scholarly journals Furfural Oxidation on Gold Supported on MnO2: Influence of the Support Structure on the Catalytic Performances

2018 ◽  
Vol 8 (8) ◽  
pp. 1246 ◽  
Author(s):  
Camila Palombo Ferraz ◽  
Anderson Gabriel Marques Da Silva ◽  
Thenner Silva Rodrigues ◽  
Pedro Henrique Cury Camargo ◽  
Sébastien Paul ◽  
...  
Keyword(s):  
High Activity ◽  
Photoelectron Spectroscopy ◽  
High Selectivity ◽  
X Ray ◽  
Mild Conditions ◽  
Highly Active ◽  
Xps Study ◽  
Very High ◽  
Free Oxidation ◽  
Catalytic Performances

A series of catalysts consisting of gold nanoparticles supported on MnO2 presenting different morphologies were synthesized and tested in the base-free oxidation of furfural. Ultra-small Au particles (less than 3 nm) were deposited on low (commercial MnO2) and high (NF, nanoflowers and NW, nanowires MnO2) surface area supports. High activity was observed for Au/MnO2-NF material with very high selectivity to furoic acid. The X-ray photoelectron spectroscopy (XPS) study confirmed the presence of a significant amount of highly active Auδ+ species on the surface of the Au/MnO2-NF catalyst. These species seem to be responsible for the high activity in oxidation of furfural under mild conditions (air as oxidant, 110 °C).

Highly active carbon nanotube–promoted Rh-Mn-Li/SiO2 catalysts for the synthesis of C2+ oxygenates from syngas

2021 ◽  
pp. 174751982098472
Author(s):  
Jun Yu ◽  
Ying Han ◽  
Guoqing Chen ◽  
Xiuzhen Xiao ◽  
Haifang Mao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Co Hydrogenation ◽  
X Ray ◽  
Highly Active ◽  
Transmission Electron ◽  
Co Insertion ◽  
Temperature Programmed Surface Reaction ◽  
Temperature Programmed ◽  
Oxygenate Synthesis

The effect of carbon nanotubes on the catalytic properties of Rh-Mn-Li/SiO2 catalysts was investigated for CO hydrogenation. The catalysts were comprehensively characterized by means of X-ray power diffraction, N2 sorption, transmission electron microscope, H2–temperature-programmed reduction, CO–temperature-programmed desorption, temperature-programmed surface reaction, and X-ray photoelectron spectroscopy. The results showed that an appropriate amount of carbon nanotubes can be attached to the surface of the SiO2 sphere and can improve the Rh dispersion. Moderate Rh-Mn interaction can be obtained by doping with the appropriate amount of carbon nanotubes, which promotes the formation of strongly adsorbed CO and facilitates the progress of CO insertion, resulting in the increase in the selectivity of C2+ oxygenate synthesis.

scholarly journals Nitrogen-Doped Sponge Ni Fibers as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Kaili Zhang ◽  
Xinhui Xia ◽  
Shengjue Deng ◽  
Yu Zhong ◽  
Dong Xie ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Photoelectron Spectroscopy ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
High Performance ◽  
Active Phase ◽  
X Ray ◽  
Highly Active ◽  
N Doping ◽  
Energy Conversion Devices

Abstract Controllable synthesis of highly active micro/nanostructured metal electrocatalysts for oxygen evolution reaction (OER) is a particularly significant and challenging target. Herein, we report a 3D porous sponge-like Ni material, prepared by a facile hydrothermal method and consisting of cross-linked micro/nanofibers, as an integrated binder-free OER electrocatalyst. To further enhance the electrocatalytic performance, an N-doping strategy is applied to obtain N-doped sponge Ni (N-SN) for the first time, via NH3 annealing. Due to the combination of the unique conductive sponge structure and N doping, the as-obtained N-SN material shows improved conductivity and a higher number of active sites, resulting in enhanced OER performance and excellent stability. Remarkably, N-SN exhibits a low overpotential of 365 mV at 100 mA cm−2 and an extremely small Tafel slope of 33 mV dec−1, as well as superior long-term stability, outperforming unmodified sponge Ni. Importantly, the combination of X-ray photoelectron spectroscopy and near-edge X-ray adsorption fine structure analyses shows that γ-NiOOH is the surface-active phase for OER. Therefore, the combination of conductive sponge structure and N-doping modification opens a new avenue for fabricating new types of high-performance electrodes with application in electrochemical energy conversion devices.

scholarly journals Fe-Containing MOFs as Seeds for the Preparation of Highly Active Fe/Al-SBA-15 Catalysts in the NAlkylation of Aniline

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2695 ◽  
Author(s):  
Mhadmhan ◽  
Marquez-Medina ◽  
Romero ◽  
Reubroycharoen ◽  
Luque
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Catalytic Performance ◽  
Alkylation Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Highly Active ◽  
Milling Method ◽  
Plasma Mass Spectrometry

We have successfully incorporated iron species into mesoporous aluminosilicates (AlSBA15) using a simple mechanochemical milling method. The catalysts were characterized by nitrogen physisorption, inductively coupled plasma mass spectrometry (ICP-MS), pyridine (PY) and 2,6-dimethylpyridine (DMPY) pulse chromatography titration, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The catalysts were tested in the N-alkylation reaction of aniline with benzyl alcohol for imine production. According to the results, the iron sources, acidity of catalyst and reaction conditions were important factors influencing the reaction. The catalyst showed excellent catalytic performance, achieving 97% of aniline conversion and 96% of imine selectivity under optimized conditions.

scholarly journals Optimization of sol-immobilized bimetallic Au–Pd/TiO 2 catalysts: reduction of 4-nitrophenol to 4-aminophenol for wastewater remediation

2020 ◽  
Vol 378 (2176) ◽  
pp. 20200057
Author(s):  
Khaled Alshammari ◽  
Yubiao Niu ◽  
Richard E. Palmer ◽  
Nikolaos Dimitratos
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Reducing Agent ◽  
Wastewater Remediation ◽  
X Ray ◽  
Molar Ratios ◽  
Highly Active ◽  
Transmission Electron ◽  
Complementary Techniques

A sol-immobilization method is used to synthesize a series of highly active and stable Au x Pd 1− x /TiO 2 catalysts (where x  = 0, 0.13, 0.25, 0.5, 0.75, 0.87 and 1) for wastewater remediation. The catalytic performance of the materials was evaluated for the catalytic reduction of 4-nitrophenol, a model wastewater contaminant, using NaBH 4 as the reducing agent under mild reaction conditions. Reaction parameters such as substrate/metal and substrate/reducing agent molar ratios, reaction temperature and stirring rate were investigated. Structure-activity correlations were studied using a number of complementary techniques including X-ray powder diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. The sol-immobilization route provides very small Au–Pd alloyed nanoparticles, with the highest catalytic performance shown by the Au 0.5 Pd 0.5 /TiO 2 catalyst. This article is part of a discussion meeting issue ‘Science to enable the circular economy’.

Pb (II)-Imprinted Chitosan/TiO2 Hybrid Film for High Selectivity of Adsorption Lead Ion in Aqueous Solution

2010 ◽  
Vol 152-153 ◽  
pp. 484-488
Author(s):  
Yu Gui Tao ◽  
Hao Gu ◽  
Yan Qiu Xu ◽  
Lian Bin Ye ◽  
Qi Jin Wang
Keyword(s):  
Aqueous Solution ◽  
Nitrogen Atom ◽  
Photoelectron Spectroscopy ◽  
Competitive Adsorption ◽  
High Selectivity ◽  
Hybrid Film ◽  
Lead Ion ◽  
Adsorption Experiment ◽  
Step Process ◽  
X Ray

Pb(II)-imprinted chitosan/TiO2 hybrid film (LIHF) was synthesized through a two-step process. The selectivity of LIHF was studied via competitive adsorption experiment. The LIHF shows higher selectivity to Pb (II) ion than Cu (II) and Zn (II) ions. X-ray photoelectron spectroscopy(XPS) was used to characterize the as-obtained samples. XPS results showed that the nitrogen atom and the Pb (II) were concerned for coordination. The evidences for the imprinting process and the recognition of Pb (II) with LIHF were provided.

scholarly journals X-ray Photoelectron Spectroscopy(XPS) Study of Fracture Mechanism in Sintered Si3N4.

2000 ◽  
Vol 108 (1253) ◽  
pp. 61-64 ◽  
Author(s):  
Masahiro OZAWA ◽  
Yoichiro FURUKAWA ◽  
Mitsushige OGAWA ◽  
Kei ISOZAKI
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fracture Mechanism ◽  
X Ray ◽  
Xps Study

Platinum state in highly active Pt/CeO2 catalysts from the X-ray photoelectron spectroscopy data

2017 ◽  
Vol 58 (6) ◽  
pp. 1152-1159 ◽  
Author(s):  
A. I. Stadnichenko ◽  
V. V. Murav’ev ◽  
V. A. Svetlichnyi ◽  
A. I. Boronin
Keyword(s):  
Photoelectron Spectroscopy ◽  
Spectroscopy Data ◽  
X Ray ◽  
Highly Active

Xps Study of the Nitridation Process of A Polytitanocarbosilane into Si-Ti-N-O Ceramics

1992 ◽  
Vol 271 ◽  
Author(s):  
G. Granozzi ◽  
A. Glisenti ◽  
R. Bertoncello ◽  
G. D. Soraru
Keyword(s):  
Titanium Nitride ◽  
Firing Temperature ◽  
Photoelectron Spectroscopy ◽  
Transformation Process ◽  
Nitrogen Enrichment ◽  
X Ray ◽  
Nitridation Process ◽  
Nitride Ceramics ◽  
Xps Study

ABSTRACTThe nitridation process of a polytitanocarbosilane, leading to the formation of a Si-Ti-N-O ceramics, has been investigated mainly by means of X-ray photoelectron spectroscopy (XPS). Ti2p spectra collected on samples fired at various stages of the transformation process clearly shown that Ti-N bonds of TiOxNy mixed units start to form at 500 °C. By increasing the firing temperature, the Ti2p peak shifts toward values typical of titanium nitride ceramics, so indicating the progressive nitrogen enrichment of the mixed units up to the formation of a TiN phase.

High impact of the reducing agent on palladium nanomaterials: new insights from X-ray photoelectron spectroscopy and oxygen reduction reaction

RSC Advances ◽  
2016 ◽  
Vol 6 (15) ◽  
pp. 12627-12637 ◽  
Author(s):  
Yaovi Holade ◽  
Christine Canaff ◽  
Suzie Poulin ◽  
Têko W. Napporn ◽  
Karine Servat ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Chemical Stability ◽  
Photoelectron Spectroscopy ◽  
Reduction Reaction ◽  
High Impact ◽  
Reducing Agent ◽  
X Ray ◽  
Catalytic Performances

The nature of the reduction agent changes drastically the palladium nanomaterials chemical stability, which subsequently alters earnestly their catalytic performances.

XPS STUDY OF DOPING MECHANISM IN HEAVILY DOPED PbWO4:M3+(M = La, Nd, Gd) CRYSTALS

2007 ◽  
Vol 14 (04) ◽  
pp. 725-728
Author(s):  
XIQI FENG ◽  
WEIFENG LI ◽  
WENLIANG ZHU
Keyword(s):  
Photoelectron Spectroscopy ◽  
Rare Earth Ions ◽  
High Concentration ◽  
Lead Tungstate ◽  
X Ray ◽  
Optoelectronic Application ◽  
Trivalent Rare Earth ◽  
Heavily Doped ◽  
Doping Mechanism ◽  
Xps Study

Lead tungstate ( PbWO 4) (PWO) crystals doped with high concentration trivalent rare earth ions have demonstrated to be a promising Cherenkov radiator material and also a potential material for optoelectronic application. In this paper, the doping mechanisms of the trivalent ions ( La 3+, Nd 3+, and Gd 3+) in the PWO host were studied using X-ray photoelectron spectroscopy (XPS), and the results were consistent with those of computer simulation. It was found that when heavily doped, La 3+ may substitute for the W sites as well as the Pb sites for self-compensation by forming La dimers or small aggregates. However, the doping mechanism of heavily doped PWO: Nd 3+ and PWO: Gd 3+ might be different from that of heavily doped PWO: La 3+ crystals.

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