Photoinduced composite of Pt decorated Ni(OH)2 as strongly synergetic cocatalyst to boost H2O activation for photocatalytic overall water splitting.

Graphical abstract Highlights • Pt decorated Ni(OH) 2 composite is highly effective in activating and cleaving H 2 O. • The composite is in-situ grown on semiconductors via photoinduced deposition. • Pt/Ni(OH) 2 -C 3 N 4 achieves an AQE of 1.8% at 420 nm in overall water splitting. • Pt/Ni(OH) 2 enables TiO 2 to split pure water. Abstract Photocatalytic overall water splitting is one of the ultimate goals in solar conversion and the activation and cleavage of H 2 O molecule is the initial and often rate-determining step in this reaction. Through DFT calculations, we designed Pt cluster decorated Ni(OH) 2 nanoparticles (Pt/Ni(OH) 2) as robust cocatalyst capable of activating H 2 O and dissociating HO H bonds. Then the unique structure was fabricated through in-situ photo-oxidation of Ni 2 P to Ni(OH) 2 on semiconductor like C 3 N 4 and subsequent selective photo-deposition of Pt on Ni(OH) 2 surface. Pt/Ni(OH) 2 -C 3 N 4 is much more active in photocatalytic HER, OER and overall water splitting compared with Pt, Ni(OH) 2 and spatially separated co-loaded Ni(OH) 2 -Pt on C 3 N 4. And Pt/Ni(OH) 2 -C 3 N 4 achieves an AQE of 1.8% at 420 nm in overall water splitting by using only 0.3 wt% Pt, superior to most solid-state photocatalytic systems to date. Moreover, Pt/Ni(OH) 2 composite enables TiO 2 to split pure water in good stoichiometry. This work emphasizes the importance of H 2 O activation and may pave the way for enabling single semiconductors to efficiently split pure water. [ABSTRACT FROM AUTHOR]