Firefox hijacks YubiKey NFC

I'm using a YubiKey Neo configured as an one-time-password generator. I'd like to use it with the YubiClip app but every time I pass it next to my phone, Firefox (my default browser) opens with a blank tab. Any idea how to make Firefox stop reacting to NFC events? I don't need NFC for anything else than Yubikey so it's okay if some other functionality is broken by doing this.