Am pretty sure you can just do this on icloud.com which wipes it if ever connected to internet, and until then the regular passcode/Touch ID will stop anyone from getting through. Personally would drop it off/send it to Apple for recycling (they give partial store credit for damaged phones now) rather then sell it to some fleaBay reseller scumbag so they can pilfer any data you have left and hawk the parts to your local crooked "phone repair shop" which in turn claims they're using genuine Apple parts.