Activation of 2D cobalt hydroxide with 0D cobalt oxide decoration for microplastics degradation and hydrogen evolution.

[Display omitted] • Co 3 O 4 @Co(OH) 2 photocatalyst was synthesized by a one-pot hydrothermal method. • Co 3 O 4 @Co(OH) 2 was photocatalytic active in PS MPs degradation and H 2 production. • The photocatalytic degradation was assessed by morphological changes of the MPs. • Photocatalytic H 2 production was of 43 μmol g−1. • Band diagram and mechanism could be proposed for both applications. The 2D semiconductors are important players in environmental and energy fields due to their unique catalytic and physical properties defined by their dimensionality. Versatile functionalities on one 2D matrix will enlarge its application scopes but require dedicated engineering paths. In this work, we present a cross-dimensional strategy by decorating 0D Co 3 O 4 onto 2D Co(OH) 2 to form a multifunctional photocatalyst. The one-pot hydrothermally synthesized Co 3 O 4 @Co(OH) 2 composite is capable of degrading polystyrene microplastics with an efficiency of 40% under 0.495 W white LED illumination. In a separated experiment, H 2 evolution reaction from water splitting was evaluated in absence of sacrificial agents leading to 43 μmol g−1 and to an apparent quantum efficiency of 3.48% at 420 nm. The study of the energy band diagrams by UV–Visible and ambient photoemission spectroscopy and the analysis of the radicals involved in the reaction of photocatalytic degradation allow to unveil the mechanisms for both the processes herein studied. Finally, we could confirm that the heterostructure benefits the redox potentials of 2D and 0D counterparts and facile electron transfers when crossing two different dimensions. These results provide guidelines and inspiration for cross-dimensional activations of low-dimensional materials for versatile functionalities. [ABSTRACT FROM AUTHOR]