Surface chirality induced by rotational electrodeposition in magnetic fields

Abstract

The surfaces of minerals could serve important catalytic roles in the prebiotic syntheses of organic molecules, such as amino acids. Thus, the surface chirality is responsible for the asymmetric syntheses of biomolecules. Here, we show induction of the surface chirality of copper metal film by electrodeposition via electrochemical cell rotation in magnetic fields. Such copper film electrodes exhibit chiral behaviour in the electrochemical reaction of alanine enantiomers, and the rotating direction allows control of the chiral sign. These findings are discussed in connection with the asymmetric influence of the system rotation on the magnetohydrodynamic micro-vortices around the electrode surfaces.

Magnetic fields in electrochemistry: The Lorentz force. A mini-review

“…[10,11] Mogi et al have recently demonstrated that magneticallyprepared Ag or Cu electrodes exhibit a high sensitivity towards certain enantiomeric aminoacids, offering a novel route for the synthesis of biomolecules with a high enantioselectivity. [11,12] The effect may be explained by chirality imprinted on the electrode surface, where screw dislocations grow in a sense imposed by the direction of the magnetic field. [11] Furthermore, it is suggested by Aogaki et al M A N U S C R I P T…”

“…The enatiomeric sensitivity increases with decreasing electrode diameter, due to the supporting effect of the primary MHD flow, Fig 1b. A rotating cell can also impose the electrode chirality. [12] Hydrogen bubble formation and release during the electrolysis of water is strongly influenced by magnetically-induced flow. [14] Gas bubbles occlude the electrode surface, deforming the local current density.…”

Magneto-Dendrite Effect: Copper Electrodeposition under High Magnetic Field

“…In this sense, how to fabricate chiral catalysts is still an open question with important fundamental and technical interest. Magnetic field provides a powerful tool of fabrication for a new type of chiral electrocatalyst; by means of magnetic field and macroscopic rotation, numerous chiral screw dislocations are formed on electrode surfaces, which can donate various chiral activities to crystal nuclei1234. These catalytic activities appear on flat surfaces.…”

Silver Films with Hierarchical Chirality

“…Figure shows the voltammograms of 20 m m l ‐ and d ‐alanines taken with the R‐Ag film, S‐Ag film, and RS‐Ag film electrodes. The oxidation reaction of alanine occurred at approximately 0.6 V, where the amino group (‐NH 2 ) in the amino acid was oxidized . On the R‐Ag film electrode, the oxidation current of d ‐alanine was higher than that of l ‐alanine (Figure a), indicating that such singularity on the R‐Ag film electrode surface could be due to an electrochemically d active site, allowing the specific adsorption and the electron‐transfer reaction to occur preferentially for d ‐Ala.…”