Exploring the effect of isomorphically Al-substituted on the thermodynamical and structural properties of hematite and goethite – A DFT investigation

Towards sustainable photoelectrodes for solar to hydrogen conversion through the combination of earth-abundant elements

“…Chemical shifts to lower binding energies observed in O 1s spectra (Fig. S9e-h) corroborate that the introduction of dopants gave a more ionic character to metal-oxygen bonds at the surface of the photoanodes 31 . Also, Al 2p peaks at 73.4 eV for H-Al and H-Al-Zr photoanodes show the presence of Al 3+ (Fig.…”

“…First-principles DFT calculations show Al 3+ substitutes Fe 3+ ions giving a more ionic character to the bonds with oxygen, causing minor changes in the local energy levels. 31 Hence, Al 3+ induces a local negative strain in its surroundings lattice…”

Dual modification on hematite to minimize small polaron effects and charge recombination for sustainable solar water splitting

“…S13e–h†) corroborate that the introduction of dopants gave a more ionic character to metal–oxygen bonds at the surface of the photoanodes. 29 Moreover, the Al 2p peaks at 73.4 eV for H-Al and H-Al–Zr photoanodes show the presence of Al 3+ (Fig. S12c†), while Zr 3d spectra with doublet Zr 3d 3/2 (181.6 eV) and Zr 3d 5/2 (184.0 eV) shown in Fig.…”

“…First-principles DFT calculations show Al 3+ substitutes Fe 3+ ions giving a more ionic character to the bonds with oxygen, causing minor changes in the local energy levels. 29 Hence, Al 3+ induces a local negative strain in its surrounding lattice due to the shorter bonds with oxygen, 30 which associated with its stable valence state induces conductivity increase by impacting polaron migration. 31…”