PtMn/PtCo alloy nanofascicles: robust electrocatalysts for electrocatalytic hydrogen evolution reaction under both acidic and alkaline conditions

In this study, we synthesized PtM (M = Mn and Co) alloy nanofascicles by a bundle of ultrathin nanowires with a diameter of ∼2.0 nm. Furthermore, the compositions of alloys were tunable. These nanofascicles exhibited significantly enhanced electrocatalytic activity due to their alloy nature, ultrathin size, and attractive morphological features. Noticeably, PtM electrocatalysts exhibited superior HER performances not only in the acidic but also in alkaline conditions when the electrocatalysts were deposited on a carbon paper. Pt8Co demonstrates the smallest η10 value of 26.1 mV under acidic conditions, which is significantly lower than that of Pt/C (63.4 mV). Under alkaline conditions, the η10 of Pt8Co is 47.2 mV, which is substantially lower than that of commercial Pt/C (187.9 mV). Pt6Mn shows the lower η10 values of 39.0 and 67.5 mV under acidic and alkaline conditions, respectively. In addition, PtM electrocatalysts exhibit excellent long-term durability under alkaline conditions.