Can Half-a-Monolayer of Pt Simulate Activity Like That of Bulk Pt? Solar Hydrogen Activity Demonstration with Quasi-artificial Leaf Device

• Published in: ACS applied materials & interfaces 2020-07, Vol.12 (27), p.30420-30430
• Main Authors: Bajpai, Himanshu, Patra, Kshirodra Kumar, Ranjan, Ravi, Nalajala, Naresh, Reddy, Kasala Prabhakar, Gopinath, Chinnakonda S
• Format: Article
• Language: English
• Subjects: Energy, Environmental, and Catalysis Applications
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c07431

Pt is the best cocatalyst for hydrogen production. It is also well-known that the surface atomic layer is critical for catalysis. To minimize the Pt content as cocatalyst, herein we report on half-a-monolayer of Pt (0.5θPt) decorated on earth-abundant Ni–Cu cocatalyst, which is integrated with a quasi-artificial leaf (QuAL) device (TiO2/ZnS/CdS) and demonstrated for efficient solar hydrogen production. For the QuAL, TiO2 is sensitized with ZnS and CdS quantum dots by the SILAR method. The 0.5θPt-decorated Ni–Cu shows an onset potential of 0.05 V vs reversible hydrogen electrode for the hydrogen evolution reaction, which is almost similar to that of commercial Pt/C. Photoactivity of the present QuAL device with either bulk Pt or 0.5θPt-coated Ni–Cu cocatalyst is, surprisingly, equal. Our findings underscore that a fraction of a monolayer of Pt can enhance the activity of the cocatalyst, and it is worth exploring further for the high activity associated with atomic Pt and other noble metals.