There is increasing interest in capturing H2 generated from renewables with CO2 to produce methanol. However, renewable hydrogen production is expensive and in limited quantity compared to CO2. ...Excess CO2 and limited H2 in the feedstock gas is not favorable for CO2 hydrogenation to methanol, causing low activity and poor methanol selectivity. Now, a class of Rh‐In catalysts with optimal adsorption properties to the intermediates of methanol production is presented. The Rh‐In catalyst can effectively catalyze methanol synthesis but inhibit the reverse water‐gas shift reaction under H2‐deficient gas flow and shows the best competitive methanol productivity under industrially applicable conditions in comparison with reported values. This work demonstrates a strong potential of Rh‐In bimetallic composition, from which a convenient methanol synthesis based on flexible feedstock compositions (such as H2/CO2 from biomass derivatives) with lower energy cost can be established.
The bimetallic Rh‐In catalyst offers selective sites for capturing hydrogen and CO2 to approach methanol formation under H2‐deficient feedstock compositions with high methanol yield but minimizing the reverse water‐gas shift reaction. Using this catalyst, a convenient methanol synthesis based on renewable biomass‐derived feedstocks with lower energy costs can be established.
Extremely efficient sky‐blue organic electroluminescence with external quantum efficiency of ≈37% is achieved in a conventional planar device structure, using a highly efficient thermally activated ...delayed fluorescence emitter based on the spiroacridine–triazine hybrid and simultaneously possessing nearly unitary (100%) photoluminescence quantum yield, excellent thermal stability, and strongly horizontally oriented emitting dipoles (with a horizontal dipole ratio of 83%).
Fluorescent Cd metal–organic frameworks (MOFs), Cd2(dicarboxylate)2(NI‐bpy‐44)2 (dicarboxylate=benzene‐1,4‐dicarboxylate (1,4‐bdc, 1), 2‐bromobenzene‐1,4‐dicarboxylate (Br‐1,4‐bdc, 2), ...2‐nitrobenzene‐1,4‐dicarboxylate (NO2‐1,4‐bdc, 3), biphenyl‐4,4′‐dicarboxylate (bpdc, 4); NI‐bpy‐44=N‐(pyridin‐4‐yl)‐4‐(pyridin‐4‐yl)‐1,8‐naphthalimide)), featuring non‐ and twofold interpenetrating pcu‐type bipillared‐layer open structures with sufficient free voids of 58.4, 51.4, 51.5, and 41.4 %, respectively, have been hydro(solvo)thermally synthesized. MOFs 1–4 emitted solid‐state blue or cyan fluorescence emissions at 447±7 nm, which mainly arose from NI‐bpy‐44 and are dependent on the incorporated solvents. After immersing the crystalline samples in different solvents, that is, H2O and DMSO (1 and 2) as well as nitrobenzene and phenol (1–4), they exhibited a remarkable fluorescence quenching effect, whereas o‐xylene and p‐xylene (4) caused significant fluorescence enhancement. The sensing ability of MOFs 1–4 toward nitro compounds carried out in the vapor phase showed that nitrobenzene and 2‐nitrophenol displayed detectable fluorescence quenching with 1, 2, and 4 whereas 4‐nitrotoluene was an effective fluorescence quencher for 1 and 2; this is most likely attributed to their electron‐deficient properties and higher vapor pressures. Moreover, MOFs 1–4 are highly reusable for quick capture of volatile iodine, as supported by clear crystal color change and also by immense fluorescence quenching responses owing to the donor–acceptor interaction. Low‐pressure CO2 adsorption isotherms indicate that activated materials 1′–4′ are inefficient at taking up CO2.
Cube root: The synthesis and crystal structures of four fluorescent Cd metal–organic frameworks (MOFs), Cd2(dicarboxylate)2(NI‐bpy‐44)2 (dicarboxylate=benzene‐1,4‐dicarboxylate (1,4‐bdc, 1), 2‐bromobenzene‐1,4‐dicarboxylate (Br‐1,4‐bdc, 2), 2‐nitrobenzene‐1,4‐dicarboxylate (NO2‐1,4‐bdc, 3), biphenyl‐4,4′‐dicarboxylate (bpdc, 4); NI‐bpy‐44=N‐(pyridin‐4‐yl)‐4‐(pyridin‐4‐yl)‐1,8‐naphthalimide), featuring a pcu‐type bipillared‐layer open framework, and their potential for sensing small organic molecules and iodine capture are reported.
Summary
This study aimed to examine how different forms (still pictures vs. animations) of seductive illustrations impact text‐and‐graphic learning processes, perceptions, and outcomes. An ...eye‐tracking experiment of three groups (static, dynamic, and control) was conducted with 60 college and graduate students while learning with PowerPoint slides about infant motor development milestones. Prior knowledge, learning performance, learning perception, and visual attention were assessed by achievement tests, self‐rated scales, and eye‐tracking measures. Analysis of variance and t test results showed that, under a low task‐load condition, no seductive details effect was found for learning achievement but was found for learning process and perception. Decreased attention was found in the relevant pictures in both experimental groups. With more deeply and intensively processing on the seductive animations, the dynamic group perceived more distractions than the static group. Lag sequential analysis results revealed different visual transitional patterns for the groups, providing deep understandings about the process of seductive details effects.
Through a dual‐ligand synthetic approach, five isoreticular primitive cubic (pcu)‐type pillared‐layer metal–organic frameworks (MOFs), Zn2(dicarboxylate)2(NI‐bpy‐44)⋅x DMF⋅y H2O, in which ...dicarboxylate=1,4‐bdc (1), Br‐1,4‐bdc (2), NH2‐1,4‐bdc (3), 2,6‐ndc (4), and bpdc (5), have been engineered. MOFs 1–5 feature twofold degrees of interpenetration and have open pores of 27.0, 33.6, 36.8, 52.5, and 62.1 %, respectively. Nitrogen adsorption isotherms of activated MOFs 1′–5′ at 77 K all displayed type I adsorption behavior, suggesting their microporous nature. Although 1′ and 3′–5′ exhibited type I adsorption isotherms of CO2 at 195 K, MOF 2′ showed a two‐step gate‐opening sorption isotherm of CO2. Furthermore, MOF 3′ also had a significant influence of amine functions on CO2 uptake at high temperature due to the CO2–framework interactions. MOFs 1–5 revealed solvent‐dependent fluorescence properties; their strong blue‐light emissions in aqueous suspensions were efficiently quenched by trace amounts of nitrobenzene (NB), with limits of detection of 4.54, 5.73, 1.88, 2.30, and 2.26 μm, respectively, and Stern–Volmer quenching constants (Ksv) of 2.93×103, 1.79×103, 3.78×103, 4.04×103, and 3.21×103 m−1, respectively. Of particular note, the NB‐included framework, NB@3, provided direct evidence of the binding sites, which showed strong host–guest π–π and hydrogen‐bonding interactions beneficial for donor–acceptor electron transfer and resulting in fluorescence quenching.
Space for guests: Five isoreticular luminescent pillared‐layer metal–organic frameworks showing CO2 uptake and the sensitive detection of nitrobenzene (NB) in aqueous solution are engineered. The NB‐included framework provides direct evidence for framework–NB interactions.
Molecular lanthanide phosphonates Ln2(H3tpmm)2(H2O)6 ⋅ xH2O (Ln=Eu, EuP; Ln=Tb, TbP) were synthesized. Single‐crystal X‐ray diffraction confirmed that EuP has a sandwich‐like dinuclear structure, in ...which the Eu(III) center adopts a {EuO8} distorted dodecahedral geometry. XRPD patterns prove that TbP and EuP are isomorphous and isostructural. EuP and TbP are highly thermally stable approaching 450 °C and exhibit red‐ and green‐light emissions from the characteristic 4 f–4 f transition of the Eu3+ and Tb3+, respectively. Interestingly, luminescence modulation is achieved for the chemically mixed Eu/Tb phosphonate analogues, c‐EuxTb2–xP (x=1.5, 1, 0.5), and physically mixed Eu/Tb phosphonate materials, p‐yEuP : zTbP (y : z=3 : 1, 1 : 1, 1 : 3), with varying the excitation wavelength. Of particular note, near‐white‐light emission is also achieved for c‐EuTbP, p‐EuP : TbP, and p‐EuP : 3TbP when excited at 365 nm. Therefore, these dinuclear molecular lanthanide phosphonates emitting excitation wavelength and Eu3+ : Tb3+ ratio dependent luminescence might be potential candidates for color‐tunable luminescence materials and white‐light‐emitting materials. On the other hand, the bright green‐light emission makes TbP to be an excellent reusable luminescence sensor for selective detection of Fe3+ with Stern‐Volmer quenching constant (KSV) of 9.66×103 M−1 and detection limit (DL) of 0.42 μM through absorption competition caused luminescence quenching effect.
Color‐tunable luminescence materials: Homonuclear EuP and TbP as well as chemically and physically mixed Eu/Tb phosphonates exhibit color‐tunable luminescence even near white‐light emission, among which TbP is further used for Fe3+ detection.
Online information problem solving (OIPS) is essential for 21st century information literacy which often requires information selection competencies. However, students usually have problems in ...discriminating information from complex web sources. This study, utilizing eye-tracking technology, aims to examine the relationships among learners' visual search patterns, information anxiety and OIPS task performance in web search contexts. In this study, 46 university students volunteered to participate in a web search task for solving a landslide problem. Student’ visual behaviors were recorded by eye-trackers during the task and information anxiety was self-reported immediately after the task. Reaction time and task performance were also recorded and scored. Pearson's correlation analyses, multiple regression analyses, cluster analyses and lag sequential analyses (LSA) were conducted. The results show that learners' eye-tracking measures, information anxiety, and task performances are significantly correlated in OIPS. Students' visual attention paid onto irrelevant web information can significantly and positively predicts their information anxiety, but negatively predicts their task performance. Additionally, based on eye-tracking measures and reaction time, three visual search patterns are identified: Confused, Slow-thinking and Fast-thinking. The LSA results further show that different information selection and attentional control strategies are utilized by different groups, especially when discriminating the relevancy of web information. This study bridges the associations among eye-tracking measures, information anxiety and task performances in OIPS contexts. Future studies are suggested to analyze eye-tracking data using cluster analyses plus LSAs to profile online learners' characteristics in terms of visual search or information processing patterns.
•Eye-tracking data are analyzed using cluster analyses and lag sequential analyses.•Three visual search patterns are identified: Confused, Slow-thinking, Fast-thinking.•Ignoring irrelevant information is critical for online information problem solving.•Eye-tracking measures reflect information anxiety during online search.•Eye-tracking measures predict performance of online information problem solving.
The electrocatalytic nitrogen reduction reaction (NRR) provides a promising avenue for sustainable and decentralized green ammonia (NH3) synthesis. To promote the NRR, the design and synthesis of ...efficient electrocatalysts with an elucidated reaction mechanism is critically important. Here, surface hydrogenation‐facilitated NRR is demonstrated to yield NH3 at low overpotentials on oxygen‐deficient In2O3 plates decorated with single atom CdO5 that have a weak N2‐binding capability. Adsorbed *H is calculated to be first produced via the Volmer reaction (H2O + e− → *H + OH−) and then reacts with dissolved N2 to generate *N2H2, which is likely the rate determining step (RDS) of the whole process. Cd atoms and oxygen vacancies in In2O3 jointly enhance the activation of N2 and accelerate the RDS, boosting the NRR. An NH3 production rate of as high as 57.5 µg h−1 mgcat−1 is attained at a mild potential, which is retained to a large extent even after 44 h of continuous polarization.
Surface pre‐adsorbed hydrogen is found to facilitate N2 activation to yield NH3 on single atom CdO5 decorated In2O3 plates with oxygen vacancies that have weak N2‐binding strength. An NH3 production rate of up to 57.5 µg h−1 mgcat−1 is achieved at a mild overpotential, which is retained to a large extent even after 44 h of continuous electrolysis.
Two salicyaldimine ligands, HsalCl-3-py and HsalOMe-3-py, functionalized with the pyridyl group on the imine side and their Zn and Cu complexes with a general formula ML2, where M = Zn, ...L = salCl-3-py (1), salOMe-3-py (2); M = Cu, L = salCl-3-py (3), salOMe-3-py (4), have been synthesized and characterized by nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS), infrared (IR) spectroscopy, elemental analysis (EA), scanning electron microscope (SEM) and further by single-crystal X-ray diffraction analysis and X-ray powder diffraction (XRPD). The crystal structures of Zn– and Cu–salicyaldimine complexes exhibited that the M(II) center is coordinated by two N,O-chelated salicyaldimine ligands in a square-planar geometry, and two further pyridyl donating groups from two neighboring molecules at the axial positions, resulted in self-aggregation to form a two-dimensional (4,4)-sheet. Interestingly, apart from the strong M–N(pyridyl) coordination bond, the weak CH⋯N(pyridyl) hydrogen bonding interactions are simultaneously formed between the pyridyl N-donor and one pyridyl hydrogen of the equatorial salicyaldimine ligand. The electronic absorption spectra of the Zn– and Cu–salicyaldimine complexes in methanol solutions showed the appearance of a metal-to-ligand charge transfer absorption other than the intraligand charge transfer transitions after the complexation of azomethine (–CN–) with M(II) center. On the other hand, salicyaldimine ligands and Cu–salicyaldimine complexes showed no or weak fluorescence emissions. By contrast, Zn–salicyaldimine complexes emitted intense cyan and green light fluorescence in both solid-state and methanol solutions. Noteworthy, transmetallation of Zn–salicyaldimine complexes with Cu2+ ions would be achieved, producing corresponding Cu–salicyaldimine complexes. This implies the stronger binding ability of Cu2+ than that of Zn2+ to salicyaldimine ligands.
Transmetallation of fluorescent Zn–salicyaldimine complexes with Cu2+ ions yield corresponding non-fluorescent Cu analogues; all these Zn and Cu complexes show the simultaneous occurrence of both M–N(py) bond and CH⋯N(py) contact about a single pyridyl N-donor. Display omitted
•Zn/Cu–N coordination and CH⋯N contact are simultaneously formed about a single N-donor.•Discrete mononuclear molecules of complexes 1–4 form extended (4,4)-sheet in crystal phase.•Zn–salicyaldimine complexes 1 and 2 emit cyan and green light fluorescence, respectively.•Transmetallation of Zn–salicyaldimine complexes with Cu2+ ions is achieved.
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