Theoretical Studies on the Electronic Properties of R_2M_(14)B (R = Lanthanides from La to Lu;M = Mn,Fe, Co,and Ni)

To search for an alternative for Nd₂Fe₁₄B,we have studied the electronic structures of R₂M₁₄B compounds,where R stands for rare-earth element and M for Mn,Fe,Co and Ni.By density functional theory(DFT),we discuss the atomic coordination environment and partial density of states(PDOS)in detail,with the emphasis on the interaction between the six kinds of M sites and the R atoms.We systemically calculated the electronic structures of sixty R₂M₁₄B compounds to provide systematic and reliable results for explaining the origination of magnetism,which is important for further development of Nd₂Fe₁₄B based magnet materials.     

Density Functional Theory Study on the Complete Substitutions of Nd and Fe by Other Rare-earth and Transition-metal Elements in Nd_2Fe_(14)B Compound

To search for proper alternatives to improve the magnetic properties of Nd₂Fe₁₄B,using first-principles density functional theory calculations we have systematically studied the R₂M₁₄B(R=lanthanides from La to Lu;M=Mn,Fe,Co,and Ni)compounds with the isomorphic structure of Nd₂Fe₁₄B.The results show that for rare-earth elements,Pr is the most suitable choice for considering as an alternative of Nd.As for the substitution of Fe in Nd₂Fe₁₄ B by other transition-metal elements,Co is much more suitable than Mn and Ni because the latter two result in too significant reduction of the magnetic moment.     

Synergistic Effect of Ta_2O_5/F-C Composites for Effective Electrosynthesis of Hydrogen Peroxide from O_2 Reduction

The electrosynthesis of H₂O₂as an environmentally friendly green process has attracted great attention due to the importance of H₂O₂in industry and human lives.In this work,a new strategy was proposed to improve the electrical conductivity and H₂O₂selectivity of transition metal oxides catalysts.F-C(F doped carbon)was coupled with Ta₂O₅by calcining polyvinylidene fluoride(PVDF)as the carbon source using one step method.The Ta₂O₅/F-C composite catalysts show an excellent H₂O₂selectivity of more than 80%as well as high reactivity at 2.52 mA/cm²,which is greatly enhanced compared to the counterparts of F-C(selectivity of 59%)and Ta₂O₅-800(current density of 0.85 mA/cm²)in 0.1 M KOH solution.The onset potential for H₂O₂production on Ta₂O₅/F-C composites is 0.78 V in 0.1 M KOH,which indicates a negligible overpotential.In addition,H₂O₂selectivity of the catalyst can be stabilized at more than 80%after 10 hours of electrolysis in alkaline electrolyte.The high performance due to the introduction of F-C increases the conductivity of Ta₂O₅and the synergistic effect between F-C and Ta₂O₅.This work proposed an efficient synergistic effect among F-doped C and Ta₂O₅for H₂O₂production.