Colloidal Synthesis of Plasmonic Ultrathin Transition-Metal Oxide Nanosheets

Recently, two-dimensional plasmonic ultrathin transition-metal oxide (TMO) nanosheets have attracted wide attention due to their unique properties. However, the colloidal preparation of these nanosheets with a strong plasmonic absorption and ultrathin nature at the same time still remains to be a great challenge. Herein, a general one-step colloidal method was used to fabricate ultrathin MO3–x (M = Mo or W) nanosheets by using H2MoO4 or H2WO4 as the raw material with the assistance of oleic acid (OA) and oleylamine (OAm). The obtained MO3–x nanosheets were derived from the topotactic phase transformation by the mediated effect of OA and OAm. These MO3–x nanosheets not only displayed intense plasmonic absorptions but also exhibited high specific surface areas (13.97 and 11.82 m2 g–1 for the as-prepared MoO3–x and WO3–x nanosheets, respectively). In addition, these MO3–x nanosheets also showed superior photocatalytic H2 evolution performance through the dehydrogenation of ammonia borane under visible light irradiation. This work was expected to offer a new way for directly synthesizing ultrathin TMO nanosheets.