Flexible nanosheets for plasmonic photocatalysis: microwave-assisted organic synthesis of Ni-NiO@NiCO(OH) 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@NiCO(OH) core-shell@sheet plasmonic photocatalyst. By employing time and power dependent synthesis, this catalyst exhibits flexible NiCO(OH) nanosheets enveloping the Ni-NiO structure, surpassing the pristine Ni@NiO/NiCO core-shell counterpart. Chemical reaction mechanisms suggest that irradiation of pristine Ni-NiO/NiCO nano structures leads to breakage of amorphous NiCO to Ni and CO, which further, in the presence of water solvent, interacts with OH ions leading to the formation of Ni(CO)·Ni(OH). With enhanced light absorption and photocatalytic properties, the resulting core-shell@sheet photocatalyst demonstrates double the hydrogen evolution reaction yield (40 μmol g h) compared to the pristine catalyst (20 μmol g h). The enhanced H yield is attributed to the flexible sheets, cross-dimensional photocatalyst structure, increased surface area for surface reactions, and higher H activity of NiCO(OH). This research showcases the potential of microwave-assisted synthesis in developing flexible nanosheets with superior solar water splitting performance.