Oxygen Electrocatalysis at Mn-O -C Hybrid Heterojunction: An Electronic Synergy or Cooperative Catalysis?

The interface at the metal oxide-carbon hybrid heterojunction is the source to the well-known "synergistic effect" in catalysis. Understanding the structure-function properties is key for designing more advanced catalyst-support systems. Using a model Mn-O single-layer catalyst on carbon, we herein report a full elucidation to the catalytic synergism at the hybrid heterojunction in the oxygen reduction reaction (ORR).

[Ni(OMe)]-mediated reductive activation of CO affording a Ni(κ-OCO) complex.

Carbon dioxide is expected to be employed as an inexpensive and potential feedstock of C sources for the mass production of valuable chemicals and fuel. Versatile chemical transformations of CO, insertion of CO producing bicarbonate/acetate/formate, cleavage of CO yielding μ-CO/μ-oxo transition-metal complexes, and electrocatalytic reduction of CO affording CO/HCOOH/CHOH/CH/CH/oxalate were well documented. Herein, we report a novel pathway for the reductive activation of CO by the [Ni(OMe)(P(CH-3-SiMe-2-S))] complex, yielding the [Ni(κ-OCO˙)(P(CH-3-SiMe-2-S))] complex.

Domination of second-sphere shrinkage effect to improve photoluminescence of red nitride phosphors.

Red Ca0.99Al(1-4δ/3-x)Si(1+δ+x)N(3-x)C(x):Eu(2+)0.01 (δ = 0.

Studying the effects of Zr-doping in (Bi0.5Na0.5)TiO3via diffraction and spectroscopy.

The structural properties of (Bi0.5Na0.5)Ti1-xZrxO3 (where 0 ≤ x ≤ 0.

A complete high-to-low spin state transition of trivalent cobalt ion in octahedral symmetry in SrCo0.5Ru0.5O(3-δ).

The complex metal oxide SrCo0.5Ru0.5O(3-δ) possesses a slightly distorted perovskite crystal structure.

Key role of bismuth in the magnetoelastic transitions of Ba3BiIr2O9 and Ba3BiRu2O9 as revealed by chemical doping.

The key role played by bismuth in an average intermediate oxidation state in the magnetoelastic spin-gap compounds Ba3BiRu2O9 and Ba3BiIr2O9 has been confirmed by systematically replacing bismuth with La(3+) and Ce(4+). Through a combination of powder diffraction (neutron and synchrotron), X-ray absorption spectroscopy, and magnetic properties measurements, we show that Ru/Ir cations in Ba3BiRu2O9 and Ba3BiIr2O9 have oxidation states between +4 and +4.5, suggesting that Bi cations exist in an unusual average oxidation state intermediate between the conventional +3 and +5 states (which is confirmed by the Bi L3-edge spectrum of Ba3BiRu2O9).

Investigating the order-disorder phase transition in Nd2-xYxZr2O7via diffraction and spectroscopy.

The pyrochlore-defect fluorite phase transition in the mixed-metal zirconate Nd2-xYxZr2O7 (0 ≤ x ≤ 2) solid solution was investigated using synchrotron X-ray and neutron diffraction, as well as X-ray absorption spectroscopy. Diffraction analysis revealed a two-phase region between 1.0 ≤ x ≤ 1.

Biogeochemical reductive release of soil embedded arsenate around a crater area (Guandu) in northern Taiwan using X-ray absorption near-edge spectroscopy.

This study investigates biogeochemical reductive release of arsenate from beudantite into solution in a crater area in northern Taiwan, using a combination of X-ray absorption near-edge structure (XANES) and atomic absorption spectrometry. Total arsenic (As) concentrations in the soil were more than 200 mg/kg. Over four months of laboratory experiments, less than 0.

Anion disorder in lanthanoid zirconates Gd(2-x)Tb(x)Zr2O7.

The pyrochlore-defect fluorite order-disorder transition has been studied for a series of oxides of the type Gd(2-x)Tb(x)Zr2O7 by a combination of diffraction and spectroscopy techniques. Synchrotron X-ray diffraction data suggest an abrupt transition from the coexistence of pyrochlore and defect fluorite phases to a single defect fluorite phase with increasing Tb content. However neutron diffraction data, obtained at λ ≈ 0.

Does local disorder occur in the pyrochlore zirconates?

The zirconates Ln(2)Zr(2)O(7) (Ln = lanthanoid) have been studied using a combination of Zr L-edge X-ray absorption near edge structure (XANES) and synchrotron X-ray and neutron powder diffraction methods. These studies demonstrate that as the size of the lanthanoid cation decreases, the local structure evolves smoothly from the ideal pyrochlore toward the defect fluorite rather than undergoing an abrupt transformation. The Zr L-edge spectrum is found to be extremely sensitive to changes in the local coordination environment and demonstrates an increase in local disorder across the pyrochlore oxides.

Insight into the dinuclear {Fe(NO)2}10{Fe(NO)2}10 and mononuclear {Fe(NO)2}10 dinitrosyliron complexes.

The reversible redox transformations [(NO)(2)Fe(S(t)Bu)(2)](-) ⇌ [Fe(μ-S(t)Bu)(NO)(2)](2)(2-) ⇌ [Fe(μ-S(t)Bu)(NO)(2)](2)(-) ⇌ [Fe(μ-S(t)Bu)(NO)(2)](2) and [cation][(NO)(2)Fe(SEt)(2)] ⇌ [cation](2)[(NO)(2)Fe(SEt)(2)] (cation = K(+)-18-crown-6 ether) are demonstrated. The countercation of the {Fe(NO)(2)}(9) dinitrosyliron complexes (DNICs) functions to control the formation of the {Fe(NO)(2)}(10){Fe(NO)(2)}(10) dianionic reduced Roussin's red ester (RRE) [PPN](2)[Fe(μ-SR)(NO)(2)](2) or the {Fe(NO)(2)}(10) dianionic reduced monomeric DNIC [K(+)-18-crown-6 ether](2)[(NO)(2)Fe(SR)(2)] upon reduction of the {Fe(NO)(2)}(9) DNICs [cation][(NO)(2)Fe(SR)(2)] (cation = PPN(+), K(+)-18-crown-6 ether; R = alkyl). The binding preference of ligands [OPh](-)/[SR](-) toward the {Fe(NO)(2)}(10){Fe(NO)(2)}(10) motif of dianionic reduced RRE follows the ligand-displacement series [SR](-) > [OPh](-).

X-ray absorption near edge structure and crystallographic studies of the mixed valence oxide SrRu0.8Ni0.2O3.

Neutron diffraction methods are used to refine the structure of SrRu(0.8)Ni(0.2)O(3) at room temperature and 4 K.

Discrimination of mononuclear and dinuclear dinitrosyl iron complexes (DNICs) by S K-edge X-ray absorption spectroscopy: insight into the electronic structure and reactivity of DNICs.

In addition to probing the formation of dinitrosyl iron complexes (DNICs) by the characteristic Fe K-edge pre-edge absorption energy ranging from 7113.4 to 7113.8 eV, the distinct S K-edge pre-edge absorption energy and pattern can serve as an efficient tool to unambiguously characterize and discriminate mononuclear DNICs and dinuclear DNICs containing bridged-thiolate and bridged-sulfide ligands.

X-ray absorption and neutron diffraction studies of (Sr(1 - x)Ce(x))MnO3: transition from coherent to incoherent static Jahn-Teller distortions.

We have carried out Ce L- and Mn K-edge x-ray absorption near edge structure (XANES) measurements to experimentally determine the oxidation states of both Ce and Mn in (Sr(1 - x)Ce(x))MnO(3) (x = 0.1-0.4).

Ferromagnetic CoPt3 nanowires: structural evolution from fcc to ordered L1(2).

This investigation demonstrates the magnetic properties and nanostructures of CoPt(3) wire arrays that were fabricated by electrodeposition using a porous alumina template. The X-ray absorption analysis clearly verified the occurrence of a phase transition in CoPt(3) nanowires. This phase transition significantly influences the magnetic properties and enhances coercivity and squareness.

A solution study on the local and global structure changes of cytochrome c: an unfolding process induced by urea.

The local and global structural changes of cytochrome c induced by urea in aqueous solution have been studied using X-ray absorption spectroscopy (XAS) and small-angle X-ray scattering (SAXS). According to the XAS result, both the native (folded) protein and the unfolded protein exhibit the same preedge features taken at Fe K-edge, indicating that the Fe(III) in the heme group of the protein maintains a six-coordinated local structure in both the folded and unfolded states. Furthermore, the discernible differences in the X-ray absorption near-edge structure (XANES) of these two states are attributed to a possible spin transition of the Fe(III) from a low-spin state to a high-spin state during the unfolding process.

New members of a class of iron-thiolate-nitrosyl compounds: trinuclear iron-thiolate-nitrosyl complexes containing Fe(3)S(6) core.

The neutral trinuclear iron-thiolate-nitrosyl, [(ON)Fe(mu-S,S-C(6)H(4))](3) (1), and its oxidation product, [(ON)Fe(mu-S,S-C(6)H(4))](3)[PF(6)] (2), were synthesized and characterized by IR, X-ray diffraction, X-ray absorption, electron paramagnetic resonance (EPR), and magnetic measurement. The five-coordinated, square pyramidal geometry around each iron atom in complex 1 remains intact when complex 1 is oxidized to yield complex 2. Magnetic measurements and EPR results show that there is only one unpaired electron in complex 1 (S(total) = 1/2) and no unpaired electron (S(total) = 0) in 2.

Fabrication of nanorattles with passive shell.

This investigation describes the formation of a metal nanorattle with a pure metal shell by varying experimental parameters. The galvanic replacement reaction between silver and chloroauric acid was adopted to prepare hollow metal nanoparticles. This approach is extended to produce nanorattles of Au cores and Au shells by starting with Au(core)Ag(shell) nanoparticles as templates.

Synthesis of thermally stable zirconia-based mesoporous materials via a facile post-treatment.

A novel method of preparing thermally stable zirconia-based mesoporous materials was developed. The zirconia-based mesoporous materials of 2D-hexagonal structure were prepared using zirconium sulfate as the zirconium precursor and cetyltrimethylammonium (CTMA) as the pore-directing agent with the aid of salt in the synthesis solution to reduce the sulfate content in the final product and significantly improve the crystallographic ordering. Post-treatment of the mesoporous material with NaCl solution and lowering the ramping rate to less than 0.