Unraveling the Dual Defect Sites in Graphite Carbon Nitride for Ultra-high Photocatalytic H2O2 Evolution

Defect engineering modified graphite carbon nitride (g-C3N4) has been widely used in various photocatalytic systems due to the enhanced catalytic activity by multiple defect sites (such as vacancies or functional...

Clustering of metal dopants in defect sites of graphene-based materials

Selected defect sites in graphene thermodynamically favour single atom doping over clustering, when doped with noble and p-block elements.

Superlative Photoelectrochemical Properties of 3D MgCr- LDH Nanoflowers influencing towards Photoinduced Water Splitting Reactions

Layered double hydroxides (LDHs) are competent photocatalysts for water splitting reactions, vital to produce solar fuels, but their restricted available reactive sites, slow mass and charge transfer, are yet remain a challenge. To surmount these lacunas, Nanoflowers-like three-dimensional (3D) open structure of MgCr-LDH have been designed in a substrate-free path by one-step formamide assisted hydrothermal treatment followed by visible light irradiation and utilized as efficient photocatalysts for the H2 and O2 production. The structural, morphological, optical and photoelectrochemical (PEC) properties of the MgCr-LDH nanoflowers were extensively examined, by various physico-chemical characterization techniques. Moreover, the well-designed 3D MgCr-LDH nanoflowers with open structure were formed by a stacking of numerous 2D nanosheets, which inherently triggered with magnificent PEC properties, including high current density of 6.9 mA/cm2, smallest arc of the Nyquist plot (59.1 Ω cm−2) with photostability of 6000 s thereby enhancing the photocatalytic water splitting activity along. Moreover such a perfectly self-stacked 2D nanosheet in 3D MgCr-LDH possess defect sites as enriched 50% oxygen vacancy resulting a good contact surface within the structure for effective light absorption and easy electron and hole separation, facilitates the adsorption of protons and intermediate of water oxidation. Further, the doped Cr3+ pull up electrons from water oxidation intermediates, thereby displaying superior photocatalytic H2 and O2 production activity of 1315 µmol/h and 579 µmol/h, respectively. Favorable oxygen vacancy type defect surface with Cr3+ dopant in MgCr-LDH triggers significant PEC properties, which influences the easy charge transfer and separation mechanism and robustly enhance the photocatalytic performance of the nanoflower.

Polymer Functionalized Nanoparticles in Blue Phase LC: Effect of Particle Shape

Ethylene oxide oligomers and polymers, free and tethered to gold nanoparticles, were dispersed in blue phase liquid crystals (BPLC). Gold nanospheres (AuNPs) and nanorods (AuNRs) were functionalized with thiolated ethylene oxide ligands with molecular weights ranging from 200 to 5000 g/mol. The BPLC mixture (ΔTBP ~6 °C) was based on the mesogenic acid heterodimers, n-hexylbenzoic acid (6BA) and n-trans-butylcyclohexylcarboxylic acid (4-BCHA) with the chiral dopant (R)-2-octyl 4-[4-(hexyloxy)benzoyloxy]benzoate. The lowest molecular weight oligomer lowered and widened the BP range but adding AuNPs functionalized with the same ligand had little effect. Higher concentrations or molecular weights of the ligands, free or tethered to the AuNPs, completely destabilized the BP. Mini-AuNRs functionalized with the same ligands lowered and widened the BP temperature range with longer mini-AuNRs having a larger effect. In contrast to the AuNPs, the mini-AuNRs with the higher molecular weight ligands widened rather than destabilized the BP, though the lowest MW ligand yielded the largest BP range, (ΔTBP > 13 °C). The different effects on the BP may be due to the AuNPs accumulating at singular defect sites whereas the mini-AuNRs, with diameters smaller than that of the disclination lines, can more efficiently fill in the BP defects.

Sinonasal Packing is Not a Requisite for Successful Cerebrospinal Fluid Leak Repair

Background Numerous methods have been described to repair nasal cerebrospinal fluid (CSF) leaks. Most studies have focused on optimizing CSF leak repair success, leading to closure rates of 90 to 95%. Objective This study aimed to determine if excellent reconstruction rates could be achieved without using sinonasal packing. Methods A prospective case series of 73 consecutive patients with various CSF leak etiologies and skull base defects was conducted to evaluate reconstruction success without sinonasal packing. The primary outcome measure was postoperative CSF leak. Secondary outcome measures were postoperative epistaxis requiring intervention in operating room or emergency department, infectious sinusitis, and 22-item sinonasal outcome test (SNOT-22) changes. Results Mean age was 54.5 years and 64% were female. Multilayered reconstructions were performed in 55.3% of cases, with collagen or bone epidural inlay grafts, and nasal mucosal grafts or nasoseptal flaps for onlay layers. Onlay-only reconstructions with mucosal grafts or nasoseptal flaps were performed in 44.7% of cases. Tissue sealants were used in all cases, and lumbar drains were used in 40.8% of cases. There were two initial failures (97.4% initial success), but both resolved with lumbar drains alone (no revision surgeries). There were no instances of postoperative epistaxis requiring intervention in the operating room or emergency department. Infectious sinusitis occurred in 2.7% of patients in the first 3 months postoperatively. SNOT-22 did not change significantly from preoperatively to first postoperative visits, then improved over time. Conclusion Nasal CSF leaks from various etiologies and defect sites were successfully repaired without using sinonasal packing, and patients experienced minimal sinonasal morbidity.