The development of a platinum-free electrocatalyst for the hydrogen evolution reaction (HER) is highly essential to the large-scale production and application of water splitting devices. Herein we report a facile one-pot hydrothermal synthesis of composite MoSe 2 @Cu 2 Se. The morphology of the obtained material was characterized by scanning electron microscope (SEM) and it was found that the composite material formed a sand rose-like structure. The crystal structure and phase purity of the composite MoSe 2 @Cu 2 Se were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Then a selective electrochemical etching of copper from the composite was carried out and the porous MoSe 2 rose-like nanosphere was obtained. The robust 3D MoSe 2 rose-like structure exhibit remarkable activity and durability for electrocatalytic HER in acid maintaining a small onset overpotential of $150 mV and keeping a small overpotential of 300 mV for 6 mA cm À2 current density after 1000 cycles. Based on our data, the obtained porous sand rose-like structure material could improve the active surface area which yields higher HER catalytic activity. The present study provides a simple and effective way for the exploration of efficient Mo-based HER catalysts. Electronic supplementary information (ESI) available: One-pot hydrothermal synthesis and selective etching method of porous MoSe 2 sand rose-like structure for electrocatalytic hydrogen evolution reaction. See

The Meerwein–Ponndorf–Verley (MPV) reduction is a reaction that offers a mild reduction of aldehydes and ketones to the corresponding alcohols. Although described as a catalytic reaction, its real-life applicability suffers from the necessity of using the standard catalyst [Al­(OiPr)3] in stoichiometric amounts or even in excess. Rare-earth-metal-based catalysts are capable of performing in these reactions in a truly catalytic fashion. The ceric alkoxide [Ce­(OiPr)4]3 has been synthesized via silylamine elimination from Ce­[N­(SiHMe2)2]4 with isopropyl alcohol, its trimetallic solid-state structure has been determined by X-ray diffraction, and its performance in the MPV reduction of 4-tBu-cyclohexanone has been examined and compared to that of cerous [Ce­(OCH2 tBu)3]4. Spherical mesoporous silica nanoparticles with an MCM-41-type honeycomb pore symmetry, termed MSN-MCM-41 (particle size, ca. 250 nm diameter; pore size, 2.6 nm diameter), are employed for grafting the molecular precursors Ce­[N­(SiHMe2)2]4, [Ce­(OiPr)4]3, Ce­[N­(SiMe3)2]3, and La­[N­(SiMe3)2]3 according to the methods of surface organometallic chemistry (SOMC). The MPV reductions carried out with the homogeneous and heterogeneous catalysts reveal (a) a better performance of Ce­(III) in comparison to Ce­(IV), (b) better performance of La­[N­(SiMe3)2]3@MSN-MCM-41 in comparison to Ce­[N­(SiMe3)2]3@MSN-MCM-41 (high sensitivity of Ce­(III)-grafted materials), and (c) reusability of the grafted catalyst systems. All hybrid materials were characterized by PXRD, N2 physisorption, and 1H/13C/29Si MAS NMR and FTIR spectroscopies as well as elemental analysis.

Plastids in plants are assumed to have evolved from cyanobacteria as they have maintained several bacterial features. Recently, peptidoglycans, as bacterial cell wall components, have been shown to exist in the envelopes of moss chloroplasts. Phylogenomic comparisons of bacterial and plant genomes have raised the question of whether such structures are also part of chloroplasts in angiosperms. To address this question, we visualized canonical amino acids of peptidoglycan around chloroplasts of Arabidopsis and Nicotiana via click chemistry and fluorescence microscopy. Additional detection by different peptidoglycan-binding proteins from bacteria and animals supported this observation. Further Arabidopsis experiments with D-cycloserine and AtMurE knock-out lines, both affecting putative peptidoglycan biosynthesis, revealed a central role of this pathway in plastid genesis and division. Taken together, these results indicate that peptidoglycans are integral parts of plastids in the whole plant lineage. Elucidating their biosynthesis and further roles in the function of these organelles is yet to be achieved.

Electrical discharge machining (EDM) process is widely used to process hard materials in the industry. The process of electrical discharge is changed and called PMEDM when alloy powder is added in the oil dielectric. In the current study, the effect of tungsten carbide alloy powder added in the dielectric on the surface roughness (Ra) and the micro hardness of surface (HV) status of the workpiece SKD61 after machining is investigated. Studies show that the surface roughness and the micro hardness of surface obtained by PMEDM is generally better than that by normal EDM. The method can be applied for improving surface quality such as improving strengthening of molds and machine parts.

The success of quenching process depended heavily on the suitable choice of a quenching media. In this work, a numerical simulation of the process of quenching C-ring sample of 100Cr6 steel was discussed. The results showed an overview of the phase transformation, residual stress, distortion and hardness on the specimen throughout quenching process to the end. The simulation results also revealed that the sample is not cracked and the highest residual stress located on the inner and outer at the bottom edge of the C-ring with C-ring model being quenched in PVP-12 solution. At the same time, the obtained hardness was qualified the working requirements.