Plasma functionalized MoSe₂ for efficient nonenzymatic sensing of hydrogen peroxide in ultra-wide pH range

Enzymatic sensors have inherent problems such as the low stability and limited pH range in industrial and biomedical applications and therefore, more efficient nonenzymatic sensors are highly desirable. Herein, plasma-functionalized defective MoSe₂ is prepared and studied as a highly efficient catalyst for electrochemical sensing of H₂O₂. Experiments and theoretical computations show that the plasma-induced Se multi-vacancies and nitrogen dopants generate new active sites, expose more edge active surfaces, narrow the bandgap, and strengthen binding with the center dot OH intermediate, which imparts new fundamental knowledge about the roles of defects in catalysis. The defective MoSe₂-catalyzed sensor delivers competitive performance in hydrogen peroxide detection such as a low detection limit of 12.6 nmol/L, wide operational pH range of 1-13, good long-term stability, and high selectivity. The portable sensor produced by screen printing confirms the excellent commercial potential and in addition, the results not only reveal a novel concept to design and fabricate high-performance sensors for H₂O₂ but also provide insights into the effectiveness of surface modification of diverse catalytic materials.