Which engine is more efficient in jet engines. Turbo jet or the Turbo fan?

The term "Turbofan" is actually quite broad, but can be broken down into two categories…high and low bypass. The question you are really trying to ask is which engine type (high bypass or low bypass) turbofan engine is more efficient?

High bypass engines are used on most commercial airplanes (except the Concord) and these engines are favorable because they have a balance of high thrust, and efficiency.

Aircraft that need supersonic capabilities (like the Concord) use a low bypass turbofan engine. These engines produce the thrust required to propel a plane beyond the speed of sound, but at the cost of efficiency. They burn a lot of fuel in doing so.

So one could draw the conclusion that high bypass turbofan engines are more efficient, but this would not be true. In order to propel a plane beyond the speed of sound the low bypass turbofan engine is the most efficient way of doing so. On the flipside, the high bypass turbofan engine is most efficient for practical air travel. Both engine types are very different, but each are specialized to achieve different goals.