The electrochemical N2 fixation, which is far from practical application in aqueous solution under ambient conditions, is extremely challenging and requires a rational design of electrocatalytic ...centers. We observed that bismuth (Bi) might be a promising candidate for this task because of its weak binding with H adatoms, which increases the selectivity and production rate. Furthermore, we successfully synthesized defect‐rich Bi nanoplates as an efficient noble‐metal‐free N2 reduction electrocatalyst via a low‐temperature plasma bombardment approach. When exclusively using 1H NMR measurements with N2 gas as a quantitative testing method, the defect‐rich Bi(110) nanoplates achieved a 15NH3 production rate of 5.453 μg mgBi−1 h−1 and a Faradaic efficiency of 11.68 % at −0.6 V vs. RHE in aqueous solution at ambient conditions.
Beneficial defects: Defect‐rich bismuth nanoplates achieve a 15NH3 production rate of 5.453 μg mgBi−1 h−1 and a Faradaic efficiency of 11.68 % at −0.6 V vs. RHE in aqueous solutions at ambient conditions because of their poor binding with H adatoms, which increases the selectivity and production rate. Also, 1H NMR measurements with N2 gas ware used as a quantitative test method in aqueous electrolytes.
We developed a tandem electrocatalyst for CO2‐to‐CO conversion comprising the single Cu site co‐coordinated with N and S anchored carbon matrix (Cu‐S1N3) and atomically dispersed Cu clusters (Cux), ...denoted as Cu‐S1N3/Cux. The as‐prepared Cu‐S1N3/Cux composite presents a 100 % Faradaic efficiency towards CO generation (FECO) at −0.65 V vs. RHE and high FECO over 90 % from −0.55 to −0.75 V, outperforming the analogues with Cu‐N4 (FECO only 54 % at −0.7 V) and Cu‐S1N3 (FECO 70 % at −0.7 V) configurations. The unsymmetrical Cu‐S1N3 atomic interface in the carbon basal plane possesses an optimized binding energy for the key intermediate *COOH compared with Cu‐N4 site. At the same time, the adjacent Cux effectively promotes the protonation of *CO2− by accelerating water dissociation and offering *H to the Cu‐S1N3 active sites. This work provides a tandem strategy for facilitating proton‐coupled electron transfer over the atomic‐level catalytic sites.
A tandem catalyst composed of single Cu sites co‐coordinated with N and S and atomically dispersed Cu clusters (Cu‐S1N3/Cux) was developed for CO2‐to‐CO conversion. The Cu‐S1N3/Cux exhibited a 100 % Faradaic efficiency for CO formation (FECO), outperforming the single‐atomic Cu‐N4 analogue (FECO=54 %).
Non-layer structured nanomaterials with single- or few-layer thickness have two-dimensional sheet-like structures and possess intriguing properties. Recent years have seen major advances in ...development of a host of non-layer structured ultrathin two-dimensional nanomaterials such as noble metals, metal oxides and metal chalcogenides. The wet-chemical synthesis has emerged as the most promising route towards high-yield and mass production of such nanomaterials. These nanomaterials are now finding increasing applications in a wide range of areas including catalysis, energy production and storage, sensor and nanotherapy, to name but a few.
This study investigates the complex interplay between academic self-concept, teacher support, student engagement, and psychological wellbeing among Chinese university students. We aimed to elucidate ...the mediating role of student engagement in these relationships.
A sample of 597 Chinese undergraduate students from diverse universities participated in the study. We employed structured questionnaires to assess academic self-concept, teacher support, student engagement, and psychological wellbeing. Confirmatory factor analyses and structural equation modeling were used to test our hypothesized model.
Structural equation modeling indicated that the partial mediation model, which considered both direct and indirect effects, outperformed full mediation and direct effect models. Student engagement significantly mediated the relationships between academic self-concept, teacher support, and psychological wellbeing. Importantly, teacher support demonstrated a direct impact on psychological wellbeing, even when accounting for the mediating role of student engagement.
This study underscores the pivotal role of student engagement as a mediator in the relationship between academic self-concept, teacher support, and psychological wellbeing among Chinese university students. While student engagement plays a substantial mediating role, our findings also recognize the persistent direct influence of teacher support on psychological wellbeing. These insights have implications for educators and policymakers aiming to enhance the wellbeing of university students by fostering positive academic self-concept and teacher support while recognizing the importance of student engagement.
Although single-atomically dispersed metal-N
on carbon support (M-NC) has great potential in heterogeneous catalysis, the scalable synthesis of such single-atom catalysts (SACs) with high-loading ...metal-N
is greatly challenging since the loading and single-atomic dispersion have to be balanced at high temperature for forming metal-N
. Herein, we develop a general cascade anchoring strategy for the mass production of a series of M-NC SACs with a metal loading up to 12.1 wt%. Systematic investigation reveals that the chelation of metal ions, physical isolation of chelate complex upon high loading, and the binding with N-species at elevated temperature are essential to achieving high-loading M-NC SACs. As a demonstration, high-loading Fe-NC SAC shows superior electrocatalytic performance for O
reduction and Ni-NC SAC exhibits high electrocatalytic activity for CO
reduction. The strategy paves a universal way to produce stable M-NC SAC with high-density metal-N
sites for diverse high-performance applications.
Despite the fact that antimony triselenide (Sb2Se3) thin‐film solar cells have undergone rapid development in recent years, the large open‐circuit voltage (VOC) deficit still remains as the biggest ...bottleneck, as even the world‐record device suffers from a large VOC deficit of 0.59 V. Here, an effective interface engineering approach is reported where the Sb2Se3/CdS heterojunction (HTJ) is subjected to a post‐annealing treatment using a rapid thermal process. It is found that nonradiative recombination near the Sb2Se3/CdS HTJ, including interface recombination and space charge region recombination, is greatly suppressed after the HTJ annealing treatment. Ultimately, a substrate Sb2Se3/CdS thin‐film solar cell with a competitive power conversion efficiency of 8.64% and a record VOC of 0.52 V is successfully fabricated. The device exhibits a much mitigated VOC deficit of 0.49 V, which is lower than that of any other reported efficient antimony chalcogenide solar cell.
A heterojunction post‐annealing treatment is utilized to suppress the nonradiative recombination for a highly competitive power conversion efficiency of 8.64% and a record open‐circuit voltage (VOC) of 520 mV in Sb2Se3 thin‐film solar cells. The VOC deficit of the device is lower than that of any other reported efficient antimony chalcogenide solar cells.
As one member of the emerging class of ultrathin two‐dimensional (2D) transition‐metal dichalcogenide (TMD) nanomaterials, the ultra‐thin MoS2 nanosheet has attracted increasing research interest as ...a result of its unique structure and fascinating properties. Solution‐phase methods are promising for the scalable production, functionalization, hybridization of MoS2 nanosheets, thus enabling the widespread exploration of MoS2‐based nanomaterials for various promising applications. In this Review, an overview of the recent progress of solution‐processed MoS2 nanosheets is presented, with the emphasis on their synthetic strategies, functionalization, hybridization, properties, and applications. Finally, the challenges and opportunities in this research area will be proposed.
Sheets ahead: Solution‐based methods offer an effective route for the preparation of MoS2 nanosheets. With the an emphasis on applications, the synthetic strategies and methods for functionalization and hybridization are discussed.
X‐ray detectors are widely utilized in medical diagnostics and nondestructive product inspection. Halide perovskites are recently demonstrated as excellent candidates for direct X‐ray detection. ...However, it is still challenging to obtain high quality perovskites with millimeter‐thick over a large area for high performance, stable X‐ray detectors. Here, methylammonium bismuth iodide (MA3Bi2I9) polycrystalline pellets (PPs) are developed by a robust, cost effective, and scalable cold isostatic‐pressing for fabricating X‐ray detectors with low limit of detection (LoD) and superior operational stability. The MA3Bi2I9‐PPs possess a high resistivity of 2.28 × 1011 Ω cm and low dark carrier concentration of ≈107 cm−3, and balanced mobility of ≈2 cm2 V−1 s−1 for electrons and holes. These merits enable a sensitivity of 563 μC Gyair−1 cm−2, a detection efficiency of 28.8%, and an LoD of 9.3 nGyair s−1 for MA3Bi2I9‐PPs detectors, and the LoD is much lower than the dose rate required for X‐ray diagnostics used currently (5.5 μGyair s−1). In addition, the MA3Bi2I9‐PPs detectors work stably under high working bias field up to 2000 V cm−1 after sensing an integrated dose >320 Gyair with continuous X‐ray radiation, demonstrating its competitive advantage in practical application. These findings provide an approach to explore a new generation of low LoD, stable and green X‐ray detectors based on MA3Bi2I9‐PPs.
MA3Bi2I9 polycrystalline pellets (PPs) are fabricated by the robust, cost‐effective, and scalable cold isostatic‐pressing approach, and X‐ray detectors based on MA3Bi2I9‐PPs reach a limit of detection (LoD) of 9.3 nGyair s−1. The low LoD of the X‐ray detectors can obviously decrease the radiation dose used, thereby reducing health risks in medical diagnostics and security screening.
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