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Understanding the structure and dynamic process of water at the solid–liquid interface is an extremely important topic in surface science, energy science and catalysis1–3. As model catalysts, atomically flat single-crystal electrodes exhibit well-defined surface and electric field properties, and therefore may be used to elucidate the relationship between structure and electrocatalytic activity at the atomic level4,5. Hence, studying interfacial water behaviour on single-crystal surfaces provides a framework for understanding electrocatalysis6,7. However, interfacial water is notoriously difficult to probe owing to interference from bulk water and the complexity of interfacial environments8. Here, we use electrochemical, in situ Raman spectroscopic and computational techniques to investigate the interfacial water on atomically flat Pd single-crystal surfaces. Direct spectral evidence reveals that interfacial water consists of hydrogen-bonded and hydrated Na+ ion water. At hydrogen evolution reaction (HER) potentials, dynamic changes in the structure of interfacial water were observed from a random distribution to an ordered structure due to bias potential and Na+ ion cooperation. Structurally ordered interfacial water facilitated high-efficiency electron transfer across the interface, resulting in higher HER rates. The electrolytes and electrode surface effects on interfacial water were also probed and found to affect water structure. Therefore, through local cation tuning strategies, we anticipate that these results may be generalized to enable ordered interfacial water to improve electrocatalytic reaction rates. Interfacial water consists of hydrogen-bonded water and Na·H2O, its structure changes at hydrogen evolution reaction (HER) potentials, and when structurally ordered it aids interfacial electron transfer, resulting in higher HER rates.

Bariatric surgery for patients with severe obesity (body mass index (BMI) ≥ 50kg/m2) is technically challenging. Intragastric balloon (IGB) has been proposed for weight loss before bariatric surgery to reduce surgical risks but its efficacy remains unclear. We conducted a systematic review and meta-analysis of the effectiveness of IGB as bridging therapy and assess potential complications. Amongst 2419 citations, 13 studies were included. IGB resulted in a BMI reduction of 6.60 kg/m2 (MD=6.60, 95% CI: 5.06-8.15; I2=72%). The total post-procedural complication rate was 8.13% (95% CI: 4.04-13.17%), with majority being balloon intolerance. Overall, IGB is effective as a bridging therapy with adequate procedural safety profile, but further study is needed to evaluate the risk reduction for bariatric surgery and long-term weight-loss outcomes.

White-emitting SrSc1-xLiTeO6:xDy3+ phosphors were conveniently synthesized by a conventional high-temperature solid-state synthesis process. The crystal structure, photoluminescence spectrum characteristics, fluorescence quenching phenomenon, fluorescence lifetime analysis and the thermal stability of SrSc1-xLiTeO6:xDy3+ phosphors were comprehensively illustrated. The Egap of the SrScLiTeO6 host was approximately 4.65 eV based on diffuse reflectance spectroscopy (DRS) analysis. Moreover, the SrSc0.94LiTeO6:0.06Dy3+ phosphor exhibits two principal emission bands: the narrow-band emission at 481 nm (4F9/2→6H15/2, magnetic dipole transition, blue light area) and 573 nm (4F9/2→6H13/2, electric dipole transition, yellow light area) under the excitation of 366 nm ultraviolet light, respectively. The values of τ are determined to be 0.558, 0.380, 0.307 and 0.254 ms for SrSc1-xLiTeO6:xDy3+ (x = 0.005, 0.01, 0.04, 0.08) samples, respectively. The value of ΔE for SrSc0.94LiTeO6:0.06Dy3+ phosphor is deduced to be 0.1969 eV, which indicates excellent thermal stability. In addition, the CIE coordinates are located in the white light-emitting area. The abovementioned results show that the SrSc1-xLiTeO6:xDy3+ can serve as a phosphor with potential application value for outdoor illumination.

Dephosphorization slag is primarily composed of CaO–SiO2–FeO–P2O5 slag system. As it contains abundant valuable components, dephosphorization slag is considered a potential material to restore the degraded acid soil. To efficiently supply Ca, Si, Fe, and P elements for acid soil, the dissolution behavior of dephosphorization slag with high P2O5 content in the weakly acidic solution was investigated. It was found that the existence of citric acid could significantly promote the dissolution of slag in the aqueous solution. Most of the Ca, Si, and P was dissolved from slag at pH 5, and the Fe dissolution ratio reached 36.9%. In this case, the precipitation of Fe3(PO4)2∙8H2O was suppressed, and the majority of C2S–C3P solid phase and matrix phase was dissolved while wustite remained in the residue. The dissolution ratios of main elements from slag decreased dramatically as the pH increased. Only in the weakly acidic solution, it could make full use of dephosphorization slag, and large amounts of nutrient elements were simultaneously supplied. The dissolution ratios of nutrient elements decreased with the increase in particle size. The dissolution kinetics of slag in the citric acid solution followed the shrinking core model.

Sodium-ion batteries (SIBs), as highly promising alternatives to lithium-ion batteries (LIBs), can be widely used in a variety of next-generation energy storage systems. However, the current commercial graphite anodes of LIBs could not intercalate sodium ions to appreciable extent, and the electrochemical irreversibility hinders further application. Searching for a suitable anode material is a critical issue for the successful development of SIBs. Herein, we report a convenient, fast, and large-scale preparation method of mesoporous FeS2 nanorods. Our specially designed one-dimensional mesoporous structure of FeS2 takes full advantage of ultra-high strain relaxation as well as fast Na+ transport rate arising from microstructural characteristics. As a result, the mesoporous FeS2 nanorods exhibited excellent sodium storage performance. The discharge capacity was retained at 711.1 mAh·g−1 after 450 cycles at a current density of 1000 mA·g−1. The special microstructure and superior performance of mesoporous FeS2 nanorods represent a critical step for transition metal sulfides electrode materials toward practical SIBs application.

It is common knowledge that the core of fluorescence intensity ratio (FIR) technology is to rely on the thermal coupling energy level, which is a compulsorily needed technology in the research and development of non-contact rare earth luminescent temperature sensor. In this work, highly sensitive up-conversion phosphors LiYb(WO4)2:Ho3+ on the basis of FIR of thermal coupled levels (TCLs) (5F4,5S2/5F5) from Ho3+ were firstly synthesized, whose up-conversion spectra contained weak emission band centered at 541 nm (5F4,5S2→5I8) and a strong red band at 663 nm (5F5→5I8). Moreover, the LiYb0.98(WO4)2:0.02Ho3+ material intensively demonstrates the highest relative sensitivity (Sr) value (0.70% K− 1) at initial temperature. Results indicate that these present LiYb1 − x(WO4)2:xHo3+ phosphors can be excellently used in the versatile temperature sensing field with high sensitivity.

Wastewater containing cobalt and copper comprised of plating wash water, plant wash water, and equipment cooling and wash water is generated in the electroplating industry. These metals can be detrimental to humans, animals, plants, and the environment. Thus, it is necessary to treat electroplating wastewater to remove these toxic metals. Carbonate and hydroxide precipitation were utilized for the removal of Co (II) and Cu (II) from synthetic electroplating wastewater by jar tests in this work. The effects of solution pH, precipitant-to-metal ratio, and type of precipitant on the precipitation efficiency of cobalt and copper from the single- and co-contaminated systems were investigated. Carbonate precipitation achieved higher removal efficiency for both target metals in the single- and co-contaminated wastewater streams. Furthermore, it can operate at relatively low pH range of about 7–8. Cobalt in both pollutant systems was almost completely removed at pH 10 using both precipitant systems. Copper was found to be easily removed which was possibly brought about by precipitation-adsorption mechanism. The extent of the co-removal of cobalt with copper is significantly pH dependent. The effect of precipitant-to-metal ratio for cobalt and copper treatment varied in single- and co-contaminated streams. Carbonate precipitation led to higher sludge volume than that of hydroxide precipitation.