Don’t ask employees to be passionate about the company!
As we discussed in Stop Demotivating Employees Douglas McGregor explained theory X management (managers believe the workers will do only what they are forced, coerced into doing). Theory Y management starts with the premise that people want to do good work, the job of management is to help them do so (create systems, eliminate roadblocks, etc.). The whole post quoted above does a good job of explaining how to create that environment.
Related: Dangers of Extrinsic Motivation – Why Extrinsic Motivation Fails