Self-supported Ni 3 Se 2 /Ni(OH) 2 and Ni 3 Se 2 on Ni-foam: nanostructured arrays for the hydrogen evolution reaction

In the present research, self-supported hierarchical nanocomposites of Ni3Se2/Ni(OH)2/Ni and Ni3Se2/Ni were developed and their performance as a hydrogen evolution reaction (HER) catalyst for alkaline electrolytic water splitting was demonstrated. The composite Ni3Se2/Ni(OH)2/Ni was obtained through a hydrothermal process and subsequent selenization reaction by heat treatment, while the Ni3Se2/Ni was synthesized only through a selenization reaction by heat treatment. The materials were characterized by confocal microscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Raman spectroscopy. The results that displayed different structures were grown on the Ni-foam, such as Ni(OH)2 nanoleaflets, Ni3Se2 nanosticks composed of spheres, and Ni3Se2 nanowires between Ni(OH)2 nanoleaflets, for Ni(OH)2/Ni, Ni3Se2/Ni, and Ni3Se2/Ni(OH)2/Ni composites, respectively. The catalysts exhibited an excellent hydrogen evolution reaction activity with overpotentials of 170.0 and 194.8 mV at a current density of 10 mA cm−2, with a Tafel slope of 123.5 and 127.3 mV decade−1 for Ni3Se2/Ni and Ni3Se2/Ni(OH)2/Ni, respectively. Graphical abstract