Recent Progress in Halide Perovskite Nanocrystals for Photocatalytic Hydrogen Evolution

Abstract

Due to its environmental cleanliness and high energy density, hydrogen has been deemed as a promising alternative to traditional fossil fuels. Photocatalytic water-splitting using semiconductor materials is a good prospect for hydrogen production in terms of renewable solar energy utilization. In recent years, halide perovskite nanocrystals (NCs) are emerging as a new class of fascinating nanomaterial for light harvesting and photocatalytic applications. This is due to their appealing optoelectronic properties, such as optimal band gaps, high absorption coefficient, high carrier mobility, long carrier diffusion length, etc. In this review, recent progress in halide perovskite NCs for photocatalytic hydrogen evolution is summarized. Emphasis is given to the current strategies that enhance the photocatalytic hydrogen production performance of halide perovskite NCs. Some scientific challenges and perspectives for halide perovskite photocatalysts are also proposed and discussed. It is anticipated that this review will provide valuable references for the future development of halide perovskite-based photocatalysts used in highly efficient hydrogen evolution.

Keywords: charge separation; halide perovskite nanocrystals; heterojunction; hydrogen evolution; photocatalysis.

Figure 1

(a) Schematic illustration of the crystal structure of halide perovskite. (b) Colloidal halide perovskite CsPbX₃ NCs (X = Cl, Br, and I) exhibit size- and composition-tunable bandgap energies covering the entire visible spectral region with narrow and bright emission. (c) Typical optical absorption and PL spectra of CsPbX₃ NCs. (d) Typical optical absorption and PL spectra of CsSnX₃ NCs. (b,c) Reproduced with permission [70]. Copyright: 2015, American Chemical Society. (d) Reproduced with permission [71]. Copyright: 2016, American Chemical Society.

Figure 2

(a) Schematic illustration of charge transfer reactions that may occur at the surface and in the bulk of a semiconductor photocatalyst. (b) Energy levels of halide perovskites with the relative potential in photocatalytic applications. (a) Reproduced with permission [88]. Copyright: 2020, Wiley.

Figure 3

(a) Schematic energy band structure of MAPbI₃ powder for the photocatalytic HI splitting reaction. (b) Schematic illustration of the MAPbI₃ powder in dynamic equilibrium in saturated HI solution. The red color arrows represent dissociation and reprecipitation of MAPbI₃ crystal and ions. (c) Constructed phase map as a function of [I⁻] and [H⁺]. Each symbol represents the stable precipitate phases in saturated solutions at each [I⁻] and [H⁺] concentration. Main peaks of precipitated powder are not indexed under some conditions, expressed as empty boxes. (d) Promoted charge separation and enhanced photocatalytic H₂ evolution by formation of a bandgap funnel structure of MAPbBr_3−xI_x near the surface. (e) Schematic band diagram of MAPbI₃ and MAPb(I_1−xBr_x)₃ (x = 0.10) crystal for photocatalytic HI splitting reaction. (a–c) Reproduced with permission [44]. Copyright: 2016, Nature Publishing Group. (d) Reproduced with permission [110]. Copyright: 2018, American Chemical Society. (e) Reproduced with permission [111]. Copyright: 2019, Elsevier.

Figure 4

(a) Schematic illustration of photocatalytic H₂ evolution by MAPbI₃/rGO. (b) Comparison of the H₂ evolution performance of MAPbI₃, MAPbI₃/Pt, and MAPbI₃/rGO. (c) Stability test of MAPbI₃/rGO during 20 cycles of H₂ evolution experiments. Lines with different colors represent different cycles. (d) Photocatalytic H₂ evolution rates of BP/MAPbI₃. (e) Schematic mechanism of the photogenerated charge transfer in the BP/MAPbI₃ composite under visible light irradiation. (a–c) Reproduced with permission [41]. Copyright: 2018, Wiley. (d,e) Reproduced with permission [114]. Copyright: 2019, Elsevier.

Figure 5

(a) Schematic energy levels of MAPbBr₃ and Ta₂O₅ and the redox potentials for HBr splitting reaction. (b) Energy level diagrams of MAPbBr₃ and hole-transporting materials. (c) Schematic illustration of the reaction mechanism for MAPbBr₃ with Pt/Ta₂O₅ and PEDOT:PSS as the electron- and hole-transporting channels, respectively. (d) Schematic diagrams of energy band of MAPbI₃ and TiO₂. (e) Schematic illustration of photocatalytic HI splitting for H₂ evolution by Pt/TiO₂-MAPbI₃ hybrid system under visible light irradiation. (f) Comparison of H₂ evolution activity over Pt/MAPbI₃ and Pt/TiO₂-MAPbI₃. (a–c) Reproduced with permission [115]. Copyright: 2019, American Chemical Society. (d–f) Reproduced with permission [42]. Copyright: 2018, American Chemical Society.

Figure 6

(a) Steady-state PL spectra of the CABB/xRGO composites (x = 0, 1%, 2.5%, 5%). (b) Photocurrent responses of the CABB/xRGO samples (x = 0, 1%, 2.5%, 5%) recorded at 0 V vs. Ag/AgCl electrode. (c) Schematic mechanism of photocatalytic HBr splitting by CABB/RGO under visible light irradiation. (d) In situ observation of the reversible DMASnI₃ transformation process at 80 °C in air. (e) The relative PL intensity of CsPbBr₃/TiO₂ NCs after immersing in Milli-Q water (0–12 weeks). Inset: TEM image of CsPbBr₃/TiO₂ NCs after immersing in Millil-Q water for 12 weeks. (f) Transient photocurrent responses of CsPbBr₃ and CsPbBr₃/TiO₂ NCs electrodes at −0.1 V versus NHE. (a–c) Reproduced with permission [118]. Copyright: 2020, Elsevier. (d) Reproduced with permission [119]. Copyright: 2018, Wiley. (e,f) Reproduced with permission [120]. Copyright: 2018, Wiley.