다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

A review on g-C3N4-based photocatalysts

Microkinetic analyses of aqueous electrochemistry involving gaseous H2 or O2, i.e., hydrogen evolution reaction (HER), hydrogen oxidation reaction (HOR), oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), are revisited. The Tafel slopes used to evaluate the rate determining steps generally assume extreme coverage of the adsorbed species (θ ≈ 0 or ≈1), although, in practice, the slopes are coverage-dependent. We conducted detailed kinetic analyses describing the coverage-dependent Tafel slopes for the aforementioned reactions. Our careful analyses provide a general benchmark for experimentally observed Tafel slopes that can be assigned to specific rate determining steps. The Tafel analysis is a powerful tool for discussing the rate determining steps involved in electrocatalysis, but our study also demonstrated that overly simplified assumptions led to an inaccurate description of the surface electrocatalysis. Additionally, in many studies, Tafel analyses have been performed in conjunction with the Butler-Volmer equation, where its applicability regarding only electron transfer kinetics is often overlooked. Based on the derived kinetic description of the HER/HOR as an example, the limitation of Butler-Volmer expression in electrocatalysis is also discussed in this report.

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Insight on Tafel slopes from a microkinetic analysis of aqueous electrocatalysis for energy conversion.

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

SrFe[BP2O8(OH)2] was synthesised under mild hydrothermal conditions. The crystal structure was determined from single–crystal X–ray diffraction data: triclinic, space group P (No. 2), a = 6.6704(12) A, b = 6.6927(13) A, c = 9.3891(19) A, α = 109.829(5)°, β = 102.068(6)°, γ = 103.151(3)°, V = 364.74(12) A3 and Z = 2. The crystal structure of SrFe[BP2O8(OH)2] contains isolated borophosphate oligomers, [BP2O8(OH)2]5–, which are interconnected by FeIIIO4(OH)2 coordination octahedra. The resulting three–dimensional framework is characterised by elliptical channels running along [011]. Strontium takes positions inside the channels.

Synthesis and Crystal Structure of SrFe[BP2O8(OH)2].

CaCo(H2O)[BP2O8(OH)]·H2O was synthesized under mild hydrothermal conditions and investigated by single crystal X–ray diffraction (triclinic, space group P (No. 2), a = 6.5793(3) A, b = 7.8320(1) A, c = 8.8172(1) A, α = 68.785(7)°, β = 82.719(10)°, γ = 73.985(9)°, V = 406.930(19) A3, Z = 2). The crystal structure contains layers stacked along [011]. The layers are built from isolated borophosphate oligomers, [B2P4O16(OH)2]8– (loop branched tetrahedral hexamers), which are interconnected by dimers of CoO3O2/2(H2O) coordination octahedra. Calcium ions and crystal water are located at the borders of the layers, close to intra-layer cavities.

Synthesis and Crystal Structure of CaCo(H2O)[BP2O8(OH)]·H2O.

The Front Cover shows an unprecedented heterostructured Ca−Fe−O electrocatalyst (α-FeIIIOOH@CaCO3) for efficient alkaline oxygen evolution reaction (OER). In their Research Article, P. W. Menezes and co-workers transform a novel intermetallic CaFe6Ge6 precatalyst into a core (residual CaFe6Ge6)- shell (reconstructed Ca−Fe−O) structure by anodic activation. The comprehensive ex-situ characterizations and quasi in-situ Raman reveal that surface Fe is the active site for OER while Ca acts as a promoter for adsorption and transport of hydroxyl species, deprotonation of the OER reaction intermediates, as well as the eventual formation of O2. Moreover, the oxidative leaching of Ge from the precatalyst surface provides porous morphology, more access to exposed active sites, and an increased specific surface area, whereas its conductivity is largely preserved by the remained CaFe6Ge6 core. This work highlights the promoter effect of redox-inert metals on alkaline OER and demonstrates how such metals can play an essential role in improving the overall catalytic activity. More information can be found in the Research Article by P. W. Menezes and co-workers. 

An Intermetallic CaFe
 6
 Ge
 6
 Approach to Unprecedented Ca−Fe−O Electrocatalyst for Efficient Alkaline Oxygen Evolution Reaction

The electrochemical oxygen reduction reaction (ORR) offers a most promising and efficient route to produce hydrogen peroxide (H2O2), yet the lack of cost-effective and high-performance electrocatalysts have restricted its practical application. Herein, an entropy-enhancement strategy has been employed to enable the low-cost perovskite oxide to effectively catalyze the electrosynthesis of H2O2. The optimized Pb(NiWMnNbZrTi)1/6O3 ceramic is available on a kilogram-scale and displays commendable ORR activity in alkaline media with high selectivity over 91 % across the wide potential range for H2O2 including an outstanding degradation property for organic dyes through the Fenton process. The exceptional performance of this perovskite oxide is attributed to the entropy stabilization-induced polymorphic transformation assuring the robust structural stability, decreased charge mobility as well as synergistic catalytic effects which we confirm using advanced in situ Raman, transient photovoltage, Rietveld refinement as well as finite elemental analysis. 

Entropy Enhanced Perovskite Oxide Ceramic for Efficient Electrochemical Reduction of Oxygen to Hydrogen Peroxide

BBaCoHO9P2, triclinic, P1 (no. 2), a = 5.3147(3) Å, b = 7.9926(8) Å, c = 8.2936(8) Å, 2 = 88.63(1)°, 0 = 79.46(1)°, / = 87.14(1)°, V = 345.9 Å, Z = 2, Rgt(F) = 0.029, wRref(F) = 0.068, T = 293 K. Source of material The preparation was carried out hydrothermally by treating a mixture of 0.6332 g Ba(OH)2 · 8H2O (Merck, 98 %), 1.0000 g Co(C2H3O2)2 · 4H2O (Alfa Aesar, 99.9 %), 0.5590 g B2O3 (Chempur, 99.99 %) and 2.7771 g H3PO4 (Merck, 85 %) in the molar ratio Ba : Co : B : P = 0.5 : 1 : 2 : 6. 10 ml of deionized water were added and the solution was stirred at 373 K. Meanwhile, 1.0 ml HCl (37 %) were added to adjust the pH value to 1. The mixture was filled into a 20 ml Teflon-lined autoclave (filling degree 40 %) and heated at 443 K under autogenous pressure for two weeks. The reaction product was filtered, washed with deionized water/acetone and finally dried in air at 333 K. The reaction product contained pink platelets with dimensions ranging from 0.1 mm to 0.2 mm. The chemical composition of (Ba : Co : B : P) was confirmed by EDXS analyses. The IR spectrum and the loss of water during TG confirms the presence of P$OH groups. Experimental details The proton in the crystal struture of BaCo[BP2O8(OH)] was located in Fourier difference maps and the O—H distance was fixed to 0.80 Å during the final refinement. Discussion The hydrothermal method is extensively adopted to synthesise a wider variety of building units compared with those obtained by high-temperature routes [1]. Borophosphates represent a class of compounds with anionic buliding units of the general formula [BwPxOyHz] [2]. The charge of the anionic partial structures can either be compensated by one type of cation (M, M or M) or by a mixture of cations (MM or MM) [1,2]. Our extensive studies on borophosphates containing transition metals (Fe, Co, Ni) as well as alkaline earth metals (Mg, Ca, Sr, Ba) already led to borophosphates containing combinations of two different divalent cations [3-5] and the title compound represent a new example. The crystal structure of BaCo[BP2O8(OH)] is an isotype of the KFe [6], K-In [7], NH4-In [8], Rb-In [9], K-Sc [10], Rb-Sc [11], Pb-Zn [12], Pb-Co [12] and Ba-Fe [13] analogues. The anionic partial structure comprises an open branched 4-membered ring (a loop-branched hexamer) [BP2O8(OH)], which is formed by alternating hydrogenborate and phosphate tetrahedra sharing common vertices with two additionally branching phosphate tetrahedra. The condensation of the borophosphate anions with CoO5(OH) octahedra via common corners results in an overall three-dimensional framework containing channels running along [100]. The cross section of the channels is defined by eightmembered rings consisting of two Co coordination octahedra, four phosphate tetrahedra and two hydrogenborate-groups. Barium ions reside within the channels. Barium was found to be tenfold coordinated by oxygen and the Ba—O contacts vary from 2.742(3) Å to 2.998(3) Å. The Co—O and Co—OH bond distances range from 2.046(3) Å to 2.224(3) Å. Bond lengths d(P-O) and d(B-O) as well as bond angles within the complex anion correspond to respective values similar to related borophosphates [612]. Z. Kristallogr. NCS 223 (2008) 339-340 / DOI 10.1524/ncrs.2008.0147 339 © by Oldenbourg Wissenschaftsverlag, München Crystal: pink block, size 0.04 × 0.07 × 0.20 mm Wavelength: Mo K2 radiation (0.71073 Å) ': 0.85 cm Diffractometer, scan mode: Rigaku AFC7, +/3 2#max: 66.64° N(hkl)measured, N(hkl)unique: 6311, 2173 Criterion for Iobs, N(hkl)gt: Iobs > 2 \"(Iobs), 2079 N(param)refined: 132 Programs: SHELXS-97 [14], SHELXL-97 [15], DIAMOND [16] Table 1. Data collection and handling.

Prashanth W. Menezes

Papers

Synthesis and Crystal Structure of SrFe[BP2O8(OH)2].

Synthesis and Crystal Structure of CaCo(H2O)[BP2O8(OH)]·H2O.

An Intermetallic CaFe 6 Ge 6 Approach to Unprecedented Ca−Fe−O Electrocatalyst for Efficient Alkaline Oxygen Evolution Reaction

Entropy Enhanced Perovskite Oxide Ceramic for Efficient Electrochemical Reduction of Oxygen to Hydrogen Peroxide

Crystal structure of barium cobalt(II) (monophosphate- hydrogenmonoborate-monophosphate), BaCo[BP2O8(OH)]