Phase speciation and surface analysis of copper phosphate on high surface area silica support by in situ XAS/XRD and DFT: Assessment for guaiacol hydrodeoxygenation

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The Role of N and S Doping on Photoluminescent Characteristics of Carbon Dots from Palm Bunches for Fluorimetric Sensing of Fe³⁺ Ion

This work aims to enhance the value of palm empty fruit bunches (EFBs), an abundant residue from the palm oil industry, as a precursor for the synthesis of luminescent carbon dots (CDs). The mechanism of fIuorimetric sensing using carbon dots for either enhancing or quenching photoluminescence properties when binding with analytes is useful for the detection of ultra-low amounts of analytes. This study revealed that EFB-derived CDs via hydrothermal synthesis exceptionally exhibited luminescence properties. In addition, surface modification for specific binding to a target molecule substantially augmented their PL characteristics. Among the different nitrogen and sulfur (N and S) doping agents used, including urea (U), sulfate (S), p-phenylenediamine (P), and sodium thiosulfate (TS), the results showed that PTS-CDs from the co-doping of p-phenylenediamine and sodium thiosulfate exhibited the highest PL properties. From this study on the fluorimetric sensing of several metal ions, PTS-CDs could effectively detect Fe3+ with the highest selectivity by fluorescence quenching to 79.1% at a limit of detection (LOD) of 0.1 µmol L−1. The PL quenching of PTS-CDs was linearly correlated with the wide range of Fe3+ concentration, ranging from 5 to 400 µmol L−1 (R2 = 0.9933)

Zinc-Silver Doped Mesoporous Hydroxyapatite Synthesized via Ultrasonic in Combination with Sol-Gel Method for Increased Antibacterial Activity

Bone materials are mainly composed of an inorganic constituent called hydroxyapatite (HA). In the current study, mesoporous Zn2+/Ag+ doped hydroxyapatite nanoparticles (Zn-Ag doped HA) with high antibacterial activity were synthesized through ultrasonic coupled sol-gel techniques under calcination temperatures of 600 °C for 4 h and 1100 °C for 1 h. The variance in the molar ratio of Zn2+/Ag+ in Ca9.0Zn1.0−xAgx(PO4)6(OH)2 (x = 0.0, 0.25 to 1.0) and its effects on the chemical and physical properties of the powdered samples were investigated. The results show that the hexagonal framework of HA incorporated both the Zn2+ and Ag+ ions and the rhombohedral structure of β-TCP. The main functional groups of HA and Zn-Ag doped HA samples were hydroxyl and phosphate. All samples have mesoporous characteristics with a Type IV isotherm. The agar well diffusion process was used to examine antibacterial activity against E. coli, P. aeruginosa, S. aureus, B. cereus and B. subtilis. Effective antibacterial activity was displayed by Zn-Ag doped HA. Excellent antibacterial performance was shown by Ca9.0Zn0.75Ag0.25(PO4)6(OH)2 against all tested bacterial strains, except P. aeruginosa. This material showed inhibition zones ranging from 7 to 11 mm, implying that it is a suitable material with an antibacterial action for environmental applications, specifically for water purification

General Pyrolysis for High-Loading Transition Metal Single Atoms on 2D-Nitro-Oxygeneous Carbon as Efficient ORR Electrocatalysts

Single-atom catalysts (SACs) possess the potential to involve the merits of both homogeneous and heterogeneous catalysts altogether and thus have gained considerable attention. However, the large-scale synthesis of SACs with rich isolate-metal sites by simple and low-cost strategies has remained challenging. In this work, we report a facile one-step pyrolysis that automatically produces SACs with high metal loading (5.2–15.9 wt %) supported on two-dimensional nitro-oxygenated carbon (M1-2D-NOC) without using any solvents and sacrificial templates. The method is also generic to various transition metals and can be scaled up to several grams based on the capacity of the containers and furnaces. The high density of active sites with N/O coordination geometry endows them with impressive catalytic activities and stability, as demonstrated in the oxygen reduction reaction (ORR). For example, Fe1-2D-NOC exhibits an onset potential of 0.985 V vs RHE, a half-wave potential of 0.826 V, and a Tafel slope of −40.860 mV/dec. Combining the theoretical and experimental studies, the high ORR activity could be attributed its unique FeO-N3O structure, which facilitates effective charge transfer between the surface and the intermediates along the reaction, and uniform dispersion of this active site on thin 2D nanocarbon supports that maximize the exposure to the reactants

Reusability, Long‐Life Storage and Highly Sensitive Zirconium Nitride (ZrN) Surface‐Enhanced Raman Spectroscopy (SERS) Substrate Fabricated by Reactive Gas‐Timing Rf Magnetron Sputtering

Abstract Transition metal nitrides (TMN) are promising material alternative to replace noble metals in the field of plasmonic applications, especially surface‐enhanced Raman spectroscopy (SERS). Here  we  demonstrate a practical surface enhanced Raman spectroscopy (SERS) substrate using zirconium nitride (ZrN) thin films grown by reactive gas‐timing (RGT) rf magnetron sputtering. The tailored properties of ZrN thin film exploited for SERS activity could be achieved to obtain a highly sensitive ZrN thin film SERS substrate with the enhancement factor (EF) of 1.24 × 106 and 4.8 %RSD at 1626 cm‐1 toward methylene blue (MB) analyte which are comparable to the optimized Au sputtered thin films (EF=1.18 × 106 and with 5.1%RSD).  We  find that the spatial plasmonic hotspots on the surface of ZrN SERS substrate controlled by the turn‐on timing of Ar:N2 sputtered gas sequence, leading to the discrete conductive surface profile, strongly relates to non‐stoichiometric composition and the degree of (200)‐oriented texture at the surface of ZrN thin film. Furthermore, ZrN thin film SERS substrates exhibit an excellent recyclability more than 30 cycles with simple cleaning process and a storage time longer than 6 months. The detection and reusability of ZrN SERS substrate on the low concentration of trinitrotoluene (TNT) for homeland security are also performed