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Electrons ransported through a chiral molecule become spin−polarized; this phenomenon is known as chiral induced spin selectivity (CISS). It has implications for spintronics, for electrochemical and enantioselective reactions, and for electron transfer in biological systems. The CISS‐induced spin polarization in simulations and in experiment differs by orders of magnitude, and the detailed underlying mechanism is still an open question. Structure−property relationships can help elucidate this question. For this purpose, the effect of helix pitch is studied for a model helix of 20 carbon atoms for two quantities which have been found to correlate in some experiments: spin‐polarization in transmitted electrons and electronic circular dichroism (ECD). We find that even though the chirality of these model helices goes down with increased pitch, ECD and CISS go up, along with ultraviolet−visible (UV/Vis) spectra and magnetic and electric transition dipole moments. Orbital contributions to the most intense UV/Vis transition do not show a consistent qualitative picture. Tentatively, we can assign the increase in these properties to an increase of the electric polarizability with spatial extension of these helices by changing pitch. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is considered as a promising approach to storing renewable electricity in the form of hydrogen fuel. In this work, we report the design and electrocatalytic properties of chiral CuO@Ni with three dimensional (3D) continuous macroporous framework. With the chiral CuO@Ni as anode, the OER overpotential required to achieve the current density of 10 mA/cm2 was as low as 110 mV in 0.1 M KOH electrolyte, and the hydrogen production rate of water splitting reaction could reach 1070 nL/s. Moreover, the OER overpotential could be regulated easily by controlling the deposition time of chiral CuO layer on Ni. The high catalytic activity of chiral CuO@Ni for water splitting is closely associated with the Chiral-induced spin selectivity ( CISS ) effect, the large reactive area provided by its 3D macroporous structure, and the effective cooperation between chiral CuO and Ni foam that facilitated the transportation of spin aligned electrons from chiral CuO layer to Ni. The results shown in this work indicate a simple and promising strategy to improve the electrocatalytic activity of other chiral earth-abundant catalysts for water splitting. This work shows the design and properties of chiral CuO@Ni with three dimensional continuous macroporous framework. The chiral CuO@Ni exhibited lower OER overpotential and larger current density than many CuO-based catalysts. Its high catalytic activity for water splitting reaction is attributed to the CISS effect of chiral CuO, the large reactive area of its 3D porous structure, and the synergistic interaction between the chiral CuO and the Ni foam. Image 1 • Chiral CuO@Ni with three dimensional continuous macroporous framework. • Low OER overpotential (110 mV) to achieve 10 mA/cm2 current density. • Easy and effective way to enhance the activity of chiral earth-abundant catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • SPE modified with magnetic Fe 3 O 4 nanoparticles for the determination of Mn(II). • Magnetic field of Fe 3 O 4 nanoparticles increased mass transfer of Mn ions. • Increased net production of hydroxyl ions for electrodeposition of MnO 2. • Intermediate electron transfer enhanced by RGO. • Reduced deposition times using a disposable sensor. This study describes the robust modification of a screen-printed carbon electrode (SPE) for the magneto-electrochemical determination of Mn2+, in real soil samples, by square wave cathodic stripping voltammetry (SW-CSV). The carbon surface of a SPE was modified with electrodeposited Au, then dropcast with Fe 3 O 4 NPs functionalised with l -cysteine within a graphene oxide matrix. The magnetic Fe 3 O 4 NPs within the modification significantly increased the diffusion coefficient of the paramagnetic Mn2+ ion during deposition. Likewise, it also increased the number of hydroxyls available for the formation of the MnO 2 layer, attributed to chiral induced spin selectivity. The reduced graphene oxide (RGO) served to increase the surface area and heterogenous electron transfer rate of the intermediate reactions. The Au/ l -cys/Fe 3 O 4 /RGO modification displayed two significant improvements: enhancement of the Mn2+ response signal (212-fold increase) and improved flexibility for the analytical method (linear ranges from 0.5 to 300 µg L-1 to 62 – 1500 µg L-1 using deposition times of 300 or 30 s, respectively). Ten soil sample extracts were tested for Mn2+, by SW-CSV using the Au/ l -cys/Fe 3 O 4 /RGO modified SPE, and showed good agreement with FAAS, average error of 6.8%. [ABSTRACT FROM AUTHOR]