You Do Need power plug adapter while traveling from Palau to China.

Here is Why You Need An Adapter

The outlet and plug type used in China are A, C and I and in Palau are A and B. This is how they look like.

Palau

In Palau, outlets of type A and B are in use.

Type A

Type B

China

In China, outlets of type A, C and I are in use.

Type A

Type C

Type I