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Highlights: In situ Raman spectroscopy study of the cation regulation for interfacial water on Au@Pd core–shell nanoparticle surface during hydrogen evolution reaction process. Direct spectral evidence reveals new strategies to optimize the structure of interfacial water by the adjusting of radius and valence of the cation in the electrolyte. The optimized structure of interfacial water will improve the charge transfer efficiency between the water and electrode increasing the performance of the hydrogen evolution reaction. Interfacial water molecules are the most important participants in the hydrogen evolution reaction (HER). Hence, understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism. Unfortunately, investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment. Here, the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry, in situ core–shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques. Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction. When comparing the different cation electrolyte systems at a given potential, the frequency of the interfacial water peak increases in the specified order: Li+ < Na+ < K+ < Ca2+ < Sr2+. The structure of interfacial water was optimized by adjusting the radius, valence, and concentration of cation to form the two-H down structure. This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance. Therefore, local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure. [ABSTRACT FROM AUTHOR]

Abstract: The photoanode plays a critical role in influencing the performance of dye‐sensitized solar cells (DSSCs). In this work, Y0.80Yb0.18Er0.02OF nanorods (YYEOF NRs) are synthetized by a simple hydrothermal method and incorporated into the TiO2 film to form a bi‐layer photoanode consisting of nanoparticles (NPs) on the bottom and nanorods on top. Owing to the improved light collection efficiency and electron transport rate, the resultant YYEOF NRs are advantageous as photoanode dopants for DSSCs. Following assembly into an integrated DSSC, an enhanced photocurrent and power conversion efficiency (PCE) are observed. Benefiting from the p‐type doping effect of the YYEOF NRs, the photovoltage of the DSSCs is elevated. The cell performance can be maximized through optimization of the fraction of YYEOF NRs, and the results demonstrate that a promising PCE of 7.74 % is determined for the DSSC with 5 wt % YYEOF NRs, yielding 32.5 % enhancement in comparison to pristine TiO2 NPs‐based solar cells. This work provides a promising strategy to explore photoanode materials, which will lead to further efficiency improvements for solar cells. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a facile electrochemical exfoliation method to mass produce device quality MoS2 semiconducting nanosheets. During the exfoliation process, anionic SO4 2− and OH− ions intercalate into a bulk MoS2 and they form gaseous SO2 or O2 gas bubbles which produce a separating force for MoS2 nanosheets exfoliation. Monolayer or few layers of MoS2 nanosheets were obtained on a SiO2/Si substrate. N-type field effect transistors (n-FETs) were fabricated using the exfoliated MoS2 nanosheets and these n-FETs showed excellent device characteristics. The measured on/off current ratio was around 103, the field-effect mobility on SiO2 gate dielectrics was 2cm2/(Vs). [Copyright &y& Elsevier]

The rGO/CeO 2 /FTO nanocomposite modified electrode was prepared by an electrochemical method. A simple and highly sensitive electrochemical sensing platform for electrochemical rGO and modified CeO 2 nanoribbons directly on FTO electrodes was developed. Simultaneous determination of Pb 2+ and Cd 2+ used the differential pulse anodic stripping voltammetry (DPASV) method. The method was simple to operate, and CeO 2 nanobelts could be obtained simultaneously by electrodeposition and reduction of GO without further processing. This is an environmentally friendly electrochemical method to obtain modified electrodes under mild conditions. The experimental results showed that the linear calibration curves of Pb 2+ and Cd 2+ are 1-300 and 0.2-500 μg L -1 , respectively. At the same time, no interference from other coexisting metal ions was found during the detection process, which proved that the modified electrode had good stability and repeatability., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)