Polyoxometalate-based metal–organic framework loaded with an ultra-low amount of Pt as an efficient electrocatalyst for hydrogen production

Abstract

The development of highly active and stable electrocatalysts for HER has been received extensive attention. Among these, minimizing the Pt usage and promoting its utilization efficiency are essential prerequisites for a future hydrogen economy. Herein, we use a new ε-Keggin-type polyoxometalate-based metal–organic framework H₃[Zn₄(bimb)₂][PMo^V₈Mo^VI₄O₄₀]·12H₂O (POMOF-1) as a support to load a low amount of ultrasmall Pt nanoparticles (NPs), and then mix this material with Ketjenblack carbon (KB) to form a new composite catalyst (Pt@POMOF-1/KB). This composite catalyst shows a low Pt loading amount of 0.43 wt% and the average size of the Pt NPs is 1.5 nm. Pt@POMOF-1/KB exhibits a remarkable HER performance in 0.5 M H₂SO₄. It only requires an overpotential to of 23 mV to observe a current density of 10 mA cm⁻², which is superior to that of 20% Pt/C. The mass activity of Pt@POMOF-1/KB is almost 100 and 37 times that of 20% Pt/C at overpotentials of 50 and 100 mV, respectively, as a consequence of the very low noble-metal loading. This result may provide an approach to meet the cost requirements for large-scale applications.