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Water‐/alcohol‐soluble polyelectrolyte poly[(9, 9‐bis (3′‐(N,N‐dimethylamino) propyl)‐2, 7‐fluorene)‐alt‐2, 7‐(9, 9‐dioctylfluorene)] (PFN) used in organic solar cells (OSCs) reduces the work function of the electrode due to the effect of an interfacial dipole, which is beneficial for the energy‐level alignment between the electrode and the active layer. To date, the studies on the working mechanism of PFN are mainly conducted through topographical and electronic research. Herein, a dynamic insight into the formation mechanisms of the PFN interlayer at the molecular structural level is established. The charge transfer between PFN and the substrates is verified for the first time by X‐ray photoelectron spectroscopy (XPS) and density functional theory (DFT) studies, which results in chemisorption dipoles with their direction aligned with the intrinsic dipole of the PFN molecule, thereby reducing the work function of the substrate. The larger adsorption energy in the substrates of the nitrogen‐containing side chains of PFN is also identified, which induces the preferential orientation of PFN molecule to reduce the work function of the substrate. By incorporating this interlayer, high efficiency in single‐junction OSCs is achieved using commercial materials. The findings are of great significance for understanding and optimizing the polymer dipole interlayers for OSCs. [ABSTRACT FROM AUTHOR]

Pure and vanadium doped NaTaO3 nanoparticles were synthesized by hydrothermal conditions. From XRD studies, both pure as well as vanadium doped NaTaO3 are found to show pure orthorhombic phase of tatanlate. STEM studies show the formation of cube shape particles in all the samples with a particle size about 70 nm. UV-vis diffuse reflectance spectra clearly indicates the red-shift in the series of vanadium doped NaTaO3 catalysts, resulting in a decrease in the band gap of NaTaO3 caused by substitution of V5+ ions at Ta5+ site with an increase of vanadium doping concentration in NaTaO3. The results reveal that Vanadium doped NaTaO3 show good photocatalytic performance under visible light and RhodamineB (RB) degradation is improved with Vanadium doping. The photocatalytic mechanism was discussed by density functional theory. V5+ ions substitution of Ta5+ ions results in an intermediate band (IB) below the bottom of the conduction band (CB), which is mainly attributed to the state of V 3d. Meanwhile the broadening of valence band is formed due to the hybridization between the V 3d and O 2p states. Both these factors increase the transient behavior of the photogenerated charge carriers and inhibit the recombination of e–h+ pairs, showing enhanced activities over the entire visible region. [ABSTRACT FROM AUTHOR]

Abstract: The photodissociation of alkyl nitrites series (RONO) in gaseous state were studied using density functional theory with Amsterdam Density Functional program (ADF2000) and quantum chemical molecular dynamical method by “Colors-Excite” code. The different dissociative phenomena have been explained by this investigation. Alkyl nitrites were shifted to their excited states by capturing the light energy and the bonds of O–N (RO–NO) were broken. A two-step reaction occurred for methyl nitrite (THN) to yield the diverse products, such as RO radical, NO and HNO, whereas only one-step reaction occurred for tert-butyl nitrite (TBN). The consistent results in theoretical calculation and experiment, including geometrical structures and excitation energies, demonstrated the good performances of “Colors-Excite”. [Copyright &y& Elsevier]

Abstract: The dissociative adsorption of cyclopropane on the copper surface was studied using quantum chemical molecular dynamics method with “Colors-Excite” code and density functional theory by Amsterdam Density Functional program (ADF2000). The excited state of cyclopropane was used as adsorbate to simulate the dissociated adsorption under an irradiation energy of ca. 10eV. One of the C–C bonds in cyclopropane was broken and the two new bonds between cyclopropane and copper surface were formed. The electrons transferred from the copper atoms to cyclopropane with a value of about 0.2e. The shorter distances between the carbons and surface copper atoms showed the existence of strong interaction. Consistently, the results indicated metallacyclopentane was the most possible intermediate species in dissociative adsorption by ADF2000 and “Colors-Excite” method. [Copyright &y& Elsevier]

Abstract: The charge transfer and structural distortions that occurred in the complexes cuprous(I) bis-phenanthroline (Cu(NN)2 +) (NN denotes 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline and 2,9-di(trifluoromethyl)-1,10-phenanthroline) upon excitation with an irradiation of light were studied by density functional theory (DFT). The calculations showed that the electrons transferred from central metal Cu to ligands with the transition of the complexes Cu(NN)2 + from ground state to excited state. As a consequence, the central copper in the excited state of Cu(NN)2 + exhibited similar electronic density to that in the corresponding complex Cu(NN)2 2+. Accompanying with this transfer process, the coordination polyhedra of Cu(NN)2 + became distorted upon excitation. The structural distortion was significantly reduced by increasing the steric bulk of the 2- and 9-positions substituents in the ligands NN, which is helpful for the increase of the life time of the excited state. [Copyright &y& Elsevier]

Abstract: This work reported the investigation of the structural distortions and charge-transfer processes that occurred in the complex of cuprous(I) bis-2,9-dimethyl-1,10-phenanthroline upon oxidation to copper(II), , through a excited state of by density functional theory. The intramolecular electronic transfer from central metal-to-ligand (MLCT) upon the irradiation of light energy is confirmed. Due to this MLCT excitation, the structure of the excited state of is distorted and reorganized to adapt with the change of charge in central metal. As a result, the excited state of is formed, which has the similar electronic and structural properties with . The bulky substituents in 2- and 9-positions of the phenanthroline ligands can restrain the structural distort and decrease nonradiative decay rate. Thus, the electronic and steric effects of the ligands in the cuprous photo-sensitive complexes have important consequences in the behavior of their excited state. [Copyright &y& Elsevier]

The excitations of ligand-to-metal charge transfer in the UV–vis spectra of the complexes Cp2MCl2 (Cp=π-C5H5, M=Ti, Zr, Hf) were described with the time-dependent density functional theory and the differential self-consistent-field density functional theory (ΔSCF–DFT). The nature of the main spectral features was interpreted on the basis of the electronic structure of the complexes. The optimization of the molecular structure for Cp2MCl2 yielded consistent pseudotetrahedral geometries. With the transition from ground state to excited state, the electrons transferred from Cp ligands to the central metals M, accompanied by an increase in the binding length of M&z.sbnd;Cl. This transfer process accounted for the first two absorption bands observed experimentally. The energies and oscillator strengths for the low-lying excitations depended strongly on the nature of the central metals. With varying the central metals from Ti, Zr, and to Hf, the energy gap increased between the sets of highest occupied molecular orbitals (HOMOs) and the sets of lowest unoccupied molecular orbitals (LUMOs). This increase was originated from an increment of energy for the LUMO sets that are mainly of d orbital of the metal and a relatively stable energy level of the HOMO sets that are mainly of p-orbital of Cp and Cl ligands. The excitation energies calculated by these methods showed a small difference, which can be well understood by a relativistic effect. The predicted level patterns of the lowest triplet excited states fit well the available phosphorescence data. [Copyright &y& Elsevier]

Electronic structures and spectroscopic properties of dimers Cu2, Ag2, and Au2 have been studied by density functional theory (DFT). The relativistic effects increase with the increment in electronic number. Zero order regular approximation (ZORA) relativistic correlation gives reliable parameters of electronic structures. By applying B3LYP as the exchange–correlation functional, a same sequence of orbital levels is obtained for Cu2, Ag2, and Au2. The fully filled d-electrons are not completely inert. The contributions of d-electrons to the frontier molecular orbitals are different in these three molecules. A strong interaction between d- and s-electrons causes an up-shift of d-type and a down-shift of s-type molecular orbitals. For Cu2 and Au2, the separation in d- and s-type molecular orbitals is close and small, which account for the much similar characteristics of the excitation states. For Ag2, a big separation in d- and s-type molecular orbitals is shown owing to the extremely small contribution of d electrons to the frontier molecular orbitals. By TDDFT and DSCF, the spectroscopic terms are assigned and explained in terms of the contributions of s- and d-electrons on the excitations. The prediction based on the present calculation matches well with the experimental data. [Copyright &y& Elsevier]

The carbon dots (C-dots) mediated Sn 2 Ta 2 O 7 /SnO 2 heterostructures with spongy structure were successfully assembled by simple hydrothermal route. The photocatalytic removal efficiency of amoxicillin (AMX, 20 mg L−1) over C-dots/Sn 2 Ta 2 O 7 /SnO 2 was estimated to reach up 88.3% within 120 min simulated solar light irradiating. Meanwhile, the HPLC-MS/MS analysis and density functional theory (DFT) computation were examined to clarify the photo-degradation pathway of AMX. The mechanism investigation proposed that with the modification of C-dots, the photocatalysts improves the utilization of solar energy by harvesting the long wavelength solar light due to their unique up-converted photoluminescence (UCPL). In addition, the porous spongy structure and plenty of tiny C-dots promote the ability of adsorption by enlarged specific surface area. Furthermore, the C-dots mediated Z-type heterojunction of Sn 2 Ta 2 O 7 /SnO 2 facilitates the efficient separation and transfer of photo-induced carriers. Our work affords a promising approach for the design of the high-efficient photocatalysts to remedy poisonous antibiotics in aqueous environment. Image 1 • C-dots mediated Z-type Sn 2 Ta 2 O 7 /SnO 2 heterojunction was successfully assembled. • C-dots/Sn 2 Ta 2 O 7 /SnO 2 displays high photocatalytic activity and reusability to AMX. • UCPL effect of C-dots and self-doping of Sn2+-Sn4+ pair extend solar light harvest. • C-dot accelerates electron transport due to its good electrical conductivity. • High redox potentials are maintained by a Z-type electron's transfer tunnel. [ABSTRACT FROM AUTHOR]

CdTe quantum dots (QDs) were anchored on NaTaO3 nanocubes with the aim into tuning the charge kinetics for spatial separation of the photogenerated electrons and holes by modifying the relative potential of the conduction band of CdTe QDs. In this work, CdTe QDs (particle size 2–3 nm) and NaTaO3 were synthesized via reflux and hydrothermal reaction. Thioglycolic acid (TGA) acted as both a stabilizer and linker molecules during the synthesis of CdTe QDs and NaTaO3/CdTe heterostructure. On accounts of density functional theory (DFT) predictions, electrons can transfer from NaTaO3 to CdTe due to the difference of the Fermi level between two semiconductors, which will establish a built-in electric field at semiconductor interfaces, accelerating the charge separation kinetics between CdTe and NaTaO3. In response, electronic structure tunable CdTe QDs were surface engineered on NaTaO3 nanocubes to enhance the visible light (VL) harvesting capability. By carefully controlling the fine nature of CdTe QDs, photogenerated electrons in CdTe can be efficiently injected into the conduction band of NaTaO3, leading to spatial charge separation between CdTe and NaTaO3. This could be affirmed by applied bias photo to current efficiency (ABPE), incident photocurrent responses as well as electrochemical impedance curves. With well-defined crystallinity, electronic structure, and interfacial contact between NaTaO3 and CdTe, the optimized photocatalytic activity toward hydrogen production over NaTaO3/CdTe heterostructure achieved an evolution rate of 56 μmol·g−1·h−1, which is far surpassed than that of pristine NaTaO3 and CdTe. Graphical abstract [ABSTRACT FROM AUTHOR]

Abstract The study of the microstructure and electrochemical property of palladium-loaded tantalum oxide (Pd/Ta 2 O 5) particles is presented. Pd/Ta 2 O 5 belongs to the orthorhombic phase. The palladium states onto the Pd/Ta 2 O 5 surface are Pd0 and Pd2+ forms. From the morphology and size analysis of the loaded Pd particles using transmission electron microscopy, one can see that the nanosized-Pd particles are loaded onto the Ta 2 O 5 surface. A Pd/Ta 2 O 5 film-modified Pt (Pd/Ta 2 O 5 -Pt) electrode further exhibits excellent catalytic activity toward electro-oxidation of ethylene glycol (EG) in acid conditions. Density functional theory was also utilized to clarify the effect on microstructure of Ta 2 O 5 after Pd loading showing that the density of states is increased and the density of electrons in the loading region is enlarged after Ta 2 O 5 is loaded with Pd. Therefore, Pd loading improves the conductivity and electrochemical property of the Pd/Ta 2 O 5 -Pt electrode. Graphical abstract Unlabelled Image Highlights • The Pd loaded Ta 2 O 5 particles were synthesized successfully with the flux method. • The density of state of Ta 2 O 5 was enhanced after palladium loaded. • Palladium loading improved the conductivity and electrocatalytic activity of Ta 2 O 5. • The Pd/Ta 2 O 5 -Pt electrode exhibited high electrocatalytic activity for EG oxidation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ag/Bi°-BiVO 4 catalysts with multi-active sites were fabricated toward high-efficient reduction of aromatic nitrobenzene. • The catalysts presented excellent catalytic activity and good stability to 4-NP reduction. • The BiVO 4 , Bi° and Ag offered multi-active sites to synergistically act on the reduction of nitrophenol. Abstract In this work, we report on the preparation of silver nanoparticles modified bismuth/bismuth vanadate (Bi°-BiVO 4) catalyst with multi-active sites toward efficient reduction of aromatic nitrobenzene, aiming to tailor the synergistic effects of multi-active sites and specify the underlying catalytic mechanism. The as-prepared catalysts were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray and X-ray photoelectron spectroscopy. It is observed that Ag nanoparticles with diameter of ˜30 nm were anchored evenly on the surface of rod-shaped BiVO 4 , which offered multi-active sites to contact with the reactants effectively and transfer interfacial electron to 4-nitrophenol (4-NP) rapidly. The activity factor k of Ag/Bi°-BiVO 4 for 4-NP reduction is estimated to ˜3933.4 min−1 g−1, which is much higher than that obtained from pristine BiVO 4 catalyst, Bi° and noble metal Ag nanoparticles. According to the experimental results, the reaction mechanism and reaction path of 4-NP reduction for BiVO 4 , Bi and Ag were studied through the density functional theory (DFT) theoretical calculation, which suggested that they exhibit synergistic catalytic effect in the reaction process. This work may provide a feasible foundation for the mechanism research of semiconductor reduction to 4-nitrophenol. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Co@NCNT and Ni@NCNT catalysts were synthesized using the calcination method. • The Co@NCNT and Ni@NCNT catalysts exhibited good electrocatalytic activity for the ORR. • Their electrocatalytic activity of both catalysts was due to the rich N-doped active C sites. • The good catalytic activity was also due to synergistic reaction between Co (Ni) and NCNTs. Electrocatalysts based on nanosized cobalt or nickel particles encapsulated by nitrogen-doped carbon nanotubes (M@NCNTs (M = Co or Ni)) were synthesized using the calcination method. They were served as the catalyst toward an oxygen reduction reaction (ORR). The results implied that the M@NCNT electrocatalysts had ORR catalytic activity in an alkaline electrolyte. The half-wave potential (E 1/2) on the Co@NCNT catalyst reached 0.881 V, which was higher than for commercial Pt/C (0.856 V). The M@NCNT electrocatalysts exhibited good stability in the ORR. After 3000 cycles, the E 1/2 for the Co@NCNTs was almost completely unchanged, whereas for the Ni@NCNTs, shifted negatively to 19 mV, was less than for commercial Pt/C (34 mV). These promising electrochemical properties were due to abundant active carbon sites and the synergistic reaction between Co/Ni and NCNTs. Density functional theory calculations indicated that the OOH had strong absorption on the C atoms (adjacent to pyridinic N) in the Co@NCNT and Ni@NCNT catalysts. [ABSTRACT FROM AUTHOR]

In this work, the disordered SnNb x O y with controlled structural distortion was developed in order to uncover the underlying origination for highly enhanced photocatalytic activity of the disordered materials. Synchrotron radiation wide-angle X-ray scattering (SR-WAXS) and transmission electron microscopy (TEM) results indicated that the as-prepared catalysts show disordered features with controlled short range ordering limits. In combination with optical diffuse reflectance spectra, valence band X-ray photoelectron spectroscopy (VB-XPS) and density functional theory (DFT) prediction, the disordered structure engineering can induce continuous band gap broadening and downward valence band edge, predicting enhanced oxidation driving force. Moreover, transient absorption spectroscopy (TAS), electron spin resonance (EPR) spectra suggested that the highly enhanced photocatalytic activity mainly originates from defect-assisted charge separation, which implies that abundant defective centers may serve as trap centers for efficient charge separation and improve charge transfer rate to suppress the charge recombination process. Photocatalytic test demonstrated that the optimal photocatalytic activity toward H 2 evolution of the disordered catalyst shows ∼11.7 times improvement with respect to that of the crystalline counterpart. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Fe 3 C@NCNTs was successfully synthesized using one-step calcination method. • The Pd nanoparticles were loaded onto the surface of the Fe 3 C@NCNT electrocatalyst. • The synergistic effect of Pd enhanced the catalytic activity of the Pd/Fe 3 C@NCNTs. • The Pd/Fe 3 C@NCNT electrocatalyst had excellent catalytic activity for ORR and EOR. • The electrocatalytic activity of Pd/Fe 3 C@NCNTs was superior to commercial Pd/C and Pt/C. Iron carbide-encapsulated nitrogen-doped carbon nanotubes (Fe 3 C@NCNTs) and Pd that is loaded onto Fe 3 C@NCNTs (Pd/Fe 3 C@NCNTs) electrocatalysts were synthesized. The valence state of Pd that was loaded onto the Pd/Fe 3 C@NCNTs surface is in the Pd0 and Pd2+ forms and Pd0 is the main form. The electrochemical measurement results imply that the Fe 3 C@NCNT catalyst exhibits an electrocatalytic property in the oxygen reduction reaction (ORR). The Pd/Fe 3 C@NCNT electrocatalyst has a good catalytic property toward ORR and ethanol oxidation reaction (EOR) in an alkaline solution. The half-wave potential (E 1/2) on the Pd/Fe 3 C@NCNT electrocatalyst toward the ORR can reach 0.904 V, which is higher than that on commercial 20 wt% Pt/C (0.856 V). The forward oxidation peak current density (j f) on the Pd/Fe 3 C@NCNT electrocatalyst for ethanol oxidation is 1.655 A mg−1, which is larger than that on commercial 10 wt% Pd/C (0.430 A mg−1). The excellent electrocatalytic property of the Pd/Fe 3 C@NCNT electrocatalyst is contributed to the many active sites and synergistic effects between Pd and Fe 3 C@NCNTs. The density functional theory (DFT) calculation result implies that the electron mobility increases in the recombination area for Pd and Fe 3 C@NCNTs. [ABSTRACT FROM AUTHOR]

In this work, lanthanum-doped tantalum oxide (La-Ta 2 O 5 ) particles were synthesized for the methanol and ethanol oxidation. X-ray diffractometry (XRD) revealed that the Ta 2 O 5 cells swelled after lanthanum doping. X-ray photoelectron spectroscopy (XPS) indicated that the state of lanthanum on Ta 2 O 5 surface is trivalent. The electronic structure of La-Ta 2 O 5 was calculated using density functional theory (DFT) and this indicated that the band gap of Ta 2 O 5 is narrow when it is doped with lanthanum, which explains the improvement in the conductivity and electrocatalytic activity of the Ta 2 O 5 . The electrocatalytic activity of a Pt electrode modified with La-Ta 2 O 5 film (La-Ta 2 O 5 /Pt electrode) was investigated in a solution of 0.5 mol dm −3 H 2 SO 4 and 1 mol dm −3 methanol (ethanol) using cyclic voltammetry (CV). The CV results indicated that the La-Ta 2 O 5 /Pt electrode has high electrocatalytic activity toward the methanol and ethanol oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The visible-light responsive 3D/2D Bi 2 WO 6 /g-C 3 N 4 heterojunction was fabricated. • The Bi 2 WO 6 /g-C 3 N 4 catalyst presented superior removal performance of ATZ herbicide. • The catalyst possessed superior separation and migration rate for charge carriers. • Reactive radicals and intermediates of ATZ were identified and proposed. Atrazine (ATZ), as a widely used s-triazine herbicide, has persistence and biological toxicity in the environment. Photocatalytic technique is considered as sustainable and promising strategy for the degradation of emerging organic pollutants. Thus, 3D/2D Bi 2 WO 6 /g-C 3 N 4 heterojunction photocatalysts were synthesized via one-step hydrothermal method for ATZ degradation. The Bi 2 WO 6 /g-C 3 N 4 -0.15 exhibited 99.96% removal efficiency for ATZ and the rate constant was approximately 25, 4.8 and 10 times greater than the rate constants of Bi 2 WO 6 , g-C 3 N 4 and "Bi 2 WO 6 + g-C 3 N 4 ", respectively. The influence of synthesis reaction factors of Bi 2 WO 6 /g-C 3 N 4 and various environmental factors including catalyst dosage, ATZ concentration, pH, common anions and HA on photocatalytic property of Bi 2 WO 6 /g-C 3 N 4 were also investigated. The radical-quenching experiments proved that holes (h+), 1O 2 and O 2 – played pivotal roles in ATZ degradation in Bi 2 WO 6 /g-C 3 N 4 photocatalytic system. The ATZ degradation pathway involved dealkylation, alkyl hydroxylation, alkyl oxidation, dechlorination-hydroxylation and deamination-hydroxylation reactions, which was proposed by HPLC–MS/MS results and density functional theory (DFT) analysis. Moreover, quantitative structure–activity relationship (QSAR) evaluation showed that the ecotoxicity of many intermediates declined compared with ATZ. The 3D/2D Bi 2 WO 6 /g-C 3 N 4 heterojunction exhibited excellent photostability and pH adaptability, showing efficient practicality in the removal of refractory organic pollutants in wastewater. [ABSTRACT FROM AUTHOR]

Abstract: In this work, lithium-doped tantalum oxide (lithium-Ta2O5) particles were synthesized using a low-temperature hydrothermal method. X-ray photoelectron spectroscopy (XPS) indicated that the state of lithium on the Ta2O5 surface is the Li+ form. The crystal phase of the samples was analyzed using X-ray diffraction (XRD). The analysis revealed that the lithium-Ta2O5 particles are well crystallized into an orthorhombic phase. Calculation from density functional theory (DFT) indicated that the band gap of Ta2O5 narrows when it is doped with lithium, resulting in improved conductivity and electrocatalytic activity over Ta2O5. The electrocatalytic activity of a lithium-Ta2O5 film coated electrode was investigated in a 0.1moldm−3 KCl solution containing ascorbic acid (AA) using cyclic voltammetry (CV). The lithium-Ta2O5 film coated electrode has excellent electrocatalytic activity toward the oxidation of AA with much reduced overpotential. The anodic peak potential of AA shifted from 0.72V (versus Ag|AgCl) on a bare glassy carbon electrode (GCE) to 0.42V on the lithium-Ta2O5 film coated electrode. [Copyright &y& Elsevier]

Abstract: Cerium-doped tantalum oxide (cerium-Ta2O5) particles were synthesized using a low-temperature hydrothermal method. The crystal structure of the samples was investigated using X-ray diffraction (XRD). The XRD results revealed that the Ta2O5 cells shrunk after cerium doping. The electronic structure of cerium-Ta2O5 was calculated using density functional theory (DFT). The DFT results indicated that the energy band of Ta2O5 was narrow when it was doped with cerium, which might have resulted in the improved electrocatalytic activity of Ta2O5. Therefore, calculation of results could be used as a direct theory by which the electrocatalytic activity of cerium-Ta2O5 may be studied. The electrocatalytic activity of cerium-Ta2O5 was investigated in a KCl solution containinng methylene blue (MB) using cyclic voltammetry (CV). The CV results showed that the cerium-Ta2O5 exhibited excellent electrocatalytic activity toward MB reduction. The cathodic peak potential of MB shifted from −0.22V on a glass carbon electrode to −0.01V on a cerium-Ta2O5 film electrode. [Copyright &y& Elsevier]

• The octahedral pyrochlore K 2 Ta 2 O 6 and cubic perovskite KTaO 3 were synthesized successfully. • The Pd nanoparticles were loaded onto the K x Ta x O 3x (x = 1 or 2) by a reflux method. • Pd loading enhanced the electron transfer between Pd and K x Ta x O 3x. • The Pd/K x Ta x O 3x electrocatalysts exhibited excellent electrocatalytic activity for EG oxidation. • The electrocatalytic activity of Pd/K x Ta x O 3x was superior to that of commercial Pd/C (10%). In this work, potassium tantalates (K x Ta x O 3x , x = 1 or 2) with different crystal structures and morphologies are synthesized with a one-step hydrothermal method. The concentration of the KOH reactant played a crucial role in controlling the morphology of K x Ta x O 3x. When the concentration of KOH is low, an octahedral pyrochlore (K 2 Ta 2 O 6) is obtained. In contrast, the cubic perovskite (KTaO 3) is obtained at high KOH concentrations. Pd nanoparticles loaded onto K 2 Ta 2 O 6 and KTaO 3 (Pd/K 2 Ta 2 O 6 , Pd/KTaO 3) electrocatalysts are then prepared with reflux reduction in ethanol. X-ray photoelectron spectroscopy results imply that the loading palladium is in the main Pd° form. The electrocatalytic activity of the Pd/K 2 Ta 2 O 6 and Pd/KTaO 3 electrocatalysts is investigated using cyclic voltammetry (CV) toward ethylene glycol (EG) oxidation in an alkaline medium. The CV results show that Pd/K 2 Ta 2 O 6 and Pd/KTaO 3 electrocatalysts modified glassy carbon electrodes have excellent catalytic activity for EG electrooxidation in an alkaline medium, superior to that of commercial Pd/C (10%). The enhancement of their electrocatalytic activity was owing to the synergistic reaction between Pd and K x Ta x O 3x. In addition, the electronic structure of the Pd/K 2 Ta 2 O 6 and Pd/KTaO 3 electrocatalysts was assessed using density functional theory. The calculation results indicated that electron transfer occurred in the complex region of Pd and K x Ta x O 3x. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The urchin-like niobium oxide (U-Nb 2 O 5) microspheres was successfully synthesized. • The Pd nanoparticles were uniformly loaded onto the surface of U-Nb 2 O 5 microspheres. • The synergistic effect of Pd improved the catalytic activity of Pd/U-Nb 2 O 5 electrocatalyst. • The Pd/U-Nb 2 O 5 electrocatalyst had excellent catalytic activity for EG oxidation. • The electrocatalytic activity of Pd/U-Nb 2 O 5 was superior to commercial Pd/C (10 %). Urchin-like niobium oxide (U-Nb 2 O 5) microspheres are obtained using a low-temperature hydrothermal method. The nanosized palladium (Pd) particles loading onto U-Nb 2 O 5 (Pd/U-Nb 2 O 5) microspheres are successfully prepared using a reflux method. X-ray diffraction results imply that the U-Nb 2 O 5 and Pd/U-Nb 2 O 5 microspheres belong to the orthorhombic phase, and Pd loading does not change the crystalline phase. The average size of nanosized Pd particles loaded is 4.25 nm. In addition, the valence states of Pd on the surface of the Pd/U-Nb 2 O 5 microspheres are mainly of a Pd° form. The catalytic activity of the different loading amount Pd/U-Nb 2 O 5 electrocatalysts is carried out in a 0.5 M KOH and 1 M ethylene glycol (EG). When the usage of palladium acetate is 10 mg (the mass ration of Pd to Nb 2 O 5 is 10 %), the Pd/U-Nb 2 O 5 electrocatalyst exhibits high catalytic activity for the electrooxidation of EG in an alkaline medium. The current density of EG electrooxidation on the Pd/U-Nb 2 O 5 modified glassy carbon electrode is higher than that on commercial Pd/C (10 %). Moreover, the Pd/U-Nb 2 O 5 electrocatalyst exhibits strong anti-CO poisoning ability and good stability for EG oxidation in alkaline medium. After 6000 s, the maintained current density on the Pd/U-Nb 2 O 5 electrocatalyst is 12.7 times that on commercial Pd/C. This remarkable performance of the Pd/U-Nb 2 O 5 electrocatalyst is owing to the synergistic effect between Pd and Nb 2 O 5. The calculation results imply that the synergistic effect improves electron transfer. [ABSTRACT FROM AUTHOR]

• A strong chemisorption was confirmed of aspirin on Ti-doped graphene by DFT method. • Aspirin is directionally adsorbed to the positive charged Ti sites in TG. • The electron transfer path is from O of aspirin to Ti and then to C of graphene. • A narrowed band gap is achieved via decorating Ti into graphene frame. • Doping Ti into graphene could control the adsorptive mode and capacity of pollutant. Focused on the decontamination of pharmaceutical pollutants via an adsorption approach, the adsorptive mode and capacity of adsorbents have been explored with a strategy by incorporating Ti into graphene (TG) frame using the density functional theory (DFT). Aspirin is used as a model molecule and pristine graphene (PG) as comparative substrate in this study. It is notified for PG, aspirin is adsorbed with a C-ring parallel orientation. It presents a weak physical adsorption through π-π interaction with an energy value of −0.846 eV. Whereas, a stronger chemical adsorption of aspirin on surface of TG with even lager adsorption energy of −2.772 eV is confirmed. The analysis based on Hirshfeld population and electronic distribution show the electrons of aspirin transfer to TG with an electron transport channel of O-Ti-C, which contribute to steer the enhanced adsorption. Furthermore, band structure and density of state display more densely and successive semimetal feature with a very slight band gap for TG, confirming the enhanced harvesting ability for wide wavelength regions of solar light. Consequently, the present investigation demonstrates by incorporating metal into PG frame, a strong adsorption material toward pharmaceutical contaminant could be achieved. [ABSTRACT FROM AUTHOR]

The poor durability of commercial Pt/C catalyst in the electrocatalytic oxidation of alcohols is mainly due to the weak corrosion resistance of carbon carrier to acid and alkali, and the exfoliation/aggregation and weak resistance to CO poisoning of Pt nanoparticles. Herein, sodium tantalate, such as NaTaO 3 and Na 2 Ta 2 O 6 , was introduced as carrier material of Pt based electrocatalyst. Various characterizations and density functional theory calculations indicated that Na 2 Ta 2 O 6 exhibited superior synergistic effect on alcohol electro-oxidation, involving the improvement of electron transport, selective adsorption of CO molecule, and excellent corrosion resistance to acid and alkali. Accordingly, Pt/Na 2 Ta 2 O 6 catalyst showed the excellent electrocatalytic performances, including enhanced catalytic activity, high durability and strong CO-tolerance, toward methanol and ethanol oxidation reaction in both acid and base environment. The superior synergistic effect of Na 2 Ta 2 O 6 contributed to the improved alcohol electro-oxidation of Pt/Na 2 Ta 2 O 6 , especially the long-term durability and CO-tolerance. Unlabelled Image [ABSTRACT FROM AUTHOR]