Size-Dependent Appearance of Intrinsic O_<i>x</i>^<i>q</i> “Activated Oxygen” Molecules on Ceria Nanoparticles

Size-Dependent Appearance of Intrinsic O_<i>x</i>^<i>q</i> “Activated Oxygen” Molecules on Ceria Nanoparticle

Determining the Oxidation State of Small, Hydroxylated Metal-Oxide Nanoparticles with Infrared Absorption Spectroscopy

Metal-oxide nanoparticles (MONPs) are of broad interest as catalysts and catalyst supports in automotive, industrial, and biomedical applications. In water-containing environments, MONPs adsorb hydroxyl groups at nanoparticle corners, edges, and faces. While adsorbed surface groups will influence MONP properties, including oxidation state and the availability and accessibility of catalytically active sites, determination of the density, distribution, and effects of such groups is experimentally challenging. Here, focusing on CeO₂ nanoparticles (CNPs) as a representative MONP system, we report computational and experimental results showing that, for small, hydroxylated CNPs, the presence or absence of strongly infrared (IR) absorbing O–H stretching modes associated with O–H–OH complexes present on fully oxidized CNPs can be used to probe the configuration of surface-adsorbed hydroxyl groups and the CNP net oxidation state. As the vibrational modes of O–H–OH complexes are distinct from those of molecular water (3240 vs 3404 cm^–1), these results demonstrate that IR absorption spectroscopy can be used to determine the oxidation state of small, hydroxylated CNPs, as well as other MONPs, more generally, in water-containing environments

Band Gap Insensitivity to Large Chemical Pressures in Ternary Bismuth Iodides for Photovoltaic Applications

Ternary bismuth iodides (A₃Bi₂I₉, where A is a monovalent cation) have been recently suggested as less toxic alternatives to lead halide perovskites for photovoltaic applications. Using density functional theory based calculations, we predict that the band gap in these compounds is insensitive to chemical pressure applied by changing the size of A-site cations, which is confirmed experimentally. We further show that the band gap in A₃Bi₂I₉ compounds increases (or decreases) by stretching (or compressing) Bi₂I₉ bioctahedra, and the observed band gap insensitivity is a direct result of the counteractive interplay of three factors: the size of the A-site cations, the presence of H-bonds with organic A-site cations, and spin–orbit coupling (SOC) effects. Our study demonstrates that the layered structure of A₃Bi₂I₉ compounds intrinsically limits any significant modification of their band gap and highlights the need for three-dimensional connectivity of BiI₆ octahedra in order to achieve high efficiency Bi-based photovoltaics

The quantitative screening procedure.

The establishment of an evaluation indicator system that can accurately assess the sustainability of a supply chain while further enhancing its performance is vital and relevant. Based on the connotation of sustainable supply chains and triple bottom line theory, indicators are initially proposed from economic, environmental, and social dimensions. To increase the explanatory power of the indicator system and decrease information redundancy, the coefficient of variation is applied to identify the indicators with weak interpretation intensity, the ill-conditioned index cycle method is utilized to filter out indicators with redundant information, and data on 100 Chinese listed companies from 2019 to 2021 are used as samples. A performance evaluation indicator system of sustainable supply chains with 16 indicators is ultimately established. The information interpretation strength index and cumulative information contribution rate verify the rationality of the final indicator system. The outcome demonstrates that this screening method can strengthen the representativeness of the indicator system and rapidly reduce redundancy, leading to the better discrimination of the evaluation results. The findings of this study provide an indicator system and a methodological reference for both companies and policymakers and can aid in the transformation of supply chains toward sustainability.</div

Compositionally Induced Twin Defects Control the Shape of Ternary Silver Halide Nanocrystals

We demonstrate that the anion composition of ternary silver bromoiodide, AgBr_1–<i>x</i>I_<i>x</i>, nanocrystals determines their shape through the introduction of twin defects as the nanocrystals are made more iodide-rich. AgBr_1–<i>x</i>I_<i>x</i> nanocrystals grow as single-phase, solid solutions with the rock salt crystal structure for anions compositions ranging from 0 ≤ <i>x</i> < 0.38. With increasing iodide content, the morphology of the nanocrystals evolves from cubic to truncated cubic to hexagonal prismatic. Structural characterization indicates the cubic nanocrystals are bound by {100} facets, whereas the hexagonal platelet nanocrystals possess {111} facets as their top and bottom surfaces. Calculations based on first-principles density functional theory show that iodide substitution in AgBr stabilizes {111} surfaces and that twin defects parallel to these surfaces possess a low formation energy. Our experimental observations and calculations are consistent with a growth model in which the presence of multiple twin defects parallel to a {111} surface enhances lateral growth of the side facets and changes the nanocrystal shape. This new method to control nanoscale morphology based on anion composition provides a route to study structure–activity relationships in silver halide photocatalysts

The indicator system of sustainable supply chain performance evaluation.

The indicator system of sustainable supply chain performance evaluation.</p

Standardization of data.

The establishment of an evaluation indicator system that can accurately assess the sustainability of a supply chain while further enhancing its performance is vital and relevant. Based on the connotation of sustainable supply chains and triple bottom line theory, indicators are initially proposed from economic, environmental, and social dimensions. To increase the explanatory power of the indicator system and decrease information redundancy, the coefficient of variation is applied to identify the indicators with weak interpretation intensity, the ill-conditioned index cycle method is utilized to filter out indicators with redundant information, and data on 100 Chinese listed companies from 2019 to 2021 are used as samples. A performance evaluation indicator system of sustainable supply chains with 16 indicators is ultimately established. The information interpretation strength index and cumulative information contribution rate verify the rationality of the final indicator system. The outcome demonstrates that this screening method can strengthen the representativeness of the indicator system and rapidly reduce redundancy, leading to the better discrimination of the evaluation results. The findings of this study provide an indicator system and a methodological reference for both companies and policymakers and can aid in the transformation of supply chains toward sustainability.</div

Raw data of indicators.

The establishment of an evaluation indicator system that can accurately assess the sustainability of a supply chain while further enhancing its performance is vital and relevant. Based on the connotation of sustainable supply chains and triple bottom line theory, indicators are initially proposed from economic, environmental, and social dimensions. To increase the explanatory power of the indicator system and decrease information redundancy, the coefficient of variation is applied to identify the indicators with weak interpretation intensity, the ill-conditioned index cycle method is utilized to filter out indicators with redundant information, and data on 100 Chinese listed companies from 2019 to 2021 are used as samples. A performance evaluation indicator system of sustainable supply chains with 16 indicators is ultimately established. The information interpretation strength index and cumulative information contribution rate verify the rationality of the final indicator system. The outcome demonstrates that this screening method can strengthen the representativeness of the indicator system and rapidly reduce redundancy, leading to the better discrimination of the evaluation results. The findings of this study provide an indicator system and a methodological reference for both companies and policymakers and can aid in the transformation of supply chains toward sustainability.</div

The results of the first round of redundancy screening.

The results of the first round of redundancy screening.</p

The preliminary indicators of sustainable supply chain performance evaluation.

The preliminary indicators of sustainable supply chain performance evaluation.</p