Preparation Of Ultrafine Powders And Study On Anti - Agglomeration Performance

Such precious metals as platinum as well as its compounds act as the major catalyst in the fields of petrochemical engineering and organic synthesis, and the catalytic effect stands out in particular in such reactions as catalytic cracking and hydrogenation reduction. In over a decade, the superfine powder technology rose rapidly and aroused public attention. It’s found that the relatively large specific area pertaining to superfine platinum powder particle enables it to present better catalytic effect than common platinum materials, which arouses the public’s great interest in the synthesis of superfine platinum powder particle and its catalytic application. The catalytic performance of superfine platinum powder particle is known to be closely linked to its size and morphology, hence how to control the synthesis of superfine platinum powder in an effectively manner has become one of the research hotspots of the present superfine powder materials.This paper prepares the superfine platinum powder of different grain sizes and morphologies by the chemical reduction method, makes a comparison on the reducibility between different reducing agents through experiments, including sodium borohydride, sodium citrate, and hydrazine hydrate, and ascertains the appropriate reducing agent for chemical reduction method. With the hydrazine hydrate as the main reducing agent, this paper also studies the influence of such experimental parameters as solution temperature, concentration of reducing agent and chloroplatinic acid and dispersing agent on the size and morphology of the particles hereof by liquid phase reduction method. Moreover, through optimizing the experimental parameters, it’s found that the size and morphology of superfine powder particles can be better with better dispersity while the mass of hydrazine hydrate is2%, the concentration of chloroplatinic acid is5×10-3mol·dm-3, the reaction temperature is500℃and the concentration of PVP is12g·dm-3. In addition, it combines the analysis results of UV-vis、SEM、FTIR、TEM, analyzes and discusses the growth and transformation mechanism of platinum particle in liquid phase, the main reasons for the formulation of agglomeration in the preparation process of superfine powder and the corresponding agglomeration mechanism; moreover, in allusion to the reasons for the agglomeration, it accordingly analyzes and finds out a series of ways to reduce and eliminate the agglomeration in the preparation process of superfine platinum powder.