Highly Efficient Electrochemical Hydrogen Evolution with Ultra-Low Loading of Strongly Adhered Pt Nanoparticles on Carbon.

The development of robust electrocatalysts with low platinum content for acidic hydrogen evolution reaction (HER) is paramount for large scale commercialization of proton exchange membrane electrolyzers. Herein, a simple strategy is reported to synthesize a well anchored, low Pt containing Vulcan carbon catalyst using ZnO as a sacrificial template. Pt containing ZnO (PZ) is prepared by a simultaneous borohydride reduction. PZ is then loaded onto Vulcan carbon to produce a very low Pt content electrocatalyst, PZ@VC. PZ@VC with 2 wt.% Pt shows excellent performance for acidic HER in comparison to the commercial Pt/C (20 wt.%) catalyst. PZ@VC with a very low Pt loading shows significantly low η 10 and η 100 values (15 and 46 mV, respectively). PZ@VC on coating with Nafion (PZ@VC-N) shows further improvement in its performance (η 10 of 7 mV, η 100 of 28 mV) with ≈300 h of stability (≈10 mA cm -2 ) with only 4 µg Pt cm -2 . PZ@VC-N shows a record high mass activity of 71 A mg Pt -1 (32 times larger than Pt/C (20 wt.%) at 50 mV of overpotential. Post reaction characterizations reveal Pt nanoparticles are embedded onto VC with no traces of zinc, suggestive of a strong metal-support interaction leading to this high stability at low Pt loading.