I would like to know if I can get/generate semicore pseudopotentials (some core electrons are also considered along with valence electrons) to be used in Quantum Espresso DFT. Actually, it would be more helpful to know the steps/procedure to get semicore pseudopotentials of any materials of the periodic table.
There are many pseudopotential libraries available to choose from. Below is a (most definitely incomplete) list of pseudopotential libraries compatible with Quantum ESPRESSO that are either curated or original reference libraries:
These libraries will provide norm-conserving, ultra soft, and PAW potentials to choose from. Some are harder (contain more semi-core states) than others, so take a look to see if these meet your requirements.
Otherwise, if you are dead set on generating your own pseudopotentials, take a look at these notes prepared by Paolo Giannozzi. You can create pseudopotentials using the atomic (ld1.x) code in QE. Generating good pseudopotentials is a bit of an art and requires a lot of testing. Paolo's notes are definitely worth a read before starting to generate your own pseudos.