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Heavy-weight concrete (HWC) is a widely adopted radiation shielding material in the nuclear industry. In this study, two kinds of high-density aggregate, namely, iron sand (IS) and steel slag coarse aggregate (SSCA), were adopted to fully replace river sand and natural coarse aggregate, respectively, producing ultra-heavy-weight concrete (UHWC) with a unit weight >3800 kg/m3, to ensure excellent radiation shielding performance. However, IS and SSCA seriously impaired the passing ability of UHWC as the cement paste could not hold the IS and SSCA as firmly as natural aggregates, owing to their high density. To overcome this, the rheology of UHWC should be optimised by partially replacing the cement with superfine silica fume (SSF) and using a suitable amount of superplasticiser (SP) to enhance the wet packing density (WPD). A total of 28 UHWC mixes with different replacement ratios of SSF and different SP dosages were tested for segregation width, flowability, L-box passing ability, unit weight and WPD. Results revealed that incorporating an appropriate quantity of SSF and SP improved the WPD of UHWC, resulting in improved segregation resistance, enhanced flowability, increased passing ability and a higher unit weight. Lastly, there is a positive correlation between flowability, passing ability and WPD. [ABSTRACT FROM AUTHOR]

Designing high‐entropy oxyhydroxides (HEOs) electrocatalysts with controlled nanostructures is vital for efficient and stable water‐splitting electrocatalysts. Herein, a novel HEOs material (FeCoNiWCuOOH@Cu) containing five non‐noble metal elements derived by electrodeposition on a 3D double‐continuous porous Cu support is created. This support, prepared via the liquid metal dealloying method, offers a high specific surface area and rapid mass/charge transfer channels. The resulting high‐entropy FeCoNiWCuOOH nanosheets provide a dense distribution of active sites. The heterostructure between Cu skeletons and FeCoNiWCuOOH nanosheets enhances mass transfer, electronic structure coupling, and overall structural stability, leading to excellent activities in the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and water splitting reaction. At 10 mA cm−2, the overpotentials for OER, HER, and water splitting in 1.0 m KOH solution are 200, 18, and 1.40 V, respectively, outperforming most current electrocatalysts. The catalytic performance remains stable even after operating at 300 mA cm−2 for 100, 100, and over 1000 h, correspondingly. This material has potential applications in integrated hydrogen energy systems. More importantly, density functional theory (DFT) calculations demonstrate the synergy of the five elements in enhancing water‐splitting activity. This work offers valuable insights for designing industrial water electrolysis systems. [ABSTRACT FROM AUTHOR]

2D Ruddlesden─Popper (RP) halide perovskites are attracting increasing research interest due to their enhanced stability compared to 3D perovskites. However, the quantum confinement effect of bulk organic spacers hinders the separation and transport of photo‐generated carriers. Here, a multiple aromatic ring spacer, 3‐benzothiophene methylammonium (BTMA), is developed for a new 2D RP perovskite. The BTMA spacer is demonstrated, with a significant dipole moment, can impair the influence of the quantum confinement effect, and the presence of S atoms or thiophene is favorable for enhancing the interaction between organic spacers and inorganic sheets, improving the stability of perovskites. The perovskite photodetector with BTMA as spacers displays higher device performance than the control sample with 1‐naphthalene methylammonium (NMA) as spacers. Importantly, the outstanding stability of BTMA‐based perovskite films and devices is also confirmed under moisture, heat, and illumination conditions. Combining the asymmetric coplanar nanogap electrode architecture, the photodetectors' enhanced responsivity, detectivity, and external quantum efficiency of 314 A W−1, 3.4 × 1013 Jones, and 865%, respectively, are demonstrated. Importantly, the nanogap photodetectors display promising self‐power characteristics, which makes them attractive for numerous energy‐efficient applications. The work highlights a new route toward developing high‐performance 2D RP perovskite‐based photodetectors with excellent long‐term stability. [ABSTRACT FROM AUTHOR]

Although metal‐organic frameworks (MOFs) show promise as electrocatalysts due to their unique intrinsic features, their activity and stability often fall short. Herein, NiFe‐MOFs is used as a model to introduce group VIB metalates (Na2WO4, Na2CrO4, and Na2MoO4) into the topological conversion process of layer double hydroxide (LDHs)/MOFs, creating a series of interstitial VIB element‐doped LDHs/MOFs catalysts. The metalates engage in the alkaline hydrolysis process of MOF, generating LDHs on the MOF surface. Furthermore, altering the pH value in the reaction environment can modify the catalysts' morphology, dopant/LDHs content, and electronic structure. Consequently, the prepared interstitial W‐doped NiFe‐LDHs/MOFs catalyst displays superior catalytic performance, with overpotentials of only 250 mV at 500 mA cm−2. Moreover, a homemade anion‐exchange membrane water electrolysis (AEMWE) system featuring the fabricated electrocatalyst as the anode can operate stably for 500 hours at 1 A cm−2. The exceptional catalytic activity and stability stem from optimized intermediate adsorption/desorption behavior and the unique LDHs/MOFs nanostructure. This work not only highlights the potential of the catalysts for practical applications but also offers a new design approach for modulating MOFs using an alkaline hydrolysis strategy. [ABSTRACT FROM AUTHOR]

Micro/nanoscale lasers that span the entire visible spectrum, especially those in red, green, and blue colors, are not only essential for a variety of optical devices but also have important applications in visible color communication, multi‐color fluorescence sensing, and wavelength division multiplexing. Despite the great efforts made to achieve multi‐color lasing using a variety of approaches, on‐chip white light emission and even red, green, and blue multi‐color lasers still suffer from considerable challenges in micro‐nano structures. Here, CdSxSe1−x, CdS, and ZnS micro‐tripod structures are successfully prepared using chemical vapor deposition approaches. The micro‐photoluminescence (µ‐PL) spectra and PL‐mapping of these micro‐tripods reveal various emissions at 630, 508, and 460 nm, respectively. Additionally, white‐light emissions based on these composition‐tunable tripods are realized through an end‐coupling structure system. Moreover, room‐temperature modes tunable lasers are observed clearly from three legs of these micro‐tripods, with a low threshold of ≈48.39 µJ cm−2 and a high quality factor of 1227.3. The realization of micro‐tripods‐based lasers may provide an innovative way for highly integrated photonic circuits and communications. [ABSTRACT FROM AUTHOR]