Photothermal and pyroelectric effects in hollow FeS₂/CdS nanocomposites for enhanced photocatalytic hydrogen evolution

In this paper, a hollow structure of FeS₂/CdS is designed to improve the photocatalytic generation of hydrogen by capitalizing on the synergistic interplay between the photothermal effect of FeS₂ and the pyroelectric effect of CdS. The heat generated by the photothermal effect of FeS₂ provides the hot end for the pyroelectric effect of CdS, and the condensate in the photocatalytic system provides the cold end. CdS undergoes spontaneous polarization and a thermoelectric impact in response to temperature fluctuations (ΔT), releasing surface charges. This process effectively governs the direction and rate of carrier migration within the FeS₂ nanoparticles. The hydrogen production test demonstrates that FeS₂/CdS-3 exhibited a hydrogen production rate of 154.0 μmol·g⁻¹·h⁻¹, which is 5.8 times higher than that of FeS₂ (23.4 μmol·g⁻¹·h⁻¹), and it has excellent cycle stability. Furthermore, characterization through ultraviolet–visible spectroscopy, photoluminescence, electrochemical impedance spectroscopy, and linear sweep voltammetry confirms the outstanding carrier migration capability of the composite photocatalyst.