Flexible nanosheets for plasmonic photocatalysis: microwave-assisted organic synthesis of Ni-NiO@Ni₂CO₃(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@Ni2CO3(OH)(2) core-shell@sheet plasmonic photocatalyst. By employing time and power dependent synthesis, this catalyst exhibits flexible Ni2CO3(OH)(2) nanosheets enveloping the Ni-NiO structure, surpassing the pristine Ni@NiO/NiCO3 core-shell counterpart. Chemical reaction mechanisms suggest that irradiation of pristine Ni-NiO/NiCO3 nano structures leads to breakage of amorphous NiCO3 to Ni2+ and CO32-, which further, in the presence of water solvent, interacts with OH- ions leading to the formation of Ni(CO3)Ni(OH)(2). With enhanced light absorption and photocatalytic properties, the resulting core-shell@sheet photocatalyst demonstrates double the hydrogen evolution reaction yield (40 mu mol g(-1) h(-1)) compared to the pristine catalyst (20 mu mol 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 Ni2CO3(OH)(2). This research showcases the potential of microwave-assisted synthesis in developing flexible nanosheets with superior solar water splitting performance.