Mo_(2)P Monolayer as a Superior Electrocatalyst for Urea Synthesis from Nitrogen and Carbon Dioxide Fixation:A Computational Study

Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather challenging.Herein,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea production.Our results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic properties.Interestingly,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.35 eV)for C-N coupling,low limiting potential(-0.39 V),and significant suppressing effects on the competing side reactions.The outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active sites.Our findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.

Structure and Raman scattering of Mg-doped ZnO nanoparticles prepared by sol-gel method

Mg-doped ZnO （MgxZn1-xO, x=0-0.10） nanoparticles were prepared by sol-gel method. Structural characterization by X-ray diffraction （XRD） indicates that the lattice parameter a increases and c decreases linearly with the increase in Mg content （x） due to the substitution of Mg2＋ for Zn2＋ in ZnO lattice. The blueshift of Raman modes is observed, impling the increase in force constant of atom vibration in the MgxZn1-xO （MgZnO） nanoparticles. Resonant Raman spectra show longitudinal optical phonon overtones up to fifth order, revealing that the short part of the electron-phonon interaction is enhanced and long-range part is weakened by Mg doping.

Deoximation Reaction in Room Temperature Ionic Liquids under Mild Conditions

Deoximation in metal chloride ionic liquids based on 1-alkyl-3-methylimidazolium and triethylene ammonium cations, such as AmimBr（Cl）-MClx （A=ethyl, butyl, benzyl; M=Al, Fe, Cu, Sn and Zn; x=2, 3） and Et3NHCl-FeCl3 were investigated under mild conditions. Ferrate chloride ionic liquid was proved to be an effective catalyst for deoximation of cyclohexanone oxime, exhibiting high conversion of oximes and selectivity to cyclo- hexanone. Good performance for the deoximation of other oximes such as salicylald oxime, acetone oxime, benzo- phenone oxime, 4-nitrobenzald oxime, acetophenone oxime, 2-chlorobenzaldehyde oxime, Acetald oxime, 2-butanone oxime and （1R）-camphor oxime was also achieved with bmimBr-FeCl3 as catalyst and solvent. The de- oximation was determined to carry out via acid-catalytic hydrolysis and the reaction mechanism was proposed.