrene–divinylbenzene resin, phenol–formaldehyde resin, Saran, and Kevlar.
Image source: Reprinted by permission from Springer Nature Customer Service Centre GmbH: Springer Adsorption "Organic acid-assisted soft-templating synthesis of ordered mesoporous carbons" Choma et al. Copyright 2013.