Controllability of cupric particle synthesis by linear alcohol chain number as additive and pH control in cupric acetate solution using X-ray radiolysis

Abstract

Synthesis and immobilization of caltrop cupric particles onto a Si substrate using X-ray radiolysis directly from a liquid solution of Cu(COOCH3)2 is demonstrated. Caltrop cupric oxide particles are formed in the X-ray radiolysis of aqueous solutions of Cu(COOCH3)2, which also contain methanol, ethanol, 2-propanol or 1-propanol as ^\bulletOH scavenger. The blade lengths of the caltrop particles are dependent on the alcohol chain length. In particular, it was found that an alkyl alcohol whose chain length is longer than four is unable to synthesize any particles in aqueous solutions of Cu(COOCH3)2 in X-ray radiolysis. These results are attributed to the alkyl alcohol chain length influencing the rate of reaction of radicals and determines the solvable ratio of its alcohol into water. In addition, it was found that the synthesized particle geometric structure and composition can also be controlled by the pH of the aqueous solution in the X-ray radiolysis. This study may open a door to understanding and investigating a novel photochemical reaction route induced under X-ray irradiation. The development of the X-ray radiolysis process enables us to achieve the rapid and easy process of synthesis and immobilization of higher-order nano/microstructure consisting of various materials.

Solid/liquid-interface-dependent synthesis and immobilization of copper-based particles nucleated by X-ray-radiolysis-induced photochemical reaction

“…They also reported that the synthesized candy-like Cu 4 O 3 microstructure exhibits good long-term antibacterial activities to both E. coli and S. aureus bacteria because the release of Cu 2+ ions from the Cu 4 O 3 is responsible for the antibacterial activity. On the other hand, Yamaguchi et al have added the X-ray-radiolysisinduced photochemical synthesis of copper oxide materials as liquid-based phase reaction (Yamaguchi et al, 2016a(Yamaguchi et al, ,b, 2017(Yamaguchi et al, , 2019Saegusa et al, 2019). Until now, a single Cu 4 O 3 phase has not been obtained by X-ray-irradiation of the liquid phase.…”

“…We performed synchrotron-radiation-induced X-ray radiolysis experiments using beamline BL8S2 at the Aichi Synchrotron Radiation Center, Aichi Science and Technology Foundation (Yamaguchi et al, 2015(Yamaguchi et al, , 2016a(Yamaguchi et al, ,b, 2017(Yamaguchi et al, , 2019Saegusa et al, 2019). The storage ring current and energy were in operation at 300 mA and 1.2 GeV with super-bending magnets of 5 T. The X-ray spectrum is displayed in Fig.…”

“…Here, we focus on the preparation of metal and oxide nano/microparticles on various substrates as it is a key issue in all fields of modern science and technology covering electronics, photonics, catalysis, biotechnology and so on. Electrochemical and electroless wet chemical deposition and other methods utilizing lasers (Bae et al, 2002;Akamatsu et al, 2004), ion beams (Yamaguchi et al, 2005), electron beams (Jonah & Miller, 1977), X-rays (Ma et al, 2000;Borse et al, 2004;Karadas et al, 2005;Oyanagi et al, 2014;Yamaguchi et al, 2015Yamaguchi et al, , 2016aYamaguchi et al, ,b, 2017Yamaguchi et al, , 2019Saegusa et al, 2019;Bharti et al, 2016;Remita et al, 2007) and -rays (Bá rta et al, 2010;Dey, 2005) have also been studied for incorporating metal clusters onto substrates in the desired chemical and morphological states. In particular, photochemical processes induced by broad-sense light irradiation in heterogeneous systems have been widely used in recent years because of their easy operation and wide applications.…”

“…The reduction effect induced by the additive alcohol has also been investigated in sonochemistry, hydrothermal microwave irradiation and photochemical reactions using UV, laser, X-ray and -ray irradiation. The role of support materials is to assist the electron transfer resulting in reduction of metal or oxide particles and clusters, frequently having the functionality as scavenger (Yamaguchi et al, 2016b(Yamaguchi et al, , 2017(Yamaguchi et al, , 2019Saegusa et al, 2019;Dey, 2005).…”

“…Caltrop cupric oxide micro/nanoparticles including both Cu 2 O and CuO have been directly synthesized from Cu(COOCH 3 ) 2 aqueous solution by X-ray radiolysis with additive alcohols (Yamaguchi et al, 2017(Yamaguchi et al, , 2019Saegusa et al, 2019). Recently, it has been found that alkyl alcohols with a chain length longer than four are unable to synthesize any particles in aqueous solutions of Cu(COOCH 3 ) 2 due to X-ray-radiolysis-induced photochemical reaction (Yamaguchi et al, 2019). From these results it is deduced that the solvable ratio of alcohol to water plays a significant role in the synthesis, growth and aggregation of particles.…”