Absolutely, as they have been given more.
You are referring to the idea of a progressive income tax, meaning tax rates increase as a person's income increases. This is the tax system utilized by almost all developed countries, and for good reason. The moral justification of the rich being obligated to give back more to society lies in the fact that generally, the rich have taken more from society. While individual effort is no doubt a significant aspect of a person's ability to amass wealth, there are background factors which play a much larger role. Economic exchange, the route to wealth, is only possible due to a strong community and economy. In a ravaged, third world country, a man could work as hard as any other, but still fail to become as prosperous because they suffer from a lack of advantages such as inadequate education, fewer economic connections, etc. Even here in America, your capability to get richer than the next guy is in part influenced by an upper hand you have been given at some point in your life, one you may not even see or understand. Therefore, we can assume that to some degree, those who achieve have benefited from these advantages that the poor have not. Thus, it makes sense that they should carry a greater responsibility to contribute to society.