High-surface-area plasmonic MoO3−x: rational synthesis and enhanced ammonia borane dehydrogenation activity

Abstract

Well-crystallized, high-surface-area plasmonic MoO_3−x was synthesized by combining an evaporation induced self-assembly (EISA) process and a subsequent hydrogen reduction at a certain temperature. The intrinsic anisotropic crystal growth process of tiny MoO₃ nuclei to MoO₃ nanosheets was successfully inhibited. Detailed characterization by means of XRD, TEM, N₂ physisorption, and XPS measurements revealed that the synthesized MoO_3−x not only showed a strong localized surface plasmon resonance (LSPR) under incident light but also had a relatively large specific surface area. The specific surface area (S_BET) of MoO_3−x after reduction at 200 °C was 30.0 m² g⁻¹, which was 22.7 and 9.1 times higher than those of commercially available MoO₃ and our previously reported MoO_3−x nanosheets, respectively. We also demonstrate that such a semiconductor with a large surface area could be used as a highly efficient catalyst that dramatically enhances the dehydrogenation activity for ammonia borane (NH₃BH₃; AB) under visible light irradiation.