Publications by authors named "Sachin M Chavan"

The synthesis of Ce-fumarate and Zr-fumarate metal-organic framework (MOF) is monitored for the first time with in situ Raman spectroscopy in custom-built solvothermal reactors. Several synthesis conditions were explored for Ce-fumarate at room temperature. The use of the method for high-temperature synthesis of Zr-fumarate is also demonstrated.

View Article and Find Full Text PDF

Metal-organic frameworks (MOFs) with a Zr-oxo cluster [(ZrO(OH))] are exceptionally stable and offer vast potential for a wide range of applications. Synthesis parameters strongly affect the quality, stability, morphology, , of the MOFs. In this study, we present an experimental set-up that allows following element-specific chemical transformations during synthesis and the effect of various reaction parameters on the reaction products.

View Article and Find Full Text PDF

The effective removal and displacement of fluids is important in many industrial and environmental applications, such as for operation and cleaning of process equipment, fluid injection in porous media for oil recovery or aquifer remediation, or for achieving subsurface zonal isolation in new or abandoned wells. The accurate measurement of the residual fluid wall film left behind after displacement by a cleaning fluid is a long-standing challenge, particularly so for very thin fluid films where the thickness can be of the order of micrometer. We focus on the characterization of oil films left on the wall of a horizontal pipe after the pipe has been displaced by water, and develop a novel, non-intrusive analytical technique that allows the use of relevant pipe materials.

View Article and Find Full Text PDF

Metal-organic frameworks (MOFs) are a class of porous organic-inorganic solids extensively explored for numerous applications owing to their catalytic activity and high surface area. In this work MOF thin films deposited in a one-step, molecular layer deposition (MLD), an all-gas-phase process, on glass wool fibers are characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and their capabilities towards toxic industrial chemical (TIC) capture and chemical warfare agents (CWA) degradation are investigated. It is shown that despite low volume of the active material used, MOFs thin films are capable of removal of harmful gaseous chemicals from air stream and CWA from neutral aqueous environment.

View Article and Find Full Text PDF

Unlabelled: Pink stem borer, (Walker, 1856) (Lepidoptera: Noctuidae) is reported to infest many graminaceous crops and cause significant losses. cause damage by killing the central shoot and producing a characteristic symptom called "dead heart". Since graminaceous crops are an important source of food for humans and their livestock, impetus should be given on designing efficient management strategies against pink stem borer.

View Article and Find Full Text PDF

C-H activation reactions are generally associated with relatively low turnover numbers (TONs) and high catalyst concentrations due to a combination of low catalyst stability and activity, highlighting the need for recyclable heterogeneous catalysts with stable single-atom active sites. In this work, several palladium loaded metal-organic frameworks (MOFs) were tested as single-site catalysts for the oxidative coupling of arenes (-xylene) C-H/C-H activation. Isolation of the palladium active sites on the MOF supports reduced Pd(0) aggregate formation and thus catalyst deactivation, resulting in higher turnover numbers (TONs) compared to the homogeneous benchmark reaction.

View Article and Find Full Text PDF

We describe the synthesis and corresponding full characterization of the set of UiO-66 metal-organic frameworks (MOFs) with 1,4-benzenedicarboxylate (CH(COOH), hereafter HBDC) and 1,4-naphthalenedicarboxylate (CH(COOH), hereafter HNDC) mixed linkers with NDC contents of 0, 25, 50, and 100%. Their structural (powder X-ray diffraction, PXRD), adsorptive (N, H, and CO), vibrational (IR/Raman), and thermal stability (thermogravimetric analysis, TGA) properties quantitatively correlate with the NDC content in the material. The UiO-66 phase topology is conserved at all relative fractions of BDC/NDC.

View Article and Find Full Text PDF

A series of amine-functionalized mixed-linker metal-organic frameworks (MOFs) of idealized structural formula Zr6O4(OH)4(BDC)(6-6X)(ABDC)6X (where BDC = benzene-1,4-dicarboxylic acid, ABDC = 2-aminobenzene-1,4-dicarboxylic acid) has been prepared by solvothermal synthesis. The materials have been characterized by thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and Fourier transform infrared (FTIR) spectroscopy with the aim of elucidating the effect that varying the degrees of amine functionalization has on the stability (thermal and chemical) and porosity of the framework. This work includes the first application of ultraviolet-visible light (UV-vis) spectroscopy in the quantification of ABDC in mixed-linker MOFs.

View Article and Find Full Text PDF

Systematic studies of H2 adsorption by variable temperature infrared (VTIR) spectroscopy have added value in the characterization of hydrogen storage materials. As a key study to describe the potential of the method, here we report VTIR spectroscopy results of H2 adsorption at isostructural MOFs CPO-27-M (M = Mg, Mn, Co, Ni, Zn). The strongest perturbation of H2 vibrational frequency is due to the interaction with an open metal site.

View Article and Find Full Text PDF