Engineering topics
Publications and source records attributed to Turaczy, Kevin K..
Transition metal nitrides are promising catalysts for a variety of reactions. This work outlines their use for C 1 molecule upgrading, biomass valorization, and hydrogen evolution, and presents challenges and future opportunities for these catalysts.
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It is well established that hydrogen binding energy (HBE) is a key descriptor for hydrogen evolution reaction (HER) activity, and such a relationship is a useful tool for searching efficient and cost-effective HER catalysts. However, in almost all cases, the HBE values are obtained from density functional theory (DFT) calculations. Here in this study, temperature programmed desorption (TPD) was used to experimentally determine the HBE values of metal monolayers supported on molybdenum nitride (Mo 2 N), and electrochemical measurements were performed on the same surfaces. Combined DFT and kinetic Monte Carlo (kMC) simulations were used to validate the trend observed with TPD and the electrochemical HER activity. Depositing one monolayer of Pt on Mo 2 N led to similar HBE values seen for bulk Pt, and electrochemical measurements showed that monolayer Pt on Mo 2 N had similar HER activity to that of bulk Pt. Similar studies were also performed for monolayer Pd on Mo 2 N to confirm the correlation. This work also demonstrates that Mo 2 N is a promising support to reduce precious metal loading in HER catalysts.
The greenhouse effect arises when thermal radiation is forced to undergo absorption and re-emission many times before escaping, while sunlight transmits largely unimpeded. Although this effect is responsible for global warming, it is generally weak in solid-state materials because radiation can be easily overpowered by other modes of heat transfer. Here, we report on the use of infrared plasmonic nanoparticles to enhance the greenhouse effect in transparent mesoporous materials. Local surface plasmon resonances in transparent conducting oxide nanoparticles (TCO NPs) selectively shorten the mean free path of thermal photons while maintaining high solar transmittance. The addition of a small amount of TCO NPs (<0.1% by volume) nearly halves the heat losses at 700 °C. This leads to an experimentally demonstrated effective thermal emittance of ~0.17 at 700 °C, which is the lowest reported value to date, among all selective surfaces and transparent insulating materials measured at 650 °C or above. Furthermore, our results show that plasmon-enhanced greenhouse selectivity (PEGS) is a promising mechanism for spectral control of radiative heat transfer, and more specifically, for conversion of minimally concentrated sunlight into high-temperature heat.