Black Phosphorus Nanosheet/CuMn2O4 Nanoparticle Heterojunction as Electrochemical Sensors for Sensitive Detecting Hydrogen Peroxide

Detecting trace amounts of hydrogen peroxide (H₂O₂) is critical in biomedical and environmental fields, yet conventional methods face challenges in efficiency and sensitivity. This study presents a convenient and sensitive heterojunction electrochemical sensor composed of black phosphorus nanosheets (BPNS) and spinel CuMn₂O₄ nanoparticles (BP-CuMn₂O₄) for sensitive H₂O₂ detection. The engineered BP-CuMn₂O₄ heterojunction is fabricated via liquid-phase exfoliation, coprecipitation, and subsequent calcination, featuring a well-defined two-dimensional lamellar morphology with a high specific surface area (68.35 m² g^–1). X-ray photoelectron spectroscopy (XPS) testing confirms the existence of electronic acceptor–donor interfacial interactions between BPNS and CuMn₂O₄. Furthermore, the construction of BP-CuMn₂O₄ heterojunction not only addresses BPNS instability through interfacial P–Cu bonding but also enhances charge transfer efficiency during electrochemical sensing. Consequently, the developed BP-CuMn₂O₄ heterojunction possesses a wide linear detection range (0.3–10 nM), an ultralow detection limit (0.1 nM), and excellent selectivity against common interferents. Additionally, the heterojunction also exhibits robust stability due to synergistic interactions between BPNS and CuMn₂O₄. This work highlights the potential of BPNS-based heterojunctions in advancing electrochemical sensing technologies for biomedical diagnostics and environmental monitoring and offers a scalable strategy to integrate 2D materials with bimetallic oxides for high-performance sensors.