Efficient electrochemical biosensing of hydrogen peroxide on bimetallic Mo_1-xW_xS₂ nanoflowers

Two-dimensional transition-metal dichalcogenides can serve as emerging biosensing platforms after rational structural optimization. Herein, we develop a series of Mo_1-xW_xS₂ and investigate the composition-dependent sensing of hydrogen peroxide (H₂O₂). Among them, the Mo_0.75W_0.25S₂ affords high sensitivity (1290 μA mM^-1 cm^-2), good selectivity, and wide applicable concentration range (4 × 10^-1-1.0 × 10⁴ μM). As indicated by theoretical investigations, such prominent performance stems from the bimetallic electronic configurations and the enhanced *OH binding on surface. Moreover, the Mo_0.75W_0.25S₂ is capable of monitoring trace amounts of H₂O₂ released from normal cells and various cancer cells, which provides efficient cell detection for clinical diagnosis. In addition, the composition-dependence, as a result of electronic modulation on Mo_1-xW_xS₂ surface, is further evidenced on electrocatalytic hydrogen evolution reaction, which highlights the promise in sensing and electrocatalysis that share similar electrochemical fundamentals.