Showing papers by "Jeffrey A. Reimer published in 2014"

Metal-organic frameworks with precisely designed interior for carbon dioxide capture in the presence of water

Abstract: The selective capture of carbon dioxide in the presence of water is an outstanding challenge. Here, we show that the interior of IRMOF-74-III can be covalently functionalized with primary amine (IRMOF-74-III-CH2NH2) and used for the selective capture of CO2 in 65% relative humidity. This study encompasses the synthesis, structural characterization, gas adsorption, and CO2 capture properties of variously functionalized IRMOF-74-III compounds (IRMOF-74-III-CH3, -NH2, -CH2NHBoc, -CH2NMeBoc, -CH2NH2, and -CH2NHMe). Cross-polarization magic angle spinning 13C NMR spectra showed that CO2 binds chemically to IRMOF-74-III-CH2NH2 and -CH2NHMe to make carbamic species. Carbon dioxide isotherms and breakthrough experiments show that IRMOF-74-III-CH2NH2 is especially efficient at taking up CO2 (3.2 mmol of CO2 per gram at 800 Torr) and, more significantly, removing CO2 from wet nitrogen gas streams with breakthrough time of 610 ± 10 s g–1 and full preservation of the IRMOF structure.

Introduction to carbon capture and sequestration

Abstract: The aim of the book is to provide an understanding of the current science underpinning Carbon Capture and Sequestration (CCS) and to provide students and interested researchers with sufficient background on the basics of Chemical Engineering, Material Science, and Geology that they can understand the current state of the art of the research in the field of CCS. In addition, the book provides a comprehensive discussion of the impact of CCS on the energy landscape, society, and climate as these topics govern the success of the science being done in this field. The book is aimed at undergraduate students, graduate students, scientists, and professionals who would like to gain a broad multidisciplinary view of the research that is being carried out to solve one of greatest challenges of our generation.

Near-band-gap photo-induced nuclear spin dynamics in semi-insulating GaAs: Hyperfine- and quadrupolar-driven relaxation

Abstract: Understanding and manipulating spin polarization and transport in the vicinity of semiconductor-hosted defects is a problem of present technological and fundamental importance. Here, we use high-field magnetic resonance to monitor the relaxation dynamics of spin-3/2 nuclei in semi-insulating GaAs. Our experiments benefit from the conditions created in the limit of low illumination intensities, where intermittent occupation of the defect site by photo-excited electrons leads to electric field gradient fluctuations and concomitant spin relaxation of the neighboring quadrupolar nuclei. We find indication of a heterogeneous distribution of polarization, governed by different classes of defects activated by either weak or strong laser excitation. Upon application of a train of light pulses of variable repetition rate and on/off ratio, we uncover an intriguing regime of mesoscale nuclear spin diffusion restricted by long-range, non-uniform electric field gradients. Given the slow time scale governing nuclear spin evolution, such optically-induced polarization patterns could be exploited as a contrast mechanism to expose dark lattice defects or localized charges with nanoscale resolution.