Vitalize, energize, activate can all mean to arouse to activity, animation, or life something inactive, inert, latent, or arrested (as in development).
Vitalize may stress the arousal of something more or less inert or lifeless to vital activity, often by communicating an impetus or force, or an imparting of significance or interest to (something) or a making one aware of its inherent significance or interest; the term usually suggests a vigor, freshness, or health in the effect.
Energize implies an arousing to activity by an imparting of strength or a source of power that increases capacity for activity or an acting with a vitality presumably induced by such power.
Activate implies a passing from an inactive to an active state; though the process involved can be equivalent to that implied by energize the stress is quite different and is consistently upon an arousing to activity by the influence of an external agent.