Cocatalytic Effect of SrTiO₃ on Ag₃PO₄ toward Enhanced Photocatalytic Water Oxidation

Abstract

Ag3PO4 has been reported to be an excellent photocatalyst for O2 evolution from aqueous solution, which makes it a promising candidate for designing a Z-scheme water-splitting system. In this work, in order to further improve the photocatalytic activity, a series of SrTiO3/Ag3PO4 composite photocatalysts was constructed by introducing SrTiO3 (with a less positive valence band minimum) to Ag3PO4 and was synthesized by two consecutive hydrothermal processes. The obtained photocatalysts were systematically characterized by XRD, SEM, BET, UV–vis, etc., showing that SrTiO3/Ag3PO4 composites were formed by coating SrTiO3 onto a Ag3PO4 polyhedron. Photocatalytic O2 evolution results demonstrated that a small amount of SrTiO3 brought about significant enhancement of photocatalytic activity of Ag3PO4 and that the apparent quantum yield at 420 nm reached 16.2% with a molar ratio of SrTiO3 to Ag3PO4 equal to 1/20, which led to the fact that SrTiO3 could serve as cocatalyst for water oxidation providing both accelerated electron–hole separation by band gap alignment and more active sites by enlarged surface area.

Graphene-wrapped Ag 3 PO 4 /LaCO 3 OH heterostructures for water purification under visible light

“…This approach exploits the combination of a wide band gap semiconductor with a narrow band gap semiconductor and seeks to identify the parameters that affect the physicochemical properties as well as the photocatalytic activity. Since, both the conduction band minimum (CBM) and valence band maximum (VBM) of LaCO 3 OH are negative compared to those of Ag 3 PO 4 , various oxidation reactions can be initiated in the APO/LCO composite [27,28]. In addition, carbon based materials such as g-C 3 N 4 , graphene (GR) are also recognized as a large surface area materials with high electronic conductivity and with scope for tailored morphologies.…”

Electronic Structures and Photocatalytic Responses of SrTiO3(100) Surface Interfaced with Graphene, Reduced Graphene Oxide, and Graphane: Surface Termination Effect

“…These STO-based composites show significantly enhanced photocatalytic activity. [20][21][22][23][24][25][26][27][28][29] Recently, graphene (GR), a two-dimensional carbon material with very high mobility of charge carriers, has been used to synthesize STO/GR nanocomposites as a photocatalyst by Xian et al 30 The experimental results show that compared to the pure STO nanoparticles, the STO/GR composites exhibit significantly enhanced photocatalytic activity under ultraviolet (UV) light irradiation.…”

Magnetic core–shell carbon microspheres (CMSs)@ZnFe2O4/Ag3PO4 composite with enhanced photocatalytic activity and stability under visible light irradiation

“…It is also known that the room-temperature photoluminescence (PL) emission spectrum could be used to investigate the migration and separation efficiency of photogenerated charge carriers in the samples. And lower PL emission intensity implies a lower electron-hole recombination rate and corresponds to higher photocatalytic activity [1,35]. Thus in this study, the PL emission spectra of the as-prepraed catalysts were recorded.…”

“…The methods include innovations in structure and morphology (N-dimensional nanostructures or facet-controlled structure) [5][6][7][8][9][10][11][12][13], cation/anion doping [14], metal deposition [15][16][17][18], immobilization with the support materials (such as graphene [19][20][21][22][23], CNTs [24,25], bentonite [26], polyacrylonitrile nanofiber [27,28], attapulgite [29], hydroxyapatite [30], layered double hydroxides [31], or flaky layered double hydroxides [32]), and fabrication of a special heterojunction/core-shell structure with other appropriate semiconductors, for example, Ag 3 PO 4 /WO 3 [33], Ag 3 PO 4 /CeO 2 [34], Ag 3 PO 4 /SrTiO 3 [35], Ag 3 PO 4 /Cr-SrTiO 3 [36] , Ag 3 PO 4 /In(OH) 3 [37], BiOCl/Ag 3 PO 4 [38], Ag 3 PO 4 /BiVO 4 [39], Ag 3 PO 4 /Bi 2 MoO 6 [40], BiPO 4 /Ag 3 PO 4 [41], Ag 3 PO 4 /N-Sr 2 Nb 2 O 7 [42], AgX/Ag 3 PO 4 (X = Cl, Br, I) [43][44][45], Ag@(Ag 2 S/Ag 3 PO 4 ) [46], g-C 3 N 4 -Ag 3 PO 4 …”