Size-controlled synthesis of copper nanoparticles in supercritical water

Chemistry in supercritical fluids for the synthesis of metal nanomaterials

“…However, H2O cannot act as a reducing agent and thus the participation of additional reducing agents is indispensable. In this regard, several types of reductants have been studied including formic acid/formate anion, 103,108,109,[112][113][114]157 polyvinylpyrrolidone (PVP), 96,158,159 1-hexanethiol, 104 formaldehyde, 105 hydrazine, 110,160 glucose, 116 and glycerol. 97 Formic acid is convenient to use as it is in liquid form and totally miscible with H2O under ambient conditions, and its thermal decomposition in an aqueous environment yields mostly CO2 and H2.…”

The Roles of Hydrazine and Ethylenediamine in Wet Synthesis of Cu Nanowire

“…However, these are still used as powerful techniques to synthesize nanowire in the high crystalline ratio. The wet synthesis in producing copper nanowires had been explored by many authors using different capping agents and reductors [8][9][10][11][12][13]. Perhaps, the simplest and fastest in producing copper nanowire in wet synthesis is done using copper salt, N 2 H 4 (hydrazine) as a reductor, and an amine group as a capping agent such as done by Rathmell and his group [11][12].…”

“…Many authors have studied different kinds methods to synthesize copper nanowires, including synthesis using template materials [1][2][3][4][5][6], solvothermal or hydrothermal [7,8], and wet synthesis [9][10][11][12][13]. Although the template technique produces a quite clean and straight copper nanowires, but the process requires cleaning the sacrificed materials which considered as a delicate and time-consuming process.…”

“…A further study was carried by another group using hydrazine as the reductor but by replacing ethylenediamine with oleylamine solution through a Ni(acac) 2 catalytic formation process in searching the effective process [14]. Using ethylenediamine tetraacetic acid (EDTA) as capping agent and Na OH together with supercritical water, the synthesis of CuNW was carried successfully from a precursor copper sulfate [8].…”

“…Although the template technique produces a quite clean and straight copper nanowires, but the process requires cleaning the sacrificed materials which considered as a delicate and time-consuming process. The solvothermal and template technique might produce a long nanowire ranging about hundred nanometers in diameter with ten micrometers in length [1][2][3][4][5][6][7][8], but the process usually took a number of hours. And therefore, it is considered as time-consuming.…”