A facile aqueous-phase synthesis of Co-based nanostructures composed of cobalt hydroxide and cobalt oxide for enhanced photocatalytic activity of dye-sensitized H2 production

Abstract

Transition metal catalysts are more cost competitive than noble metal catalysts, but there is a drawback in that catalyst activity must be greatly increased for industrial use. In this research, we report the formation of cobalt-based mixture nanostructures composed of cobalt hydroxide having high photoelectron attracting force, electron transfer ability, and easy access and cobalt oxide having facile charge transfer based on the interchangeability to significantly increase the activity of transition metal-based catalysts. Furthermore, the Co-based nanostructures (CNS) were easily synthesized via an aqueous-phase synthesis, and the molar ratio of α-Co(OH)2/Co3O4 was controlled by simply varying the reaction time. Due to the well-mixed structure of α-Co(OH)2 and Co3O4, which could have a beneficial effect on each other in a photocatalytic reaction, the CNS exhibited 11 times superior hydrogen production than the commercial α-Co(OH)2 in a photocatalytic hydrogen production reaction.