some torrent files are archived there, but i don't think scihub is serving the pdfs from IPFS, they likely use private storage network.

I believe libgen.fun which is a new (official) libgen mirror is running fully on ipfs, and it serves some scientific papers, but I wasn't able to search by DOI or title there, looks like it redirects to scihub, also there is no index of the papers on IPFS.

Edit: this doc talks about scihub+ipfs (it was created by the leader of Scihub rescue effort on Reddit, /u/shrine): https://freeread.org/ipfs/