Thermocatalytic CO2 Conversion over a Nickel-Loaded Ceria Nanostructured Catalyst: A NAP-XPS Study

Despite the increasing economic incentives and environmental advantages associated to their substitution, carbon-rich fossil fuels are expected to remain as the dominant worldwide source of energy through at least the next two decades and perhaps later. Therefore, both the control and reduction of CO2 emissions have become environmental issues of major concern and big challenges for the international scientific community. Among the proposed strategies to achieve these goals, conversion of CO2 by its reduction into high added value products, such as methane or syngas, has been widely agreed to be the most attractive from the environmental and economic points of view. In the present work, thermocatalytic reduction of CO2 with H2 was studied over a nanostructured ceria-supported nickel catalyst. Ceria nanocubes were employed as support, while the nickel phase was supported by means a surfactant-free controlled chemical precipitation method. The resulting nanocatalyst was characterized in terms of its physicochemical properties, with special attention paid to both surface basicity and reducibility. The nanocatalyst was studied during CO2 reduction by means of Near Ambient Pressure X-ray Photoelectron Spectroscopy (NAP-XPS). Two different catalytic behaviors were observed depending on the reaction temperature. At low temperature, with both Ce and Ni in an oxidized state, CH4 formation was observed, whereas at high temperature above 500 °C, the reverse water gas shift reaction became dominant, with CO and H2O being the main products. NAP-XPS was revealed as a powerful tool to study the behavior of this nanostructured catalyst under reaction conditions.

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Electrochemical reduction of CO2 in ionic liquid: Mechanistic study of Li–CO2 batteries via in situ ambient pressure X-ray photoelectron spectroscopy

Nano Energy ◽

10.1016/j.nanoen.2021.105830 ◽

2021 ◽

Vol 83 ◽

pp. 105830

Author(s):

Yu Wang ◽

Wanwan Wang ◽

Jing Xie ◽

Chia-Hsin Wang ◽

Yaw-Wen Yang ◽

...

Keyword(s):

Ionic Liquid ◽

Electrochemical Reduction ◽

Photoelectron Spectroscopy ◽

Ambient Pressure ◽

Mechanistic Study ◽

X Ray ◽

Reduction Of Co2

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Evolution of Copper Supported on Fe3O4 Nanorods for WGS Reaction

Catalysts ◽

10.3390/catal8100415 ◽

2018 ◽

Vol 8 (10) ◽

pp. 415 ◽

Cited By ~ 4

Author(s):

Lingjuan Ma ◽

Hongbin Ma ◽

Dawei Han ◽

Mingyue Qiu ◽

Yafei Guan ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Ambient Pressure ◽

Phase Evolution ◽

Precipitation Method ◽

X Ray Diffraction ◽

X Ray ◽

In Situ Xrd ◽

Wgs Reaction ◽

Transmission Electron ◽

Temperature Programmed

Rod-shaped Cu1Fe9Ox precursor was successfully prepared through an aqueous precipitation method. The shape and phase composition were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that Cu1Fe9Ox is composed of CuFe2O4 and Fe2O3. The reduction performance of Cu1Fe9Ox was studied by in situ XRD and H2 temperature-programmed reduction (H2-TPR). Cu/Fe3O4 nanorod catalyst is obtained through the controllable reduction of Cu1Fe9Ox nanorod, and the formed Cu/Fe3O4 nanorod catalyst does not have low-temperature water gas shift (WGS) activity, but exhibits high-temperature WGS reaction activity. Ambient pressure X-ray photoelectron spectroscopy (AP-XPS) studies showed that the main species of copper is Cu+ during the WGS reaction. The interaction between Cu and Fe3O4 rod and phase evolution of Cu species are quite different from Cu/Fe3O4 nanoparticles.

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In Situ probing of solid/liquid interfaces of potassium–oxygen batteries via ambient pressure X-ray photoelectron spectroscopy: New reaction pathways and root cause of battery degradation

Energy Storage Materials ◽

10.1016/j.ensm.2021.01.010 ◽

2021 ◽

Vol 36 ◽

pp. 341-346 ◽

Cited By ~ 1

Author(s):

Wanwan Wang ◽

Yu Wang ◽

Chia-Hsin Wang ◽

Yaw-Wen Yang ◽

Yi-Chun Lu

Keyword(s):

Photoelectron Spectroscopy ◽

Ambient Pressure ◽

Reaction Pathways ◽

Liquid Interfaces ◽

X Ray ◽

Root Cause ◽

Battery Degradation ◽

Solid Liquid

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Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽

10.3390/catal11030346 ◽

2021 ◽

Vol 11 (3) ◽

pp. 346

Author(s):

Sonam Goyal ◽

Maizatul Shima Shaharun ◽

Ganaga Suriya Jayabal ◽

Chong Fai Kait ◽

Bawadi Abdullah ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Catalyst Support ◽

Oxidation Potential ◽

Molar Ratio ◽

X Ray Diffraction ◽

X Ray ◽

Molar Ratios ◽

Optimum Parameters ◽

Reduction Of Co2 ◽

Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

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Improved Water–Gas Shift Performance of Au/NiAl LDHs Nanostructured Catalysts via CeO2 Addition

Nanomaterials ◽

10.3390/nano11020366 ◽

2021 ◽

Vol 11 (2) ◽

pp. 366

Author(s):

Margarita Gabrovska ◽

Ivan Ivanov ◽

Dimitrinka Nikolova ◽

Jugoslav Krstić ◽

Anna Maria Venezia ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Nanostructured Catalysts ◽

Water Gas Shift ◽

Precipitation Method ◽

Conversion Degree ◽

Pure Hydrogen ◽

Medium Temperature ◽

X Ray ◽

Supported Gold ◽

Water Gas

Supported gold on co-precipitated nanosized NiAl layered double hydroxides (LDHs) was studied as an effective catalyst for medium-temperature water–gas shift (WGS) reaction, an industrial catalytic process traditionally applied for the reduction in the amount of CO in the synthesis gas and production of pure hydrogen. The motivation of the present study was to improve the performance of the Au/NiAl catalyst via modification by CeO2. An innovative approach for the direct deposition of ceria (1, 3 or 5 wt.%) on NiAl-LDH, based on the precipitation of Ce3+ ions with 1M NaOH, was developed. The proposed method allows us to obtain the CeO2 phase and to preserve the NiAl layered structure by avoiding the calcination treatment. The synthesis of Au-containing samples was performed through the deposition–precipitation method. The as-prepared and WGS-tested samples were characterized by X-ray powder diffraction, N2-physisorption and X-ray photoelectron spectroscopy in order to clarify the effects of Au and CeO2 loading on the structure, phase composition, textural and electronic properties and activity of the catalysts. The reduction behavior of the studied samples was evaluated by temperature-programmed reduction. The WGS performance of Au/NiAl catalysts was significantly affected by the addition of CeO2. A favorable role of ceria was revealed by comparison of CO conversion degree at 220 °C reached by 3 wt.% CeO2-modified and ceria-free Au/NiAl samples (98.8 and 83.4%, respectively). It can be stated that tuning the properties of Au/NiAl LDH via CeO2 addition offers catalysts with possibilities for practical application owing to innovative synthesis and improved WGS performance.

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Synthesis and characterization of analcime (ANA) zeolite using a kaolinitic rock

Scientific Reports ◽

10.1038/s41598-021-92862-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Daniela Novembre ◽

Domingo Gimeno

Keyword(s):

Ambient Pressure ◽

Added Value ◽

Emission Spectrometry ◽

Quantitative Phase Analysis ◽

Crystallization Time ◽

Experimental Protocol ◽

Economic Point ◽

Cell Parameters ◽

Synthesis Protocol

AbstractAnalcime is nowadays an important component in dental porcelain systems, in heterogeneous catalysis, in the nanoelectronic field, in selective adsorption and in stomatology (dental filling and prosthesis). Analcime synthesis from an impure, silica-rich kaolinite rock coming from Romana (Sassari, Italy) is here presented. A synthesis protocol is proposed that aims to make an improvement of synthesis conditions compared to the past. The hydrothermal treatment is in fact here achieved without aging times and without the use of sodium silicate or other additional silica source reported in the literature. Lower calcination temperature, synthesis temperature and crystallization time are verified in this work. The kaolin is subjected to calcination at the temperature of 650 °C and then mixed with NaOH. The experiment is performed at ambient pressure and 170 ± 0.1 °C. The degree of purity of analcime is calculated in 97.57% at 10 h. Analcime is characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, inductively coupled plasma optical emission spectrometry and thermal analysis. Density is also calculated. Cell parameters and the amount of amorphous phase in the synthesis powders is estimated with quantitative phase analysis using the combined Rietveld and reference intensity ratio methods. The experimental conditions make the synthesis protocol particularly attractive from an economic point of view. Also this work does not use a commercial kaolin but silica-rich impure kaolinitic rock from a disused quarry. This further reduces the costs of the experimental protocol. It also gives the protocol an added value, as the synthesis of a useful mineral is obtained through the valorization of an otherwise unused georesource. Both chemical and physical characterization of analcime is satisfactory making the experimental protocol very promising for an industrial transfer.

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In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy

Communications Chemistry ◽

10.1038/s42004-021-00487-1 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Marc Benjamin Hahn ◽

Paul M. Dietrich ◽

Jörg Radnik

Keyword(s):

Dna Damage ◽

Radiation Damage ◽

Photoelectron Spectroscopy ◽

Ambient Pressure ◽

In Situ Monitoring ◽

Strong Increase ◽

Oh Radicals ◽

Strand Breaks ◽

X Ray

AbstractIonizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.

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Insights into the Development of Cu-based Photocathodes for Carbon Dioxide (CO2) Conversion

Green Chemistry ◽

10.1039/d0gc04417b ◽

2021 ◽

Author(s):

Wenzhang Li ◽

Keke Wang ◽

yanfang Ma ◽

Yang Liu ◽

Weixin Qiu ◽

...

Keyword(s):

Carbon Dioxide ◽

Fossil Fuels ◽

Environmental Issues ◽

Energy Crisis ◽

Co2 Conversion ◽

Carbon Dioxide Co2 ◽

Reduction Of Co2

The ever-growing factitious over-consumption of fossil fuels and the accompanying massive emissions of CO2 have caused severe energy crisis and environmental issues. Photoelectrochemical (PEC) reduction of CO2 that can combine...

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