Publications by authors named "Nick Gys"

Controlling the structure and functionality of crystalline metal-organic frameworks (MOFs) using molecular building units and post-synthetic functionalisation presents challenges when extending this approach to their amorphous counterparts (aMOFs). Here, we present a new bottom-up approach for synthesising a series of Zr-based aMOFs, which involves linking metal-organic clusters with specific ligands to regulate local connectivity. In addition, we overcome the limitations of post-synthetic modifications in amorphous systems, demonstrating that homogeneous functionalisation is achievable even without regular internal voids.

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While synthesis-properties-performance correlations are being studied for organophosphonic acid grafted TiO , their stability and the impact of the exposure conditions on possible changes in the interfacial surface chemistry remain unexplored. Here, the impact of different ageing conditions on the evolution of the surface properties of propyl- and 3-aminopropylphosphonic acid grafted mesoporous TiO over a period of 2 years is reported, using solid-state P and C NMR, ToF-SIMS and EPR as main techniques. In humid conditions under ambient light exposure, PA grafted TiO surfaces initiate and facilitate photo-induced oxidative reactions, resulting in the formation of phosphate species and degradation of the grafted organic group with a loss of carbon content ranging from 40 to 60 wt %.

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Modification of metal oxides with organophosphonic acids (PAs) provides the ability to control and tailor the surface properties. The metal oxide phosphonic acid bond (M-O-P) is known to be stable under harsh conditions, making PAs a promising candidate for the recovery of metals from complex acidic leachates. The thiol functional group is an excellent regenerable scavenging group for these applications.

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Amino-alkylphosphonic acid-grafted TiO materials are of increasing interest in a variety of applications such as metal sorption, heterogeneous catalysis, CO capture, and enzyme immobilization. To date, systematic insights into the synthesis-properties-performance correlation are missing for such materials, albeit giving important know-how towards their applicability and limitations. In this work, the impact of the chain length and modification conditions (concentration and temperature) of amino-alkylphosphonic acid-grafted TiO on the surface properties and adsorption performance of palladium is studied.

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Surface functionalization of complex three-dimensional (3D) porous architectures has not been widely investigated despite their potential in different application domains. In this work, silanization was performed in silica 3D-printed porous structures, and the homogeneity of functional groups within the architecture was investigated by comparing the extent of the functionalization in the walls and core of the monolith. A silica ink was used for direct ink writing (DIW) to shape fibers and monoliths with different architectures and stacking designs.

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