Rational synthesis of phosphorous rich iridium diphosphide (IrP₂) nanostructures for electrochemical H₂S detection

Although iridium diphosphide (IrP₂) has emerged as a promising electrocatalyst, the harsh synthetic conditions requiring high temperature (≥ 850 ℃) limits its wide application. This paper demonstrates a facile synthetic approach of single-phase IrP₂ nanoparticles under a mild condition. Instead of commonly used iridium chloride precursors (e.g., IrCl_x), Ir(OH)₃ formed via acid/base precipitation reaction was employed as the iridium source. The following phosphorization step at 650 °C under argon atmosphere successfully produced IrP₂ nanoparticles. Moreover, the electroactivity of as-prepared IrP₂ nanoparticles for electrochemical oxidation of hydrogen sulfide (H₂S) was investigated for the first time. IrP₂ nanoparticles showed an excellent amperometric response to H₂S with ca. 2.5-fold greater sensitivity than iridium phosphide (Ir₂P), presenting the feasibility of IrP₂ as an efficient electrode material for electrochemical H₂S sensing.