Sulfurization-Assisted Cobalt Deposition on Sm₂Ti₂S₂O₅ Photocatalyst for Water Oxidation under Visible Light Irradiation

Abstract

Deposition of cocatalyst is an efficient way for photocatalytic water splitting to improve solar energy conversion efficiency, and its deposition method has been known to make a great effect. In this work, we introduced a sulfurization-assisted deposition method to load earth-abundant cobalt cocatalyst for the purpose of promoting water oxidation performance of Sm 2 Ti 2 S 2 O 5 oxysulfide that is characterized with wide visible light absorption. The cobalt deposition introduced here undergoes first formation of CoS x by sulfurization at high temperature and subsequent conversion into CoO x by calcinations in air. Compared to conventionally impregnated cobalt or IrO 2 colloids, the sulfurization-assisted cobalt deposition well maintains structure of photocatalyst and inhibits the formation of defect sites leading to better separation of photogenerated carriers and water oxidation performance. The apparent quantum efficiency of the optimized sample reaches 5.0% at 420 nm. The sulfurization-assisted deposition actually open a new way to modify the (oxy)sulfide semiconductors.

Earth-abundant cocatalysts for semiconductor-based photocatalytic water splitting

“…(iii) Cocatalysts could suppress the photo-corrosion and increase the stability of semiconductor photocatalysts. For instance, many visible-light-responsive semiconductors, such as (oxy)sulfides 12,16,22,27,28,37,52,60,61,79,[81][82][83]85,[97][98][99] and (oxy)nitrides, 25,69,75,76,80,[100][101][102][103][104][105][106] are susceptible to oxidation by photogenerated holes, resulting in their self-decomposition. The loading of cocatalysts on these semiconductors could inhibit their decomposition by extracting the photogenerated holes for O 2 evolution, thus enhancing the robustness of semiconductors.…”

“…In recent years, several cost-effective cocatalysts, such as CoO x , 99,101,102,123,191 Co 3 O 4 , 122 Co-Pi, 106,192 MnO x , 123 NiO x , 123 FeO x , 123 and B 2 O 3Àx N x , 95 for the photocatalytic O 2 -production have been exploited (Table 3). Among them the Co-based cocatalysts have received much attention due to their outstanding performance for O 2 evolution.…”

Understanding the Effect of Crystalline Structural Transformation for Lead‐Free Inorganic Halide Perovskites

“…The prolonged lifetime of charge carriers will be consequently favorable for the photogenerated charge separation and transfer to participate in subsequent surface reactions. [ 30 ]…”

Recent Progress in the Development of Semiconductor‐Based Photocatalyst Materials for Applications in Photocatalytic Water Splitting and Degradation of Pollutants

“…Among them, anatase displays better photocatalytic activity . Since TiO 2 was initially employed as a photocatalyst, hundreds of oxynitride, sulfides, and oxides, such as SnS 2 , ZnO, BiVO 4 , SnO 2 , ZnS, BiOX (X = Cl, Br, I), AgP 3 O 4 , Bi 2 MO 6 (M = W, Mo), H 2 WO 4 , BiPO 4 , ATaO 3 and ANbO 3 (A = Li, Na, and K), ZnSnO 3 , RuO 2 , IrO 2 , LiNbO 3 , Ag 3 PO 4 , AMWO 6 (A = Rb, Cs; M = Nb, Ta), AgMO 2 (M = Al, Ga, In), ZrO 2 , CoS, NiS, NiS 2 , CuS, MoS 2 , MoS 3 , WS 2 , AgTaO 3 , GaN, graphitic carbon nitride (g‐C 3 N 4 ), Ge 3 N 4 , Sm 2 Ti 2 S 2 O 5 , Ta 3 N 5 , TaON, Fe 3 O 4 , metal chalcogenides, SrTiO 3 , NiO, CuO, SrNb 2 O 6 , Sr 2 M 2 O 7 (M = Nb and Ta), Bi 12 TiO 20 , NaNbO 3 , AgBr, SbMO 4 (M = Nb, Ta), Bi 24 Al 2 O, and others have been utilized as a photocatalyst in water purification applications.…”