Efficient activity and stability of Cobalt(II) tetraphenylporphyrin/CdS heterostructures for photocatalytic H2 evolution

Abstract

In the realm of photocatalysis, the integration of conventional photocatalysts with porphyrins has been identified as a promising strategy to amplify the efficiency of photocatalytic water splitting for hydrogen evolution. Despite these advancements, there remains an urgent need to investigate and engineer highly effective porphyrins. In this study, we have anchored Cobalt(II) tetraphenylporphyrin (CoT(Bim)PP) onto CdS nanorods, establishing an intrinsic chemical reaction domain that optimizes visible light absorption and expedites the relay of photogenerated carriers. Subsequent characterization confirmed the successful synthesis of CoT(Bim)PP/CdS heterostructures. Notably, the fine-tuned composite of CoT(Bim)PP/CdS exhibited an augmented hydrogen evolution rate, measuring 81.2 mmol∙g-1∙h-1 — a rate approximately 21 times higher than that of the unmodified CdS nanorods. Additionally, it exhibited excellent photostability, maintaining its performance for up to 48 h over 6 cycles with only a marginal decline of 5.8%. Delving into the underlying mechanism, it was discerned that the integration of CoT(Bim)PP with CdS nanorod surfaces curtailed the recombination of photogenerated carriers, simultaneously boosting the efficiency of capturing photogenerated electrons. This synergy cultivates a conducive milieu, predisposing H+ ions to readily engage with electrons, thus magnifying the photocatalytic activity. This research illuminates an innovative paradigm for elevating the photocatalytic prowess of established photocatalysts via the incorporation of proficient porphyrin derivatives.