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Raju Edla

Consiglio Nazionale delle Ricerche (CNR), CNR - IOM, Post-Doc

University of Trento, Physics, Graduate Student

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My research is focused on “Design and development of operando reaction cell at APE-HE Beam line” for XAS measurements at ambient pressure. Experiments to study the real time catalyst surface-gaseous reactions with various morphological thin film/powder catalysts. Research work carried out on deposition of various thin film catalysts by PLD, sputtering and chemical techniques for energy and environmental applications such as Photocatalysis for water treatment, Electrochemical water splitting, CO oxidation and H2 generation from hydrolysis of complex hydrides.

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Papers by Raju Edla

Rb Diffusion and Oxide Removal at the RbF-Treated Ga2O3/Cu(In,Ga)Se2 Interface in Thin-Film Solar Cells

ACS Applied Materials & Interfaces

Understanding Solid-Gas Reaction Mechanisms by Operando Soft X-ray Absorption Spectroscopy at Ambient Pressure: On the Importance of Surface Hydroxides in SnO <sub>2</sub> Heterogeneous Catalysts and Sensors

Social Science Research Network, 2020

On the thermodynamic path enabling a room-temperature, laser-assisted graphite to nanodiamond transformation

Scientific reports, Oct 12, 2016

Nanodiamonds are the subject of active research for their potential applications in nano-magnetom... more Nanodiamonds are the subject of active research for their potential applications in nano-magnetometry, quantum optics, bioimaging and water cleaning processes. Here, we present a novel thermodynamic model that describes a graphite-liquid-diamond route for the synthesis of nanodiamonds. Its robustness is proved via the production of nanodiamonds powders at room-temperature and standard atmospheric pressure by pulsed laser ablation of pyrolytic graphite in water. The aqueous environment provides a confinement mechanism that promotes diamond nucleation and growth, and a biologically compatible medium for suspension of nanodiamonds. Moreover, we introduce a facile physico-chemical method that does not require harsh chemical or temperature conditions to remove the graphitic byproducts of the laser ablation process. A full characterization of the nanodiamonds by electron and Raman spectroscopies is reported. Our model is also corroborated by comparison with experimental data from the lite...

Towards the Development of a Z-Scheme FeOx/g-C3N4 Thin Film and Perspectives for Ciprofloxacin Visible Light-Driven Photocatalytic Degradation

Applied Sciences, Sep 21, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more

Physical vapor deposition of mixed-metal oxides based on Fe, Co and Ni as water oxidation catalysts

Materials Science in Semiconductor Processing, 2016

Abstract Physical vapor deposition (PVD) techniques are proposed as high performing and easily tu... more Abstract Physical vapor deposition (PVD) techniques are proposed as high performing and easily tunable methods to synthesize mixed-metal oxides thin films as water oxidation catalysts (WOC). These techniques allow us to have a good control on the catalyst film surface morphology and crystallinity, with good adhesion of the catalysts on electrodes. Pure and binary metal oxides thin films based on Fe, Co and Ni were synthesized using electron beam deposition (EBD). WOC films are systematically studied through SEM microscopy, Raman spectroscopy and XPS analysis. Electrochemical characterization has been carried out to investigate the relevance of synergistic effects towards the water oxidation reaction. Among all the mixed oxides Ni–Fe oxide showed the best catalytic results.

A combined in operando approach for low-energy Scanning Transmission Electron Microscopy and Grazing Incident Small Angle X-ray Scattering

Probing the evolution of electronic, structural, and chemical properties of nanostructured materi... more Probing the evolution of electronic, structural, and chemical properties of nanostructured materials under reaction conditions is a crucial issue to determine their structure-functionality relationships. A relevant example is represented by heterogeneous catalysts, whose properties change dramatically with respect to the environment. Much of effort has been made lately in designing new solutions and technologies, or modifying the existing ones for purpose of operando conditions analysis. The use of micro- or nanoreactors, is a second approach, where ultrathin membranes can efficiently separate the high-pressure volume from the (ultra)high vacuum of the characterization chamber. Very recently, microreactor cells have been developed to integrate the capabilities of ensemble-averaging synchrotron techniques with local probe ones, as TEM to analyze the same catalytic process with different instruments. Despite the great power of this method, the extremely small probing size of TEMs rest...

Origin of a Simultaneous Suppression of Thermal Conductivity and Increase of Electrical Conductivity and Seebeck Coefficient in Disordered Cubic Cu 2 ZnSnS 4

Physical Review Applied, 2020

The parameters governing the thermoelectric efficiency of a material, Seebeck coefficient, electr... more The parameters governing the thermoelectric efficiency of a material, Seebeck coefficient, electrical, and thermal conductivities, are correlated and their reciprocal interdependence typically prevents a simultaneous optimization. Here, we present the case of disordered cubic kesterite Cu 2 ZnSnS 4 , a phase stabilized by structural disorder at low temperature. With respect to the ordered form, the introduction of disorder improves the three thermoelectric parameters at the same time. The origin of this peculiar behavior lies in the localization of some Sn lone pair electrons, leading to "rattling" Sn ions. On one hand, these rattlers remarkably suppress thermal conductivity, dissipating lattice energy via optical phonons located below 1.5 THz; on the other, they form electron-deficient Sn-S bonds leading to a p-type dopinglike effect and highly localized acceptor levels, simultaneously enhancing electrical conductivity and the Seebeck coefficient. This phenomenon leads to a 3 times reduced thermal conductivity and doubling of both electrical conductivity and the Seebeck coefficient, resulting in a more than 20 times increase in figure of merit, although still moderate in absolute terms.

Catching the Reversible Formation and Reactivity of Surface Defective Sites in Metal–Organic Frameworks: An Operando Ambient Pressure-NEXAFS Investigation

The Journal of Physical Chemistry Letters, 2021

In this work, we apply for the first time ambient pressure operando soft X-ray absorption spectro... more In this work, we apply for the first time ambient pressure operando soft X-ray absorption spectroscopy (XAS) to investigate the location, structural properties, and reactivity of the defective sites present in the prototypical metal-organic framework HKUST-1. We obtained direct evidence that Cu+ defective sites form upon temperature treatment of the powdered form of HKUST-1 at 160 °C and that they are largely distributed on the material surface. Further, a thorough structural characterization of the Cu+/Cu2+ dimeric complexes arising from the temperature-induced dehydration/decarboxylation of the pristine Cu2+/Cu2+ paddlewheel units is reported. In addition to characterizing the surface defects, we demonstrate that CO2 may be reversibly adsorbed and desorbed from the surface defective Cu+/Cu2+ sites. These findings show that ambient pressure soft-XAS, combined with state-of-the-art theoretical calculations, allowed us to shed light on the mechanism involving the decarboxylation of the paddlewheel units on the surface to yield Cu+/Cu2+ complexes and their reversible restoration upon exposure to gaseous CO2.

Transition‐Metal Dichalcogenide NiTe 2 : An Ambient‐Stable Material for Catalysis and Nanoelectronics

Advanced Functional Materials, 2020

By means of theory and experiments, the application capability of nickel ditelluride (NiTe2) tran... more By means of theory and experiments, the application capability of nickel ditelluride (NiTe2) transition‐metal dichalcogenide in catalysis and nanoelectronics is assessed. The Te surface termination forms a TeO2 skin in an oxygen environment. In ambient atmosphere, passivation is achieved in less than 30 min with the TeO2 skin having a thickness of about 7 Å. NiTe2 shows outstanding tolerance to CO exposure and stability in water environment, with subsequent good performance in both hydrogen and oxygen evolution reactions. NiTe2‐based devices consistently demonstrate superb ambient stability over a timescale as long as one month. Specifically, NiTe2 has been implemented in a device that exhibits both superior performance and environmental stability at frequencies above 40 GHz, with possible applications as a receiver beyond the cutoff frequency of a nanotransistor.

An integrated ultra-high vacuum apparatus for growth and in situ characterization of complex materials

Review of Scientific Instruments, 2020

Here, we present an integrated ultra-high vacuum apparatus-named MBE-Cluster-dedicated to the gro... more Here, we present an integrated ultra-high vacuum apparatus-named MBE-Cluster-dedicated to the growth and in situ structural, spectroscopic, and magnetic characterization of complex materials. Molecular Beam Epitaxy (MBE) growth of metal oxides, e.g., manganites, and deposition of the patterned metallic layers can be fabricated and in situ characterized by reflection high-energy electron diffraction, lowenergy electron diffraction, Auger electron spectroscopy, x-ray photoemission spectroscopy, and azimuthal longitudinal magneto-optic Kerr effect. The temperature can be controlled in the range from 5 K to 580 K, with the possibility of application of magnetic fields H up to ±7 kOe and electric fields E for voltages up to ±500 V. The MBE-Cluster operates for in-house research as well as user facility in combination with the APE beamlines at Sincrotrone-Trieste and the high harmonic generator facility for time-resolved spectroscopy.

Understanding SolidGas Reaction Mechanisms by Operando Soft XRay Absorption Spectroscopy at Ambient Pressure

Catalytic activity of PtSn4: Insights from surface-science spectroscopies

Applied Surface Science, 2020

Abstract Bulk PtSn4 has recently attracted the interest of the scientific community for the prese... more Abstract Bulk PtSn4 has recently attracted the interest of the scientific community for the presence of electronic states exhibiting Dirac node arcs, enabling possible applications in nanoelectronics. Here, by means of surface-science experiments and density functional theory, we assess its suitability for catalysis by studying the chemical reactivity of the (0 1 0)-oriented PtSn4 surface toward CO, H2O, O2 molecules at room temperature and, moreover, its stability in air. We demonstrate that the catalytic activity of PtSn4 is determined by the composition of the outermost atomic layer. Specifically, we find that the surface termination for PtSn4 crystals cleaved in vacuum is an atomic Sn layer, which is totally free from any CO poisoning. In oxygen-rich environment, as well as in ambient atmosphere, the surface termination is a SnOx skin including SnO and SnO2 in comparable amount. However, valence-band states, including those forming Dirac node arcs, are only slightly affected by surface modifications. The astonishingly beneficial influence of surface oxidation on catalytic activity has been demonstrated by electrocatalytic tests evidencing a reduction of the Tafel slope, from 442 down to 86 mV dec−1, whose origin has been explained by our theoretical model. The use of surface-science tools to tune the chemical reactivity of PtSn4 opens the way toward its effective use in catalysis, especially for hydrogen evolution reaction and oxygen evolution reaction.

Efficient hydrogen evolution reaction with platinum stannide PtSn4via surface oxidation

Journal of Materials Chemistry A, 2020

The outstanding performance of PtSn4 in HER is related to the presence of a sub-nanometric tin-ox... more

PdTe 2 Transition‐Metal Dichalcogenide: Chemical Reactivity, Thermal Stability, and Device Implementation

Advanced Functional Materials, 2019

Study of Gaseous Interactions on Co3O4 Thin Film Coatings by Ambient Pressure Soft X-ray Absorption Spectroscopy

The Journal of Physical Chemistry C, 2019

The redox process of pretreated Co3O4 thin film coatings has been studied by ambient pressure sof... more The redox process of pretreated Co3O4 thin film coatings has been studied by ambient pressure soft X-ray absorption spectroscopy. The Co3O4 coatings were composed of nanoparticles of about 10 nm in size as prepared by pulsed laser deposition. The thin film coatings were pretreated in He or in H2 up to 150 °C prior to exposure to the reactive gases. The reactivity toward carbon monoxide and oxygen was monitored by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy during gas exposures. The results indicate that the samples pretreated in He show reactivity only at high temperature, while the samples pretreated in H2 are reactive also at room temperature. X-ray photoemission spectroscopy measurements in ultra-high vacuum and NEXAFS simulations with the CTM4XAS code further specify the results.

Surface Reconstruction, Oxidation Mechanism, and Stability of Cd 3 As 2

Advanced Functional Materials, 2019

2017 ! ! There are many ideas as to how spiritual formation happens in midadolescents. Traditiona... more 2017 ! ! There are many ideas as to how spiritual formation happens in midadolescents. Traditionally, most discipleship programs encourage midadolescents to grow in their faith by participating in youth programs, to read their Bibles, and to pray. This project demonstrates that the church is God's worshipping community on earth and has been ordained since the beginning of time to be such. While a personal relationship with God is important, so is participation in the family life of the church. The church over the last few decades has placed all the responsibility of spiritual growth on the shoulders of believers. Faith has become exclusively about a personal relationship with God that is grown through personal devotion to God. Church has then become a place to go to service one's faith. It has become a collection of individuals who share a common interest but no true need for one another. This mentality has led to the atomization of church ministries. A church's various ministries, including those focusing on youth, children, women, and young adults, for example, have very little connection with one another. A sense of responsibility for one another as brothers and sisters in Christ needs to be recovered in the local church. If believers want to fully grow in their faith, they need to be present where Christ is, and Christ is found in the church. Over and over again the church is referred to as the family of faith. Christians are called "children of God," the "family of faith," "adopted," and Paul's favorite term, "brothers and sisters." Midadolescents need a family of faith for their spiritual formation. They need older siblings who mentor and care for them as younger siblings. When the church lives into its ontology, it creates the best environment for the spiritual formation of midadolescents.

Interaction of VSe 2 with Ambient Gases: Stability and Chemical Reactivity

physica status solidi (RRL) – Rapid Research Letters, 2019

Pulsed laser deposition of CoFe2O4/CoO hierarchical-type nanostructured heterojuction forming a Z-scheme for efficient spatial separation of photoinduced electron-hole pairs and highly active surface area

Applied Surface Science, 2019

Surface Instability and Chemical Reactivity of ZrSiS and ZrSiSe Nodal-Line Semimetals

Advanced Functional Materials, 2019

Control of composition and grain growth in Cu2ZnSnS4 thin films from nanoparticle inks

Thin Solid Films, 2019

Abstract Cu2ZnSnS4 (CZTS) nanocrystals (NCs) were produced via hot-injection from metal chloride ... more Abstract Cu2ZnSnS4 (CZTS) nanocrystals (NCs) were produced via hot-injection from metal chloride precursors. A systematic investigation of the influence of synthesis conditions on composition, size and microstructure of CZTS NCs is presented. The results show that the solvent amount (oleylamine) is a key parameter in the synthesis of this quaternary chalcogenide: a low solvent content leads to CZTS NCs with a prominent kesterite phase with the desired composition for use as absorber material in thin film photovoltaic cells. It is also observed that lowering the injection temperature (250 °C) favours formation of CZTS NCs in the wurtzite phase. The effect of different high temperature thermal treatments on the grain growth is also shown: large crystals are obtained with annealing in inert atmosphere, whereas nanocrystalline films are obtained introducing sulphur vapour during the heat treatment. A correlation between the grain dimension and the carbonaceous residues in the final films is investigated. It is shown that the grain growth is hindered by organic residues, amount and nature of which depend on the heat treatment atmosphere. In fact, oleylamine is removed by a complex pyrolytic process, which is affected by the presence of sulphur vapour. The latter favours the stability of oleylamine residuals against its non-oxidative release.

Rb Diffusion and Oxide Removal at the RbF-Treated Ga2O3/Cu(In,Ga)Se2 Interface in Thin-Film Solar Cells

ACS Applied Materials & Interfaces

Understanding Solid-Gas Reaction Mechanisms by Operando Soft X-ray Absorption Spectroscopy at Ambient Pressure: On the Importance of Surface Hydroxides in SnO <sub>2</sub> Heterogeneous Catalysts and Sensors

Social Science Research Network, 2020

On the thermodynamic path enabling a room-temperature, laser-assisted graphite to nanodiamond transformation

Scientific reports, Oct 12, 2016

Nanodiamonds are the subject of active research for their potential applications in nano-magnetom... more Nanodiamonds are the subject of active research for their potential applications in nano-magnetometry, quantum optics, bioimaging and water cleaning processes. Here, we present a novel thermodynamic model that describes a graphite-liquid-diamond route for the synthesis of nanodiamonds. Its robustness is proved via the production of nanodiamonds powders at room-temperature and standard atmospheric pressure by pulsed laser ablation of pyrolytic graphite in water. The aqueous environment provides a confinement mechanism that promotes diamond nucleation and growth, and a biologically compatible medium for suspension of nanodiamonds. Moreover, we introduce a facile physico-chemical method that does not require harsh chemical or temperature conditions to remove the graphitic byproducts of the laser ablation process. A full characterization of the nanodiamonds by electron and Raman spectroscopies is reported. Our model is also corroborated by comparison with experimental data from the lite...

Towards the Development of a Z-Scheme FeOx/g-C3N4 Thin Film and Perspectives for Ciprofloxacin Visible Light-Driven Photocatalytic Degradation

Applied Sciences, Sep 21, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more

Physical vapor deposition of mixed-metal oxides based on Fe, Co and Ni as water oxidation catalysts

Materials Science in Semiconductor Processing, 2016

Abstract Physical vapor deposition (PVD) techniques are proposed as high performing and easily tu... more Abstract Physical vapor deposition (PVD) techniques are proposed as high performing and easily tunable methods to synthesize mixed-metal oxides thin films as water oxidation catalysts (WOC). These techniques allow us to have a good control on the catalyst film surface morphology and crystallinity, with good adhesion of the catalysts on electrodes. Pure and binary metal oxides thin films based on Fe, Co and Ni were synthesized using electron beam deposition (EBD). WOC films are systematically studied through SEM microscopy, Raman spectroscopy and XPS analysis. Electrochemical characterization has been carried out to investigate the relevance of synergistic effects towards the water oxidation reaction. Among all the mixed oxides Ni–Fe oxide showed the best catalytic results.

A combined in operando approach for low-energy Scanning Transmission Electron Microscopy and Grazing Incident Small Angle X-ray Scattering

Probing the evolution of electronic, structural, and chemical properties of nanostructured materi... more Probing the evolution of electronic, structural, and chemical properties of nanostructured materials under reaction conditions is a crucial issue to determine their structure-functionality relationships. A relevant example is represented by heterogeneous catalysts, whose properties change dramatically with respect to the environment. Much of effort has been made lately in designing new solutions and technologies, or modifying the existing ones for purpose of operando conditions analysis. The use of micro- or nanoreactors, is a second approach, where ultrathin membranes can efficiently separate the high-pressure volume from the (ultra)high vacuum of the characterization chamber. Very recently, microreactor cells have been developed to integrate the capabilities of ensemble-averaging synchrotron techniques with local probe ones, as TEM to analyze the same catalytic process with different instruments. Despite the great power of this method, the extremely small probing size of TEMs rest...

Origin of a Simultaneous Suppression of Thermal Conductivity and Increase of Electrical Conductivity and Seebeck Coefficient in Disordered Cubic Cu 2 ZnSnS 4

Physical Review Applied, 2020

The parameters governing the thermoelectric efficiency of a material, Seebeck coefficient, electr... more The parameters governing the thermoelectric efficiency of a material, Seebeck coefficient, electrical, and thermal conductivities, are correlated and their reciprocal interdependence typically prevents a simultaneous optimization. Here, we present the case of disordered cubic kesterite Cu 2 ZnSnS 4 , a phase stabilized by structural disorder at low temperature. With respect to the ordered form, the introduction of disorder improves the three thermoelectric parameters at the same time. The origin of this peculiar behavior lies in the localization of some Sn lone pair electrons, leading to "rattling" Sn ions. On one hand, these rattlers remarkably suppress thermal conductivity, dissipating lattice energy via optical phonons located below 1.5 THz; on the other, they form electron-deficient Sn-S bonds leading to a p-type dopinglike effect and highly localized acceptor levels, simultaneously enhancing electrical conductivity and the Seebeck coefficient. This phenomenon leads to a 3 times reduced thermal conductivity and doubling of both electrical conductivity and the Seebeck coefficient, resulting in a more than 20 times increase in figure of merit, although still moderate in absolute terms.

Catching the Reversible Formation and Reactivity of Surface Defective Sites in Metal–Organic Frameworks: An Operando Ambient Pressure-NEXAFS Investigation

The Journal of Physical Chemistry Letters, 2021

In this work, we apply for the first time ambient pressure operando soft X-ray absorption spectro... more In this work, we apply for the first time ambient pressure operando soft X-ray absorption spectroscopy (XAS) to investigate the location, structural properties, and reactivity of the defective sites present in the prototypical metal-organic framework HKUST-1. We obtained direct evidence that Cu+ defective sites form upon temperature treatment of the powdered form of HKUST-1 at 160 °C and that they are largely distributed on the material surface. Further, a thorough structural characterization of the Cu+/Cu2+ dimeric complexes arising from the temperature-induced dehydration/decarboxylation of the pristine Cu2+/Cu2+ paddlewheel units is reported. In addition to characterizing the surface defects, we demonstrate that CO2 may be reversibly adsorbed and desorbed from the surface defective Cu+/Cu2+ sites. These findings show that ambient pressure soft-XAS, combined with state-of-the-art theoretical calculations, allowed us to shed light on the mechanism involving the decarboxylation of the paddlewheel units on the surface to yield Cu+/Cu2+ complexes and their reversible restoration upon exposure to gaseous CO2.

Transition‐Metal Dichalcogenide NiTe 2 : An Ambient‐Stable Material for Catalysis and Nanoelectronics

Advanced Functional Materials, 2020

By means of theory and experiments, the application capability of nickel ditelluride (NiTe2) tran... more By means of theory and experiments, the application capability of nickel ditelluride (NiTe2) transition‐metal dichalcogenide in catalysis and nanoelectronics is assessed. The Te surface termination forms a TeO2 skin in an oxygen environment. In ambient atmosphere, passivation is achieved in less than 30 min with the TeO2 skin having a thickness of about 7 Å. NiTe2 shows outstanding tolerance to CO exposure and stability in water environment, with subsequent good performance in both hydrogen and oxygen evolution reactions. NiTe2‐based devices consistently demonstrate superb ambient stability over a timescale as long as one month. Specifically, NiTe2 has been implemented in a device that exhibits both superior performance and environmental stability at frequencies above 40 GHz, with possible applications as a receiver beyond the cutoff frequency of a nanotransistor.

An integrated ultra-high vacuum apparatus for growth and in situ characterization of complex materials

Review of Scientific Instruments, 2020

Here, we present an integrated ultra-high vacuum apparatus-named MBE-Cluster-dedicated to the gro... more Here, we present an integrated ultra-high vacuum apparatus-named MBE-Cluster-dedicated to the growth and in situ structural, spectroscopic, and magnetic characterization of complex materials. Molecular Beam Epitaxy (MBE) growth of metal oxides, e.g., manganites, and deposition of the patterned metallic layers can be fabricated and in situ characterized by reflection high-energy electron diffraction, lowenergy electron diffraction, Auger electron spectroscopy, x-ray photoemission spectroscopy, and azimuthal longitudinal magneto-optic Kerr effect. The temperature can be controlled in the range from 5 K to 580 K, with the possibility of application of magnetic fields H up to ±7 kOe and electric fields E for voltages up to ±500 V. The MBE-Cluster operates for in-house research as well as user facility in combination with the APE beamlines at Sincrotrone-Trieste and the high harmonic generator facility for time-resolved spectroscopy.

Understanding SolidGas Reaction Mechanisms by Operando Soft XRay Absorption Spectroscopy at Ambient Pressure

Catalytic activity of PtSn4: Insights from surface-science spectroscopies

Applied Surface Science, 2020

Abstract Bulk PtSn4 has recently attracted the interest of the scientific community for the prese... more Abstract Bulk PtSn4 has recently attracted the interest of the scientific community for the presence of electronic states exhibiting Dirac node arcs, enabling possible applications in nanoelectronics. Here, by means of surface-science experiments and density functional theory, we assess its suitability for catalysis by studying the chemical reactivity of the (0 1 0)-oriented PtSn4 surface toward CO, H2O, O2 molecules at room temperature and, moreover, its stability in air. We demonstrate that the catalytic activity of PtSn4 is determined by the composition of the outermost atomic layer. Specifically, we find that the surface termination for PtSn4 crystals cleaved in vacuum is an atomic Sn layer, which is totally free from any CO poisoning. In oxygen-rich environment, as well as in ambient atmosphere, the surface termination is a SnOx skin including SnO and SnO2 in comparable amount. However, valence-band states, including those forming Dirac node arcs, are only slightly affected by surface modifications. The astonishingly beneficial influence of surface oxidation on catalytic activity has been demonstrated by electrocatalytic tests evidencing a reduction of the Tafel slope, from 442 down to 86 mV dec−1, whose origin has been explained by our theoretical model. The use of surface-science tools to tune the chemical reactivity of PtSn4 opens the way toward its effective use in catalysis, especially for hydrogen evolution reaction and oxygen evolution reaction.

Efficient hydrogen evolution reaction with platinum stannide PtSn4via surface oxidation

Journal of Materials Chemistry A, 2020

The outstanding performance of PtSn4 in HER is related to the presence of a sub-nanometric tin-ox... more

PdTe 2 Transition‐Metal Dichalcogenide: Chemical Reactivity, Thermal Stability, and Device Implementation

Advanced Functional Materials, 2019

Study of Gaseous Interactions on Co3O4 Thin Film Coatings by Ambient Pressure Soft X-ray Absorption Spectroscopy

The Journal of Physical Chemistry C, 2019

The redox process of pretreated Co3O4 thin film coatings has been studied by ambient pressure sof... more The redox process of pretreated Co3O4 thin film coatings has been studied by ambient pressure soft X-ray absorption spectroscopy. The Co3O4 coatings were composed of nanoparticles of about 10 nm in size as prepared by pulsed laser deposition. The thin film coatings were pretreated in He or in H2 up to 150 °C prior to exposure to the reactive gases. The reactivity toward carbon monoxide and oxygen was monitored by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy during gas exposures. The results indicate that the samples pretreated in He show reactivity only at high temperature, while the samples pretreated in H2 are reactive also at room temperature. X-ray photoemission spectroscopy measurements in ultra-high vacuum and NEXAFS simulations with the CTM4XAS code further specify the results.

Surface Reconstruction, Oxidation Mechanism, and Stability of Cd 3 As 2

Advanced Functional Materials, 2019

2017 ! ! There are many ideas as to how spiritual formation happens in midadolescents. Traditiona... more 2017 ! ! There are many ideas as to how spiritual formation happens in midadolescents. Traditionally, most discipleship programs encourage midadolescents to grow in their faith by participating in youth programs, to read their Bibles, and to pray. This project demonstrates that the church is God's worshipping community on earth and has been ordained since the beginning of time to be such. While a personal relationship with God is important, so is participation in the family life of the church. The church over the last few decades has placed all the responsibility of spiritual growth on the shoulders of believers. Faith has become exclusively about a personal relationship with God that is grown through personal devotion to God. Church has then become a place to go to service one's faith. It has become a collection of individuals who share a common interest but no true need for one another. This mentality has led to the atomization of church ministries. A church's various ministries, including those focusing on youth, children, women, and young adults, for example, have very little connection with one another. A sense of responsibility for one another as brothers and sisters in Christ needs to be recovered in the local church. If believers want to fully grow in their faith, they need to be present where Christ is, and Christ is found in the church. Over and over again the church is referred to as the family of faith. Christians are called "children of God," the "family of faith," "adopted," and Paul's favorite term, "brothers and sisters." Midadolescents need a family of faith for their spiritual formation. They need older siblings who mentor and care for them as younger siblings. When the church lives into its ontology, it creates the best environment for the spiritual formation of midadolescents.

Interaction of VSe 2 with Ambient Gases: Stability and Chemical Reactivity

physica status solidi (RRL) – Rapid Research Letters, 2019

Pulsed laser deposition of CoFe2O4/CoO hierarchical-type nanostructured heterojuction forming a Z-scheme for efficient spatial separation of photoinduced electron-hole pairs and highly active surface area

Applied Surface Science, 2019

Surface Instability and Chemical Reactivity of ZrSiS and ZrSiSe Nodal-Line Semimetals

Advanced Functional Materials, 2019

Control of composition and grain growth in Cu2ZnSnS4 thin films from nanoparticle inks

Thin Solid Films, 2019

Abstract Cu2ZnSnS4 (CZTS) nanocrystals (NCs) were produced via hot-injection from metal chloride ... more Abstract Cu2ZnSnS4 (CZTS) nanocrystals (NCs) were produced via hot-injection from metal chloride precursors. A systematic investigation of the influence of synthesis conditions on composition, size and microstructure of CZTS NCs is presented. The results show that the solvent amount (oleylamine) is a key parameter in the synthesis of this quaternary chalcogenide: a low solvent content leads to CZTS NCs with a prominent kesterite phase with the desired composition for use as absorber material in thin film photovoltaic cells. It is also observed that lowering the injection temperature (250 °C) favours formation of CZTS NCs in the wurtzite phase. The effect of different high temperature thermal treatments on the grain growth is also shown: large crystals are obtained with annealing in inert atmosphere, whereas nanocrystalline films are obtained introducing sulphur vapour during the heat treatment. A correlation between the grain dimension and the carbonaceous residues in the final films is investigated. It is shown that the grain growth is hindered by organic residues, amount and nature of which depend on the heat treatment atmosphere. In fact, oleylamine is removed by a complex pyrolytic process, which is affected by the presence of sulphur vapour. The latter favours the stability of oleylamine residuals against its non-oxidative release.