The oxygen evolution reaction (OER) is known as the efficiency-limiting step for the electrochemical cleavage of water mainly due to the large overpotentials commonly used materials on the anode side cause. Since Ni-Fe oxides reduce overpotentials occurring in the OER dramatically they are regarded as anode materials of choice for the electrocatalytically driven water-splitting reaction. We herewith show that a straightforward surface modification carried out with AISI 304, a general purpose austenitic stainless steel, very likely, based upon a dissolution mechanism, to result in the formation of an ultra-thin layer consisting of Ni, Fe oxide with a purity > 99%. The Ni enriched thin layer firmly attached to the steel substrate is responsible for the unusual highly efficient anodic conversion of water into oxygen as demonstrated by the low overpotential of 212 mV at 12 mA/cm 2 current density in 1 M KOH, 269.2 mV at 10 mA/cm 2 current density in 0.1 M KOH respectively. The Ni, Fe-oxide layer formed on the steel creates a stable outer sphere, and the surface oxidized steel samples proved to be inert against longer operating times (> 150 ks) in alkaline medium. In addition Faradaic efficiency measurements performed through chronopotentiometry revealed a charge to oxygen

The cheap stainless commodity steel AISI 304, which basically consists of Fe, Ni, and Cr, was surface-oxidized by exposure to Cl2 gas. This treatment turned AISI 304 steel into an efficient electrocatalyst for water splitting at pH 7 and pH 13. The overpotential of the anodic oxygen evolution reaction (OER), which typically limits the efficiency of the overall water-splitting process, could be reduced to 260 mV at 1.5 mA/cm2 in 0.1 M KOH. At pH 7, overpotentials of 500–550 mV at current densities of 0.65 mA/cm2 were achieved. These values represent a surprisingly good activity taking into account the simplicity of the procedure and the fact that the starting material is virtually omnipresent. Surface-oxidized AISI 304 steel exhibited outstanding long-term stability of its electrocatalytic properties in the alkaline as well as in the neutral regime, which did not deteriorate even after chronopoteniometry for 150 000 s. XPS analysis revealed that surface oxidation resulted in the formation of Fe oxide and Cr oxide surface layers with a thickness in the range of a few nanometers accompanied by enrichment of Cr in the surface layer. Depending on the duration of the Cl2 treatment, the purity of the Fe oxide/Cr oxide mixture lies between 95% and 98%. Surface oxidation of AISI 304 steel by chlorination is an easy and scalable access to nontoxic, cheap, stable, and efficient electrocatalysts for water splitting.

SERS microscopy is a novel staining technique in immunohistochemistry, which is based on antibodies labeled with functionalized noble metal colloids called SERS labels or nanotags for optical detection. Conventional covalent bioconjugation of these SERS labels cannot prevent blocking of the antigen recognition sites of the antibody. We present a rational chemical design for SERS label-antibody conjugates which addresses this issue. Highly sensitive, silica-coated gold nanoparticle clusters as SERS labels are non-covalently conjugated to primary antibodies by using the chimeric protein A/G, which selectively recognizes the Fc part of antibodies and therefore prevents blocking of the antigen recognition sites. In proof-of-concept two-color imaging experiments for the co-localization of p63 and PSA on non-neoplastic prostate tissue FFPE specimens, we demonstrate the specificity and signal brightness of these rationally designed primary antibody-protein A/G-gold nanocluster conjugates.

An organic-inorganic hybrid polymer, composed of poly(methylsilsesquioxane) (PMSSQ) and poly(4-vinyl benzaldehyde) (PStCHO), is prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization of 4-vinyl benzaldehyde (StCHO) using a macro-chain transfer agent (CTA) based on PMSSQ. The obtained PMSSQ-PStCHO is spin-coated on substrates such as silicon wafers or copper plates to afford aldehyde-functionalized surfaces. Successful Kabachnik-Fields post-polymerization modifi cation (KF-PMR) of the aldehyde-functionalized surfaces is conducted with amines and dialkyl phosphonates, and characterized by surface analysis techniques including IR, energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS) measurements, documenting the installation of α-amino phosphonates onto surfaces with practically quantitative conversion of aldehydes. In addition, the generated α-amino phosphonates are successfully deprotected to afford the corresponding α-amino phosphonic acids on surfaces, which make this route a reliable tool-enabling surface functionalization with α-amino phosphonic acids.surfaces. To expand the scope of functional materials featuring designed surface characteristics, a number of highly reactive and selective reactions, so-called "click reactions", have been employed. This includes Cu(I)-catalyzed and metal-free 1,3-dipolar cycloaddition (CuCAAC) reaction of organo-azides and alkynes, [ 1,2 ] thiol-ene, thiol-maleimide, [ 3 ] nucleophile-isocyanate, [ 4 ] and activated ester-amine reactions, which all realize a facile functionalization of substrate surfaces. [5][6][7][8] In spite of the fact that these click reactions have been employed in surface modifi cation chemistry, the intrinsic drawbacks of these conventional "click reactions" are: 1) only one functionality per one reaction can be achieved and 2) no functionality owing to linkages that are generated via reactions. In order to target material surfaces featuring more sophisticated functionalities, chemists need to propose a synthetic strategy realizing installation two or more functional molecules per single reactive site accompanied with a generation of an attracting linkage.

The properties of β-NaEuF4/NaGdF4 core-shell nanocrystals have been thoroughly investigated. Nanoparticles with narrow size distribution and an overall diameter of ∼22 nm have been produced with either small β-NaEuF4 cores (∼3 nm diameter) or large β-NaEuF4 cores (∼18 nm diameter). The structural properties and core-shell formation are investigated by X-ray diffraction, transmission electron microscopy and electron paramagnetic resonance, respectively. Optical luminescence measurements and X-ray photoelectron spectroscopy are employed to gain information about the optical emission bands and valence states of the rare earth constituents. Magnetic characterization is performed by SQUID and X-ray magnetic circular dichroism measurements at the rare earth M(4,5) edges. The characterization of the core-shell nanoparticles by means of these complementary techniques demonstrates that partial intermixing of core and shell materials takes place, and a significant fraction of europium is present in the divalent state which has significant influence on the magnetic properties. Hence, we obtained a combination of red emitting Eu(3+) ions and paramagnetic Gd(3+) ions, which may be highly valuable for potential future applications.