Transition-metal-doped Fe2O3 nanoparticles for oxygen evolution reaction

Hematite(α-Fe_2O_3)has been extensively studied as a promising photocatalyst,with the capacity to split water under visible light.To tune its electronic structure and improve the performance for oxygen evolution reaction(OER),high-quality single crystals ofα-Fe_2O_3nanoparticles were synthesized and doped by various transition metals(M=V,Cr,Mn,Zn,Co,Ni,Cu,Nb,Mo,Ti)by a molten-salt flux method.Optical,electronic and catalytic properties of transition-metal-dopedα-Fe_2O_3(TM-dopedα-Fe_2O_3)have been systematically investigated.Cobalt has been identified as the best dopant forα-Fe_2O_3,reducing the OER overpotential by 0.16 V with respect to the undoped.     

二元赤铁矿粉粒度级配技术研究

以颗粒级配和紧密堆积理论为基础,优选不同粒度的赤铁矿粉为加重材料,按照不同比例二元复配加入到山东G级高抗硫油井水泥中,通过对水泥浆流变和强度性能的测定,研究了颗粒级配与高密度水泥浆性能的关系。研究结果表明,流变和强度性能好的配方,其级配曲线表现出两种形式,一种是颗粒较细,粒径全部在10um以下;另一种是在10um附近（5um~30um）出现明显的断层区,即该粒径范围的颗粒较缺失,而该粒径范围恰是水泥颗粒的主要分布区,与水泥颗粒形成连续级配,对强度和流变性更有利;流变性能较差的配方,超过70％颗粒的粒径大于10um,尤其是3um-10um的颗粒最为缺失。此结论可作为多元铁矿粉复配的参考。     

Sulfurized hematite for photo-Fenton catalysis

A hematite/amorphous sulfur composite was prepared via simple heating hematite and α-sulfur in Teflon-lined autoclave at low temperature. The composite was characterized by X-ray diffraction(XRD), Raman spectrum,Thermal Gravity Analysis(TGA), Transmission Electron Microscopy(TEM) and X-ray photoelectron spectroscopy(XPS). The results revealed that an allotrope sulfur at 5-37% weight percent was found in the composite.After sulfuration, S_n~(2-) or S_2~(2-) was doped in the lattice of hematite, large amounts of OH and SO_4 were adsorbed on the surface of hematite. Hematite/amorphous sulfur composite had superior photo-Fenton activities than pure hematite. This work also demonstrated that amorphous sulfur also had the activity of photo-Fenton catalysis. OH~-and SO_4 radicals facilitated dye adsorption and acted as a bridge to link H_2 O_2. Moreover, SO_4 radicals on hematite served as electron trapping center that can receive photo-induced electron from conduction band of hematite and transfer it to the adsorbed H_2 O_2, increasing the rate of photo-Fenton reaction eventually.     

电化学表面处理和Ti掺杂制备高光电化学性能的Fe2O3光阳极

通过金属有机物分解的方法合成了Ti掺杂Fe_2O_3光阳极.通过XRD、紫外—可见吸收光谱、X射线光电子能谱(XPS)、扫描电镜(SEM)对Fe_2O_3光阳极进行表征,并对Fe_2O_3光阳极进行了光电化学表征.为了提高Ti掺杂Fe_2O_3光阳极的光电性能,对Ti掺杂Fe_2O_3光阳极的Ti掺杂浓度进行了优化.光电化学测试结果表明电化学表面处理能够提高Ti掺杂Fe_2O_3光阳极的光电化学性能.说明Ti掺杂和电化学表面处理可以增加Fe_2O_3光阳极光电流.基于Mott-Schottky曲线和电化学阻抗谱(EIS)分析了Fe_2O_3光阳极光电流增加的机理.     

Neutron diffraction studies on ‘‘simple’’ iron oxides under pressure： Fe3O4, a-Fe2O3, and FeO

Fe3O4（magnetite）, a-Fe2O3（hematite）, and Fe O（wu¨ stite） are the three major iron oxides and some of the most fundamental solids in nature. Interest in these systems is due to their abundance as minerals in the Earth and other telluric planets as well as their interesting electronic and magnetic properties which have been studied for decades. In this article, we review high-pressure studies on these three systems using neutron powder diffraction in the0–14 GPa range with a particular focus on the behavior of magnetism under pressure. Unpublished data on the pressure dependence of the Ne′el temperature in Fe O are presented. This review will give at the same time an introduction into technical aspects and illustrate the potential of high-pressure neutron scattering in the future.     

The role of isotropic and anisotropic Hubbard corrections for the magnetic ordering and absolute band alignment of hematite α-Fe_2O_3(0001)surfaces

An isotropic (+U) and anisotropic [+(U-J)] corrected Density Functional Theory study for bulk hematite (α-Fe_2O_3) was carried out,and several competing terminations of its (0001) surface modeled via slabs of increasing thickness from twelve to thirty-six Fe-layers.In spite of small quantitative differences,the use of either U or (U-J)corrections showed not to qualitatively affect the results of the simulations both for bulkα-Fe_2O_3 and the lowestenergyα-Fe_2O_3(0001) surface studied,regardless of the thickness of the slab used.The energy favored antiferromagnetic ordering of bulkα-Fe_2O_3 was preserved in the relaxed slabs,with the largest surface-induced effects limited to the outermost three Fe-layers in the slabs.Mixed O-and Fe-terminations were found to be energetically favored and insulating.Conversely,fully O-or Fe-terminated surfaces were calculated to be energetically disfavored and metallic.Finally,the role of Fe-or O-termination for the semiconducting or metallic nature as well as absolute band alignment ofα-Fe_2O_3 (0001) surfaces was analyzed and discussed with respect to the challenges in enhancing the activity ofα-Fe_2O_3 samples as photo-electrode for water splitting.     

燃料对高磷鲕状赤铁矿气化脱磷的影响

以酒泉烟煤、阳泉无烟煤、焦煤混合物和木炭作为燃料,在900℃下模拟烧结预热层进行焙烧,研究燃料种类和用量对气化脱磷的影响。结果表明：由于不同煤和木炭的挥发分不同,对于气化脱磷的影响不同,在配碳量为4％时,挥发分最高的烟煤脱磷效果最好。