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Chemistry

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City University of New York (CUNY)

Surface chemistry

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Full-Text Articles in Physical Sciences and Mathematics

Kinetics Of Photochemical And Mechanochemical Organic Reactions On Surface, Yerzhan Zholdassov Sep 2023

Kinetics Of Photochemical And Mechanochemical Organic Reactions On Surface, Yerzhan Zholdassov

Dissertations, Theses, and Capstone Projects

Solvents used in traditional chemical processes account for a large percentage of reaction mass and waste and can pose significant environmental and health risks. The environmentally friendly nature of mechanochemistry, in addition to other benefits, makes it a promising approach for sustainable chemistry over traditional solvent-based methods. However, it is still not a widely adopted method for performing chemical reactions on an industrial scale. This is partially due to the significant challenge associated with understanding the reaction kinetics under mechanochemical conditions. Many variations of scanning probe lithography (SPL) techniques are able to manipulate the organic molecules with precise control over …


Tools And Strategies For The Patterning Of Bioactive Molecules And Macromolecules, Daniel J. Valles Sep 2021

Tools And Strategies For The Patterning Of Bioactive Molecules And Macromolecules, Daniel J. Valles

Dissertations, Theses, and Capstone Projects

Hypersurface Photolithography (HP) is a printing method for fabricating structures and patterns composed of soft materials bound to solid surfaces and with ~1 micrometer resolution in the x, y, and z dimensions. This platform leverages benign, low intensity light to perform photochemical surface reactions with spatial and temporal control of irradiation, and, as a result, is particularly useful for patterning delicate organic and biological material. In particular, surface- initiated controlled radical polymerizations can be leveraged to create arbitrary polymer and block- copolymer brush patterns. Chapter 1 will review the advances in instrumentation architectures from our group that have made these …


Exploring The Silent Aspect Of Carbon Nanopores, Teresa J. Bandosz Feb 2021

Exploring The Silent Aspect Of Carbon Nanopores, Teresa J. Bandosz

Publications and Research

Recently, owing to the discovery of graphene, porous carbons experienced a revitalization in their explorations. However, nowadays, the focus is more on search for suitable energy advancing catalysts sensing, energy storage or thermal/light absorbing features than on separations. In many of these processes, adsorption, although not emphasized sufficiently, can be a significant step. It can just provide a surface accumulation of molecules used in other application-driving chemical or physical phenomena or can be even an additional mechanism adding to the efficiency of the overall performance. However, that aspect of confined molecules in pores and their involvement in the overall performance …


Tio2/S-Doped Carbons Hybrids: Analysis Of Their Interfacial And Surface Features, Teresa Bandosz, Alfonso Policicchio, Marc Florent, Po S. Poon, Juan Matos Oct 2019

Tio2/S-Doped Carbons Hybrids: Analysis Of Their Interfacial And Surface Features, Teresa Bandosz, Alfonso Policicchio, Marc Florent, Po S. Poon, Juan Matos

Publications and Research

Hybrids containing approximately equal amounts of P25 TiO2 and S-doped porous carbons were prepared using a water-based slurry mixing method. The materials were extensively characterized by adsorption of nitrogen, potentiometric titration, thermal analysis in air and in helium, XRD, XPS and SEM. The collected results showed the significant blockage of carbon micropores by TiO2 particles deposited on their outer surface. The formation of a new interface, especially for the S-rich samples, might also contribute to the porosity alteration. Analysis of surface chemistry suggested the presence of Ti-S bonds with an involvement of sulfur from thiophenic species in the carbon phase. …


Efficient Air Desulfurization Catalysts Derived From Pig Manure Liquefaction Char, Rajiv Wallace, Sundaramurthy Suresh, Elham H. Fini, Teresa Bandosz Nov 2017

Efficient Air Desulfurization Catalysts Derived From Pig Manure Liquefaction Char, Rajiv Wallace, Sundaramurthy Suresh, Elham H. Fini, Teresa Bandosz

Publications and Research

Biochar from the liquefaction of pig manure was used as a precursor of H2S desulfurization adsorbents. In its inorganic matter, it contains marked quantities of calcium, magnesium and iron, which are known as hydrogen sulfide oxidation catalysts. The char was used either as-received or mixed with 10% nanographite. The latter was added to increase both the content of the carbon phase and conductivity. ZnCl2 in two different ratios of char to an activation agent (1:1 and 1:2) was used to create the porosity in the carbon phase. The content of the later was between 18–45%. The activated samples adsorbed 144 …


Toxic Gas Sensing On Nanoporous Carbons, Nikolina-Eleni Travlou Sep 2017

Toxic Gas Sensing On Nanoporous Carbons, Nikolina-Eleni Travlou

Dissertations, Theses, and Capstone Projects

Activated carbons, either synthetic, developed in our laboratory, or commercial, were prepared or further modified, in order to introduce specific heteroatoms such as oxygen, nitrogen and sulfur to their matrices. Chips coated with thin layers of the carbon samples were used for the sensing of gaseous ammonia. They were exposed to continuous cycles of various ammonia concentrations (10-500 ppm), and changes in normalized resistance were analyzed. In all cases linear responses were recorded and the chips reached sensitivities as high as 31%, which are comparable to those of modified graphene-based sensors. The applied specific surface chemical modifications were an effective …