2D CeO2 and a Partially Phosphated 2D Ni-Based Metal-Organic Framework Formed an S-Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution.

Here, an S-scheme heterojunction was constructed on the basis of the modification of a Ni-based metal-organic framework (Ni-MOF) by different in situ treatment strategies. First, NiS2, NiO, and Ni2P were derived in situ on the surface of Ni-MOF through surface sulfonation, oxidation, and phosphatizing treatments. They can efficiently accept the electrons from the conduction band of Ni-MOF as the trap centers, thus improving the hydrogen production activity. Additionally, phosphatizing makes the electronegativity of Ni-MOF/P stronger than that of the original Ni-MOF, which can enhance the absorption of protons, thus promoting the hydrogen evolution reaction. Next, the S-scheme heterojunction was successfully built by the coupling of 2D CeO2 with Ni-MOF/P. The maximum hydrogen production rate of the hybrid catalyst (6.337 mmol g-1 h-1) is 14.18 times that of the untreated Ni-MOF due to the full utilization of photo-induced electrons. Finally, the probable hydrogen evolution mechanism was proposed by analyzing a series of characterization results and by the density functional theory (DFT) calculation.

Enhancing Ru-Cl interaction via orbital hybridization effect in Ru0.4Sn0.3Ti0.3 electrode for efficient chlorine evolution.

Chlorine evolution reaction (CER) is a commercially valuable electrochemical reaction used at an industrial scale. However, oxygen evolution reaction (OER) during the electrolysis process inevitably leads to the decreased efficiency of CER. It is necessary to improve the selectivity of CER by minimizing or even eliminating the occurrence of OER. Herein, a ternary metal oxide (Ru0.4Sn0.3Ti0.3) electrode was fabricated and employed as an active and robust anode for CER. The Ru0.4Sn0.3Ti0.3 electrode exhibits an excellent CER performance in 6.0 M NaCl solution, with a low potential of 1.17 V (vs. saturated calomel electrode, SCE) at 200 mA cm-2 current density, a high Cl2 selectivity of over 90 %, and robust durability after consecutive operation for 160 h under 100 mA cm-2. The maximum O2-Cl2 potential difference between OER and CER further demonstrates the high Cl2 selectivity of Ru0.4Sn0.3Ti0.3 electrode. Theoretical studies show that the strong Ru 3d-Ti 3d orbitals hybridization effect makes the d-band center (εd) of Ru 3d and Ti 3d orbitals positively and negatively shifted, respectively, endowing Ru site with enhanced Cl adsorption ability (i.e. enhanced Ru-Cl interaction) and Ru0.4Sn0.3Ti0.3 electrode with superior CER activity. This work offers valuable insights into the development of advanced electrodes for CER in practical application.

Engineering antibonding orbital occupancy of NiMoO4-supported Ru nanoparticles for enhanced chlorine evolution reaction.

Chlorine evolution reaction (CER) is crucial for industrial-scale production of high-purity Cl2. Despite the development of classical dimensionally stable anodes to enhance CER efficiency, the competitive oxygen evolution reaction (OER) remains a barrier to achieving high Cl2 selectivity. Herein, a binder-free electrode, Ru nanoparticles (NPs)-decorated NiMoO4 nanorod arrays (NRAs) supported on Ti foam (Ru-NiMoO4/Ti), was designed for active CER in saturated NaCl solution (pH = 2). The Ru-NiMoO4/Ti electrode exhibits a low overpotential of 20 mV at 10 mA cm-2 current density, a high Cl2 selectivity exceeding 90%, and robust durability for 90h operation. The marked difference in Tafel slopes between CER and OER indicates the high Cl2 selectivity and superior reaction kinetics of Ru-NiMoO4/Ti electrode. Further studies reveal a strong metal-support interaction (SMSI) between Ru and NiMoO4, facilitating electron transfer through the Ru-O bridge bond and increasing the Ru 3d-Cl 2p antibonding orbital occupancy, which eventually results in weakened Ru-Cl bonding, promoted Cl desorption, and enhanced Cl2 evolution. Our findings provide new insights into developing electrodes with enhanced CER performance through antibonding orbital occupancy engineering.

Visible-light-driven two dimensional metal-organic framework modified manganese cadmium sulfide for efficient photocatalytic hydrogen evolution.

The morphology modification and the construction of heterojunction of the photocatalyst are considered as the main means to significantly improve the performance of photocatalytic hydrogen evolution. In this study, Mn0.2Cd0.8S nanorods are successfully assembled on the surface of Ni-MOF-74 with flake morphology. Specifically, the Ni-S bond is constructed between Ni-MOF-74 and Mn0.2Cd0.8S, which provides a unique transfer channel for photo-induced carriers. Meanwhile, the electrons in the conduction band of Mn0.2Cd0.8S can be injected into the conduction band of Ni-MOF-74 quickly due to the potential energy difference between the two. This shows that the recombination of photogenerated carriers in Mn0.2Cd0.8S can be greatly inhibited. Fluorescence spectroscopy and electrochemical characterization reveal that the composite catalyst has the longest carrier lifetime, the fastest charge transfer rate and the lowest overpotential compared with the Mn0.2Cd0.8S and Ni-MOF-74. The optimal hydrogen production rate of the composite can reach 7.104 mmol g-1h-1, which is 6.96 times that of Mn0.2Cd0.8S. This work provides a novel strategy for the modification of MnCdS-based photocatalysts by metal-organic framework materials.

A novel materials manganese cadmium sulfide/cobalt nitride for efficiently photocatalytic hydrogen evolution.

The CoN which with excellent performance was introduced into Mn0.2Cd0.8S through simple electrostatic self-assembly for the first time, then the composite photocatalyst with low cost and high catalytic activity was prepared. The introduction of CoN improves the absorption intensity of catalyst to visible light. CoN accepts photo-induced electrons from Mn0.2Cd0.8S as an excellent electron acceptor in the form of active sites due to its suitable conduction band position and good conductivity. The surface interaction of composite photocatalyst formed by electrostatic self-assembly is strong, which is conducive to the directional transfer of photogenic carriers from Mn0.2Cd0.8S to CoN, greatly inhibits the recombination of photogenic carriers and improves the separation and the transfer rate of photogenic carriers. The introduction of CoN greatly improved the hydrogen production rate of photocatalyst up to 14.612 mmol g-1 h-1, it was 17.3 times that of pure MCS. This work provides inspiration for transition metal nitrides as cocatalysts in the sphere of photocatalytic splitting of water for hydrogen production.

Efficient hydrogen production at a rationally designed MoSe2@Co3O4 p-n heterojunction.

During the past several years, transition metal compounds have shown high activity in the field of photocatalysis. Therefore, the MoSe2@Co3O4 with excellent photocatalytic properties through simple hydrothermal and physical mixing methods was prepared. This composite material was composed of n-type semiconductor MoSe2 and p-type semiconductor Co3O4. After optimizing the loading of Co3O4, the optimal hydrogen production can reached 7029.2 µmol g-1h-1, which was 2.34 times that of single MoSe2. In addition, some characterization methods were used to explore the hydrogen production performance of the composite catalyst under EY sensitized conditions. Among them, the UV-vis diffuse reflectance spectra suggests that MoSe2@Co3O4 exhibits stronger visible light absorption performance than the single material. Fluorescence performance and photoelectrochemical characterization experiments further prove that, the special structure formed by MoSe2 and Co3O4 and the existence of p-n heterojunction effectively accelerate the separation and transfer of carriers meanwhile inhibit the recombination probability of electron-hole pairs. Combined with other characterizations such as XRD, XPS, SEM and BET, the possible hydrogen production mechanism was proposed.

Label-Free Classification of a Nasopharyngeal Carcinoma Tissue Test at Different Stages Based on Raman Spectroscopy.

Raman spectroscopy (RS) of nasopharyngeal carcinoma (NPC) tissue provides substantial biomolecular information and various biomedicine features for tissue at different stages of cancer development. This study suggested an automatic and quick method for the classification of Raman spectra at different stages of NPC by multivariate statistical analysis. During RS measurement, Raman spectra were acquired from all NPC tissues in two groups of samples: 30 early-stage NPC patients (stages I and II) and 46 advanced-stage NPC patients (stages III and IV). In addition, a tentative diagnostic algorithm comprising principal components analysis and support vector machine was used to effectively classify multivariate data from the Raman spectra to yield sensitivities (70%; 21 of 30 samples) and specificities (91%; 42 of 46 samples) by the leave-one-out cross-validation method. Meaningful chemical compositions in the classification process were then deduced by analyzing the classified mathematical model. This beneficial work provides a great potential clinical method for the automatic classification of NPC stages and the speculation of the chemical compositions for NPC staging.