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.