In Situ Anchoring Massive Isolated Pt Atoms at Cationic Vacancies of α-NixFe1-x(OH)2 to Regulate the Electronic Structure for Overall Water Splitting

Rational design and preparation of single-atom catalysts provide a promising strategy to significantly improve the electrocatalytic activity for water splitting. In particular, single atoms anchored at cationic vacancies can enhance the stability of the catalysts and improve reaction kinetics. In this work, Pt single atoms are loaded at layered alpha-Ni2/3Fe1/3(OH)(2) by oxidizing Fe2+ with H2PtCl6, and specifically, Pt atoms are anchored at in situ generated iron cationic vacancies during the process, resulting in stabilized Pt single atoms in the surface of alpha-Ni2/3Fe1/3(OH)(2) with the maximum loading of approximate to 6.15 wt%. The Pt single atoms not only act as active sites for hydrogen evolution reaction but also regulate the electronic structure of NiFe hydroxides and activate Ni atoms adjacent to Pt for oxygen evolution reaction. Therefore, the water-splitting electrolyzer assembled with such a bifunctional catalyst shows a smaller overpotential than that with RuO2 and 20 wt% Pt/C catalysts as the anode and cathode, respectively, and efficient solar-to-hydrogen conversion. The results demonstrate the practical application of single-atom Pt catalysts with low cost, large loading, and facile preparation route.

Automated summary

Rational design and preparation of single-atom catalysts can significantly improve the electrocatalytic activity for water splitting. In this work, Pt single atoms were loaded on layered alpha-Ni2/3Fe1/3(OH)(2) with the maximum loading of approx. 6.15 wt%. These Pt single atoms act as active sites for hydrogen evolution reaction and regulate the electronic structure of NiFe hydroxides to activate adjacent Ni atoms for oxygen evolution reaction.