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TiH2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ti2+ is bonded in a body-centered cubic geometry to eight equivalent H1- atoms. All Ti–H bond lengths are 1.92 Å. H1- is bonded to four equivalent Ti2+ atoms to form a mixture of corner and edge-sharing HTi4 tetrahedra.
TiH2 is Fluorite structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ti2+ is bonded in a body-centered cubic geometry to eight equivalent H1- atoms. All Ti–H bond lengths are 1.92 Å. H1- is bonded to four equivalent Ti2+ atoms to form a mixture of corner and edge-sharing HTi4 tetrahedra.
TiH2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Ti2+ is bonded to six equivalent H1- atoms to form a mixture of corner and edge-sharing TiH6 octahedra. The corner-sharing octahedral tilt angles are 58°. There is two shorter (1.82 Å) and four longer (1.84 Å) Ti–H bond length. H1- is bonded in a trigonal planar geometry to three equivalent Ti2+ atoms.
TiH2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Ti2+ is bonded in a 9-coordinate geometry to nine H1- atoms. There are a spread of Ti–H bond distances ranging from 1.90–2.10 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to four equivalent Ti2+ atoms to form HTi4 tetrahedra that share corners with twelve equivalent HTi5 square pyramids, corners with four equivalent HTi4 tetrahedra, edges with four equivalent HTi5 square pyramids, and edges with four equivalent HTi4 tetrahedra. In the second H1- site, H1- is bonded to five equivalent Ti2+ atoms to form distorted HTi5 square pyramids that share corners with four equivalent HTi5 square pyramids, corners with twelve equivalent HTi4 tetrahedra, edges with eight equivalent HTi5 square pyramids, and edges with four equivalent HTi4 tetrahedra.
Ti2ZrH4 is Spinel structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Zr is bonded to four equivalent H atoms to form ZrH4 tetrahedra that share corners with twelve equivalent TiH6 octahedra. The corner-sharing octahedral tilt angles are 62°. All Zr–H bond lengths are 2.04 Å. Ti is bonded to six equivalent H atoms to form TiH6 octahedra that share corners with six equivalent ZrH4 tetrahedra and edges with six equivalent TiH6 octahedra. All Ti–H bond lengths are 1.89 Å. H is bonded to one Zr and three equivalent Ti atoms to form a mixture of edge and corner-sharing HZrTi3 tetrahedra.
The electrochemical nitrate reduction reaction (NO3RR) on titanium introduces significant surface reconstruction and forms titanium hydride (TiH x , 0 < x ≤ 2). With ex situ grazing-incidence X-ray diffraction (GIXRD) and X-ray absorption spectroscopy (XAS), we demonstrated near-surface TiH2 enrichment with increasing NO3RR applied potential and duration. This quantitative relationship facilitated electrochemical treatment of Ti to form TiH 2 /Ti electrodes for use in NO3RR, thereby decoupling hydride formation from NO 3 RR performance. A wide range of NO 3 RR activity and selectivity on TiH2/Ti electrodes between -0.4 and -1.0 VRHE was observed and analyzed with density functional theory (DFT) calculations on TiH 2 (111). Finally, this work underscores the importance of relating NO 3 RR performance with near-surface electrode structure to advance catalyst design and operation.
A method (500) for producing a titanium product is disclosed. The method (500) can include obtaining TiO2-slag (501) and reducing impurities in the TiO2-slag (502) to form purified TiO2 (503). The method (500) can also include reducing the purified TiO2 using a metallic reducing agent (504) to form a hydrogenated titanium product comprising TiH2 (505). The hydrogenated titanium product can be dehydrogenated (506) to form a titanium product (508). The titanium product can also be optionally deoxygenated (507) to reduce oxygen content.