Chemistry researcher Dr Andrew Graham has been awarded £205k of a total grant of £350K from the Leverhulme Trust for a collaborative project with Cardiff University. 

The project will determine whether nanotubular structures, such as imogolite (INTs) or germanium containing nanotubes (GeINTs) undergo surface functionalisation with organic linker molecules. The project will establish the feasibility of accessing a new class of hybrid nanocomposite materials, and identify key features leading to exploitable functionality for the development of task specific catalysts.

This research work is a continuation of a long-standing collaboration between Dr Andy Graham (School of Applied Sciences, University of South Wales) and Professor Stuart Taylor (Cardiff Catalysis Institute, Cardiff University). 

The two research groups have a successful track record of innovative research at the interface of catalysis, inorganic materials, and synthetic organic chemistry. This project further extends this relationship to develop strategies to access a new class of hierarchical nanocomposite inorganic/organic materials derived from imogolite nanotubes, and to harness their potential as novel catalytic materials.

Figure 1: Imogolite Nanotubes: a) lengthwise view; b) end on view

“Over the course of evolution, Nature has evolved novel strategies for the formation of high-performance materials displaying an impressive array of physical properties, such as improved stiffness, mechanical strength or energy dissipation abilities,” said Dr Graham. “These unique materials are formed in a hierarchical fashion, that is, with control over the microstructure to produce highly ordered structures that bridge macro-scale properties with atomic scale components. 

“Importantly, these hierarchical materials display significantly different physical characteristics to the bulk material. Nature has further extended this approach by combining an organic component with an inorganic component to produce highly ordered composite materials which are highly integrated at the nanoscale. The combination of the complimentary physical properties provided by each component gives rise to a class of compounds scientifically interesting to the research community and commercially important for the development of new industrial processes. It is therefore not surprising that recent advances in nanoscale science and nanotechnology have borrowed heavily from this rich and diverse pool for inspiration to produce hybrid materials displaying high crystallinity, well-defined pore structures or large surface areas. 

“Numerous studies have described the formation of novel ordered composite materials derived from the combination of an organic component with either metal ions, nanoparticles or metal clusters, however, routes to composite materials derived from nanotubular structures are less well developed. While the unique properties of carbon nanotubes are well-known in materials science, their functionalisation to produce hybrid materials is problematic due to their inert surfaces and high cost. In contrast, inorganic nanotubes provide a cheaper and more flexible platform for surface derivatisation for elaboration into nanocomposites. 

“Our research will investigate strategies for the formation of novel nanocomposites derived from imogolite nanotubes, which are single-walled nanostructures composed of a highly ordered combination of silica and aluminium (see Figure 1), which were originally isolated from volcanic soils,” said Dr Graham.

“These nanotubes display physical properties that make them ideally suited for further development into novel catalytic materials. Furthermore, their ease of synthesis, uniform length and diameter and highly reactive surface present an ideal gateway to access a new class of hierarchical materials with enhanced catalytic properties. Progress in this area, however, is currently limited by the ability to selectively functionalise the imogolite surface in a predictable fashion, and the implementation of successful strategies to address this problem will remove the single biggest obstacle to the exploitation of these materials in nanotechnology and catalysis.”

“Our research will lead to a deeper understanding of the synthetic technology required to access nanocomposite materials derived from imogolite nanotubes, and to identify the key features which control their molecular architecture. 

“Our initial goal is to exploit the unique properties of imogolite nanotubes as catalysts in chemical transformations, and, once achieved, will act as a platform for our subsequent work in such diverse areas as CO2 capture, gas storage, scaffolds for medical applications and tissue growth, photocatalysis and photodegradation, membranes for filtration and water treatment, nanodevices, nanosensors and nanoelectronics.”