Enhanced photoactivity for the methyl orange on heterostructure LaCO3OH/Ni–Fe layered double hydroxides prepared from complexing agent-assisted homogeneous precipitation techniques

Abstract

LaCO3OH/Ni–Fe-LDH was synthesized as a new type of layered double hydroxides (LDHs) by complexing agent-assisted homogeneous precipitation techniques. According multiple characterizations, LaCO3OH/Ni–Fe-LDH has LDH phase with platelet-like particles and mesoporous properties with 141 m2 g−1 of specific surface area. In addition, both lanthanum and iron are present in the composites, resulting in a significant decrease in the band gap to 2.04 eV, which is lower than that of either Ni–Fe-LDH (2.43 eV) or Ni–Al-LDH (4.86 eV). Compared with Ni–Fe-LDH and Ni–Al-LDH, LaCO3OH/Ni–Fe-LDH significantly improved photocatalytic performance and effectively decomposed methyl orange (MO) under visible light exposure. The increased photocatalytic efficiency from LaCO3OH/Ni–Fe-LDH is mainly ascribed to the lower band gap and higher adsorption performance. In addition, LaCO3OH/Ni–Fe-LDH has an interface region produced by the recombination of semiconductors with LaCO3OH and Ni–Fe-LDH structures, which can effectively improve the separation of photocarriers and expand the energy range of photoexcitation. Moreover, a plausible mechanism for photocatalytic decomposition of MO was presented.