Porous microstructures of thin films sputtered by magnetron sputtering onto carbon nanomaterial surface

Overview & Synopsis

Designing new nanomaterials and create innovative ways for their nanostructuration hold the key for our future technologies. At the forefront of this broad research field, surface engineering aiming at increasing surface activity and accelerating interface exchanges is the topic of huge activity which has growing of interested recently [1–3]. Moreover, the main objectives are nowadays turning to using available elements or reducing the amount of noble metals and critical raw materials and to green synthesis methods avoiding hazardous chemicals and energy consuming processes. Among the existing liquid and gas phase synthesis methods, magnetron sputtering, far less used, is the only one for which versatility, sustainability and up scalability while growing thin films with controlled thickness, stoichiometry, crystallinity and purity can be met together [4]. Unfortunately, only non-porous dense coatings are grown by conventional magnetron sputtering without post-treatment and over a large surface. In this work, we propose a one-step method to grow porous metal based thin films by a simple magnetron sputtering approach. Metal atom diffusion on the substrate surface is here frustrated by using a carbon nanomaterial (i.e. carbon nanotubes for example) of high roughness as substrate. The resulting modified growth mechanism leads to disordered microstructures with an enhanced surface. In this paper, the example of Ni2N will be described and discussed in line with the improved performances of these Ni2N/carbon nanotube hybrids found for Hydrogen Evolution Reaction and Oxygen Evolution Reaction.