194
S. Luo et al.
Fig. 5.5 The PtPd core–shell catalyst prepared by seed-mediated growth method. Reprinted from
Ref. [63]. Copyright 2014, with permission from American Chemical Society
involved. The main disadvantages of the physical method are that the particles are
not uniform, the shape is difficult to control and large-scale preparation of catalysts is difficult. On the other hand, some physical techniques, such as ultrasound,
microwave, ultraviolet and high-energy ball milling, are frequently used as assistive
means to help chemical synthesis in preparing efficient catalysts.
5.3.1 Sputtering
Sputtering is a commonly used physical technique for the preparation of thin films.
The main principle is to bombard the target with charged particles. When the accelerated ions bombard the target, they will collide with the surface atoms of the target,
and that results in the transfer of energy and momentum. The surface atoms of the
S. Luo et al.
Fig. 5.5 The PtPd core–shell catalyst prepared by seed-mediated growth method. Reprinted from
Ref. [63]. Copyright 2014, with permission from American Chemical Society
involved. The main disadvantages of the physical method are that the particles are
not uniform, the shape is difficult to control and large-scale preparation of catalysts is difficult. On the other hand, some physical techniques, such as ultrasound,
microwave, ultraviolet and high-energy ball milling, are frequently used as assistive
means to help chemical synthesis in preparing efficient catalysts.
5.3.1 Sputtering
Sputtering is a commonly used physical technique for the preparation of thin films.
The main principle is to bombard the target with charged particles. When the accelerated ions bombard the target, they will collide with the surface atoms of the target,
and that results in the transfer of energy and momentum. The surface atoms of the