Amorphous nickel hydroxide shell tailors local chemical environment on platinum surface for alkaline hydrogen evolution reaction

Elaborated catalysts design can substantially enhance performance under unfavourable reaction conditions. Amorphous nickel hydroxide proton sieve used to modify local chemical environment on a platinum surface results in unprecedented performance for alkaline hydrogen evolution reaction. In analogy to natural enzymes, an elaborated design of catalytic systems with a specifically tailored local chemical environment could substantially improve reaction kinetics, effectively combat catalyst poisoning effect and boost catalyst lifetime under unfavourable reaction conditions. Here we report a unique design of 'Ni(OH)(2)-clothed Pt-tetrapods' with an amorphous Ni(OH)(2) shell as a water dissociation catalyst and a proton conductive encapsulation layer to isolate the Pt core from bulk alkaline electrolyte while ensuring efficient proton supply to the active Pt sites. This design creates a favourable local chemical environment to result in acidic-like hydrogen evolution reaction kinetics with a lowest Tafel slope of 27 mV per decade and a record-high specific activity and mass activity in alkaline electrolyte. The proton conductive Ni(OH)(2) shell can also effectively reject impurity ions and retard the Oswald ripening, endowing a high tolerance to solution impurities and exceptional long-term durability that is difficult to achieve in the naked Pt catalysts. The markedly improved hydrogen evolution reaction activity and durability in an alkaline medium promise an attractive catalyst material for alkaline water electrolysers and renewable chemical fuel generation.

Automated summary

Elaborated catalysts design can greatly improve performance under unfavorable reaction conditions. The use of amorphous nickel hydroxide proton sieve on a platinum surface creates an unprecedented performance for alkaline hydrogen evolution reaction. Designing catalytic systems with a specifically tailored local chemical environment like natural enzymes can significantly enhance reaction kinetics and increase catalyst lifetime under unfavorable reaction conditions.