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

Abstract 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 α‐Ni 2/3 Fe 1/3 (OH) 2 by oxidizing Fe 2+ with H 2 PtCl 6 , 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 α‐Ni 2/3 Fe 1/3 (OH) 2 with the maximum loading of ≈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 RuO 2 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.