Search

In this study, novel Zn catalysts were prepared by the wet impregnation method using printing and dyeing wastewater (PDW)-modified petroleum coke (petcoke) as a carrier, and they were applied to the acetylene acetoxylation. The pretreated petroleum coke has a high specific surface area which provides sufficient space for the loading of Zn. Calcination further increases catalyst activity, but when calcination temperatures exceed 1000 °C, a significant loss of Zn occurs, resulting in a dramatic decrease in catalyst activity. This enables the conversion of acetic acid up to 85%. X-ray photoelectron spectroscopy confirmed that a large amount of N is introduced into PC from PDW, which changes the electron transfer around Zn. Temperature-programmed desorption (TPD) analysis revealed that the nitrogen-doped Zn(OAc)2 catalyst enhanced the catalytic activity by modulating the intensity of the catalyzed adsorption of acetic acid and acetylene. This study provides a new way to reuse petroleum coke and printing and dyeing wastewater to support the sustainable development of the vinyl acetate industry. [ABSTRACT FROM AUTHOR]

New Mannich bases, 3-morpholino-1-phenylpropan-1-one (MPO) and 3-morpholino-1-phenyl-3-(pyridin-4-yl) propan-1-one (MPPO), were synthesized, characterized, and studied as corrosion inhibitors for N80 steel in 1 M hydrochloric acid (HCl) solution using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and FT-IR spectroscopy. The inhibition efficiency increases with increasing inhibitor concentrations, and the corrosion inhibition efficiency of the MPO and MPPO could reach 90.3% and 91.4%, respectively, at a concentration of 300 ppm at 305 K. The effect of the temperature on the corrosion inhibition behavior of inhibitors was discussed. Electrochemical tests showed that the synthesized inhibitors are mixed. The EIS test results showed that the presence of MPO and MPPO reduced the double-layer capacitance in the corrosion process, thereby reducing the charge transfer resistance. The SEM and EDX results showed that the MPO and MPPO formed a uniform adsorption film on the surface of the N80 steel. The adsorption mechanism of the inhibitors was simulated with different adsorption models and the results showed that the inhibitors were the chemisorbed type. The results of the FT-IR spectroscopy proved that the inhibitor interacted with metal atoms on the steel surface. [ABSTRACT FROM AUTHOR]

• A fiber-optic Michelson interferometric trace DMMP sensor was proposed. • The fiber-optic sensor has the structure of a Michelson interferometer. • ZIF-8@Ag/PDDA as sensing materials is used to enhance the sensitivity. • The sensor has a sensitivity of 45.71 dB/ppm for DMMP. • The sensor has good selectivity and stability. A Michelson interference dimethyl methyl phosphate (DMMP) fiber sensor with a single-mode (SMF)-dislocated single-mode (DSMF)-hollow-core fiber (HCF) structure is proposed. To fabricate the Michelson interference structure of SMF-DSMF-HCF, one end of the DSMF was misaligned and fused to the SMF, the other end was fused to the HCF to generate a reflective surface. The structure, elemental composition, and surface morphology of ZIF-8@Ag were analyzed using X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy after the ZIF-8@Ag/PDDA composite was coated on the surface of DSMF. The result shows that the sensitivity and the detection limit of the sensor are 45.71 dB/ppm and 0.1431 ppb, respectively, and the response/recovery time is around 14/12 s. The sensor also has excellent selectivity and stability. [ABSTRACT FROM AUTHOR]

An intensity modulated fiber-optic carbon monoxide (CO) sensor by integrating in-situ solvothermal-growth Ag/Co-MOF sensing film is fabricated and evaluated. The Michelson interference sensing structure is composed of single-mode fiber (SMF), enlarged taper, thin-core fiber (TCF), and Ag film as the reflector. Ag/Co-MOF was coated on the cladding of the TCF as the sensing material, and the enlarged taper is located between TCF and SMF as the coupler. The structure, morphology, compositions and thermal stability of the Ag/Co-MOF sensing film were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), etc. The sensitivity of the sensor is 0.04515 dB/ppm, and the fitting parameter of the CO concentration is 0.99876. In addition, the sensor has the advantages of good selectivity, good signal and temperature stability, and it has potential application in trace CO detection. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs)-derived materials with a large specific surface area and rich pore structures are favorable for catalytic performance. In this work, MOFs are successfully prepared. Through pyrolysis of MOFs under nitrogen gas, zinc-based catalysts with different active sites for acetylene acetoxylation are obtained. The influence of the oxygen atom, nitrogen atom, and coexistence of oxygen and nitrogen atoms on the structure and catalytic performance of MOFs-derived catalysts was investigated. According to the results, the catalysts with different catalytic activity are Zn-O-C (33%), Zn-O/N-C (27%), and Zn-N-C (12%). From the measurements of X-ray photoelectron spectroscopy (XPS), it can be confirmed that the formation of different active sites affects the electron cloud density of zinc. The electron cloud density of zinc affects the ability to attract CH3COOH, which makes catalysts different in terms of catalytic activity. [ABSTRACT FROM AUTHOR]

A novel europium metal-organic frameworks (Eu-MOFs), based on 1,3,5-benzotricarboxylic acid (H 3 BTC), 4,4′-azopyridine (4,4′-AZ) and N , N -dimethyllformamide (DMF), was synthesized by the solvothermal method. The crystal structure, thermal stability, morphology and luminescent properties are characterized by the X-ray diffraction (XRD), thermogravimetry (TG), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and optical spectroscopic techniques. The Eu-MOFs display a unique luminescence quenching effect to nitrobenzene (NB) and copper (Cu2+) ions. The turn-off luminescence can be induced by 210 ​ppm NB or by 1000 ​μM Cu2+ ions. Furthermore, the high sensitivities (K SV ​= ​0.039 ​ppm−1 for NB, and K SV =0.029 ​μM−1 for Cu2+) and low detection limits (0.656 ​ppm for NB, and 1.395 ​μM for Cu2+) are obtained. The sensing mechanisms are reasonably explained based on the electron and energy transfer. The experimental results show that the Eu-MOFs can be used as a potential sensing luminescence quenching probes for NB and Cu2+ ions. Figure. (a) Three dimensional structure of Eu-MOFs,(b) coordination environment around Eu3+, and (c) coordination mode of H 3 BTC [Display omitted] • Eu(III) metal-organic-framework (Eu-MOF) fluorescent probe was solventhermally synthesized. • Eu-MOF probe can sensitively and selectively detect nitrobenzene and Cu2+ ions. • The mechanism of sensing properties were investigated and discussed in details. • Eu-MOF can be used as a potential luminescence quenching material in practical application. [ABSTRACT FROM AUTHOR]

Type-II superlattice (T2SL) detectors represent a promising advancement in long-wavelength infrared (LWIR) photodetector with significant potential across various applications. This study aims to explore the effect of different InAs layer thicknesses on the properties of InAs/GaSb LWIR SLs, which are fabricated by molecular beam epitaxy (MBE). By employing a comprehensive multi-technique analysis, including Atomic Force Microscopy (AFM), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray Spectroscopy (EDXS), X-ray Photoelectron Spectroscopy (XPS), and Photoluminescence (PL). We substantiate the outstanding surface morphology, high-quality strain-balanced characterization, actual growth thickness assessment, and elemental content analysis using advanced spectroscopy techniques. These results demonstrate comprehensive insights into the 14/7 ML InAs/GaSb SLs elemental composition and distribution, enhancing understanding of superlattice properties for LWIR applications. • This report investigates the properties of InAs/GaSb LWIR SLs. The SLs were fabricated using MBE and were subjected to a comprehensive analysis using various techniques, including AFM, XRD, TEM, EDXS, XPS, and PL. • The analysis revealed excellent surface morphology, precise thickness assessment, and detailed elemental analysis to characterize the InAs/GaSb SLs (14/7 ML) using advanced spectroscopy techniques. • The results highlight the potential of 14/7 ML InAs/GaSb SLs and provide valuable characterization information that can guide future research and development efforts in this field. [ABSTRACT FROM AUTHOR]