Active Facets Research Articles

Enhanced charge collection and surface activity of a CuBi2O4 photocathode via crystal facet engineering

A crystal facet engineering approach was applied to prepare a rod-like CuBi2O4 photocathode dominated with the stable and active (002) facet to boost performance by enhancing the surface activity and improving the charge collection.

Simple Synthesis of Cuo Nanosheets with Exposed (111) Active Crystal Facets and Oxygen Defects for Co Detection at Room Temperature

Simple Synthesis of Cuo Nanosheets with Exposed (111) Active Crystal Facets and Oxygen Defects for Co Detection at Room Temperature

Hierarchically fractal Co with highly exposed active facets and directed electron-transfer effect.

Hierarchically fractal Co with highly exposed active (002) facets, possessing a higher work function and more moderate hydrogen adsorption free energy, has been synthesized via a template-free self-assembly method for the directed electron-transfer design of HER catalysts. It shows a great improvement in the HER activity in comparison with that of nanostructured Co.

Seed layer-free hydrothermal synthesis of porous tungsten trioxide nanoflake arrays for photoelectrochemical water splitting.

The simple preparation of efficient nano-photoanodes has been a key issue in the development of photoelectrochemical water splitting. In this work, a convenient and seed layer-free hydrothermal approach has been developed to synthesize vertically aligned porous WO3 nanoflakes on a fluorine-doped tin oxide conductive glass substrate. The morphology of WO3 nanoflakes could be manipulated by changing the annealing time, which further affected the performance of WO3 nanoflakes as photoanodes. Under optimum conditions, the obtained photoanode can lead to a high photocurrent density of 2.34 mA cm−2 at 1.4 V vs. Ag/AgCl under one sun irradiation (100 mW cm−2) and an incident photon to current conversion efficiency of 60% at 300 nm. The excellent photoelectrochemical performance can be mainly attributed to the larger active surface area, single crystal structure with an optimum thickness and the exposed highly active facets.

Realization of Transition Metal Selenide Active Facets Via Synergistic Sulfur Doping for Bifunctional Alkaline Water Splitting Applications: A Comparative Study

Realization of Transition Metal Selenide Active Facets Via Synergistic Sulfur Doping for Bifunctional Alkaline Water Splitting Applications: A Comparative Study

Cathodic corrosion of Au in aqueous methanolic alkali metal hydroxide electrolytes: Notable role of water

AbstractCathodic corrosion is an electrochemical process that induces restructuring, roughening, and etching of metal surfaces at a highly negative surface charge density, yet, details of the reaction mechanism are not fully resolved. An in‐depth fundamental understanding of the processes and parameters underlying cathodic corrosion is crucial for tailoring the surface structure of the metal electrodes and for synthesizing shape‐ and size‐controlled nanoparticles. Here, we investigate the relevance of water and hydrogen evolution in the cathodic corrosion process. To achieve this aim, Au electrodes were polarized at ‐1.6 V versus RHE in KOH and NaOH electrolytes prepared using different water + methanol mixtures. Structural changes of the Au surfaces were studied by cyclic voltammetry and monitored by scanning electron microscopy (SEM). Most importantly, cathodic corrosion does not take place in the absence of water. There is no detectable bubble formation due to the hydrogen evolution reaction on Au in purely methanolic alkali. Furthermore, the electrochemically active surface area, facet distribution, and surface morphology of Au electrodes are significantly altered upon cathodic polarization as a function of the water concentration. Cathodic corrosion features become more and more pronounced with a further increase in water content. In addition, substantial differences in the surface structure of Au are observed as a function of the nature and concentration of alkali metal cations. Overall, this study provides a more detailed understanding of the role of water and the hydrogen evolution reaction in dominating cathodic corrosion, which might advance the understanding of this phenomenon.

On and off the common ground: Japanese final particles as (un)grounding devices

The notion of “common ground” (Clark & Brennan 1991; Clark 1996) presupposes communication or conversation as “the basic setting for language use” (Clark 1996: 11). The serialisation of Japanese sentence-final particles is highly sensitive to the likelihood of the relevant utterance being part of the common ground. This paper reconsiders the conception of common ground and grounding processes, investigating monologic as well as conversational discourse. A case study of two modernist texts which contain internal monologue (interior monologue) illustrates how three facets of grounding activities (the establishment, confirmation, and cancellation of common ground) are tactfully realised by means of the final-particle marking of a distinction between monologic and conversational discourse. Our analysis reveals that Japanese final particles (specifically, -ne and -na(a)) play an essential role in encoding the speaker’s intention to ground or unground his/her utterance (i.e., to make the utterance on or off the common ground).

Self-generating CoFe2O4 as electric channel in Z-scheme CoO(111)/CoFe2O4/Fe2O3 photocatalyst for synchronous photocatalytic degradation and hydrogen production

Semiconductor photocatalysis is a promising technology in environmental protection and renewable energy production. In this work, a novel Z-scheme CoO(111)/CoFe2O4/Fe2O3 photocatalyst with a highly active surface is successfully synthesized via solid state reaction (SSR) method and then is used to realize the synchronous photocatalytic degradation of Rhodamine B and H2 production under sunlight irradiation. The as-prepared Z-scheme CoO(111)/CoFe2O4/Fe2O3 photocatalyst heated at 450 °C for 2.0 h displays an excellent photocatalytic activity. It can be attributed to the generation of adequate amount of CoFe2O4 between CoO(111) and Fe2O3, which can be regarded as an effective electric channel to accelerate the electron migration from conduction band of Fe2O3 to valence band of CoO. Furthermore, the agglomerated electrons on the exposed (111) active facet of CoO can reduce the H+ to generate hydrogen. Under the same conditions, within four periods the Z-scheme CoO(111)/CoFe2O4/Fe2O3 photocatalyst still shows the outstanding photocatalytic activity and extraordinary photo-stability. Moreover, a related mechanism on the synchronous photocatalytic degradation of Rhodamine B and H2 production under sunlight irradiation over the Z-scheme CoO(111)/CoFe2O4/Fe2O3 photocatalyst is presented. Perhaps, this present work can offer an idea for highly efficient hydrogen production utilizing organic pollutants.

Rationally engineered BiVO4 micro-leaves as a bifunctional photocatalyst for highly durable solar water treatment and water splitting

Recently, the use of monoclinic bismuth vanadate (BiVO4) as a visible light active catalyst has continued to increase, thus minimizing major issues such as fast recombination, poor carrier mobility, and sluggish oxidation kinetics has become an increasingly crucial issue. Accordingly, we report the fabrication of phase-engineered BiVO4 micro-leaves via the facile hydrothermal route and their utilization in solar-light-driven azo dye degradation and water splitting. Notably, low-temperature calcined BiVO4 micro-leaves exhibited a monoclinic–tetragonal isotype heterostructure crystal system with highly active (110) oxidative facets that significantly improved redox chemistry, whereas exposed (040) facets facilitated charge transport from monoclinic to tetragonal crystallites. Rationally phase-engineered and (110)/(040)-oriented BiVO4 micro-leaves (mt-BiVO4) presented efficient visible-light-assisted dye-degradation efficiencies (~94%) for water treatment with high durability. Moreover, the fabricated samples displayed dominant photochemical oxygen evolution rates of 1509.62 and 1214.04 μmol h–1 g–1 in an aqueous solution of FeCl3 and AgNO3, respectively. Our results suggest that synergistic effects of exposed reactive facets, dual-phase, and morphology engineering boosted the photocatalytic activity in BiVO4 and provided a promising approach for the development of a bifunctional photocatalyst in water treatment and water-splitting devices.

Urchin-like Nb2O5 hollow microspheres enabling efficient and selective photocatalytic C–C bond cleavage in lignin models under ambient conditions

Selective cleavage of robust C−C bonds to harvest value-added aromatic oxygenates is an intriguing but challenging task in lignin depolymerization. Photocatalysis is a promising technology with the advantages of mild reaction conditions and strong sustainability. Herein, we show a novel urchin-like Nb2O5 hollow microsphere (U-Nb2O5 HM), prepared by one-pot hydrothermal method, are highly active and selective for Cα−Cβ bond cleavage of lignin β-O-4 model compounds under mild conditions, achieving 94% substrate conversion and 96% C−C bond cleavage selectivity. Systematic experimental studies and density functional theory (DFT) calculations revealed that the superior performance of U-Nb2O5 HMs arises from more exposed active sites, more efficient free charge separation and the active (001) facet, which facilitates the activation of Cβ−H bond of lignin models and generate key Cβ radical intermediates by photogenerated holes, further inducing the Cα−Cβ bond cleavage to produce aromatic oxygenates. This work could provide some suggestions for the fabrication of hierarchical photocatalysts in the lignin depolymerization system.

High active crystalline {1 1 0} facets with high surface energy in Tin monoxide photocatalyst

The activity of SnO photocatalyst with different exposed facets has been investigated based on the micrometer-sized SnO single-crystals with two different shapes. Truncated bipyramid crystals with {101} exposed facets and diskette-shaped crystals exhibiting {100} and {110} planes have been synthesized by hydrothermal method with different reacting temperatures. We demonstrated higher photocatalytic performance of {110} facets of SnO compared to those of {100} and {101}, which is ascribed to the high surface energy of {110} facets. Our work suggests that the {110} facets are the high active facets of layered SnO, and this can guide the crystal facet engineering of this good semiconducting material.

Crystal Faces-Tailored Oxygen Vacancy in Au/CeO2 Catalysts for Efficient Oxidation of HMF to FDCA.

Developing an efficient catalyst to upgrade 5-hydroxymethylfurfural (HMF) to high-value-added downstream chemicals is of great significance in biomass conversion. Nanorod (110)-, nanocube (100)-, and nanooctaheron (111)-CeO2 -supported Au nanoparticles were prepared to investigate the intrinsic effect of CeO2 crystal faces on the oxidation of HMF to 2,5-furandicarboxylic acid (FDCA). The experimental results and density functional theory calculation revealed that the concentration of oxygen vacancy (VO ) for exposed specific crystal faces was crucial to the oxygen adsorption ability, and Au/nanorod-CeO2 with the highest VO concentration promoted the formation of more oxygen active species (superoxide radical) on CeO2 (110) crystal face than (100) and (111) crystal faces. Besides, the higher VO concentration could provide a strong adsorption ability of HMF, greatly boosting the activation of HMF. Thus, these results led to a superior catalytic activity for HMF oxidation over Au/nanorod-CeO2 (FDCA yield of 96.5 %). In-situ Fourier-transform (FT)IR spectroscopy uncovered the HMF oxidation pathway, and the possible catalytic mechanism was proposed. The deep insight into the role of regulation for crystal faces provides a basis for the rational design of highly active facets for the oxidation of HMF and related reactions.

Ammonia-induced (11[formula omitted]) facet exposure of δ-MnO2 with enhanced electrochemical reactivity for high-performance supercapacitor

Crystal facet engineering is an effective way to modulate the intrinsic physicochemical properties of metal oxide materials. It is crucial to improve the ratio and site density of active facet to enhance the pseudocapacitance of electrodes. In this work, we present a simple method by using ammonia as a structure-directing agent to increase the exposure ratio of (111‾) active plane, and thus enhance the electrochemical performance of δ-MnO2. XRD and TEM results demonstrated that the presence of ammonia during synthesis can promote the exposure of (111‾) facet. As expected, the specific capacitance (192.0 F/g at 0.5 A/g) is increased by 68% compared with that of (001) facet-dominated MnO2 without ammonia. Theoretical calculations shown that the (111‾) plane of δ-MnO2 has more advantages in terms of lower adsorption energy and smaller ion diffusion barrier than the (001) plane during the faradaic reactions. Moreover, the specific surface area of the materials is largely increased with the presence of ammonia. Thus, both the increased active sites and enhanced electrochemical reactivity of the (111‾) plane enable the excellent performance of as-prepared δ-MnO2. The current findings will offer more choices for the design of metal oxide electrodes with enhanced electrochemical reactivity based on crystal facet engineering.

The roles of Rh crystal phase and facet in syngas conversion to ethanol

Design of Rh catalyst by controlling crystal phase and facet is significant for providing higher mass-specific activity and selectivity for ethanol synthesis from syngas. We demonstrate here the roles of crystal phase and facet in syngas conversion to ethanol on different crystal facets of fcc and hcp Rh by DFT calculations and microkinetic modeling. Compared to hcp Rh, fcc Rh not only exhibits higher intrinsic activity for CH and ethanol formation, but also exposes much denser active facets and inhibits methanol, especially, the mainly exposed (111). Further, for the Fe-modified Rh catalysts, fcc Rh exhibits better activity and selectivity toward ethanol, which is still superior to hcp Rh. Thus, Rh-based catalysts should be focused on the fcc crystal phase instead of hcp crystal phase. The findings in this work are significantly beneficial to the rational design of Rh-based catalysts for CO hydrogenation to desired ethanol.

Increased decision latency in alcohol use disorder reflects altered resting-state synchrony in the anterior salience network

Increased decision latency in alcohol use disorder (AUD) has been generally explained in terms of psychomotor slowing. Recent results suggest that AUD patients’ slowed decision-making might rather reflect alterations in the neural circuitry underlying the engagement of controlled processing by salient stimuli. We addressed this hypothesis by testing a relationship between decision latency at the Cambridge Gambling Task (CGT) and intrinsic brain activity in 22 individuals with AUD and 19 matched controls. CGT deliberation time was related to two complementary facets of resting-state fMRI activity, i.e. coherence and intensity, representing early biomarkers of functional changes in the intrinsic brain architecture. For both metrics, we assessed a multiple regression (to test a relationship with deliberation time in the whole sample), and an interaction analysis (to test a significantly different relationship with decision latency across groups). AUD patients’ slowed deliberation time (p < 0.025) reflected distinct facets of altered intrinsic activity in the cingulate node of the anterior salience network previously associated with the “output” motor stage of response selection. Its heightened activity in AUD patients compared with controls, tracking choice latency (p < 0.025 corrected), might represent a compensation mechanism counterbalancing the concurrent decrease of its internal coherent activity (p < 0.025 corrected). These findings provide novel insights into the intrinsic neural mechanisms underlying increased decision latency in AUD, involving decreased temporal synchronicity in networks promoting executive control by behaviourally relevant stimuli. These results pave the way to further studies assessing more subtle facets of decision-making in AUD, and their possible changes with rehabilitative treatment.

Towards a Taxonomy of Trustworthy Digital Repository Impacts

AbstractMeasuring the societal impact of digital repositories is a wicked problem. To capture information about the impacts of digital repositories that become certified as Trustworthy Digital Repositories (TDRs), a taxonomy describing activities cited as evidence of compliance with TDR standards is needed to relate those activities to socially beneficial outcomes. This paper presents a Minimum Viable Prototype (MVP) for a TDR Impacts taxonomy to enable the expression of their activities in a structured way. Our MVP provides a proof‐of‐concept that by formalizing concepts about TDRs in a taxonomy, we can investigate ways to measure whether the impacts associated with becoming and remaining a certified TDR are also impacts that generate societal value. Implications of the work described include potential strategies to identify, extract, and/or author machine‐readable descriptions of measurable facets of TDR activities and the resulting impacts on communities.

Enhanced electrocatalytic activity in dye-sensitized solar cells via interface coupling of the CoFe2O4/Co3Fe7 heterostructure

The DSSC assembled with CoFe/CFO CE exhibits a higher power conversion efficiency (8.54%), which surpasses that of conventional Pt (7.70%). Such excellent performance can be ascribed to the unique interfacial structural optimization and intimate interface coupling synergies. The original core-shell layer enriches the active sites, and further structural integration improves the interface, increasing the conductivity while synergistically accelerating the catalytic activity. • Synthesis of CoFe 2 O 4 /Co 3 Fe 7 hybrids by hydrothermal and impregnation methods. • Structural integration and multi-component synergy maximize catalytic activity. • DSSC based on CoFe 2 O 4 /Co 3 Fe 7 CE exhibited higher PCE (8.54%) than Pt (7.70%). The exploitation of high-efficient yet non-precious counter electrode (CE) materials is of great significance for practical applications of dye-sensitized solar cells (DSSCs). Herein, Co 3 Fe 7 alloy anchored on the porous core-shell CoFe 2 O 4 composites (CoFe 2 O 4 /Co 3 Fe 7 ) were successfully manufactured as a counter electrode for DSSC. The detailed electrochemical measurements verified that the introduction of Co 3 Fe 7 alloys modifies the original core-shell structure, contributing to enhance electrical conductivity and promote interfacial electron transfer. While the porous structure increases the potential for exposing active sites and accelerates the diffusion of iodide ions. Moreover, the formation of hetero-junction facilitates the generation of active facet sharing and multi-component synergy, thus prominently boosting the reduction of triiodide and accelerating reaction kinetics. As a consequence, DSSCs structured with CoFe 2 O 4 /Co 3 Fe 7 -modified CEs achieve a satisfactory power conversion efficiency (PCE) of 8.54%, which surpasses that of conventional platinum (7.70%). Meanwhile, the stability of CoFe 2 O 4 /Co 3 Fe 7 CE is also enhanced than noble metals platinum. This work highlights that the heterogeneous CoFe 2 O 4 /Co 3 Fe 7 with a rich interface can effectively stimulate the catalytic activity of reducing triiodide to enhance the performance of the solar cell. This strategy also paves the way for enhancing material activity in the field of energy storage and conversion.

Évaluer les compétences des apprenants afin de les faire progresser

The evaluation of students’ achievement from grading to success and progress &#x0D; ABSTRACT: As an inherent component of the instructive-educational process, the evaluation evolved in time from the traditional approach that put the relationship of equity between evaluation-grading, until nowadays, when it covers multiple aspects. Through this research paper, we aim to emphasize the fact that evaluation is considered to be another facet of remedial activities, a process through which the teacher gathers information in order to correct any type of errors and make a final decision.&#x0D;

Developing A Strategic Halal Trade Performance Framework for Halal Food Import in Malaysia

The considerably increasing demand for trading across border have involved massive border operation activities, thus dragged the supply chain into complicated activities. Trade facilitation becomes significant as it brings successful international measures to eliminate unnecessary time and cost burden associated with border administrative operations. Four main principles, namely simplification, harmonization, standardization, and transparency form the foundations of trade facilitation. These principles are translated into specific operational objectives namely speed, dependability, quality, cost and flexibility to measure the principal goals. Concurrently, the rising number of Muslim populations has called for more research in the trading of halal food. Asia Pacific, being the home of 240 million Muslims also contributes to its importance. Specifically, halal food is becoming highly concerned issues that is not limited to its production, but also in larger trading activities among countries. This study aims to develop a strategic halal trade performance framework for halal food import operations. Based on 15 semi structured interviews with stakeholders of food import border clearance, this study found that regulation, policy, knowledge, experience, visibility, commitment, attitude, mentality, and consistency were significant operational determinants to strategic operational performance across every facet of the border clearance activities in the context of Halal trade across the Malaysian border.

Does individual coping mechanism build relational resilience among romantic partners? Understanding resilience in the age of COVID-19

ABSTRACT The COVID-19 pandemic has changed the narratives in many facets of human activities including romantic relationships. As such, this study sought to investigate if COVID-19 stress affects relational resilience among romantic partners. Using the relational resilience theory which has an interpersonal communication theory, we engaged 510 married individuals with self-administered survey questions that elicited information regarding their stress levels, depressive symptoms, anxiety, and coping processes with relational resilience. The study makes interesting and purposeful findings. Results show that COVID-19 stress was negatively significant to relational resilience. Findings also indicated that COVID-19 was positively associated with stress to depressive symptoms, anxiety, and coping process. Besides, the coping process was also significant but negatively associated with relational resilience. Also findings showed that depression, anxiety, and coping mediated the relationship between COVID-19 stress and relational resilience.