A "split" bitcoin wallet is a strategy of protecting your bitcoin by having your wallet split into an offline "cold storage" wallet and an online "watching only" wallet.
Create a fedora-25-electrum template using the Qubes VM Manager or running qvm-clone fedora-25 fedora-25-electrum in dom0.
Start the new template: qvm-start fedora-25-electrum qvm-run fedora-25-electrum xterm
Install electrum to fedora-25-electrum template VM. From fedora-25-electrum terminal enter: sudo dnf update. sudo dnf install electrum.
Shut down your fedora-25-electrum template
Create an offline-bitcoin qube based on fedora-25-electrum using the Qubes VM Manager or running qvm-create -t fedora-25-electrum -l black offline-bitcoin and qvm-prefs -s offline-bitcoin netvm none in dom0.
Follow the electrum documentation in creating an offline wallet
Create a watching-bitcoin qubes based on fedora-25-electrum connecting to the internet how ever you prefer using the Qubes VM Manager or running for example qvm-create -t fedora-25-electrum -l green watching-bitcoin and qvm-prefs -s watching-bitcoin netvm sys-whonix in dom0.
Follow the electrum documentation in creating an online watching-only wallet
offline-bitcoin.