Making hydrogen and carbon black out of renewable natural gas

Renewable natural gas (RNG), made from the decomposition of organic waste like livestock manure, is not necessarily net-zero if it's burned to run a turbine or drive a car. But what if the RNG is not burned, but is rather pyrolyzed, breaking it down into hydrogen and another product called "carbon black," an essential component of car tires, among other things? Then the hydrogen can be used and the carbon black can be sold in solid form instead of releasing the carbon into the atmosphere. Fro...