A Non-van der Waals Two-Dimensional Material from Natural Titanium Mineral Ore Ilmenite

Abstract

Two-dimensional (2D) materials from naturally occurring minerals are promising and possess interesting physical properties. A new 2D material "Ilmenene" has been exfoliated from the naturally occurring titanate ore ilmenite (FeTiO 3 ) by employing liquid phase exfoliation in a dimethylformamide solvent by ultrasonic bath sonication. Ilmenene displays a [001] orientation that is confirmed by transmission electron microscopy. Probable charge transfer excitation from Fe 2+ Ti 4+ to Fe 3+ Ti 3+ results in ferromagnetic ordering along with the antiferromagnetic phase accompanied by enhanced anisotropy due to surface spins. The 2D nature and band gap states help ilmenene form a heterojunction photocatalyst with titania nanotube arrays, capable of broad spectrum light harvesting and separating/transferring the photogenerated charges effectively for solar photoelectrochemical water splitting.

FeTiO3 as Anode Material for Sodium‐Ion Batteries: from Morphology Control to Decomposition

“…Moreover, is the most abundant Ti‐containing mineral used for the production of TiO 2 . Natural occurring ilmenite is often associated with variable amount of impurity (mainly Cr, Mg, Mn, V, Al, Si, Ca rare earth depending on the geological history), variable content of titanium ranging from 40 to 65 % (and the formula can be expressed as FeTiO 3 : TiO 2 ) and different possible combination of Fe 2+ /Ti 4+ or Fe 3+ /Ti 3+ . Commercial extraction of titania from ilmenite dates back the 1920’s and nowadays the world production is about 5.3 million metric tons with continuous growing of the worldwide TiO 2 demand, while the ilmenite natural reserves estimated for 800.000 tons .…”

“…Reduced particle size and high specific superficial area can be obtained during the synthesis following wet chemistry routes. Although synthesis of ilmenite with specific morphology have been reported, the bottom up approach may not represent the best preparation method as FeTiO 3 is a cheap natural product and already commercially available. For this reason, the top down approach has been followed: small particles were obtained by ball milling processes followed by hydrothermal treatment leading to a significant modification of the particle's morphology and the appearance of nano‐flower like structures.…”

Two‐Dimensional Amorphous Cr2O3 Modified Metallic Electrodes for Hydrogen Evolution Reaction

“…Subsequent to the discovery of Graphene, a plethora of 2D materials were exfoliated. Among them, the notable 2D materials belonging to the “beyond graphene” regime are hexagonal boron nitrides (h‐BN), transition metal dichalcogenides (TMDs), elemental analogues of graphene such as silicene, germanene, stanene and phosphorene, hematene, ilmenene, and transition metal oxides . These 2D materials exhibit superlative physical and chemical properties when compared to their bulk counterparts and they find innumerable applications in the area of sensors, battery electrodes, and electrocatalysis.…”

Friction of magnetene, a non–van der Waals 2D material

“…The vast majority of 2D materials are produced by cleavage of weak van der Waals (vdW) bonds between layers. However, a series of non-vdW–bonded 2D materials from transition metal oxides have been recently exfoliated ( 6 – 12 ). Of particular note, the iron oxide materials including hematene (Fe 2 O 3 ), magnetene (Fe 3 O 4 ), and chromiteen (FeCr 2 O 4 ) are 2D versions of bulk ores, which present thicknesses down to a monolayer despite featuring covalent bonding out of plane ( 6 – 8 ).…”