Hollow structured Fe@C nanorods for boosting dehydrogenation properties ofα-AlH_(3)

α-AlH_(3)is regarded as one of the most promising hydrogen storage materials due to its high hydrogen storage capacity(10.1 wt.%,148 kg·m^(-3)).However,in practical applications,the associated hydrogen release temperature remains relatively high.To effectively address this issue,hollow structured Fe@C nanorods derived from Fe-MOF are introduced as highly efficient catalyst to optimize the dehydrogenation properties ofα-AlH_(3).Comparatively,the initial hydrogen release temperature ofα-AlH_(3)+3 wt.%Fe@C is reduced to 94.2℃,which is significantly lower than that of pureα-AlH_(3)(137.8℃).At 100 and 120℃,it exhibits hydrogen capacities of 5.38 wt.%and 7.47 wt.%,respectively,whereas pureα-AlH_(3)only delivers hydrogen capacities of 0.24 wt.%and 5.94 wt.%under the same temperatures.The density functional theory(DFT)calculations further indicate that the existence of Fe@C catalyst can make the length of Al-H bond increase,which is more conducive to the release of hydrogen.The results show that the synergistic effect of Fe and porous carbon in Fe@C nanorods can improve the hydrogen desorption kinetics ofα-AlH_(3),providing a good prospect for the application ofα-AlH_(3)in hydrogen storage fields.

Construction of metal-organic frameworks with unsaturated Cu sites for efficient and fast reduction of nitroaromatics:A combined experimental and theoretical study

Metal-organic frameworks(MOFs)functionalized with open metal sites(OMSs)have received widespread attention in various applications due to their fascinating electronic properties and unique interactions with guest molecules.However,rational tailoring of the coordination environment of metal nodes dur-ing the synthesis of MOFs remains a great challenge due to their tendency of saturated coordination with linkers.Herein,we reported the construction of three new MOFs featuring unsaturated Cu(Ⅱ)sites,namely[Cu(HCOO)(pzta)]_(n)(HL-1),{[Cu(PTA)0.5(pzta)(H_(2)O)]·2H_(2)O}_(n)(HL-2)and[Cu(NA)0.5(pzta)]_(n)(HL-3)(Hpzta=3-pyrazinyl-1,2,4-triazole;PTA=terephthalic acid;NA=1,4-naphthalene dicarboxylic acid),based on the mixed-linker strategy via specific selection of versatile Hpzta ligand and carboxylate ligands.Re-markably,the obtained MOFs exhibited excellent activity and good recyclability for the catalytic reduction of nitroaromatics under mild conditions(25℃and 1 atm).In particular,the complete conversion of 4-nitrophenol(4-NP)took only 30 s on HL-2,reaching a record-high TOF value compared with previously reported metal catalysts.The combined experimental and theoretical studies on HL-2 revealed that the open Cu site with positive-charged nature could improve the adsorption and subsequent electron trans-port between the substrates,and was responsible for the outstanding performance.This work shined lights on the further enhancement of performance for MOFs through rational OMSs construction.

Spherical Polyelectrolyte Brush Nanoreactor:Preparation of Hollow TiO_(2) Nanospheres and Characterization by Small Angle X-Ray Scattering

Titanium dioxide(TiO_(2))hollow nanoparticles present significant potential for photocatalytic applications while their straightforward preparation with precise structure control is still challenging.This work reports the approach to preparing tunable hollow TiO_(2) nanospheres by utilization of spherical polyelectrolyte brushes(SPB)as nanoreactors and templates.During the preparation,the evolution of the structure was characterized by small angle X-ray scattering(SAXS),and in combination with dynamic light scattering and transmission electron microscopy.The formation of TiO_(2) shell within the brush(SPB@TiO_(2))is confirmed by the significant increase of the electron density,and its internal structure has been analyzed by fitting SAXS data,which can be influenced by Titanium precursors and ammonia concentration.After calcining SPB@TiO_(2) in a muffle furnace,hollow TiO_(2) nanospheres are produced,and their transition to the anatase crystal form is triggered,as confirmed by X-ray diffraction analysis.Utilizing the advantages of their hollow structure,these TiO_(2) nanospheres exhibit exceptional catalytic degradation efficiency of methylene blue(MB),tetracycline(TC),and 2,4-dichlorophenoxyacetic acid(2,4-D),and also demonstrate excellent recyclability.