I travel with a service dog and he uses a mat like this:
https://www.petsmart.com/dog/bowls-and-feeders/placemats/kong-pet-feeding-placemat-51195.html?cgid=100206
I read recently to never use plastic as it can not be cleaned properly & will hold germs & to always use Stainless. He has two stainless like this:
https://www.tractorsupply.com/tsc/product/ruffin-it-stainless-steel-non-skid-dish?cm_vc=-10005