Synthesis and photocatalytic activity in hydrogen evolution reaction of nickel-modified g-C3N4

In this work, organonickel complex [NiBr(Mes)(bpy)], where Mes – 2,4,6–trimethylphenyl, bpy – 2,2′–bipyridine, was used for in situ synthesis of NiO x /g-C 3 N 4 (1 wt % of Ni) photocatalyst. The obtained photocatalysts were characterized by XRD, UV–vis spectroscopy, XPS, and HRTEM techniques. The activity of as-prepared [NiBr(Mes)(bpy)]/g-C 3 N 4 (1 wt % of Ni) photocatalyst was tested in photocatalytic hydrogen production from triethanolamine solution (λ = 410 nm). For photocatalytic hydrogen evolution in situ transformation of the deposited [NiBr(Mes)(bpy)] complex to highly dispersive Ni and NiO nanoparticles over the surface of g-C 3 N 4 with simultaneous grow of the hydrogen evolution rate was observed. The activity in H 2 production for this Ni/NiO/g-C 3 N 4 photocatalyst was 5 times higher than in the case of 1 wt % Ni/g-C 3 N 4 photocatalyst prepared by conventional precipitation of Ni from Ni(NO 3 ) 2 by NaBH 4 reduction. The obtained numerical values of activity at photocatalyst loading of 0.2 g L −1 , namely, 340 μmol H 2 h −1 g −1 , are at the level of or exceed the results for systems based on carbon nitride and nickel-containing cocatalysts. • Organonickel complex [NiBr(Mes)(bpy)] was used for active photocatalyst preparation. • [NiBr(Mes)(bpy)]/g-C 3 N 4 (1 wt % of Ni) was tested in H 2 evolution (λ = 410 nm). • Transformation of [NiBr(Mes)(bpy)] into nickel nanoparticles was observed. • Highest activity equal to 340 μmol H 2 h −1 g −1 was achieved using obtained catalyst.