The development of low-dimensional perovskite micro/nanostructures with high water stability for novel photonic/electronic applications is highly desirable. Herein, one-dimensional (1D) ...organic-inorganic hybrid perovskite micro-belts (AD)Pb
2
Cl
5
(OIHP-AD, AD = acridine) were facilely synthesized through fast precipitation in aqueous solution at room temperature without any organic solvent and expensive alkyl halide. Luminescent properties and water stability are efficiently enhanced due to the highly regular arrangement of the protonated AD dyes with larger steric hindrance distributed in the perovskite host-guest system, which can afford denser crystal packing to prevent water erosion. The OIHP-AD micro-belts present upconversion fluorescence, polarized photoemission and optical waveguide performances with a low loss coefficient (0.004 dB μm
−1
) during propagation, thus extending the applications of 1D perovskite micro/nanostructures to potential optical communication micro-devices.
The development of low-dimensional perovskite micro/nanostructures with high water stability for novel photonic/electronic applications is highly desirable.
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IJS, KILJ, NUK, UL, UM, UPUK
Embedding cubane M4(OH)4 (M=Ni, Co) clusters within the matrix of metal–organic frameworks (MOFs) is a strategy to develop materials with unprecedented synergistic properties. Herein, a new material ...type based on the pore‐space partition of the cubic primitive minimal‐surface net (MOF‐14‐type) has been realized. CTGU‐15 made from the Ni4(OH)4 cluster not only has very high BET surface area (3537 m2 g−1), but also exhibits bi‐microporous features with well‐defined micropores at 0.86 nm and 1.51 nm. Furthermore, CTGU‐15 is stable even under high pH (0.1 m KOH), making it well suited for methanol oxidation in basic medium. The optimal hybrid catalyst KB&CTGU‐15 (1:2) made from ketjen black (KB) and CTGU‐15 exhibits an outstanding performance with a high mass specific peak current of 527 mA mg−1 and excellent peak current density (29.8 mA cm−2) at low potential (0.6 V). The isostructural cobalt structure (CTGU‐16) has also been synthesized, further expanding the application potential of this material type.
Split pores: A new 3D microporous metal–organic framework containing cubane Ni4(OH)4 clusters can serve as an electrocatalyst for the methanol oxidation reaction (MOR). The optimal hybrid material shows impressive electrocatalytic performance including a high mass specific peak current of 527 mA mg−1 and excellent peak current density (29.8 mA cm−2) at a very low potential (0.6 V).
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract The current industrial ammonia synthesis relies on Haber–Bosch process that is initiated by the dissociative mechanism, in which the adsorbed N 2 dissociates directly, and thus is limited by ...Brønsted–Evans–Polanyi (BEP) relation. Here we propose a new strategy that an anchored Fe 3 cluster on the θ-Al 2 O 3 (010) surface as a heterogeneous catalyst for ammonia synthesis from first-principles theoretical study and microkinetic analysis. We have studied the whole catalytic mechanism for conversion of N 2 to NH 3 on Fe 3 /θ-Al 2 O 3 (010), and find that an associative mechanism, in which the adsorbed N 2 is first hydrogenated to NNH, dominates over the dissociative mechanism, which we attribute to the large spin polarization, low oxidation state of iron, and multi-step redox capability of Fe 3 cluster. The associative mechanism liberates the turnover frequency (TOF) for ammonia production from the limitation due to the BEP relation, and the calculated TOF on Fe 3 /θ-Al 2 O 3 (010) is comparable to Ru B5 site.
The formation of high‐nuclearity silver(I) clusters remains elusive and their potential applications are still underdeveloped. Herein, we firstly prepared a chain‐like thiolated AgI complex ...{Ag18(StBu)10(NO3)8(CH3CN)2(H2O)2 ⋅ Ag18(StBu)10(NO3)8(CH3CN)6}n (abbreviated as Ag18) in which two similar Ag18 clusters are assembled by NO3− anions. The solution containing Ag18 reacted with hydrogen sulfide with controlled concentration, promptly producing another identifiable and bright red‐emitting high‐nuclearity silver(I) cluster, Ag62(S)13(StBu)32(NO3)4 (abbreviated as Ag62). We tracked the transformation using time‐dependent electrospray ionization mass spectrometry (ESI‐MS), UV/Vis absorption and photoluminescence spectra. Based on this cluster transformation, we further developed an ultra‐sensitive turn‐on sensor detecting H2S gas with an ultrafast response time (30 s) at a low detection limit (0.13 ppm). This work opens a new way of understanding the growth of metal clusters and developing their luminescent sensing applications.
Two similar Ag18 clusters are assembled via NO3− anions to form a chain‐like thiolated AgI complex (abbreviated as Ag18). The solution containing Ag18 reacted with H2S with controlled concentration, promptly producing another identifiable and bright red‐emitting high‐nuclearity silver(I) cluster Ag62. Based on this cluster transformation, an ultra‐sensitive turn‐on sensor was developed to the detection of H2S gas with an ultrafast response time (30 s) at a low concentration (0.13 ppm).
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Methodological quality (risk of bias) assessment is an important step before study initiation usage. Therefore, accurately judging study type is the first priority, and the choosing proper tool is ...also important. In this review, we introduced methodological quality assessment tools for randomized controlled trial (including individual and cluster), animal study, non-randomized interventional studies (including follow-up study, controlled before-and-after study, before-after/ pre-post study, uncontrolled longitudinal study, interrupted time series study), cohort study, case-control study, cross-sectional study (including analytical and descriptive), observational case series and case reports, comparative effectiveness research, diagnostic study, health economic evaluation, prediction study (including predictor finding study, prediction model impact study, prognostic prediction model study), qualitative study, outcome measurement instruments (including patient - reported outcome measure development, content validity, structural validity, internal consistency, cross-cultural validity/ measurement invariance, reliability, measurement error, criterion validity, hypotheses testing for construct validity, and responsiveness), systematic review and meta-analysis, and clinical practice guideline. The readers of our review can distinguish the types of medical studies and choose appropriate tools. In one word, comprehensively mastering relevant knowledge and implementing more practices are basic requirements for correctly assessing the methodological quality.
Combining the advantages of homogeneous and heterogeneous catalysts, single‐atom catalysts (SACs) are bringing new opportunities to revolutionize ORR catalysis in terms of cost, activity and ...durability. However, the lack of high‐performance SACs as well as the fundamental understanding of their unique catalytic mechanisms call for serious advances in this field. Herein, for the first time, we develop an Ir‐N‐C single‐atom catalyst (Ir‐SAC) which mimics homogeneous iridium porphyrins for high‐efficiency ORR catalysis. In accordance with theoretical predictions, the as‐developed Ir‐SAC exhibits orders of magnitude higher ORR activity than iridium nanoparticles with a record‐high turnover frequency (TOF) of 24.3 e− site−1 s−1 at 0.85 V vs. RHE) and an impressive mass activity of 12.2 A mg−1Ir, which far outperforms the previously reported SACs and commercial Pt/C. Atomic structural characterizations and density functional theory calculations reveal that the high activity of Ir‐SAC is attributed to the moderate adsorption energy of reaction intermediates on the mononuclear iridium ion coordinated with four nitrogen atom sites.
Ir‐N‐C: Single‐atom catalysts (SACs) combine the advantages of homogeneous and heterogeneous catalysts. A single‐atom iridium catalyst coordinated with four nitrogen atoms has been designed and synthesized to mimic homogeneous iridium porphyrins for high‐efficiency oxygen reduction reaction catalysis.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A high loading of Mn(ii)-metalated porphyrin was achievable in a 2D porphyrin-based Mn-MOF induced by an ionic liquid. The excellent stability, sufficient redox potential, atomically dispersed ...porphyrin Mn(ii) sites, desired CO2 affinity, high visible light-harvesting and efficient charge separation, endow this MOF with the overall photocatalytic conversion of CO2 to CH4 in gas–solid conditions.
Energy storage challenges have triggered growing interest in various battery technologies and electrocatalysis. As a particularly promising variety, the Li–O2 battery with an extremely high energy ...density is of great significance, offering tremendous opportunities to improve cell performance via understanding catalytic mechanisms and the exploration of new materials. Furthermore, focus on nonaqueous electrolyte‐based Li–O2 batteries has markedly intensified since there could be a higher probability of commercialization, compared to that of solid‐state or aqueous electrolytes. The recent advancements of the nonaqueous Li–O2 battery in terms of fundamental understanding and material challenges, including electrolyte stability, water effect, and noncarbon cathode materials are summarized in this review. Further, the current status of water impact on discharge products, possible mechanisms, and parasitic reactions in nonaqueous electrolytes are reviewed for the first time. The key challenges of noncarbon oxygen electrode materials, such as noble metals and metal oxides‐based cathodes, transition metals, transition metal compounds (carbides, oxides) based cathodes as well as noncarbon supported catalysts are discussed. This review concludes with a perspective on future research directions for nonaqueous Li–O2 batteries.
Energy storage challenges have triggered growing interest in various battery technologies and electrocatalysis. As a particularly promising variety, the Li–O2 battery with an extremely high energy density is of great significance, offering tremendous opportunities to improve cell performance via understanding catalytic mechanisms and the exploration of new materials.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A water-stable cationic MOF could be used as a single crystal container to capture Cr(vi)-oxyanions via ion exchange with high capacity and selectivity. It is the first report that demonstrates that ...CrO42- ions could be traced and confirmed via a single-crystal to single-crystal (SC-SC) pattern.
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