Virus-directed formation of electrocatalytically active nanoparticle-based Co₃O₄ tubes

Abstract

Spinel-type CoO finds applications in a wide range of fields, including clean energy conversion, where nanostructured CoO may provide a cost-efficient alternative to platinum- and iridium-based catalysts for electrocatalytic water-splitting. We here describe a novel strategy in which basic cobalt carbonate - a precursor to CoO - is precipitated as sheet-like structures and microspheres covered with fine surface protrusions, via ammonium carbonate decomposition at room temperature. Importantly, these mild reaction conditions enable us to employ bio-inspired templating approaches to further control the mineral structure. Rod-like tobacco mosaic viruses (TMV) were used as biotemplates for mineral deposition, where we profit from the ability of Co(ii) ions to mediate the ordered assembly of the virus nanorods to create complex tubular superstructures of TMV/ basic cobalt carbonate. Calcination of these tubules is then achieved with retention of the gross morphology, and generates a hierarchically-structured solid comprising interconnected CoO nanoparticles. Evaluation of these CoO materials as electrocatalysts for the oxygen evolution reaction (OER) demonstrates that the activity of CoO prepared by calcination of ammonia diffusion-grown precursors in both, the absence or presence of TMV exceeds that of a commercial nanopowder.

Highly ordered protein cage assemblies: A toolkit for new materials

“…The authors have since experimented with the alternative metal ions Ni 2+ and Co 2+ , as well as five dihydroxamate linkers, all resulting in robust crystalline assemblies (Bailey et al, 2017). Similarly, native TMV has been found to crystallize into ordered arrays in the presence of divalent cations (Nedoluzhko & Douglas, 2001;Schenk et al, 2017). Among all of the cations tested, only Ba 2+ rendered needle-like crystals, tens of microns long.…”

TMV Particles: The Journey From Fundamental Studies to Bionanotechnology Applications

“…The external surface of TMV has also been used as a template for a diversity of chemical deposition reactions. These include the cocrystallization of CdS and PbS, oxidative hydrolysis yielding iron oxides, condensation of SiO 2 , and (NH 4 ) 2 CO 3 decomposition producing electrocatalytically active Co 3 O 4 (Fowler et al, 2001;Schenk et al, 2017;Shenton et al, 1999).…”

“…Such deposition is often carried out using particles displaying mineralizationdirecting peptides either genetically or chemically attached to the particle surface (Altintoprak et al, 2015;Love et al, 2015). In some cases, striking mesostructured superassemblies such as composite threads, nanoparticles with radial channels, and hierarchically arranged microtubes were obtained (Fowler et al, 2001;Schenk et al, 2017). In fact, the use of plant virus particles, including TMV Shenton et al, 1999) as mineralization-guiding agents, may be regarded the dawn of "structural TMV nanotechnology" (Fig.…”

Bioinspired Materials: From Living Systems to New Concepts in Materials Chemistry

“…In fact, all material properties which originate or are, at least, partially active on the mesoscale, can be affected by non-classical, particle-mediated crystallization pathways. Today, non-classical crystallization processes are consequently of high interest due to the possibilities of tailoring mechanical, magnetic, optical, phononic, thermoelectric, or photonic properties or the surface area of materials [47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62]. This highly active field, which can be seen as a new field of solid-state materials chemistry, profits and is motivated by the detailed analysis of biomineralization and biomimetic crystallization studies by revealing the short-comings of the classical crystallization models [19,29,63,64,65,66,67,68,69].…”