Can I create an Automator application to start Tomcat when I need?
When you run a shell command or script in Automator it is passed your system's default PATH, not the one in your bash profile. This is why bash cannot find the catalina command.

You should always specify the full path to the command in shell scripts. If it was installed via HomeBrew this is probably /usr/local/bin/catalina but you can confirm this by running which catalina in a terminal session.