X-ray Photoelectron Spectroscopy Spectra Research Articles

Activated carbon from agricultural industry waste for use as an adsorbent of sulfamethazine: Fascinating and environmentally friendly process

Lignocellulosic wastes have garnered interest in activated carbon (AC) production owing to their abundance and cost-effectiveness. This research utilized coffee husk as a precursor for AC. The methodology involves impregnating the waste with varying proportions of phosphoric acid (H3PO4), 1:1 and 1:3 (masswaste:massH3PO4), and activation in a microwave oven, with different power and activation times. The N2 adsorption/desorption results demonstrated high surface areas (SBET) for the ACs. The optimized AC (C1:3-1000-10) was obtained using a time of 10 min, high impregnation ratio, and power, resulting in an SBET of 1200 m2 g−1. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra confirmed the presence of functional groups, such as hydroxyl and ester, on the AC surface. Adsorption tests with sulfamethazine (SMZ) showed a 225 mg g−1 remotion capacity, highlighting the waste potential for sustainable and economical AC production. This underscores the importance of optimizing activation parameters to enhance performance and application versatility in AC production from lignocellulosic sources.

Stabilization of arsenic-cadmium co-contaminated soil with the iron-manganese sludge derived amendment: Effects and mechanisms

An iron-manganese sludge-derived amendment was proposed to remediate arsenic (As) and cadmium (Cd) co-contaminated soil, with a strong adsorptive capacity across pH 4 to 10. The Langmuir model defined maximum adsorption at 78.17 mg/g for As(III), 110.48 mg/kg for As(V), and 65.77 mg/g for Cd(II). The X-ray photoelectron spectroscopy (XPS) spectra provided insights into the chemical interactions: As was predominantly complexed or ligand exchanged with iron(hydr)oxides. In contrast, cadmium exhibited a tendency to bond with acylamino and carboxyl groups, in addition to the ferric hydroxyl groups. Notably, 42.15% of the adsorbed As(III) was oxidized into As(V) by Mn(IV) oxides present in the amendment. The soil-verification experiment demonstrated that an amendment dosage of 40 g/kg was efficacious in reducing the leaching concentration of As and Cd to maintained below the safety thresholds of 0.1 mg/L and 0.01 mg/L, respectively, for pH levels 4 to 11, meeting the Chinese Surface Water Quality Standard V (GB3838-2002). After the stabilization, the exchangeable fractions of As and the acid-soluble fractions of Cd were significantly reduced, with these elements being transformed into more stable forms. The amendment maintained the soil's neutral pH and adjusted the soil physicochemical properties. This article presents a holistic approach by examining the organic-inorganic composite of iron-manganese oxides with polyacrylamide, modified as a stabilizing amendment for As and Cd co-contaminated soil. This innovative amendment adeptly navigates the previously conflicting stabilization mechanisms for anionic and cationic metals. Offering dual advantages, the amendment not only remediates soil but also addresses the disposal of waste, presenting a win-win solution for environmental management.

Benchmark Study of Core-Ionization Energies with the Generalized Active Space-Driven Similarity Renormalization Group.

X-ray photoelectron spectroscopy (XPS) is a powerful experimental technique for probing the electronic structure of molecules and materials; however, interpreting XPS data requires accurate computational methods to model core-ionized states. This work proposes and benchmarks a new approach based on the generalized active space-driven similarity renormalization group (GAS-DSRG) for calculating core-ionization energies and treating correlation effects at the perturbative and nonperturbative levels. We tested the GAS-DSRG across three data sets. First, the vertical core-ionization energies of small molecules containing first-row elements are evaluated. GAS-DSRG achieves mean absolute errors below 0.3 eV, which is comparable to high-level coupled cluster methods. Next, the accuracy of GAS-DSRG is evaluated for larger organic molecules using the CORE65 data set, with the DSRG-MRPT3 level yielding a mean absolute error of only 0.34 eV for 65 core-ionization transitions. Insights are provided into the treatment of static and dynamic correlation, the importance of high-order perturbation theory, and notable differences from density functional theory in the predicted energy ordering of core-ionized states for specific molecules. Finally, vibrationally resolved XPS spectra of diatomic molecules (CO, N2, and O2) are simulated, showing excellent agreement with experimental data.

Regulated Photocatalytic CO2-to-CH3OH Pathway by Synergetic Dual Active Sites of Interlayer.

Herein, composites of nanosheets with van der Waals contacts are employed to disclose how the interlayer-microenvironment affects the product selectivity of carbon dioxide (CO2) photoreduction. The concept of composites of nanosheets with dual active sites is introduced to manipulate the bonding configuration and promote the thermodynamic formation of methanol (CH3OH). As a prototype, the CoNi2S4-In2O3 composites of nanosheets are prepared, in which high-resolution transmission electron microscopy imaging, X-ray photoelectron spectroscopy spectra, and zeta potential tests confirm the presence of van der Waals contacts rather than chemical bonding between the In2O3 nanosheets and the CoNi2S4 nanosheets within the composite. The fabricated CoNi2S4-In2O3 composites of nanosheets exhibit the detection of the key intermediate *CH3O during CO2 photoreduction through in situ Fourier transform infrared spectra, while the In2O3 nanosheets and CoNi2S4 nanosheets alone do not show this capability, further verified by the density functional theory calculations. Accordingly, the CoNi2S4-In2O3 composites of nanosheets show the ability to produce CH3OH, whereas the CoNi2S4 and In2O3 nanosheets solely generate carbon monoxide products from CO2 photoreduction.

MoⅣ boosted carrier density of MoO3-X for Surface-enhanced Raman spectroscopy

Molybdenum oxides (MoO3-X) with the same surface plasmon resonance (SPR) effect as Au/Ag, and occupies an irreplaceable value in SERS detections. MoO3-X SERS substrates with oxygen-rich defects tend to show better SERS performance, but the preparation and characterization of tunable O defects remain challenging. It cannot be ignored that the oxidation state of metal cations is also influenced by O defects. Here, a series of MoO3-X SERS sensors with regulable Mo valence state were fabricated using magnetron sputtering technology. By changing the Mo sputtering power and the O2/Ar2 ratio, the Mo/O element ratio of the substrate can be easily regulated to readjust the O defects. The X-ray Photoelectron Spectroscopy (XPS) and Raman spectra were performed to investigate the change and related relationship between Mo mixed valence state and SERS sensitivity. The abundant incompletely coordinated electrons produced by low valence MoⅣ act as free carriers, increasing the free carrier density of MoO3-X substrates, which is beneficial for the SERS effect. It has also been proven by Hall effect measurement. The SERS measurement shows that the enhancement factor (EF) reached 3.70×105, which is exceedingly close to Au/Ag. The MoO2.5 substrate also exhibited a repeatable and consistent response, high stability, and repeatability, which proves the splendid application potential in complex environments.

Ligand-free Ni-Cu bimetallic nanocatalyst: Laser synthesis, characterization and its high performance for borohydride assisted catalytic reduction of 4-nitrophenol

In the present work, nickel and copper bimetallic nanoparticles with three different concentration ratios of 70:30, 50:50, and 30:70 were synthesized by laser ablation of Ni and Cu in deionized water. The suitability of Ni-Cu bimetallics as nanocatalysts was investigated in the catalytic reduction of pollutant 4-nitrophenol. The nanocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible (UV-Vis) spectroscopy. The morphology using SEM and TEM indicated that Cu had an elongated or flake-like structure, whereas Ni had a quasi-spherical structure. XPS investigation has been performed to study the elemental composition and chemical states near-surface regions of the generated Ni-Cu bimetallic nanoparticles. XRD and XPS confirm high oxidation of Cu to CuO with approximately no residual Cu metal. However, the XRD patterns did not show complete Ni oxidation to NiO, confirming the presence of a Ni dopant part in the Ni-Cu samples. The behavior of the photoelectron peaks in the XPS spectra suggested that the Ni-Cu nanocomposites exhibited surface charge transfer. Pulsed laser ablation developed ligand-free Ni-Cu nanoparticles, which affected the structure and catalytic properties. The nanocatalyst for 50:50 of Ni and Cu had the highest rate constant, corresponding to the shortest time required to achieve 100% conversion/reduction of the pollutant dye. The apparent synergistic effect between Ni and Cu is clearly dictated by the amount of Cu embedded in the nanocomposites, with this becoming a key factor in lowering the band gap energy values. Overall, the surface charge transfer rate can enhance the catalytic performance by tuning the Ni and Cu concentrations.

Low-Energy Argon Ion Beam Irradiation for the Surface Modification and Reduction of Graphene Oxide: Insights from XPS

Developing environmentally friendly methods for reducing graphene oxide (GO) is essential. This study investigates the surface modification and reduction of GO films using 200 eV argon ion (Ar+) beam irradiation. X-ray Photoelectron Spectroscopy (XPS) analysis reveals significant chemical changes on the GO surface. GO was irradiated with a 200 eV Ar+beam for varying times (0 to 80 sec). XPS survey spectra showed the presence of carbon and oxygen, with an increasing carbon atomic percentage over time. High-resolution XPS spectra of C 1s revealed peaks corresponding to sp2, C-OH, O-C-O, C=O, and O-C=O bonds. In the O 1s spectra, C=O, O-C-O, and C-OH groups were observed. Upon irradiation, the C=O peak consistently decreased, the O-C-O peak fluctuated, and the C-OH peak increased, indicating effective reduction of C=O groups, dynamic changes in O-C-O functionalities, and the formation of additional C-OH groups. The C/O ratio increased from ∼ 2.4 to 2.7, underscoring the reduction process and enhanced carbon content. This method proves to be an efficient approach for producing reduced graphene oxide (rGO) with improved properties for advanced applications.

Efficient hole transport layers for silicon heterojunction solar cells by surface plasmonic modification in MoOx/Au NPs/MoOx stacks

This study explores the integration of Au nanoparticles (NPs) into molybdenum oxide (MoOx) thin films to form a MoOx/Au NPs/MoOx (MAM) stack. This stack serves as a hole transport layer (HTL) in silicon heterojunction solar cells, aiming to address the challenges of safety concerns and inefficient carrier transport. Ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy spectra demonstrate that the incorporation of Au NPs notably raises the work function of MAM to 5.85 eV and stabilize Mo6+ concentrations at 94.07%. In addition, Au NPs effectively act as a shield against detrimental interactions with Ag, thereby improving the interfacial stability between the back electrode and HTL. This strategic enhancement facilitates the formation of surface plasmon polaritons, reduces the contact resistance to 41.19 mΩ cm2, and boosts the quantum efficiency by injecting hot electrons and intensifying the surface electric field. These advancements lead to a significant enhancement in the fill factor and short-circuit current, leading to the development of a heterojunction solar cell with an increased efficiency (Eff) from 19.81% to 22.03%. This investigation underscores the transformative potential of engineered nanomaterials in elevating the performance and stability of photovoltaic devices, promoting the wider adoption of renewable energy technologies.

Boosting O2 activation by internal electric field regulation in vacancy-enhanced S-scheme heterojunction for efficient degradation of bisphenol A

The photocatalytic molecular oxygen (O2) activation is hindered by the weak O2 adsorption capacity and obstacles to electron transfer. Herein, a vacancy-enhanced BiOI/g-C3N4 S-scheme heterojunction was designed to enhance the O2 adsorption capacity and accelerate electron transfer in water treatment. The density functional theory calculation (DFT), in-situ irradiation X-ray photoelectron spectroscopy (XPS) spectra and experiments demonstrate that the S-scheme charge transfer mechanism. And the introduction of N vacancies in g-C3N4 can adjust the electronic structure, strengthen the internal electric field in S-scheme heterojunction, thereby broadening the light response range and further improving the separation rate of photoinduced electron-hole pairs. Besides, the presence of N vacancies can function as the active sites for the adsorption of O2 and facilitate the capture of electrons, promoting the generation of superoxide radicals (•O2−). Thanks to the synergistic effect of the S-type charge transfer route with N vacancies in g-C3N4, degradation rate of bisphenol A (BPA) for BCN-680 increases to 0.0433 min−1, which is 1.86 and 10.56 times higher than BiOI and CN-680. This work presents a valuable method for O2 activation through designing the S-scheme heterojunction with abundant active sites by vacancy construction.

Investigating the impact of strontium doping on neodymium manganite Nanoperovskites: Analysis of structural, optical, and dielectric properties

Nd1-xSrxMnO3 (x = 0, 0.3, 0.5, 0.7) nanoperovskites were fabricated through combustion process, a low-cost technique in contrast to the vacuum methodologies for growth. The singular phase orthorhombic Pbnm crystallized for x = 0 to 0.5; nevertheless, both orthorhombic and monoclinic phases were discerned at x = 0.7. Employing X-ray photoelectron spectroscopy (XPS) spectra, the surface chemistry has been conducted, encompassing the intricate parameters associated with the oxygen reduction reaction (ORR).The BDS analysis at ambient temperature, encompassing the frequency span from 1 Hz to 1000 KHz, elucidates various facets of dielectric properties. Elevated dielectric constants at the low-frequency spectrum are explained by the Maxwell–Wagner effect. With an escalation in doping concentration, there is a concurrent rise in the dielectric constant. The escalation in AC conductivity within the high-frequency domain conforms to Johnscher's universal power law, whereas the ramifications of electrode polarization are delineated through a log-log representation.

Exploring Electrochemical Sensing for Fungicide Detection: Utilization of Newly Synthesized Oligomers.

The determination of thiabendazole is crucial for ensuring food safety, environmental protection, and compliance with regulatory standards. Accurate detection helps prevent harmful exposure, ensuring the safety of agricultural products and safeguarding public health. Therefore, this study investigates the electrochemical sensing capabilities of newly synthesized oligo 3-amino-5-mercapto-1,2,4-triazole (oligo AMTa) using hydrogen tetrachloroaurate (III) (HAuCl4) as an oxidizing agent at room temperature for thiabendazole (TBZ) detection, employing a simple electrode fabrication process. The prepared oligo AMTa was thoroughly characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution mass spectroscopy (HR-MS), and Fourier-transform infrared spectroscopy (FT-IR) to confirm its oligomerization structure and properties. The IR spectrum of oligo AMTa reveals a new peak at 1449 cm-1, indicating the conversion of -NH2 groups to -N=N- groups during oligomerization, unlike AMTa. Additionally, the disappearance of the -SH group peak at 2615 cm-1 in oligo AMTa suggests an S-S linkage involvement in the oligomerization process. In the oligo AMTa XPS spectrum, the presence of C=N is displayed by a small peak at 287.3 eV, and oligomerization via -NH and N=N is confirmed by the lack of a 284.0 eV peak for C-C or C=C. Gold nanoparticle formation is not demonstrated by the 84.8 eV peak, which implies that the gold atom is not in the Au0 state. The HR-MS spectrum of oligo AMTa shows a peak at m/z 564.08, indicating a chain of five monomers, and another peak at m/z 435.03, confirming the presence of a tetrameric form of AMTa. After that, the GC electrode was directly linked to the oligo AMTa by the potentiodynamic method. SEM, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) were all employed to confirm the fabrication of oligo AMTa. The SEM image illustrates the formation of a particlelike structure with a uniform size of the oligomer after cycling in 0.1 M H2SO4. After electrocycling, the size of the oligomer was reduced from 2.6 μm to 30 nm. The oligo AMTa-modified electrode possesses the highest electroactive surface area and electrical conductivity due to several key factors. First, the presence of amino (-NH2) and thiol (-SH) functional groups in AMTa enhances the surface coverage and density of electroactive sites, increasing the electroactive surface area. Additionally, the conjugated structure of AMTa facilitates efficient electron transfer, resulting in enhanced electrical conductivity compared to unmodified electrodes. Eventually, the electrochemical oxidation of TBZ occurred using the fabricated electrodes. The GC/oligo AMTa electrode exhibited a four-fold increase in oxidation current for TBZ compared to unmodified GC electrodes. This enhancement is due to the improved surface properties from the oligo AMTa modification, which significantly boosts TBZ adsorption through strong interactions like hydrogen bonding and π-π stacking. These interactions, along with the increased surface area and catalytic properties, facilitate effective electron transfer, resulting in a higher oxidation current. As an outcome, the film was employed to determine the sensitivity level of TBZ, and a LOD of 1.8 × 10-11 M (S/N = 3) was found. The straightforward method's practical utility was proven by measuring TBZ in tap water, water spinach, and pear juice samples. The comprehensive characterization of oligo AMTa provided insights into its interaction mechanisms with thiabendazole, contributing to the development of a reliable, cost-effective, and efficient sensor.

A robust 3D nanostructured composite polymer electrolyte with novel dual-ion channels toward solid-state sodium metal batteries

The high energy density and low cost of sodium metal batteries enable them to be the rising star of next-generation batteries. However, the growth of sodium dendrites and the high activity of sodium metal may lead to significant safety risks for liquid sodium metal batteries. Composite polymer electrolytes (CPEs), which combine the advantages of inorganic solid-state electrolyte and solid-state polymer electrolytes, have become a promising candidate to replace liquid electrolytes. In this study, a novel Na-beta-Al2O3/polyacrylonitrile (PAN) CPE with a 3D network nanostructure (NAP) has been synthesized by electrospinning method. NAP membrane provides synergistic dual-ion channels for the migration of sodium ions, exhibiting ionic conductivity of 7.22 × 10−4 S cm−1, a sodium-ion transport number of 0.73, and an electrochemical stabilization window as high as 4.92 V. Compared with pure PAN, NAP presents enhanced mechanical strength, superior electrochemical properties and interfacial stability. NAP-based sodium symmetric cell achieves stable plating and stripping for 800 h. At room temperature, the capacity retention ratios of NAP-based Na3V2(PO4)3//Na cell are 92.02 % (0.2C, 200 cycles) and 73.10 % (0.5C, 1000 cycles), respectively. The capacity retention is 72.49 % after 250 cycles at 0.5C and a high temperature of 60 ℃. X-ray photoelectron spectroscopy spectra indicate that solid electrolyte interphase formed in NAP-based battery contains higher NaF component, R–(CO)O–Na content and interfacially favorable organic components, which are beneficial to accelerate the sodium-ion transfer at the interface. This work provides new insights into the construction of 3D nanostructured CPEs with fast ion transport for solid-state sodium metal batteries.

Effects of Si4+/Al3+ molar concentration ratio on the self-reduction process of Yb3+ to Yb2+ ions and optical properties of Bin+/Ybm+, Bin+/Er3+ and Bin+/Er3+/Ybm+ (n, m = 3, 2) co-doped magnesium aluminum silicate glass

In this paper, we investigate and report the effects of Si4+/Al3+ (SiO2/Al2O3) molar concentration ratio on the self-reduction process of Yb3+ to Yb2+ ions and upconversion (UC)-, visible (VIS)- emission spectra, direct optical bandgaps (DOB), indirect optical bandgaps (IOB) of Bin+/Ybm+, Er3+/Bin+, and Er3+/Bin+/Ybm+ (n, m = 3, 2) co-doped SiO2–Al2O3–MgO–TiO2 (SAMT) magnesium aluminum silicate glasses. The valence states of the bismuth (Bi), and Ytterbium (Yb) elements in the raw materials mixture existing in the SAMT glass were determined using X-ray photoelectron spectroscopy (XPS) spectra analysis. With the increase of Al3+ molar concentration from 16 mol. % up to 20, 24, 28 and 32 mol. % corresponding to the Si4+/Al3+ (SiO2/Al2O3) molar concentration ratio of 3.4, 2.5, 1.9, 1.5, and 1.2, the self-reduction process of Yb3+ to Yb2+ ions was enhanced and thus significantly affected the DOB, IOB, the intensities of UC-, VIS- emission spectra of Bin+/Ybm+, Bin+/Er3+, and Bin+/Er3+/Ybm+ (n = 2, 3) co-doped SAMT glasses under excitation of 473 nm, 808 laser diode (LD) and 980 nm LD. In addition, the CIE 1931(x, y) color coordinates for VIS- and UC- emissions spectra of Bin+/Ybm+, Bin+/Er3+ (n = 2, 3) co-doped SAMT under excitation of 473 nm and 808 nm LD are also calculated and determined in the CIE 1931(x, y) chromaticity diagram.

Efficient deep-blue electroluminescence from Ce-based metal halide

Rare earth ions with d-f transitions (Ce3+, Eu2+) have emerged as promising candidates for electroluminescence applications due to their abundant emission spectra, high light conversion efficiency, and excellent stability. However, directly injecting charge into 4f orbitals remains a significant challenge, resulting in unsatisfied external quantum efficiency and high operating voltage in rare earth light-emitting diodes. Herein, we propose a scheme to solve the difficulty by utilizing the energy transfer process. X-ray photoelectron spectroscopy and transient absorption spectra suggest that the Cs3CeI6 luminescence process is primarily driven by the energy transfer from the I2-based self-trapped exciton to the Ce-based Frenkel exciton. Furthermore, energy transfer efficiency is largely improved by enhancing the spectra overlap between the self-trapped exciton emission and the Ce-based Frenkel exciton excitation. When implemented as an active layer in light-emitting diodes, they show the maximum brightness and external quantum efficiency of 1073 cd m−2 and 7.9%, respectively.

Photocatalytic degradation of methyl orange by a Pt(II) complex under visible light irradiation

An extremely effective photocatalytic complex, PtLCl2 (1), was synthesized with (4-([2,2':6',2''-terpyridin]-4'-yl)phenyl)boronic acid as ligand and further characterized through single crystal X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis spectrum. Multipoint hydrogen bonds and three kinds of π-π stacking interactions are observed in the supramolecular structure of 1. More significantly, the Pt(II) complex exhibits outstanding photocatalytic degradation efficiency (94.76%) for methyl orange within 120 min under visible light irradiation. The kinetic rate constant (k) for 1 (10 mg) is 0.02505 min−1, which is approximately 70 times higher than that of the ligand (0.00036 min−1). Moreover, its photocatalysis mechanism proposed that ·O2 − and h+ were the main active species for MO degradation, providing a great prospect for development of a new efficient photocatalytic complex.

Charge transfer effects in (HfNbTiVZr)C—Shown by ab initio calculations and X‐ray photoelectron spectroscopy

AbstractConsidering charge transfer effects and the variability of the bonding between elements with different electronegativity opens up a deeper understanding of the electronic structure and as a result many of the properties in high entropy‐related materials. This study investigates the importance of the diverse bonding and chemical environments when discussing multicomponent carbide materials. A combination of ab initio calculations and X‐ray photoelectron spectroscopy (XPS) was used to investigate the electronic structure of multicomponent thin films based on the (HfNbTiVZr)C system. The charge transfer was quantified theoretically using relaxed and nonrelaxed multicomponent as well as binary carbide reference structures, employing a fixed sphere model. High‐resolution XPS spectra from (HfNbTiVZr)C magnetron‐sputtered thin films displayed core‐level binding energy shifts and broadening effects as a result of the complex chemical environment. Charge transfer effects and a changed electronic structure in the multicomponent material, compared with the reference binary carbides, are observed both experimentally and in the density functional theory (DFT) simulations. The observed effects loosely follow electronegativity considerations, leading to a deviation from an ideal solid solution structure assuming nondistinguishable chemically equivalent environments.

Customizing pyridinic nitrogen coordination in Ni–N–C for electrocatalytic CO2 reduction towards CO

Nickel anchored N-doped carbon electrocatalysts (Ni–N–C) are rapidly developed for the electrochemical reduction reaction of carbon dioxide (CO2RR). However, the high-performanced Ni–N–C analogues design for CO2RR remains bewilderment, for the reason lacking of definite guidance for its structure-activity relationship. Herein, the correlation between the proportion of nitrogen species derived from various nitrogen sources and the CO2RR activity of Ni–N–C is investigated. The x-ray photoelectron spectroscopy (XPS) spectrum combined with the CO2RR performance results show that pyridinic-N content has a positive correlation with CO2RR activity. Moreover, density functional theory (DFT) demonstrates that pyridinic-N coordinated Ni–N4 sites offers optimized free energy and favorable selectivity towards CO2RR compared with pyrrolic-N. Accordingly, Ni–Na–C with highest pyridinic-N content (ammonia as nitrogen source) performs superior CO2RR activity, with the maximum carbon monoxide faradaic efficiency (FECO) of 99.8% at −0.88 V vs. RHE and the FECO surpassing 95% within potential ranging of −0.88 to −1.38 V vs. RHE. The building of this parameter for CO2RR activity of Ni–N–C give instructive forecast for low-cost and highly active CO2RR electrocatalysts.

Luminescence, XPS and Raman of crystalline quartz affected to high pressure by detonation

The Raman spectra, x-ray photoelectron spectroscopy (XPS), and x-ray excited luminescence spectra of crystalline quartz samples subjected to different pressure levels through detonation were compared with the spectra of the original samples. In the samples under study, the luminescence of a self-trapped exciton (STE) was analyzed, which, when excited by x-rays, has a high energy yield (∼20%) in crystalline α-quartz not treated by detonation. The deviations of the luminescence spectrum are small in the pressure range from 9 to 27 GPa relative to untreated samples, which means the presence of crystalline quartz grains. A sharp change in the spectrum occurs for the sample subjected to a pressure of 34 GPa. The STE band practically disappeared and a band appeared at 350 nm. This band appears in thermally stimulated luminescence (in contrast to the STE band, which is not observed at all in thermally stimulated luminescence) and, therefore, can be attributed to some defects arising due to high pressure. This luminescence is not similar to the luminescence of a stishovite single crystal, but analysis of the XPS spectra suggests the formation of non-crystalline stishovite in detonated samples. In the Raman scattering spectra, a single sharp line at 465 cm−1, characteristic of α-quartz, was observed in the samples after detonation pressure for the remaining small crystal grains. This line decreased greatly for the sample subjected to a pressure of 34 GPa. Against the structureless background of exposed samples of ‘poor’ optical quality, other Raman bands did not appear. It can be assumed that there are very broad bands of Raman scattering caused by the amorphization of stishovite under high detonation pressure. Amorphization explains the absence of luminescence, similar to the stishovite crystal.

ZBS glass synthesized containing both Eu3+-Eu2+ CsPbBr3 quantum dots with multi-color luminescence for white LEDs

In this article, zinc-borosilicate silicon（ZBS） glass containing europium (Eu) ions and CsPbBr3 quantum dots (QDs) (ZEQ) was synthesized via melting crystallization route. The composition and luminescent properties are investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and photoluminescence (PL) spectra. The XRD and XPS results imply that Eu 3+, Eu 2+ ions and CsPbBr3 QDs are coexisted in ZBS glass. The dual-mode emission from cyan to orange-red can be achieved by adjusting the melting temperature. Besides, the ZEQ has good water resistance, outstanding light irradiation and excellent heating-cooling cycle stability. Moreover, based on the ZEQ, the light-emitting diodes (LEDs) are designed to obtain the white light with the correlated color temperature (CCT) of 5255 K, the Coherent Infrared Energy (CIE) color coordinate of (0.337 0.313), the NSCT color gamut of 116 % and 87 % of Rec.2020. Thus, this article provides a novel material ZEQ, which is tunable luminescence and ultra-stable. The strategy provides the route that the luminescence of Eu ions and QDs can be observed at the same time, solving the difficulty of the rare earth ions entering into the QDs lattice. Moreover, the ZEQ is expected to be used as the light source for solid-state lighting and also provides valuable research results for future exploration of functional glass containing both rare-earth ions and QDs materials.

Effect of wet media milling on starch-quercetin complex: Enhancement of Pickering emulsifying ability and oxidative resistance

This research explored the effect of media milling on complexation of corn starch (CS) and quercetin (QC), interaction mechanism and Pickering emulsifying ability of corn-quercetin (CS-QC) complex. CS-QC with QC/CS ratio of 1:24 had the highest encapsulation efficiency of 76.00 ± 1.30 %. Average volume-mean diameter, average whole molecular size (Rh) and debranchedamylopectinchain length of CS-QC were significantly decreased after milling. Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) spectra confirmed the complexation between CS and QC. Emulsifying capacity and emulsion stability of Pickering emulsion stabilized by 5 % CS-QC complex particles after 120 min milling reached 100.00 % and 100.00. Pickering emulsions stabilized by these complex particles demonstrated superior oxidative stability. These results demonstrated that media milling could be an efficient physical approach to obtain starch-polyphenol complex by enhancing non-covalent interactions, which could not only be used as food-grade Pickering emulsifiers, but also retard lipid oxidation.