On sermonaudio.com, you may put the word Catholic or Catholicism in the search engine. You will find many audio sermons on this subject. You will also find some online video sermons.

According to God's Word
Reaching Catholics
http://www.reachingcatholics.org/2000.htm
http://www.reachingcatholics.org/
This radio program encourages Catholics to look to the Bible alone for everything about God. HostMcMahon discusses questions regarding the authority of Scripture. You can listen the radio program online on this website.

How to Lead a Roman Catholic to Christ
SermonAudio.com
https://www.sermonaudio.com/sermoninfo.asp?SID=3120719733
https://www.sermonaudio.com/
This audios sermon is delivered by Dr. John Barnett. If you want to know how lead a Roman Catholic to Christ, then listen to this sermon. You can listen on it online or download it to your computer for offline listening.

Is Roman Catholicism Christian?
SermonAudio.com
https://www.sermonaudio.com/sermoninfo.asp?SID=82092210294
https://www.sermonaudio.com/
This sermon by Dr. Alan Cairns answers the question about Roman Catholicism being a Christian. The sermon is brief, straightforward, and Bible-based.

Roman Catholicism
SermonAudio.com
https://www.sermonaudio.com/search.asp?currSection=sermonstopic&keyword=catholic&keyworddesc=Roman+Catholicism
https://www.sermonaudio.com/
There are many audio sermons about Roman Catholicism. You can find the sermons on Sermon Audio. Just type catholic or catholicism in the search engine.