Layered Perovskite Compound NaLaTiO₄ Modified by Nitrogen Doping as a Visible Light Active Photocatalyst for Water Splitting

Abstract

Sr 2 TiO 4 and NaLaTiO 4 are structural congeners with K 2 NiF 4 -type layered perovskite structure. However, nitrogen doping results in distinct modifications to their visible light absorption. Na/La ordering in the structure of NaLaTiO 4 brings interesting structural features that are critical to a wealth of important factors such as nitrogen uptake, defect concentration, microstructures, and so forth. In sharp contrast to nitrogen-doped Sr 2 TiO 4 (i.e., Sr 2 TiO 4−x N y ) whose photocatalytic activity is negligible under visible light illumination, nitrogen-doped NaLaTiO 4 (i.e. NaLaTiO 4−x N y ) demonstrates very high activities for both photocatalytic water reduction and oxidation reactions. High apparent quantum efficiency ∼3.2% at 420 ± 20 nm has been recorded for NaLaTiO 4−x N y , outperforming many other active metal oxynitride photocatalysts investigated under similar conditions. Theoretical calculations reveal that Na/La ordering incurs a strong electric field across Ti(O, N) 6 octahedron layers and breaks the coplanar settlement of highest occupied molecular orbitals and lowest unoccupied molecular orbitals which are helpful to inhibit intralayer charge recombination.

Sn(IV) Polyanionic Materials as Efficient Visible-Light-Driven Water-Splitting Photocatalysts

“…Alternatively, the monoclinic BiVO 4 ( m -BiVO 4 ), which has a decent band gap of 2.4 eV, oxidizes water to O 2 but cannot reduce H + /H 2 because of its misaligned CBM. , The literature abounds with such imperfect photocatalysts. Of studied materials, oxides pervade the mainstream of photocatalysis research − because of their structural stability and tunability, , yet they suffer from a wide band gap often exceeding 3 eV . Replacing oxygen with the less electronegative sulfur and selenide has been the chief hope of rectifying the wide band gap in oxides.…”

Modulating Electronic Structure to Improve the Solar to Hydrogen Efficiency of Cobalt Nitride with Lattice Doping

“…The electrochemical properties and STH conversion performances of these M-Co 3.75 N 0.14 samples increase in the sequence of V-Co 3.75 N 0.14 > W-Co 3.75 N 0.14 > Mo-Co 3.75 N 0.14 , which is in agreement with the trend for the formation of metal−N bonds in M-Co 3.75 N 0.14 . It is well-known that the formation of metal− N bonds boosts the electronic properties of the samples as compared to metal−O bonds 52. Obviously, the formation of metal−N bonds heavily affects the STH conversion performances of the M-Co 3.75 N 0.14 samples.…”

Flat and Stretched Delafossite α-AgGaO2: Manipulating Redox Chemistry under Visible Light

“…The photocatalytic transformation of organic compounds into value-added chemicals is an evolving technique due to its energy saving and environmentally friendly characteristics. − By engineering the band positions of the photocatalysts, a series of redox reactions have been achieved, including hydrogenation, partial oxidation, and coupling reactions. − Since pristine photocatalysts show poor catalytic activities in most organic transformations due to severe recombination of photogenerated charge carriers, − surface engineering is required to accelerate the interfacial charge transfer. − Employing metal nanoparticles can promote spatial charge separation and catalyze elementary reactions in some cases; − however, the cost and stability of the catalysts limit their applications.…”

“…Shape engineering of the photocatalysts to expose desired facets that display unique redox features offers an alternative path for efficient charge separation. − Representatively, the elongated anatase and rutile TiO 2 with dominant (001) and (110) facets show enhanced performances in photocatalytic H 2 evolution and selective coupling of alcohol into pinacols. − Bismuth-based photocatalysts also exhibit a facet-dependent photocatalytic performance toward alcohol oxidation. ,, However, these materials normally have characteristic valence and conduction bands (VB and CB), thus resulting in a limited adjustment of the redox potential for different reactions. , Noticeably, noble metal nanoparticles (NPs) are still required as a cocatalyst to achieve a better catalytic performance. , …”

“…20,25,26 However, these materials normally have characteristic valence and conduction bands (VB and CB), thus resulting in a limited adjustment of the redox potential for different reactions. 15,17 Noticeably, noble metal nanoparticles (NPs) are still required as a cocatalyst to achieve a better catalytic performance. 27,28 Recently, delafossite (ABO 2 ) materials have appeared as promising photocatalysts owing to their rich physicochemical properties originating from a wide choice of A and B site metals.…”