One‐Pot Synthesis of Octahedral Cu₂O Nanocages via a Catalytic Solution Route

Abstract

lithography process, using the increase in the T g of the photoresist particles caused by UV-induced crosslinking. Subsequent deposition of silica through the patterned-colloidal mask yielded ordered domains of nanoscale-hole arrays on a micrometer length scale. The present technique produces a spatially organized mask with multiple length scales for colloidal lithography. As such, various functional materials can be deposited through these multiscale colloidal masks, fabricating nanopatterned substrates, which are of practical significance in a wide range of applications from biosensors to optoelectronic devices. ExperimentalSynthesis of Photoresist Particles: MMA (Aldrich, > 99 %) and GMA (Aldrich, > 95 %) were used as supplied. Potassium persulfate (KPS) was used as an initiator for emulsion polymerization. A 100 mL two-necked round-bottom flask was filled with KPS dissolved in 50 mL of distilled water, and a monomer mixture of MMA and GMA. The content of KPS was fixed at 1 wt.-%. The content of GMA was varied in the range 5-30 wt.-% of the total monomer content, which was fixed at 10 wt.-%. The system was kept under a nitrogen atmosphere and the reaction mixture was stirred magnetically at 300 rpm. When the KPS was dissolved completely, the mixture was heated to 75°C using an oil bath. After 12 h, the mixture was separated by centrifugation and was purified with distilled water several times. The size of the particles, measured by SEM, ranged from 360 to 420 nm. Later, the cationic photoinitiator, Irgacure 250, was introduced to the photoresist particles by spin-coating.Measurement of T g : The glass-transition temperatures of the UV-exposed and UV-screened poly(MMA-co-GMA) particles were determined using a differential scanning calorimeter (DSC, TA Instruments, Q1000) under a nitrogen atmosphere at a heating rate of 10°C min -1 . To measure the T g of UV-exposed particles, the particles were fully baked at 150°C for 2 h after UV exposure, because the crosslinking reaction could proceed during the DSC measurement. Therefore, the measured T g could be higher than the T g of the UV-exposed particles in the patterning. Meanwhile, T g of the UV-screened particles was compared with that estimated using the rule-of-mixtures theory where T g = 115°C for polyMMA and T g = 75°C for polyGMA [19].Deposition of Silica: Silica was deposited in a batch reactor under atmospheric pressure at room temperature. The sample was sequentially exposed to water vapor for 30 min, dried in argon gas for purging the reactor, and then SiCl 4 vapor for 20 min. The reactant vapors were carried by argon gas under atmospheric pressure. The concentration of SiCl 4 was 0.05 vol.-% in moisture-free argon gas and the relative humidity of water vapor was 50 %. (Caution: silicon tetrachloride is a very corrosive liquid. Use it only with adequate ventilation, and wear protective clothing and safety goggles.) The thickness of the silica layer was controlled by the exposure time to the precursor vapor and around 50 nm for 30 min exposure was obtained.

Serial Ionic Exchange for the Synthesis of Multishelled Copper Sulfide Hollow Spheres

“…Herein, we exploited the capacity of the ionic exchange reaction for forming multishelled structures and found that with proper manipulation of a precursor system and thus reaction kinetics, a series of anionic exchanges with a solid precursor can actually be conducted in a consecutive manner, which leads to formation of single-, double-, triple-, or even quadruple shells. More specifically, as shown in Figure 1, we will use a hybrid of cuprous oxide (cuprites, a p-type metal oxide [22][23][24] ) and poly(vinylpyrrolidone) (PVP) as a precursor solid to establish some general principles in controlling ionic exchange and the hollowing process for fabrication of complex multishelled Cu 2 S (chalcocite [25][26][27] ) hollow spheres. The colloidal Cu 2 O spheres ( Figure 1, step 1) were synthesized with a PVP-assisted polyol method (Supporting Information, Section S1), and the product arising from this process was mesocrystalline in nature, in which the Cu 2 O crystallites are actually incorporated with PVP, giving rise to a form of inorganic-organic hybrids.…”

Hollow Structured Li3VO4 Wrapped with Graphene Nanosheets in Situ Prepared by a One-Pot Template-Free Method as an Anode for Lithium-Ion Batteries

“…5 The properties of inorganic hollow structures can be well tuned by tailoring their morphology and crystallinity. [14][15][16] However, it is a great challenge to develop feasible methods for the one-pot, template-free, solution synthesis of single-crystalline particles with well-defined non-spherical morphologies. 17 Here, we reported the preparation of a composite of hollow Li 3 VO 4 microboxes with a wall thickness of about 40 nm wrapped by graphene nanosheets (LVO/G).…”

“…The main action is due to the hollowing of the initial microrods by an oxygen-engaged oxidation process from V 2 O 3 into VO 4 3-, 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 …”

Cuprous oxide/titanium dioxide nanotube-array with coaxial heterogeneous structure synthesized by multiple-cycle chemical adsorption plus reduction method

“…Sensitizing TiO 2 NTAs with a narrow band gap semiconductor can result in the formation of heterogeneous structure and produce a novel photocatalyst with continuously changed band gap, thereby effectively enhancing the photoresponse. It was recently reported that Cuprous oxide (Cu 2 O) can be used as a promising sensitizer due to its nontoxicity, low cost, and outstanding optical properties [13,14]. Cuprous oxide is a typical narrow band gap semiconductor (Eg=2.17eV), and also has a favorable match of energy band structure with TiO 2 in order to separate the photogenerated electron and hole.…”