Nanomaterials - 02

Abstract

Hetero-assembly of different nanosheets and the interfacial synergistic effect are expected to enhance catalytic activity of the resultant composites.[1] Meanwhile, modulation of atomic composition and introduction of vacancies are also effective strategies to improve the performance of multicomponent catalysts.[2] In the current work, monolayer NiFe-LDH nanosheets with vacancies (NiFe-LDHV) were firstly prepared (Fig.1 a&a₁). Then, hetero-assembly of LDH nanosheets with oppositely charged reduced graphene oxide (rGO) or molybdenum disulfide (MoS₂) nanosheets was conducted, respectively (Fig.1 b&b₁, c&c₁). The activities of the LDH nanosheets after vacancy generation as well as their hetero-assembed composites in electrochemcial water splitting were studied and compared in Figure 1a₂-c₂. NiFe-LDHV/rGO exhibited the lowest overpotential of 218 mV for oxygen evolution reaction (OER) at 10 mA cm-2 (Fig.1 b₂), while NiFe-LDHV/MoS₂ exhibited a low overpotential of 194 mV at 10 mA cm-2 for hydrogen evolution reaction (HER) (Fig.1 c₂), respectively. The enhanced activity of the composites is attributable to a possible electronic coupling effect generated at the interfaces between LDH nanosheets and rGO or MoS₂, which synergistically promotes the adsorption of OER and HER intermediates, thereby effectively accelerating the water splitting reaction. These results suggest that the modulation of the composite interface provides a promising approach for designing advanced electrocatalysts.