Highly stable and re-dispersible nano Cu hydrosols with sensitively size-dependent catalytic and antibacterial activities

Abstract

Highly stable monodispersed nano Cu hydrosols were facilely prepared by an aqueous chemical reduction method through selecting copper hydroxide (Cu(OH)2) as the copper precursor, poly(acrylic acid) (PAA) and ethanol amine (EA) as the complexing agents, and hydrazine hydrate as the reducing agent. The size of the obtained Cu colloidal nanoparticles was controlled from 0.96 to 26.26 nm by adjusting the dosage of the copper precursor. Moreover, the highly stable nano Cu hydrosols could be easily concentrated and re-dispersed in water meanwhile maintaining good dispersibility. A model catalytic reaction of reducing p-nitrophenol with NaBH4 in the presence of nano Cu hydrosols with different sizes was performed to set up the relationship between the apparent kinetic rate constant (kapp) and the particle size of Cu catalysts. The experimental results indicate that the corresponding kapp showed an obvious size-dependency. Calculations revealed that kapp was directly proportional to the surface area of Cu catalyst nanoparticles, and also proportional to the reciprocal of the particle size based on the same mass of Cu catalysts. This relationship might be a universal principle for predicting and assessing the catalytic efficiency of Cu nanoparticles. The activation energy (Ea) of this catalytic reaction when using 0.96 nm Cu hydrosol as a catalyst was calculated to be 9.37 kJ mol(-1), which is considered an extremely low potential barrier. In addition, the synthesized nano Cu hydrosols showed size-dependent antibacterial activities against Pseudomonas aeruginosa (P. aeruginosa) and the minimal inhibitory concentration of the optimal sample was lower than 5.82 μg L(-1).

Nano-Strategies to Fight Multidrug Resistant Bacteria—“A Battle of the Titans”

“…and Zhang et al . showed that copper NPs are capable of inhibiting the growth of MDR bacteria, namely, P. aeruginosa and MRSA (Zhang et al, 2014 , 2015b ; Kruk et al, 2015 ). The antimicrobial activity of these NPs is comparable to that of AgNPs but at a lower cost (Kruk et al, 2015 ).…”

One-step synthesized 3D-structured MOF foam for efficient and convenient catalytic reduction of nitrogen-containing aromatic compounds

“…As the molecular weight of HKUST-1 is 604.87 g/mole, the amount of Cu within HKUST-1 foam could be estimated as 10.5 mol% of HKUST-1. Interestingly, in comparison with the many reported catalysts, HKUST-1 foam had certainly exhibited noticeably higher TOF and AF than many reported Cu-based and other catalysts [45][46][47][48][49][50], validating that HKUST-1 foam was a promising catalyst for 4-NP reduction. To probe in the mechanism of 4-NP reduction to 4-AP by HKUST-1 foam, the chemical compositions and the elemental status of HKUST-1 foam and even the pristine Cu foam were further investigated by XPS in Fig.…”

“…To further compare the catalytic activity of HKUST-1 foam with other reported catalysts, activity factors (AF) and turn over frequencies (TOF) of relevant reported catalysts are calculated using the following equations and summarized in Table 2 [45][46][47][48][49][50][51].…”

Insight into the Morphology‐Dependent Catalytic Performance of CuO/CeO2 Produced by Tannic Acid for Efficient Hydrogenation of 4‐Nitrophenol

“…During the synthetic procedure of CuO/CeO 2 , plenty of capping agents have been employed to stabilize Cu nanoparticles, such as polyethylene glycol, [12] polyacrylic acids, [13] and polyvinylpyrrolidone [14] . Recently, biomolecules or natural substances are believed to be nontoxic and safe to the environment, which curbs the use and generation of hazardous chemicals [15] .…”