Nitrogen has been demonstrated to be effective for the regeneration of Co3Mo3N from Co6Mo6N, albe... more Nitrogen has been demonstrated to be effective for the regeneration of Co3Mo3N from Co6Mo6N, albeit at higher temperature and longer duration than, when employing H2/N2. In some instances, incomplete regeneration yielding a mixture of the two line phases is observed, which has been interpreted on the possible basis of a crystallite size distribution. Temperature programmed reduction of Co3Mo3N, prepared so as to eliminate the possible contribution of NHx groups, demonstrates the significant production of ammonia although in much lower quantities than NHx–containing Co3Mo3N samples.Graphical Abstract
Waste Management & Research: The Journal for a Sustainable Circular Economy, 2022
This article describes the catalytic cracking of low-density polyethylene over attapulgite clay a... more This article describes the catalytic cracking of low-density polyethylene over attapulgite clay and iron substituted tungstophosphate/attapulgite clay (Fe-POM/attapulgite) composite materials to evaluate their suitability and performance for recycling of plastic waste into liquid fuel. The prepared catalysts enhanced the yield of liquid fuel (hydrocarbons) produced in cracking process. A maximum yield of 82% liquid oil fraction with a negligible amount of coke was obtained for 50% Fe-POM/attapulgite composite. Whereas, only 68% liquid oil fractions with a large amount of solid black residue was produced in case of non-catalytic pyrolysis. Moreover, Fe-POM/attapulgite clay composites showed higher selectivity towards lower hydrocarbons (C5–C12) with aliphatic hydrocarbons as major fractions. These synthesised composite catalysts significantly lowered the pyrolysis temperature from 375°C to 310°C. Hence, recovery of valuable fuel oil from polyethylene using these synthesised catalysts...
A Tantalum Pentoxide (Ta2O5) based resistive nonvolatile memory device with bipolar switching beh... more A Tantalum Pentoxide (Ta2O5) based resistive nonvolatile memory device with bipolar switching behaviour was developed to demonstrate the new concept of memory in e-skin. The memory device showed stable switching behavior under preprogrammed voltage stimuli after an initial forming process. The memory cell was then integrated with a commercial tactile sensor with a new interface circuit, which enabled the switching of the memory cell through the electrical output from the sensor. This study provides a novel method for handling the transport and storage of large tactile data and will trigger advances towards memorable e-skin.
We report here alumina-substituted Keggin tungstoborate/kaolin clay composite materials (KAB/kaol... more We report here alumina-substituted Keggin tungstoborate/kaolin clay composite materials (KAB/kaolin) as polyethylene cracking catalysts. KAB/kaolin composites with varying concentrations of KAB (10–50 wt.%) were synthesized by the wet impregnation method and successfully characterized by Fourier-transform infrared spectroscopy, powder X-ray diffraction, thermo-gravimetric analysis and scanning electron microscopy with energy dispersive X-ray spectroscopy analytical techniques. Use of KAB loaded kaolin composites as the catalyst for low-density polyethylene (LDPE) cracking exhibited a higher percentage of polymer conversion (99%), producing 84 wt.% of fuel oil and negligible amount (˂ 1 wt.%) of solid residue while thermal cracking produced ~22 wt.% residue. Furthermore, gas chromatography–mass spectrometry analysis of oil obtained by non-catalytic cracking exhibited a high selectivity to high molecular weight hydrocarbons (C13–C23) compared to the catalytic cracking where 70 mol.% o...
Although major difficulties are experienced for hydrogen- storage materials to meet performance r... more Although major difficulties are experienced for hydrogen- storage materials to meet performance requirements for mobile applications, alternative fuel cell feedstocks such as ammonia can be stored in the solid state safely at high capacity. We herein describe the NiX2 -NH3 (X=Cl, Br, I) systems and demonstrate their exceptional suitability for NH3 storage (up to 43 wt % NH3 with desorption that begins at 400 K). The structural effects that result from the uptake of NH3 were studied by powder X-ray diffraction (PXD), FTIR spectroscopy and SEM. NH3 release at elevated temperatures was followed by in situ PXD. The cycling capabilities and air stability of the systems were also explored. NH3 is released from the hexaammines in a three-step process to yield the diammine, monoammine and NiX2 dihalides respectively and (re)ammoniation occurs readily at room temperature. The hexaammines do not react with air after several hours of exposure.
Nitrogen has been demonstrated to be effective for the regeneration of Co3Mo3N from Co6Mo6N, albe... more Nitrogen has been demonstrated to be effective for the regeneration of Co3Mo3N from Co6Mo6N, albeit at higher temperature and longer duration than, when employing H2/N2. In some instances, incomplete regeneration yielding a mixture of the two line phases is observed, which has been interpreted on the possible basis of a crystallite size distribution. Temperature programmed reduction of Co3Mo3N, prepared so as to eliminate the possible contribution of NHx groups, demonstrates the significant production of ammonia although in much lower quantities than NHx–containing Co3Mo3N samples.Graphical Abstract
Waste Management & Research: The Journal for a Sustainable Circular Economy, 2022
This article describes the catalytic cracking of low-density polyethylene over attapulgite clay a... more This article describes the catalytic cracking of low-density polyethylene over attapulgite clay and iron substituted tungstophosphate/attapulgite clay (Fe-POM/attapulgite) composite materials to evaluate their suitability and performance for recycling of plastic waste into liquid fuel. The prepared catalysts enhanced the yield of liquid fuel (hydrocarbons) produced in cracking process. A maximum yield of 82% liquid oil fraction with a negligible amount of coke was obtained for 50% Fe-POM/attapulgite composite. Whereas, only 68% liquid oil fractions with a large amount of solid black residue was produced in case of non-catalytic pyrolysis. Moreover, Fe-POM/attapulgite clay composites showed higher selectivity towards lower hydrocarbons (C5–C12) with aliphatic hydrocarbons as major fractions. These synthesised composite catalysts significantly lowered the pyrolysis temperature from 375°C to 310°C. Hence, recovery of valuable fuel oil from polyethylene using these synthesised catalysts...
A Tantalum Pentoxide (Ta2O5) based resistive nonvolatile memory device with bipolar switching beh... more A Tantalum Pentoxide (Ta2O5) based resistive nonvolatile memory device with bipolar switching behaviour was developed to demonstrate the new concept of memory in e-skin. The memory device showed stable switching behavior under preprogrammed voltage stimuli after an initial forming process. The memory cell was then integrated with a commercial tactile sensor with a new interface circuit, which enabled the switching of the memory cell through the electrical output from the sensor. This study provides a novel method for handling the transport and storage of large tactile data and will trigger advances towards memorable e-skin.
We report here alumina-substituted Keggin tungstoborate/kaolin clay composite materials (KAB/kaol... more We report here alumina-substituted Keggin tungstoborate/kaolin clay composite materials (KAB/kaolin) as polyethylene cracking catalysts. KAB/kaolin composites with varying concentrations of KAB (10–50 wt.%) were synthesized by the wet impregnation method and successfully characterized by Fourier-transform infrared spectroscopy, powder X-ray diffraction, thermo-gravimetric analysis and scanning electron microscopy with energy dispersive X-ray spectroscopy analytical techniques. Use of KAB loaded kaolin composites as the catalyst for low-density polyethylene (LDPE) cracking exhibited a higher percentage of polymer conversion (99%), producing 84 wt.% of fuel oil and negligible amount (˂ 1 wt.%) of solid residue while thermal cracking produced ~22 wt.% residue. Furthermore, gas chromatography–mass spectrometry analysis of oil obtained by non-catalytic cracking exhibited a high selectivity to high molecular weight hydrocarbons (C13–C23) compared to the catalytic cracking where 70 mol.% o...
Although major difficulties are experienced for hydrogen- storage materials to meet performance r... more Although major difficulties are experienced for hydrogen- storage materials to meet performance requirements for mobile applications, alternative fuel cell feedstocks such as ammonia can be stored in the solid state safely at high capacity. We herein describe the NiX2 -NH3 (X=Cl, Br, I) systems and demonstrate their exceptional suitability for NH3 storage (up to 43 wt % NH3 with desorption that begins at 400 K). The structural effects that result from the uptake of NH3 were studied by powder X-ray diffraction (PXD), FTIR spectroscopy and SEM. NH3 release at elevated temperatures was followed by in situ PXD. The cycling capabilities and air stability of the systems were also explored. NH3 is released from the hexaammines in a three-step process to yield the diammine, monoammine and NiX2 dihalides respectively and (re)ammoniation occurs readily at room temperature. The hexaammines do not react with air after several hours of exposure.
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Papers by Duncan Gregory