Bi-modified octahedral cuprous oxide with exposed high-active surface for Fenton-like catalytic degradation of complex polluted water.

Organic pollutants pose a serious threat to aquatic environments, necessitating the development of efficient, cost-effective, and environmentally friendly treatment technologies. In this study, heterogeneous photo-thermally enhanced Fenton-like catalyst bismuth-modified octahedral cuprous oxide microparticles (BiCu2O MPs) was designed for dye contaminant treatmeng. The catalyst features highly active exposed Cu2O {111} facets and is fabricated by in situ reduction to load nanoscale bismuth particles. The incorporation of Bi introduces a localized surface plasmon resonance (LSPR) effect under near-infrared (808 nm) irradiation, enabling excellent photothermal conversion and markedly increasing the local temperature. Under an irradiation power density of 3 W cm-2, the sample rapidly heated to 56.9 °C within 180 s and further reached 70.4 °C at 360 s. This thermal effect facilitates the reduction of Cu2+ to Cu+, thereby sustaining an efficient Fenton-like catalytic cycle. As a result, at pH = 3, the system achieved 99.9 % degradation of MB within 40 min under 2 W cm-2 NIR irradiation, and even under alkaline conditions (pH = 11), more than 98 % of MB was degraded within 100 min. The catalyst maintains strong activity in both natural water systems and after five successive cycles. Furthermore, plant growth and cytotoxicity assays indicate that the degradation products exhibit low biological toxicity. This work provides a new strategy for the design of photothermal-assisted Fenton-like catalysts and shows great potential for environmental remediation applications.