Seeded Growth of Au@CuxO Core–Shell Mesoporous Nanospheres and Their Photocatalytic Properties

Abstract

We report a facile synthesis of Au@CuxO core–shell mesoporous nanospheres with tunable size in the aqueous phase via seeded growth. The success of the current work relies on the use of a halide-free copper (Cu) precursor and n-oleyl-1,3-propanediamine as a capping agent to facilitate the formation of a copperish oxide shell with a mesoporous structure and the presence of mixed oxidation states of Cu. By varying the amount of spherical Au seeds while keeping other parameters unchanged, their diameters could be readily tuned without noticeable change in morphology. As compared with commercial Cu2O, the as-prepared Au@CuxO core–shell mesoporous nanospheres exhibit the higher adsorption ability, enhanced activity, and excellent stability toward photocatalytic degradation of methyl orange (MO) under visible light irradiation, indicating their potential applications in water treatment.

Seeded Growth of Gold–Copper Janus Nanostructures as a Tandem Catalyst for Efficient Electroreduction of CO2 to C2+ Products

“…Unlike previous studies widely using hexadecylamine as the capping agent, for the first time, we introduced OPDA as the capping agent for water‐based synthesis of Cu nanocrystals. [ 23 ] Despite the molecular structure similar to oleylamine, it has one more amine group, which exhibits a better colloidal stability in water and provides a better surface protection for Cu nanoparticles. As shown in Figure S9e (Supporting Information), most Au seeds were isolated in the absence of OPDA, indicating homogeneous nucleation and growth of Cu occurred.…”

Synthetic Approaches to Colloidal Nanocrystal Heterostructures Based on Metal and Metal-Oxide Materials

“…Owing to these advantageous features, these CNHSs can serve not only as catalytic nanoreactors or capacitors, but also as sacrificial templates for the preparation of hollow oxide capsules upon etching of the metal core [ 27 ]. Valuable prototypes of Au@Cu 2 O [ 65 , 66 , 67 ] and Au@CeO 2 [ 68 ] CNHSs were also delivered by aqueous routes. Shape-tailored Au@Cu 2 O CNHSs were synthesized by a room-temperature alkaline CuCl 2 reduction with NH 2 OH on shaped Au CNC seeds in the presence of sodium dodecylsulphate as a surfactant [ 65 ].…”

“…Regardless of the appreciable differences between the lattice parameters of Au and Cu 2 O, the as-derived core@shell CNHSs incorporated epitaxial interfaces: the shell could be tailored either with a profile conformal to that of the Au core or shaped independently over a broad size range [ 65 ] ( Figure 1 c–e). More recently, the formation of near-spherical Au@Cu 2 O CNHs with a mesoporous Cu 2 O shell was achieved by reduction of copper acetylacetonate over Au seeds in the presence of ascorbic acid as reductant and of n -oleyl-1,3-propanediamine as capping agent at 100 °C [ 66 ] A conceptually similar approach was utilized to produce electrocatalytically active spherical Au@Cu 2 O CNHSs provided with thin Cu 2 O shell [ 67 ]. In the synthesis of Au@CeO 2 CNHs [ 68 ], a CeO 2 shell with an adjustable degree of continuity could be deposited over Au seeds, starting from Ce(NO 3 ) 2 in an aqueous alkaline medium: the precursor was induced to hydrolyze and oxidize by dissolved O 2 in the presence of citrate anions as a complexing agent for cerium ions and stabilizer for the evolving oxide [ 68 ].…”

“…Unfortunately, in such environments, the heterostructure population is observed to develop with broad size variance and to suffer from poor colloidal stability against irreversible precipitation. A few case exceptions may be found, such as the circumstances in which Fe x O y @Au and Fe x O y @Ag CNHSs bearing thick metal shells were synthesized [ 85 , 86 ] These heterostructures were obtained by directing metal deposition onto weakly-passivated Fe x O y seeds upon reduction of Au(III) salts with hydroxylamine [ 66 ] or AgNO 3 with NaBH 4 [ 85 ], respectively, in aqueous suspension or water-in-oil microemulsions. In another report, the preparation of Fe 3 O 4 @Au CNHSs with a star-shaped Au shell was described [ 87 ].…”

Photocatalytic Removal of Antibiotics on g-C3N4 Using Amorphous CuO as Cocatalysts

“…Transition metal oxides are extremely promising materials for semiconductor photocatalysts ( Zhang G. et al, 2021 ; Shan et al, 2021 ). Especially, CuO is very important due to its high abundance, low cost, non-toxic property, high intrinsic thermal safety, and environmental benignity.…”