scholarly journals Dynamic transformation of cubic copper catalysts during CO2 electroreduction and its impact on catalytic selectivity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Philipp Grosse ◽  
Aram Yoon ◽  
Clara Rettenmaier ◽  
Antonia Herzog ◽  
See Wee Chee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Copper Catalysts ◽  
Underlying Structure ◽  
Structure Property ◽  
Product Analysis ◽  
Time Resolved ◽  
Catalytic Selectivity ◽  
Structure Property Relationships ◽  
Co2 Electroreduction ◽  
The Impact

AbstractTo rationally design effective and stable catalysts for energy conversion applications, we need to understand how they transform under reaction conditions and reveal their underlying structure-property relationships. This is especially important for catalysts used in the electroreduction of carbon dioxide where product selectivity is sensitive to catalyst structure. Here, we present real-time electrochemical liquid cell transmission electron microscopy studies showing the restructuring of copper(I) oxide cubes during reaction. Fragmentation of the solid cubes, re-deposition of new nanoparticles, catalyst detachment and catalyst aggregation are observed as a function of the applied potential and time. Using cubes with different initial sizes and loading, we further correlate this dynamic morphology with the catalytic selectivity through time-resolved scanning electron microscopy measurements and product analysis. These comparative studies reveal the impact of nanoparticle re-deposition and detachment on the catalyst reactivity, and how the increased surface metal loading created by re-deposited nanoparticles can lead to enhanced C2+ selectivity and stability.

Rational chemical doping of metal halide perovskites

2019 ◽  
Vol 48 (2) ◽  
pp. 517-539 ◽  
Author(s):  
Xinyuan Zhang ◽  
Lina Li ◽  
Zhihua Sun ◽  
Junhua Luo
Keyword(s):  
Metal Halide ◽  
Underlying Structure ◽  
Chemical Doping ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Halide Perovskites

This review summarizes recent significant work on metal-halide doped perovskites, disclosing the underlying structure–property relationships to provide useful insights into their applications.

scholarly journals Extensive Analysis of Structure-Property Relationships in Thin-Film Solar Cells Using Scanning Electron Microscopy in Combination with Focused Ion Beam

2013 ◽  
Vol 19 (S2) ◽  
pp. 1096-1097
Author(s):  
D. Abou-Ras ◽  
K. Tsyrulin ◽  
N. Schäfer ◽  
M. Nichterwitz ◽  
H. Kropf ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Thin Film Solar Cells ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Extensive Analysis ◽  
Scanning Electron

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

Investigating the impact of three-dimensional learning interventions on student understanding of structure–property relationships

2021 ◽  
Author(s):  
Sonia M. Underwood ◽  
Alex T. Kararo ◽  
Gabriela Gadia
Keyword(s):  
General Chemistry ◽  
Active Learning ◽  
Boiling Point ◽  
Three Dimensional ◽  
Intermolecular Forces ◽  
Control Group ◽  
Chemistry Curriculum ◽  
Structure Property ◽  
Structure Property Relationships ◽  
The Impact

The ability to predict macroscopic properties using a compound's chemical structure is an essential idea for chemistry as well as other disciplines such as biology. In this study we investigate how different levels of interventions impact the components of students’ explanations (claims, evidence, and reasoning) of structure–property relationships, particularly related to boiling point trends. These interventions, aligned with Three-Dimensional Learning (3DL), were investigated with four different cohorts of students: Cohort 1 – a control group of students enrolled in an active learning general chemistry course; Cohort 2 – students enrolled in the same active learning general chemistry course but given Intervention 1 (a 3DL worksheet administered during class time); Cohort 3 – students enrolled in the same active learning general chemistry course but given Intervention 1 and Intervention 2 (a 3DL course exam question administered after instruction); and Cohort 4 – a reference group of students enrolled in a transformed active learning general chemistry curriculum in which 3DL is an essential feature and includes Intervention 1 and Intervention 2 as part of the curriculum. We found that Cohort 2 students (with the 3DL worksheet intervention) were more likely than the control group (Cohort 1) to correctly predict the compound with a higher boiling point as well as incorporate ideas of strength of intermolecular forces into their explanations of boiling point differences. When a 3DL exam question was given as a follow up to the 3DL worksheet, students in Cohort 3 were more likely than Cohorts 1 and 2 to correctly identify the claim. Further comparison showed that Cohort 4 (transformed general chemistry curriculum) were more likely than Cohorts 1–3 to also include the ideas of energy needed to overcome stronger forces for a more sophisticated explanation (50% of Cohort 4 students compared to 17–33% for Cohorts 1–3). In addition, 80% of Cohort 4 students were able to construct a correct representation of hydrogen bonding as a non-covalent interaction compared to 13–57% for the other three cohorts.

scholarly journals Polymorph engineering of CuMO2 (M = Al, Ga, Sc, Y) semiconductors for solar energy applications: from delafossite to wurtzite

2015 ◽  
Vol 71 (6) ◽  
pp. 702-706 ◽  
Author(s):  
David O. Scanlon ◽  
Aron Walsh
Keyword(s):  
Band Gaps ◽  
Underlying Structure ◽  
Structure Property ◽  
Conducting Oxides ◽  
Energy Applications ◽  
Structure Property Relationships ◽  
Earth Abundant ◽  
Chalcopyrite Lattice ◽  
Group 3 ◽  
The Difference

The cuprous oxide based ternary delafossite semiconductors have been well studied in the context of p-type transparent conducting oxides. CuAlO2, CuGaO2 and CuInO2 represent a homologous series where the electronic properties can be tuned over a large range. The optical transparency of these materials has been associated with dipole forbidden transitions, which are related to the linear O—Cu—O coordination motif. The recent demonstration that these materials can be synthesized in tetrahedral structures (wurtzite analogues of the chalcopyrite lattice) opens up a new vista of applications. We investigate the underlying structure–property relationships (for Group 3 and 13 metals), from the perspective of first-principles materials modelling, towards developing earth-abundant photoactive metal oxides. All materials studied possess indirect fundamental band gaps ranging from 1 to 2 eV, which are smaller than their delafossite counterparts, although in all cases the difference between direct and indirect band gaps is less than 0.03 eV.

scholarly journals Synthesis and Physicochemical Evaluation of Bees’ Chitosan-Based Hydrogels Modified with Yellow Tea Extract

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3379
Author(s):  
Sonia Kudłacik-Kramarczyk ◽  
Anna Drabczyk ◽  
Magdalena Głąb ◽  
Paweł Gajda ◽  
Anna Jaromin ◽  
...  
Keyword(s):  
Contact Angles ◽  
Structure Property ◽  
Swelling Properties ◽  
Structure Property Relationships ◽  
Physicochemical Evaluation ◽  
Measurement Methodology ◽  
Ft Ir ◽  
Tea Extract ◽  
The Impact ◽  
Dressing Materials

The novelty of the research involves designing the measurement methodology aimed at determining the structure–property relationships in the chitosan-based hydrogels containing yellow tea extract. Performed investigations allowed us to determine the swelling properties of hydrogels in selected time intervals, evaluate the mutual interactions between the hydrogels and simulated physiological liquids via pH measurements and directly assess the impact of such interactions on the chemical structure of hydrogels using Fourier transform infrared (FT-IR) spectroscopy and their wettability by the measurements of the flatness of the drop on the surface of the tested samples via the static drop method. Next, the surface morphology of hydrogels was characterized by the Scanning Electron Miscorcopy (SEM) and their elasticity under the tension applied was also verified. It was proved that incubation in simulated physiological liquids resulted in a decrease in contact angles of hydrogels, even by 60%. This also caused their certain degradation which was reflected in lower intensities of bands on FT-IR spectra. Further, 23% v/v yellow tea extract in hydrogel matrices caused the decrease of their tensile strength. An increase in the amount of the crosslinker resulted in a decrease in the sorption capacity of hydrogels wherein their modification caused greater swelling ability. In general, the investigations performed provided much information on the tested materials which may be meaningful considering their application, e.g., as dressing materials.

scholarly journals On the Nature of Luminescence Thermochromism of Multinuclear Copper(I) Benzoate Complexes in the Crystalline State

Crystals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 36 ◽  
Author(s):  
Katarzyna Jarzembska ◽  
Michał Hapka ◽  
Radosław Kamiński ◽  
Wojciech Bury ◽  
Sylwia Kutniewska ◽  
...  
Keyword(s):  
Crystalline State ◽  
Crystal Packing ◽  
High Energy ◽  
Theoretical Modelling ◽  
Spectroscopic Techniques ◽  
Structure Property ◽  
Time Resolved ◽  
Structure Property Relationships ◽  
Phosphorescence At Room Temperature ◽  
Metal Charge Transfer

A model luminescent [(PhCO2)4Cu4] (Cu4) complex in the crystalline state was investigated via combined crystallographic and spectroscopic techniques contributed substantially by theoretical modelling. The complex appeared to exhibit luminescence thermochromism, i.e., red phosphorescence at room temperature which changes to green when lowering the temperature to 90 K. The low-energy emissive state was assigned as a cluster-centred triplet, 3CC. The emission from this state predicted in TDDFT (~635 nm) matches the experimental red band observed at 660–715 nm. In contrast, the nature of the high-energy “green” band was less straightforward. The next reached cluster-centred triplet excited state occurred to be energetically close to the experimental value of ~545 nm. The two excited states also exhibit significant metal-to-ligand and ligand-to-metal charge transfer characteristics, especially for solid-state distorted geometries. In both cases the cluster core was expected to become notably contracted when compared to the ground state. Time-resolved photocrystallographic results supported the computationally predicted core contraction upon excitation. Additionally, the differences between the spectroscopic behaviour of the related tetra- and hexanuclear copper(I) complexes, Cu4 and Cu6 (i.e., [(PhCO2)6Cu6]) in the crystalline state were discussed and examined. It appeared that crystal packing may constitute an important factor as far as the lack of luminescence thermochromism in the latter case is concerned. Synopsis: Structure–property relationships characterising a model luminescent [(PhCO2)4Cu4] (Cu4) complex in the crystalline state were investigated via combined crystallographic and spectroscopic techniques contributed by theoretical modelling, and compared with the properties of the related [(PhCO2)6Cu6] (Cu6) complex.

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