Method of manufacturing nano-platinum catalyst on nano-sized silicon dioxide

The present disclosure uses a nano-SiO2 powder as a supporter with H2PtCl6 added as an electro-catalyst precursor. A chemical reduction is processed at a high temperature to adhere nano-sized Pt ions on the nano-SiO2 powder through reduction. Thus, a nano-Pt catalyst using nano-SiO2 as supporter is manufactured for fuel cells, organic compound reactions and the textile industry.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This application claims priority from Taiwan Patent Application No. 098136790, filed in the Taiwan Patent Office on Oct. 30, 2009, entitled “Method of Manufacturing Nano-Platinum Catalyst on Nano-Size Silicon Dioxide,” and incorporates the Taiwan patent application in its entirety by reference.

TECHNICAL FIELD OF THE DISCLOSURE

The present disclosure relates to platinum (Pt) catalyst; more particularly, relates to adhering Pt complex ions on a powder of nano-sized silicon dioxide (nano-SiO2) in a reaction using ethylene glycol (EG) at a high temperature for manufacturing a nano-Pt catalyst having a supporter of nano-SiO2.

DESCRIPTION OF THE RELATED ART

A preferred electro-catalyst of direct methanol fuel cell (DMFC) is Pt catalyst particles. A method for manufacturing such Pt catalyst particles is sol-gel stabilization. The sol-gel stabilization is a kind of wet chemistry process where Pt catalyst particles are deposited on carbon electrodes. A solvent and a stabilizer, like EG, are used for reduction with a Pt precursor and a reductant to form a suspension of Pt colloidal particles. Because the stabilizer can not be easily removed, the formed Pt colloidal catalyst is usually directly used in catalytic reactions; or is covered on a supporter and then the stabilizer is removed at a temperature higher than 200° C. before being used in catalytic reactions. However, the existence of the stabilizer and the process of removing the stabilizer at a temperature higher than 200° C. are both not good to the performance of the Pt catalyst used as an electro-catalyst in DMFC. Hence, the prior art does not fulfill all users' requests on actual use.

SUMMARY OF THE DISCLOSURE

The main purpose of the present disclosure is to manufacture a nano-Pt catalyst having a supporter of nano-SiO2.

The second purpose of the present disclosure is to manufacture a catalyst for fuel cells and organic compound reactions.

The third purpose of the present disclosure is to adhere Pt complex ions on a nano-SiO2powder in a reaction using EG at a high temperature.

To achieve the above purposes, the present disclosure is a method of manufacturing a nano-Pt catalyst on nano-sized SiO2, comprising steps of: (a) adding a powder of nano-SiO2into a solution of EG; (b) processing ultrasonic vibration and high speed agitation to obtain a paste of nano-SiO2; (c) adding a solution of EG having an electro-catalyst precursor into the paste of nano-SiO2; (d) processing high speed agitation to obtain a mixed solution; (e) heating the mixed solution at a temperature of 160±10° C. to remove hydrogen and chlorine in the electro-catalyst precursor and to adhere metal catalyst particles in the electro-catalyst precursor to nano-SiO2and thus to obtain a powder of nano-SiO2; (f) hot-drying the powder of nano-SiO2in vacuum with EG being removed; (g) washing the powder of nano-SiO2by using de-ionized water with remained EG being removed; and (h) hot-drying the powder of nano-SiO2in vacuum with de-ionized water being removed. Accordingly, a novel method of manufacturing a nano-Pt catalyst on nano-SiO2is obtained.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Please refer toFIG. 1, which is a flow view showing a preferred embodiment according to the present disclosure. As shown in the figure, the present invention is a method of manufacturing a nano-platinum (Pt) catalyst on nano-sized silicon dioxide (SiO2), comprising the following steps:(a) Pretreatment11: A powder of SiO2is added into a solution of ethylene glycol (EG), where the powder of SiO2having a scale of nanometers or a larger scale.(b) Ultrasonic vibration and high speed agitation12: Ultrasonic vibration and high speed agitation are processed to form a paste of SiO2;(c) Precipitation13: A solution of EG having an electro-catalyst precursor is added into the paste of SiO2, where the electro-catalyst precursor is chloroplatinic acid (H2PtCl6).(d) High speed agitation14: High speed agitation is processed to obtain a mixed solution.(e) Heating15: The mixed solution is heated through microwaving at a temperature of 160±10° C. for 30 minutes to remove hydrogen and chlorine in H2PtCl6and to adhere Pt catalyst particles in H2PtCl6to SiO2and thus to obtain a powder of SiO2. Or, the mixed solution can be heated through thermocouple.(f) Hot-drying16: The powder of SiO2is hot-dried in vacuum while EG is removed.(g) Washing17: The powder of SiO2is washed by using de-ionized water while remained EG is removed.(h) Hot-drying18: The powder of SiO2is hot-dried in vacuum while de-ionized water is removed.

Thus, a novel method of manufacturing a nano-Pt catalyst on nano-SiO2(Pt/nano-SiO2) is obtained.

In the present disclosure, the nano-SiO2powder is used as a supporter; the Pt precursor, raw material; and, EG, reductant. Through chemical reduction, Pt complex ions are reduced to nano-sized clusters and are adhered on the nano-SiO2powder. Thus, adhesion and absorption of the Pt catalyst particles in SiO2is increased. Through doping SiO2(having a smaller adhesion than carbon nanotube) and EG, EG is easily removed through hot-drying in vacuum after the reduction at the high temperature. Since Pt catalyst has high activity, wide application and nano-SiO2can be easily processed to be applied in many fields, Pt/nano-SiO2is fit to be used as a catalyst in direct methanol fuel cell (DMFC) and proton exchange membrane fuel cell (PEMFC). Hence, Pt/nano-SiO2can be used in fuel cells and organic compound reactions, like gas phase dehydrogenation of simple molecules and hydrogen generation through molecular rearrangement.

To sum up, the present disclosure is a method of manufacturing a nano-Pt catalyst on nano-SiO2, where the present disclosure uses a nano-SiO2powder as a supporter of a Pt catalyst; EG is used to be reacted at a high temperature for adhering Pt complex ions on nano-SiO2powders after reduction; adhesion and absorption of the Pt catalyst particles in SiO2are increased; through doping SiO2 (having a smaller adhesion than carbon nanotube) and EG, EG is easily removed through hot-drying in vacuum after reduction at a high temperature; and the present disclosure is thus fit to be applied to fuel cells and organic compound reactions.

The preferred embodiment herein disclosed is not intended to unnecessarily limit the scope of the disclosure. Therefore, simple modifications or variations belonging to the equivalent of the scope of the claims and the instructions disclosed herein for a patent are all within the scope of the present disclosure.