Evaluation of Micro- and Nanostructured Nickel Oxide as Photocatalysts for Hydrogen Evolution from Water.

摘要

Nickel (II) oxide (NiO) is a p-type semiconductor that has been commonly used as a co-catalyst for photocatalytic water-splitting. Here, NiO is investigated for its optical properties, electrochemical photo-onsets and photo-currents, and photocatalytic activity for hydrogen evolution in 20% aqueous methanol. Nano NiO (10 nm thick, 50-100 nm wide disks) and bulk NiO (0.05-2 m) were synthesized and platinated by photodeposition (1 mol %); the crystal structures were verified by XRD and TEM. We show that NiO is photocatalytically active for H2 evolution from water in the presence of the electron donor methanol. Platinated nano NiO had the highest rate of oxygen evolution (162.3 mol H2 g-1 hr-1), followed by nano NiO (43.1 mol H2 g-1 hr-1), platinated bulk NiO (4.0 mol H2 g-1 hr-1), and bulk NiO (2.0 mol H2 g-1 hr-1). Overall, these findings show the first use of NiO as a water-splitting photocatalyst.