Can polarized capacitors be used for negative voltage generation?
The only rule for polarized capacitors, such as electrolytic, tantalum etc., is that a potential on a positive (\$+\$) terminal is higher than the potential on a negative (\$-\$) terminal. If you reverse polarity, the polarized capacitor will most probably blow. That said, the capacitor doesn't know what is "negative voltage". As long as \$V_+\$ is higher than \$V_-\$, you're okay.

As for non-polarized capacitors, such as ceramic, film etc., it doesn't matter how you connect them, as they're not polarized.