CuNi-LDH sheets and CoS nanoflakes decorated on graphitic carbon nitride heterostructure catalyst for efficient photocatalytic H2 production

Abstract

Incorporating cobalt sulfide (CoS) and CuNi-layered double hydroxide (CuNi-LDH) nanospecies on the surface of g-C3N4 by hydrothermal and precipitation methods respectively, ternary heterostructured (CuNi-LDH/CoS/g-C3N4) photocatalysts were synthesized. Morphological analysis verified the ternary heterostructures comprising nanosheet and nanoflake CuNi-LDH, g-C3N4, and CoS. Cu1Ni3-LDH/CoS/g-C3N4 afforded remarkable hydrogen production (3981 µmol/g) and an outward quantum efficiency of 20.1 % using 10 % aqueous TEOA (sacrificial reagent), attributed to the synergistic effect of Cu1Ni3-LDH (hole scavenger) and effective charge carrier transfer channels. These features prolonged the lifetime of the photoinduced charge carriers and increased the photocurrent density for H2 generation. Hydrogen generation with Cu1Ni3-LDH/CoS/g-C3N4 changed minimally after six cycles. The charge transfer mechanism for H2 evolution over CuNi-LDH- and CoS-decorated graphitic carbon nitride was elucidated. This strategy is promising for increasing the efficiency, stability, and recyclability of photocatalysts by using co-catalysts and for utilizing earth-abundant resources for enhancing photocatalytic H2 production.