A systematic comparative study of the efficient co-catalyst-free photocatalytic hydrogen evolution by transition metal oxide nanofibers

摘要

The efficiencies of a series of hydrogen evolving catalysts based on metal oxide nanofibers (NiO, Co3O4, Mn3O4) are investigated for the photocatalytic hydrogen evolution from water without using any co-catalyst under the visible light irradiation by using triethanolamine (TEOA) as an electron donor and Eosin-Y (EY) dye as a photosensitizer. It is found that the photocatalytic hydrogen evolution activities follow the order as: Mn3O4Co3O4NiO (196 mu molg(-1)h(-1), 5552 mu molg(-1) h(-1), 7757 mu mol(-1)h(-1), respectively). Moreover, the catalytic behavior of these nanofibers on the hydrogen production has been also compared to bulk forms of NiO, Co3O4 and Mn3O4 by producing hydrogen 937 mu molg(-1)h(-1), 901 mu molg(-1)h(-1) and 135 mu molg(-1)h(-1), respectively. The nanofiber structures demonstrated much higher photocatalytic activity than bulk forms due to the effect of the increased surface to volume ratio deduced from the fibrous character. The photocatalytic plausible pathway for the hydrogen production is also discussed. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.