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

Na 3 Pb II [B(O 3 POH) 4 ] was synthesized under hydrothermal conditions. The crystal structure determination from single-crystal X-ray diffraction data (l4 1 /a, Z= 4, a = 6.9182(8) A, c = 27.309 (3) A, V = 1307.0(3) A 3 ) revealed the presence of [B(O 3 POH) 4 ] 5- oligomers and heterocubane-like units Na 3 PbO 4 with mixed-occupied metal cation sites.

Na3PbII[B(O3POH)4]: An Alkali-Metal Lead Borophosphate with Heterocubane-like Units Na3PbO4

Use of Cellulose for the Production of Photocatalytic Films for Hydrogen Evolution Along the Lines of Paper Production

Cobalt‐iron oxyhydroxides (CoFeOOHx) are among the most active catalysts for the oxygen evolution reaction (OER). However, their redox behavior and the electronic and chemical structure of their active sites are still ambiguous. To shed more light on this, the complete and rapid reconstruction of four helical cobalt‐iron borophosphates with different Co:Fe ratios into disordered cobalt‐iron oxyhydroxides can be achieved, which are electrolyte‐penetrable and thus most transition metal sites can potentially participate in the OER. To track the redox behavior and to identify the active structure, quasi in situ X‐ray absorption spectroscopy is applied. Iron in high oxidation states ≥ IV (Fe4+) and its substantial redox behavior with an average oxidation state of around 2.8 to above 3.2 is detected. Furthermore, a 6% contraction of the Fe‐O bond length compared to Fe3+OOH references is observed during OER and a strong distortion of the [MO6] octahedra is identified. It is hypothesized that this bond contraction is caused by the presence of oxyl radicals and that di‐µ‐oxyl radical bridged cobalt‐iron centers are the active sites. It is anticipated that the detailed electronic and structural description can substantially contribute to the debate on the nature of the active site in bimetallic iron‐containing OER catalysts.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/aenm.202203886

In Situ Detection of Iron in Oxidation States ≥ IV in Cobalt‐Iron Oxyhydroxide Reconstructed during Oxygen Evolution Reaction

The compound NaSc[BP2O6(OH)3][(HO)PO3] was prepared under mild hydrothermal conditions. The crystal structure was determined from single crystal X-ray data: monoclinic, space group P21/c (No. 14), a = 5.0010(1) A, b = 12.4271(9) A, c = 15.8340(14) A, β = 94.201(4), V = 981.41(11) A3 and Z = 2. The crystal structure comprises of isolated borophosphate oligomers, [BP2O6(OH)3]2–, and isolated hydrogenphosphate groups, [(HO)PO3]2–, which are interconnected by ScO6 coordination octahedra by sharing common corners. The resulting three-dimensional framework is characterized by channels running along [100] forming four-, six-, and twelve-membered rings. Sodium ions reside within the six-membered ring channels.

Prashanth W. Menezes

Papers

Na3PbII[B(O3POH)4]: An Alkali-Metal Lead Borophosphate with Heterocubane-like Units Na3PbO4

Use of Cellulose for the Production of Photocatalytic Films for Hydrogen Evolution Along the Lines of Paper Production

In Situ Detection of Iron in Oxidation States ≥ IV in Cobalt‐Iron Oxyhydroxide Reconstructed during Oxygen Evolution Reaction

NaSc[BP2O6(OH)3][(HO)PO3]: Synthesis and Crystal Structure of an Alkali-Metal Scandium Borophosphate Hydrogenphosphate

Preparation and characterization of the layered borophosphates MII(H2O)2[B2P2O8(OH)2]·H2O (MII = Fe, Co, Ni)