The reaction is endothermic, or in other words, it absorbs heat. This is the way to make hydrogen from coal or coke. The usual way that heat is supplied to the above reaction is to burn some of the product to produce heat. To my knowledge, nobody has ever used a solar concentrator to drive this reaction. It is pretty dumb, though.
Carbon is black, absorbs heat.
Seems like a simple thing to do. There HAS been some interest in using another reaction to store and transport solar heat. I think this reaction is called the reverse methanation reaction. Other reactions involve carbon dioxide and water and carbon and hydrogen. God only knows what.