Efficient electrochemical biosensing of hydrogen peroxide on bimetallic Mo

Two-dimensional transition-metal dichalcogenides can serve as emerging biosensing platforms after rational structural optimization. Herein, we develop a series of Mo1-xWxS2 and investigate the composition-dependent sensing of hydrogen peroxide (H2O2). Among them, the Mo0.75W0.25S2 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 Mo0.75W0.25S2 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 Mo1-xWxS2 surface, is further evidenced on electrocatalytic hydrogen evolution reaction, which highlights the promise in sensing and electrocatalysis that share similar electrochemical fundamentals.