Seed‐Induced Growth of Flower‐Like Au–Ni–ZnO Metal–Semiconductor Hybrid Nanocrystals for Photocatalytic Applications

Abstract

The combination of metal and semiconductor components in nanoscale to form a hybrid nanocrystal provides an important approach for achieving advanced functional materials with special optical, magnetic and photocatalytic functionalities. Here, a facile solution method is reported for the synthesis of Au-Ni-ZnO metal-semiconductor hybrid nanocrystals with a flower-like morphology and multifunctional properties. This synthetic strategy uses noble and magnetic metal Au@Ni nanocrystal seeds formed in situ to induce the heteroepitaxial growth of semiconducting ZnO nanopyramids onto the surface of metal cores. Evidence of epitaxial growth of ZnO{0001} facets on Ni {111} facets is observed on the heterojunction, even though there is a large lattice mismatch between the semiconducting and magnetic components. Adjustment of the amount of Au and Ni precursors can control the size and composition of the metal core, and consequently modify the surface plasmon resonance (SPR) and magnetic properties. Room-temperature superparamagnetic properties can be achieved by tuning the size of Ni core. The as-prepared Au-Ni-ZnO nanocrystals are strongly photocatalytic and can be separated and re-cycled by virtue of their magnetic properties. The simultaneous combination of plasmonic, semiconducting and magnetic components within a single hybrid nanocrystal furnishes it multifunctionalities that may find wide potential applications.

Seed‐Mediated Growth of Colloidal Metal Nanocrystals

“…[166,167] Thehybridization of acatalytic metal such as Pt or Pd with aplasmonic metal such as Au or Ag has given rise to anumber of unique photocatalysts. [166,167] Thehybridization of acatalytic metal such as Pt or Pd with aplasmonic metal such as Au or Ag has given rise to anumber of unique photocatalysts.…”

Small Gold Nanoparticles as Crystallization “Catalysts”: Effect of Seed Size and Concentration on Au-ZnO Hetero Nanoparticles

“…22 The Au seed nanoparticles frequently remain attached to the center of the hexagonal base of ZnO pyramid nanocrystals, as can be readily observed from inspection of the TEM images of Figure 1a-c. The Au nanoparticles were synthesized in a polycrystalline form, consisting of multitwinned crystals with the (111) facets exposed.…”

Keimvermitteltes Wachstum kolloidaler Metallnanokristalle

“…Beispielsweise führten Hybridnanokristalle aus einem Edelmetall und einem Halbleiter (z. B. ZnO, MoS 2 und TiO x ) zur Entwicklung einer Reihe von Strukturen für photokatalytische, photovoltaische, wasserspaltende und sensorische Anwendungen …”

“…Werden die Pt-Schalen auf eine Dicke von nur wenigen Atomlagen reduziert, ist eine Kombination aus Ligandeneffekten und geometrischen Effekten zu beobachten. [ [166,167] Ausder Hybridisierung eines katalytischen Metalls wie Pt oder Pd mit einem plasmonischen Metall wie Au oder Ag gingen einige einzigartige Photokatalysatoren hervor. [168] Zu diesem Zweck wurden Au-Nanostäbchen mit Pt-Spitzen für die plasmonengestützte Herstellung von H 2 aus Wasser und Methanol synthetisiert.…”