Modulating CsPbBr3 nanocrystals encapsulated in PCN-224(Zr) for boosting full-spectrum-driven CO2 reduction: S-scheme transfer, photothermal-synergistic effect, and DFT calculations

Abstract

Due to their superior light-harvesting ability and high carrier mobility, CsPbBr₃ perovskites have become alternative catalysts for solar CO₂ reduction. In this study, a p–n heterojunction was assembled by encapsulating CsPbBr₃ nanocrystals into a PCN-224(Zr) framework. Essentially, the p–n heterojunction in tandem induces a strong built-in electric field, leading to interfacial electron redistribution. Based on the well-matched electronic band structures, a staggered S-scheme charge-transfer model was revealed through density functional theory (DFT) calculations, in situ irradiation X-ray photoelectron spectroscopy (ISI-XPS), and fluorescence decay analysis. This band-bending and charge-migration model conferred the architecture with a strong redox ability, sufficient excitation dissociation, and admirable optoelectronic characteristics. Moreover, the heterostructure attained a broad absorption spectrum response, outperforming the photothermal effect. The synergistic effect from the S-scheme charge-transfer pathway and the photothermal effect lead to enhanced efficiency in solar-driven CO₂ reduction. The resulting CsPbBr₃@PCN-224(Zr)-10 photocatalyst delivered an average CO yield and total electron consumption of up to 73.85 and 178.9 μmol g⁻¹ h⁻¹ without a sacrificial agent, representing a 4.47- and 1.47-fold enhancement over CsPbBr₃ and PCN-224(Zr) alone, respectively. This work provides a plausible method towards the design of highly efficient photocatalysts for artificial photosynthesis with photothermal coupling.