The word Emoji makes it sound to an English speaker like it should have something to do with emotions (like emoticon does), but that is pure coincidence: it just means 'picture character' in Japanese (see e.g. https://en.wikipedia.org/wiki/Emoji)
While it is a coincidence that e+moji sounds like emotion, that is their purpose: to communicate emotions. And it is the origin of emoticons which preceded them.