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.