Hollow Multishelled Structured SrTiO₃ with La/Rh Co‐Doping for Enhanced Photocatalytic Water Splitting under Visible Light

Abstract

Photocatalytic overall water splitting (OWS) is an ideal and sustainable solar-to-chemical energy conversion process. [1][2][3][4][5] One important key to improve the solar energy conversion efficiency in this process is enhancing the harvesting of the incident light, which mainly lies on two factors. [6] First, increasing coverage of the solar spectrum by extending the absorption edge of the photocatalysts, especially utilizing visible light (400-700 nm) which occupies 39% of the energy of the total solar irradiation spectrum. [7][8][9][10] Second, sufficient La-and Rh-co-doped SrTiO 3 (STO:La/Rh) hollow multishelled structures (HoMSs) are fabricated by adding La 3+ and Rh 3+ ions during the hydrothermal process of converting TiO 2 HoMSs to STO HoMSs. STO:La/Rh HoMSs have successfully expanded the light absorption edge to 520 nm. Accompanied with the benefits of the unique hierarchical structure and relatively thin shells, STO:La/Rh HoMSs exhibit elevated light-harvesting capacity and charge separation efficiency. Compared with STO:La/Rh nanoparticles (NPs), STO:La/Rh HoMSs demonstrate enhanced photocurrent response, photocatalytic hydrogen evolution activity, and the quantum efficiency. Moreover, overall water splitting is realized by a Z-scheme system combining STO:La/ Rh HoMSs with BiVO 4 (BVO) nanosheets with 1 wt% Pt as the co-catalyst. Steady evolution of hydrogen and oxygen is performed under both visible light and simulated sunlight irradiation. The solar-to-hydrogen efficiency of double-shelled STO:La/Rh HoMS-BVO photocatalysts reaches 0.08%, which is twofold higher than STO:La/Rh NP-BVO photocatalysts.

Sulfur‐Deficient ZnIn2S4/Oxygen‐Deficient WO3 Hybrids with Carbon Layer Bridges as a Novel Photothermal/Photocatalytic Integrated System for Z‐Scheme Overall Water Splitting

“…[1][2][3][4][5][6][7] Photocatalysts with adequate light absorption, efficient carrier generation and transfer, and a low H 2 and O 2 reaction barrier are needed to realize high-performance overall water splitting. [8][9][10][11] Although numerous strategies have been applied to enhance the optical absorption and the charge separation efficiency of photocatalysts, including the structural design and defect engineering of materials, [12][13][14] the construction of hybrid materials, [15][16][17] and the deposition of effective cocatalysts, [18][19][20] a high solar-to-hydrogen (STH) efficiency in overall water splitting remains elusive (The widely reported STH efficiency is around 1%). [21][22][23][24] From the phase-interface perspective, the gas produced by water splitting in the conventional liquid/solid/gas triphase photocatalytic overall water splitting reaction is passively transported through the liquid water, which results in a low diffusion rate of the H 2 and O 2 gas in the liquid water.…”

Simultaneously Efficient Solar Light Harvesting and Charge Transfer of Hollow Octahedral Cu2S/CdS p–n Heterostructures for Remarkable Photocatalytic Hydrogen Generation

“…5a, a characteristic absorption edge in the visible-light range can be observed at ~ 510 nm for CdS [32]. Notably, hollow octahedrons exhibit a stronger light absorption than other products due to the multiple reflections of incident light inside the hollow nanostructure [8][9][10][11][12][13][14]. The improved light capture derived from the hollow structure is expected to enhance the light response capacity of Cu 2 S/CdS for photocatalytic application.…”

“…Among various nanostructures, three-dimensional (3D) hierarchical materials received extensive attention owing to their unique physical and chemical advantages. Particularly, hollow architectures with a larger surface area and abundant reactive sites can enhance solar light utilization and photocatalytic performance [8][9][10][11][12][13][14]. For example, hierarchical Co 9 S 8 @ZnIn 2 S 4 heterostructures as photocatalysts exhibited an excellent hydrogen production rate of 6250 μmol/(g•h) for photocatalytic water splitting [12].…”

“…Hierarchical Co/NGC@ZnIn 2 S 4 hollow heterostructures without cocatalyst presented superior hydrogen generation activity and outstanding stability [13]. Hollow La/Rh-doped SrTiO 3 nanostructures showed a highly efficient hydrogen generation rate owing to their high light absorption ability [14]. Thus, it is a challenge to develop hollow metal chalcogenides nanostructures for photocatalytic water splitting.…”

Multidimensional Tungsten Oxides for Efficient Solar Energy Conversion

“…[59] More importantly, the thin shells constructed by the 0D subunits decrease the diffusion length of minority carriers, thus suppress the charge recombination. [60] However, due to the difficulties in the synthesis of WO 3 HoMSs, reports on their photocatalytic applications are still scarce. [61] Encouragingly, Zhang et al synthesized WO 3 HoMSs with tunable shell numbers and realized the precise carving of shell thickness synchronously by skillfully exploiting the sequential templating approach (STA) process (Figure 7a, b).…”