A kitchen apron should be both beautiful and safe, that is, not exposed to burning. It can be glass, ceramics, metal or stone.
Ceramic tile is familiar to everyone, it serves for a long time and looks beautiful, but it requires skill in installation.
Flat clinker brick took a place in the kitchen much later, it attracts lovers of loft and industrial styles.
Glass in the interior of the kitchen will look fresh and modern, you can apply any pattern to it.
If funds allow, it is possible to make a panel behind a stove and a sink from artificial stone.
Perhaps the most non-standard option will be metal as an apron. It is as practical as possible, and you can give it a different look.
All of these materials are classified as non-combustible, so you can not worry about their safety from red-hot particles and fire of gas burners.