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Some budding scientists in Mainz have come up with this stuff and I think they’re on the wrong track. 

They say:

V₂O₅ nanowires exhibit an intrinsic catalytic activity towards classical peroxidase substrates such as 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 3,3,5,5,-tetramethylbenzdine (TMB) in the presence of H₂O₂. These V₂O₅₂O₅ nanowires mediate the oxidation of ABTS in the presence of H₂O₂ with a turnover frequency (k_cat) of 2.5 × 10³ s⁻¹. The K_M values of the V₂O₅ nanowires for ABTS oxidation (0.4 μM) and for H₂O₂ (2.9 μM) at a pH of 4.0 are significantly smaller than those reported for horseradish peroxidases (HRP) and V-HPO indicating a higher affinity of the substrates for the V₂O₅ nanowire surface. Based on the kinetic parameters and similarity with vanadium-based complexes a mechanism is proposed where an intermediate metastable peroxo complex is formed as the first catalytic step. The nanostructured vanadium-based material can be re-used up to 10 times and retains its catalytic activity in a wide range of organic solvents (up to 90%) making it a promising mimic of peroxidase catalysts. nanowires show an optimum reactivity at a pH of 4.0 and the catalytic activity is dependent on the concentration. The Michaelis-Menten kinetics of the ABTS oxidation over these nanowires reveals a behavior similar to that of their natural vanadium-dependent haloperoxidase (V-HPO) counterparts.

I’ve been studying this field for a number of years and what they haven’t taken into account is the following:

Self-assembly of adsorbed species is markedly influenced by weak mutual interactions and the local strain of the surface induced by the adsorption. Nano-structuring taking place on the surface is well explained by the notion of a quasi-molecule provided by the reaction of surface atoms with adsorbed species. Self-assembly of quasi-molecules by weak internal bonding provides quasi-compounds on a specific surface. Various nano-structuring phenomena are discussed: (i) self-assembly of absorbed molecules and atoms; (ii) self-assembly of quasi-compounds; (iii) formation of nano-composite surfaces; (iv) controlled growth of nano-materials on composite surfaces. Nano-structuring processes are not always controlled by energetic feasibility, that is, the formation of nano-composite surface and the growth of nano-particles on surfaces are often controlled by the kinetics. The idea of the “kinetic controlled molding” might be valuable to design nano-materials on surfaces. 

I’ll be quite happy to discuss this over a coffee at the Tin Shed on Wheels and set them straight.

They can buy… 

PS
My core area of expertise is a bit different – the effect of micro vortices on  laminar flow over light alloy convex dihedral secondary control surfaces with rotational and reflectional symmetries and the use of stub deflectors to achieve even dispersion.


I just picked up this nano business as I went along….


We could even get Prof Dr Mr Helen along to round off the group with a discussion on the timing of Proterozoic deformation and magmatism in a tectonically reworked orogen.

Should be fun…