Balancing photocatalytic efficiency and ecological safety: an S-scheme LaCoO3/PTP-DABDT heterojunction for "Kill-and-Clean" algal bloom control without secondary pollution

The conflict between high-efficiency algal inactivation and ecological safety represents a critical bottleneck in the photocatalytic control of harmful algal blooms (HABs). Conventional copper-based photocatalysts, although effective, often cause severe secondary pollution and aquatic toxicity. To address this trade-off, we constructed a biologically safe S-scheme heterojunction by covalently anchoring LaCoO 3 (LCO) octahedrons onto PTP-DABDT amide–imine functional polymers. Unambiguous spectroscopic evidence, including femtosecond transient absorption (fs-TA) spectroscopy and in-situ irradiated X-ray photoelectron spectroscopy (XPS), confirms the formation of an internal electric field (IEF). This field drives ultrafast S-scheme charge transfer, effectively suppressing charge-carrier recombination while preserving strong redox potentials. Consequently, the optimized 20LCO/PTP-DABDT composite exhibits a remarkable “Kill-and-Clean” effect, achieving 64.39% degradation of chlorophyll-a in Microcystis aeruginosa to suppress algal blooms while simultaneously degrading the released microcystins. More importantly, comparative toxicity analysis reveals a paradigm shift: unlike conventional Cu-based algicides, which induce 100% mortality in non-target organisms ( Lateolabrax japonicus ), our system maintains a survival rate exceeding 90%. This study presents a pioneering “ecological regulation” strategy, offering a sustainable solution that balances efficient algal inactivation with intrinsic environmental biosafety. A LaCoO 3 /PTP-DABDT S-scheme heterojunction was developed for photocatalytic algal control, achieving 64.39% chlorophyll-a degradation and microcystin removal, while maintaining > 90% fish survival, thus balancing efficiency with ecological safety. Download: Download high-res image (418KB) Download: Download full-size image