Flexible nanosheets for plasmonic photocatalysis: microwave-assisted organic synthesis of Ni-NiO@Ni 2 CO 3 (OH) 2 core-shell@sheet hybrid nanostructures.

Visible light-active nickel-based plasmonic photocatalysts provide a cost-effective alternative to noble metals. However, their rarity, fragility, and limited understanding pose challenges. This work presents a microwave-assisted organic synthesis of a Ni-NiO@Ni 2 CO 3 (OH) 2 core-shell@sheet plasmonic photocatalyst. By employing time and power dependent synthesis, this catalyst exhibits flexible Ni 2 CO 3 (OH) 2 nanosheets enveloping the Ni-NiO structure, surpassing the pristine Ni@NiO/NiCO 3 core-shell counterpart. Chemical reaction mechanisms suggest that irradiation of pristine Ni-NiO/NiCO 3 nano structures leads to breakage of amorphous NiCO 3 to Ni 2+ and CO 3 2- , which further, in the presence of water solvent, interacts with OH - ions leading to the formation of Ni(CO 3 )·Ni(OH) 2 . With enhanced light absorption and photocatalytic properties, the resulting core-shell@sheet photocatalyst demonstrates double the hydrogen evolution reaction yield (40 μmol g -1 h -1 ) compared to the pristine catalyst (20 μmol g -1 h -1 ). The enhanced H 2 yield is attributed to the flexible sheets, cross-dimensional photocatalyst structure, increased surface area for surface reactions, and higher H 2 activity of Ni 2 CO 3 (OH) 2 . This research showcases the potential of microwave-assisted synthesis in developing flexible nanosheets with superior solar water splitting performance.