A general strategy toward the large-scale synthesis of the noble metal-oxide nanocrystal hybrids with intimate interfacial contact for the catalytic reduction of p-nitrophenol and photocatalytic degradation of pollutants

The construction of noble metal-oxide nanocrystal hybrids (MOHs) with good interface contact, broadly tunable composition and high yield is critical for their application in the advanced fields. In this paper, a general route was developed for constructing MOHs with intimate interfacial contact based on the coordination of an organic agent with multiple kinds of metal precursors. In the synthesis, critic acid, desirable sources for metal nanoparticles (NPs; for example, Ag+ salts), oxides (for example, Zn2+ salts) and ethylene glycol were dissolved in water. After heating at low temperature to produce the precursor gels and subsequent calcination under air, one kind of the ions (Zn2+) was transformed into an oxide (ZnO) in company with the reduction of another ion (Ag+) to generate metal NPs (Ag). Benefitting from the uniform distribution of Ag and Zn precursor in the gels, the Ag/ZnO composites with good interface contact were finally formed. The Ag/ZnO hybrids can be used as effective catalysts for the catalytic reduction of p-nitrophenol and photocatalytic degradation of pollutants. Under optimized conditions, the Ag/ZnO showed a rate approximately 1.5 times higher than that of Degussa P25 TiO2 for the degradation of rhodamine B. The OH· radicals and ·O2 − play predominant roles in the photocatalytic reaction. The Ag/ZnO can also act as an effective catalyst for the reduction of p-nitrophenol with good reuse performance. The present route is also suitable to construct MOHs with other components (Pt/TiO2, Pt/ZnO, etc.). The route is promising to produce MOHs due to the virtues of the easy synthesis process and high yields.