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HighlightsThe Bi2O3 nanoplates homogeneously decorated free-standing exfoliated graphene (Bi2O3/FEG) was prepared by a facile electrochemical deposition method.The Bi2O3/FEG first used as nitrogen reduction electrocatalyst exhibits excellent electrocatalysis performance and stability for nitrogen reduction reaction in neutral media.The superior electrocatalytic nitrogen reduction activity is attributed to the strong interaction of the Bi 6p band with the N 2p orbitals, binder-free nature of the electrodes, and facile electron transfer through the graphene nanosheets.Electrocatalytic nitrogen reduction reaction is a carbon-free and energy-saving strategy for efficient synthesis of ammonia under ambient conditions. Here, we report the synthesis of nanosized Bi2O3 particles grown on functionalized exfoliated graphene (Bi2O3/FEG) via a facile electrochemical deposition method. The obtained free-standing Bi2O3/FEG achieves a high Faradaic efficiency of 11.2% and a large NH3 yield of 4.21 ± 0.14 μgNH3 h−1 cm−2 at − 0.5 V versus reversible hydrogen electrode in 0.1 M Na2SO4, better than that in the strong acidic and basic media. Benefiting from its strong interaction of Bi 6p band with the N 2p orbitals, binder-free characteristic, and facile electron transfer, Bi2O3/FEG achieves superior catalytic performance and excellent long-term stability as compared with most of the previous reported catalysts. This study is significant to design low-cost, high-efficient Bi-based electrocatalysts for electrochemical ammonia synthesis.

Electrochemical reduction of CO2 to syngas (CO and H2) offers an efficient way to mitigate carbon emissions and store intermittent renewable energy in chemicals. Herein, the hierarchical one‐dimensional/three‐dimensional nitrogen‐doped porous carbon (1D/3D NPC) is prepared by carbonizing the composite of Zn‐MOF‐74 crystals in situ grown on a commercial melamine sponge (MS), for electrochemical CO2 reduction reaction (CO2RR). The 1D/3D NPC exhibits a high CO/H2 ratio (5.06) and CO yield (31 mmol g−1 h−1) at −0.55 V, which are 13.7 times and 21.4 times those of 1D porous carbon (derived from Zn‐MOF‐74) and N‐doped carbon (carbonized by MS), respectively. This is attributed to the unique spatial environment of 1D/3D NPC, which increases the adsorption capacity of CO2 and promotes electron transfer from the 3D N‐doped carbon framework to 1D carbon, improving the reaction kinetics of CO2RR. Experimental results and charge density difference plots indicate that the active site of CO2RR is the positively charged carbon atom adjacent to graphitic N on 1D carbon and the active site of HER is the pyridinic N on 1D carbon. The presence of pyridinic N and pyrrolic N reduces the number of electron transfer, decreasing the reaction kinetics and the activity of CO2RR. The CO/H2 ratio is related to the distribution of N species and the specific surface area, which are determined by the degree of spatial confinement effect. The CO/H2 ratios can be regulated by adjusting the carbonization temperature to adjust the degree of spatial confinement effect. Given the low cost of feedstock and easy strategy, 1D/3D NPC catalysts have great potential for industrial application. The hierarchical one‐dimensional/three‐dimensional nitrogen‐doped porous carbon (1D/3D NPC) was prepared by carbonizing the composite of Zn‐MOF‐74 crystals in situ grown on a commercial melamine sponge, for electrochemical CO2 reduction reaction (CO2RR). The 1D/3D NPC exhibits a high CO/H2 ratio (5.06) and CO yield (31 mmol g−1 h−1) at −0.55 V, which is 13.7 times and 21.4 times of 1D porous carbon (derived from Zn‐MOF‐74) and N‐doped carbon (carbonized by MS), respectively. This is attributed to the spatial confinement effect of 3D N‐doped carbon framework on 1D porous carbon, which significantly improves the reaction kinetics of CO2RR by increasing specific surface areas, CO2 adsorption, mass transport, and facilitating electron transfer from the 3D N‐doped carbon framework to 1D carbon.

HighlightsRecent advances in the metal–organic framework (MOF)-related catalysts for electrochemical ammonia synthesis protocols under ambient reaction conditions are summarized and discussed.The design and fabrication of efficient electrocatalysts from MOF for the reduction of N2 and NO3− are systematically analyzed.Based on the current advances, the ongoing challenges and promising perspectives are highlighted.Electrocatalytic synthesis under mild conditions has become increasingly important as one of the practical alternatives for industrial applications, especially for the green ammonia (NH3) industry. A properly engineered electrocatalyst plays a vital role in the realization of superior catalytic performance. Among various types of promising nanomaterials, metal–organic frameworks (MOFs) are competitive candidates for developing efficient electrocatalytic NH3 synthesis from simple nitrogen-containing molecules or ions, such as N2 and NO3−. In this review, recent advances in the development of electrocatalysts derived from MOFs for the electrosynthesis of NH3 are collected, categorized, and discussed, including their application in the N2 reduction reaction (NRR) and the NO3− reduction reaction (NO3RR). Firstly, the fundamental principles are illustrated, such as plausible mechanisms of NH3 generation from N2 and NO3−, the apparatus of corresponding electrocatalysis, parameters for evaluation of reaction efficiency, and detection methods of yielding NH3. Then, the electrocatalysts for NRR processes are discussed in detail, including pristine MOFs, MOF-hybrids, MOF-derived N-doped porous carbons, single atomic catalysts from pyrolysis of MOFs, and other MOF-related materials. Subsequently, MOF-related NO3RR processes are also listed and discussed. Finally, the existing challenges and prospects for the rational design and fabrication of electrocatalysts from MOFs for electrochemical NH3 synthesis are presented, such as the evolution of investigation methods with artificial intelligence, innovation in synthetic methods of MOF-related catalysts, advancement of characterization techniques, and extended electrocatalytic reactions.

Covalent organic frameworks (COFs) are newly developed crystalline substances that are garnering growing interest because of their ultra-high porosity, crystalline nature, and easy-modified architecture, showing promise in the field of photocatalysis. However, it is difficult for pure COFs materials to achieve excellent photocatalytic hydrogen production due to their severe carrier recombination problems. To mitigate this crucial issue, establishing heterojunction is deemed an effective approach. Nonetheless, many of the metal-containing materials that have been used to construct heterojunctions with COFs own a number of drawbacks, including small specific surface area and rare active sites (for inorganic semiconductor materials), wider bandgaps and higher preparation costs (for MOFs). Therefore, it is necessary to choose metal-free materials that are easy to prepare. Red phosphorus (RP), as a semiconductor material without metal components, with suitable bandgap, moderate redox potential, relatively minimal toxicity, is affordable and readily available. Herein, a range of RP/TpPa-1-COF (RP/TP1C) composites have been successfully prepared through solvothermal method. The two-dimensional structure of the two materials causes strong interactions between the materials, and the construction of heterojunctions effectively inhibits the recombination of photogenic charge carriers. As a consequence, the 9% RP/TP1C composite, with the optimal photocatalytic ability, achieves a photocatalytic H2 evolution rate of 6.93 mmol g−1 h−1, demonstrating a 10.19-fold increase compared to that of bare RP and a 4.08-fold improvement over that of pure TP1C. This article offers a novel and innovative method for the advancement of efficient COF-based photocatalysts. [Display omitted] •The RP/TP1C heterojunction is successfully constructed based on metal-free materials.•The RP/TP1C heterojunction exhibits outstanding solar-driven photocatalytic H2 production performance.•The RP/TP1C heterojunction is a two-dimensional photocatalytic system, displaying ultrahigh carrier separation efficiency.

Purpose In this era of global education reform, teacher professional learning (TPL) has emerged as a key factor in efforts to create sustainable school improvement. The same holds in Mainland China where ambitious curriculum reforms have been undertaken since 2000. The purpose of this paper is to examine the role of learning-centered leadership (LCL) and teacher trust (TT) in fostering TPL in Chinese schools. More specifically, the authors examined two research questions: (1) What is the nature of the relationship of LCL to TT and professional learning?; and (2) How LCL practices influence TT and professional learning. Design/methodology/approach The study employed a cross-sectional survey design. The authors collected survey data from 1,259 teachers in 41 primary and secondary schools in three different Chinese provinces. The research employed confirmatory factor analysis to confirm the measurement model and structural equation modeling to examine interactions among the three main variables. Findings The results affirmed a positive association between LCL and TPL, and highlighted TT as a significant mediator in this relationship. Additional analyses distinguished between the effects of different dimensions of LCL on TT and TPL. Although the results of these analyses were broadly consistent with prior findings reported in the literature, divergent findings also emerged. More specifically, there was a limited use and no significant impact of “leadership modeling” on either TT or professional learning. Research limitations/implications The authors suggest that this pattern of leadership practice is linked with features of China’s institutional cum socio-cultural context. The authors recommend the use of qualitative and mixed methods studies capable of gaining further insight into relationships. Practical implications These findings in Mainland China reaffirm the efficacy of school-level leadership that builds a safe, trusting but focussed environment for teacher learning in the workplace. This is a potentially significant finding in a society where the use of top-down directives and reliance on legitimate authority by leaders can rob teachers of the motivation and initiative that undergirds sustainable professional learning. The findings, in concert with those of other scholars, suggest that “building trust” represents a useful strategy for principals who seek to establish productive learning environments for their teachers. Originality/value The value of this study lies in two areas. First, this is one of a growing but still limited set of quantitative empirical studies of school leadership in Mainland China. Second, the study tests the nature of mediation in the relationship between leadership, trust and TPL, a topic of relatively recent vintage in the educational leadership literature.

Previous cross-sectional studies have indicated an association between the Body Roundness Index (BRI) and frailty. However, longitudinal evidence supporting this relationship remains scarce. Therefore, this study employs a longitudinal analysis to investigate the correlation between BRI and the risk of frailty in a Chinese population, and to evaluate the potential utility of BRI in the early identification and risk prediction of frailty. This study utilized data from the China Health and Retirement Longitudinal Study (CHARLS). A total of 4924 participants who completed follow-up from 2011 to 2018 were included. The BRI was calculated based on physical measurements and questionnaire data, and participants were categorized into quartiles according to BRI values. Multivariable-adjusted weighted regression models and trend tests were employed to examine the association between BRI and frailty. Furthermore, subgroup and sensitivity analyses were conducted to assess the robustness of the findings. After 7 years of follow-up, a total of 1242 participants (25.22%) developed frailty. The analysis revealed a positive association between the BRI and the risk of frailty (OR = 1.23, 95% CI: 1.15-1.33, p < 0.0001), with a significant increasing trend in frailty risk across ascending BRI quartiles (p for trend < 0.0001). Subgroup analyses and interaction tests indicated that the positive association between BRI and frailty risk remained consistent across various demographic, lifestyle, and clinical subpopulations (all p for interaction > 0.05). This study demonstrates that an elevated BRI is significantly associated with an increased risk of frailty. These findings suggest that while elevated BRI is an independent risk factor for frailty, its standalone predictive value is modest. It may serve as a supplementary indicator alongside other clinical assessments rather than an isolated diagnostic tool.

Background: Hypertrophy of the ligamentum flavum (HLF) is a common contributor to spinal stenosis which results in significant neurological impairments. Circular RNA (circRNA) circ_0003609 has been linked to HLF; however, the exact mechanism by which it causes this disease is unclear. Methods: Circ_0003609 expressions were regulated in HLF cells by overexpression vectors and RNA interference. Cell proliferation and fibrosis-related gene expression were checked by the Cell Counting Kit-8 (CCK-8) assay and western blotting. CircBank’s prediction of the association between miR-155 and circ_0003609 was supported by a dual-luciferase reporter experiment. The function of the miR-155/sirtuin 1 (SIRT1) axis in controlling HLF fibrosis was further examined. Results: Overexpression of circ_0003609 suppressed HLF cell propagation and fibrosis compared to its silencing. It was found that circ_0003609 served as the sponge for miR-155 and that the circ_0003609/miR-155 axis controlled the fibrosis of HLF cells. It was found that circ_0003609 acted as a sponge for miR-155, regulating the fibrosis of HLF cells. Further, miR-155 targets SIRT1, and the miR-155/SIRT1 axis promotes HLF cell fibrosis. Conclusion: Circ_0003609 ameliorates hypertrophied ligamentum flavum (LF) by modulating the miR-155/SIRT1 axis, indicating a potential treatment approach for HLF.

Front cover image: Electrocatalytic CO2 reduction to syngas (CO and H2) offers an efficient way to mitigate carbon emissions and store intermittent renewable energy in chemicals. However, it is tricky to produce an adjustable ratio of syngas due to the difficulty of maintaining a balance between CO2 reduction reaction (CO2RR) and the competing hydrogen evolution reaction (HER). In article number cey2.461, Zhang et al. prepare hierarchical one‐dimensional/three‐dimensional nitrogen‐doped porous carbon (1D/3D NPC) by carbonizing the composite of Zn‐MOF‐74 crystals in situ grown on a commercial melamine sponge (MS). Benefiting from the unique spatial environment of 1D/3D NPC, the reaction kinetics is significantly improved by increasing specific surface areas, CO2 adsorption, mass transport, and facilitating electron transfer from the 3D N‐doped carbon framework to 1D porous carbon. The bifunctional activity of N‐doped carbon materials for CO2RR and HER is beneficial for regulating the balance between CO2RR and HER. The carbonizing temperatures can affect the distribution of N species and further dominate syngas composition ratios.

Electrochemical reduction of CO 2 to syngas (CO and H 2 ) offers an efficient way to mitigate carbon emissions and store intermittent renewable energy in chemicals. Herein, the hierarchical one‐dimensional/three‐dimensional nitrogen‐doped porous carbon (1D/3D NPC) is prepared by carbonizing the composite of Zn‐MOF‐74 crystals in situ grown on a commercial melamine sponge (MS), for electrochemical CO 2 reduction reaction (CO 2 RR). The 1D/3D NPC exhibits a high CO/H 2 ratio (5.06) and CO yield (31 mmol g −1  h −1 ) at −0.55 V, which are 13.7 times and 21.4 times those of 1D porous carbon (derived from Zn‐MOF‐74) and N‐doped carbon (carbonized by MS), respectively. This is attributed to the unique spatial environment of 1D/3D NPC, which increases the adsorption capacity of CO 2 and promotes electron transfer from the 3D N‐doped carbon framework to 1D carbon, improving the reaction kinetics of CO 2 RR. Experimental results and charge density difference plots indicate that the active site of CO 2 RR is the positively charged carbon atom adjacent to graphitic N on 1D carbon and the active site of HER is the pyridinic N on 1D carbon. The presence of pyridinic N and pyrrolic N reduces the number of electron transfer, decreasing the reaction kinetics and the activity of CO 2 RR. The CO/H 2 ratio is related to the distribution of N species and the specific surface area, which are determined by the degree of spatial confinement effect. The CO/H 2 ratios can be regulated by adjusting the carbonization temperature to adjust the degree of spatial confinement effect. Given the low cost of feedstock and easy strategy, 1D/3D NPC catalysts have great potential for industrial application.

Mesh generation is an essential component for many engineering applications. The ability to generate meshes in parallel is critical for the scalability of the entire Finite Element Method (FEM) pipeline. However, parallel mesh generation applications belong to the broader class of adaptive and irregular problems, and are among the most complex, challenging, and labor intensive to develop and maintain. In this thesis, we summarize several years of the progress that we made in a novel framework for highly scalable and guaranteed quality mesh generation for finite element analysis in three dimensions. We studied and developed parallel mesh generation algorithms on both shared and distributed memory architectures. In this thesis we present a novel two-level parallel tetrahedral mesh generation framework capable of delivering and sustaining close to 6000 of concurrent work units (cores). We achieve this by leveraging concurrency at two different granularity levels by using a hybrid message passing and multi-threaded execution model which is suitable to the hierarchy of the hardware architecture of the distributed memory clusters. An end-user productivity and scalability study was performed on up to 6000 cores, and indicated very good end-user productivity with about 300 million tets per second and about 3600 weak scaling speedup. Both of these results suggest that: compared to the best previous algorithm, we have seen an improvement of more than 7000 times in performance, measured in terms of speed (elements per second) by using about 180 times more CPUs, for geometries that are by many orders of magnitude more complex.