25 research outputs found
Facile fabrication of mesoporous silica micro-jets with multi-functionalities
Self-propelled micro/nano-devices have been proved as powerful tools in various applications given their capability of both autonomous motion and on-demand task fulfilment. Tubular micro-jets stand out as an important member in the family of self-propelled micro/nano-devices and are widely explored with respect to their fabrication and functionalization. A few methods are currently available for the fabrication of tubular micro-jets, nevertheless there is still a demand to explore the fabrication of tubular micro-jets made of versatile materials and with the capability of multi-functionalization. Here, we present a facile strategy for the fabrication of mesoporous silica micro-jets (MSMJs) for tubular micromotors which can carry out multiple tasks depending on their functionalities. The synthesis of MSMJs does not require the use of any equipment, making it facile and cost-effective for future practical use. The MSMJs can be modified inside, outside or both with different kinds of metal nanoparticles, which provide these micromotors with a possibility of additional properties, such as the anti-bacterial effect by silver nanoparticles, or biochemical sensing based on surface enhanced Raman scattering (SERS) by gold nanoparticles. Because of the high porosity, high surface area and also the easy surface chemistry process, the MSMJs can be employed for the efficient removal of heavy metals in contaminated water, as well as for the controlled and active drug delivery, as two proof-of-concept examples of environmental and biomedical applications, respectively. Therefore, taking into account the new, simple and cheap method of fabrication, highly porous structure, and multiple functionalities, the mesoporous silica based micro-jets can serve as efficient tools for desired applications
Fundamentals of hydrogen storage in nanoporous materials
Physisorption of hydrogen in nanoporous materials offers an efficient and competitive alternative for hydrogen storage. At low temperatures (e.g. 77 K) and moderate pressures (below 100 bar) molecular H2 adsorbs reversibly, with very fast kinetics, at high density on the inner surfaces of materials such as zeolites, activated carbons and metal–organic frameworks (MOFs). This review, by experts of Task 40 ‘Energy Storage and Conversion based on Hydrogen’ of the Hydrogen Technology Collaboration Programme of the International Energy Agency, covers the fundamentals of H2 adsorption in nanoporous materials and assessment of their storage performance. The discussion includes recent work on H2 adsorption at both low temperature and high pressure, new findings on the assessment of the hydrogen storage performance of materials, the correlation of volumetric and gravimetric H2 storage capacities, usable capacity, and optimum operating temperature. The application of neutron scattering as an ideal tool for characterising H2 adsorption is summarised and state-of-the-art computational methods, such as machine learning, are considered for the discovery of new MOFs for H2 storage applications, as well as the modelling of flexible porous networks for optimised H2 delivery. The discussion focuses moreover on additional important issues, such as sustainable materials synthesis and improved reproducibility of experimental H2 adsorption isotherm data by interlaboratory exercises and reference materials
High-density hydrogen monolayer formation and isotope diffusion in porous media
This thesis is focused on two fundamental aspects of hydrogen physisorption. First, the density of a single layer of adsorbed hydrogen molecules is studied at temperatures close the boiling point (20 K). These systematic experiments give an explanation to high H2 monolayer capacity as a high-density phase of adsorbed hydrogen. Secondly, the diffusion of the hydrogen molecules through a porous material (ZIF-8) is studied using a commercially available adsorption apparatus. Establishing that gas adsorption experiments can be used to study hydrogen diffusion and isotope separation at temperatures close the boiling point
High volumetric hydrogen storage capacity using interpenetrated metal-organic frameworks
Assessment methodology of promising porous materials for near ambient temperature hydrogen storage applications
Thermodynamics, kinetics and selectivity of H<sub>2</sub> and D<sub>2</sub> on zeolite 5A below 77K
Neutron vibrational spectroscopic evidence for short H∙∙∙H contacts in the RNiInH1.4; 1.6 (R = Ce, La) metal hydride
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