Surfactant-free synthesis of ordered 1D/2D NiZn-LDH heterostructure through oriented attachment for efficient photocatalytic CO2 reduction with nearly 100% CO selectivity

Abstract

Ordered assembly of anisotropic one-dimensional (1D) and 2D nanomaterials is necessary for preparing delicate heterostructures with close contact to alleviate the energy and environmental crisis. Here, we exploited oriented attachment, a non-classical growth mechanism, as a tool for preparing ordered 1D/2D NiZn layered double hydroxide (Ni-Zn LDH) heterostructures beyond the use of surfactants. Lattice matching between the (101) plane of 1D nanoneedles (NNs) and the (100) plane of 2D nanosheets (NSs) drives the spontaneous ordered assembly of 1D NiZn-LDH NNs on 2D NiZn-LDH NSs. Accordingly, the oxygen-deficient 1D NiZn-LDH capable of CO2 adsorption is, therefore, well dispersed on the 2D platform. The oriented assembly generates strong and intimate interactions between the 1D and 2D units, enabling the efficient transfer of photogenerated electrons from 2D to 1D NiZn-LDH. The oriented 1D/2D NiZn-LDH heterostructure demonstrates superior CO2 photoreduction performance under visible light irradiation, with a CO yield rate of 16,950 µmol g−1 h−1 and a 100% CO selectivity. The findings demonstrate that the growth of anisotropic nanomaterials can be tailored for advanced heterostructure design through oriented attachment alone.