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.