Microbial dissimilatory iron reduction (DIR) is widespread in anaerobic sediments and is a key producer of aqueous Fe(II) in suboxic sediments that contain reactive ferric oxides. Previous studies have shown that DIR produces some of the largest natural fractionations of stable Fe isotopes, although the mechanism of this isotopic fractionation is not yet well understood. Here we compare Fe isot...

It is particularly significant to investigate the reduction behavior and existing form of phosphorus in metal slag phase during coal-based for efficient development utilization high-phosphorus oolitic hematite. The minerals their high hematite were systematically investigated using HSC software simulation, thermodynamic calculation, X-ray diffraction (XRD), scanning electron microscopy (SEM), e...

The Thermal Emission Spectrometer (TES) on the Mars Global Surveyor spacecraft has detected deposits of coarse-grained, gray crystalline hematite in Sinus Meridiani, Aram Chaos, and Vallis Marineris. We argue that the key to the origin of gray hematite is that it requires crystallization at temperatures in excess of about 100 ◦C. We discuss thermal crystallization (1) as diagenesis at a depth o...

To investigate the influence of the Morin transition on the photoelectrochemical (PEC) activity of hematite, electronic properties in different magnetic phases were studied on the basis of the first-principles calculations within the GGA+U approximation. The results show that the effective electron mass in the (0001) plane changes remarkably due to the spin−flop transition, while the effective ...

-Terra rossa samples were taken from the B horizons of soil profiles and from cracks within limestone in Italy. The average annual temperature (AAT) of the sites ranged from 8.4 to 20.3~ and the average annual precipitation (AAP) from 511 to 3113 mm, with either a 5-6 month water deficit or a large water surplus. Goethite and hematite were identified in all the samples. Under a moist (> 1700 mm...

Augmenting the donor density and nanostructure engineering are the crucial points to improve solar water oxidation performance of hematite (α-Fe2O3). This work addresses the sluggish water oxidation reaction associated with hematite photoanode by tweaking its internal porosity. The porous hematite photoanodes are fabricated by a novel synthetic strategy via pulse reverse electrodeposition (PRED...

A facile and economic route has been presented for mass production of micro/nanostructured hematite microcrystals based on the wet chemical controllable method. The as-prepared samples were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-Vis absorption spectroscopy. The results showed that the product was mesoporous α -Fe2O3 and near...