<p>Is there any performance impact or any kind of issues?
The reason I am doing this is that we are doing some synchronization between two set of DBs with similar tables and we want to avoid duplicate PK errors when synchronizing data.</p>

Yes, it's okay.
Note: If you have perfomance concerns you could use the "CACHE" option on "CREATE SEQUENCE":
"Specify how many values of the sequence the database preallocates and keeps in memory for faster access. This integer value can have 28 or fewer digits. The minimum value for this parameter is 2. For sequences that cycle, this value must be less than the number of values in the cycle. You cannot cache more values than will fit in a given cycle of sequence numbers. Therefore, the maximum value allowed for CACHE must be less than the value determined by the following formula:"
```
```
(CEIL (MAXVALUE - MINVALUE)) / ABS (INCREMENT)
```
```
"If a system failure occurs, all cached sequence values that have not been used in committed DML statements are lost. The potential number of lost values is equal to the value of the CACHE parameter."