3D-printed zeolite 13X-Strontium chloride units as ammonia carriers.

The selective catalytic reduction (SCR) system in automobiles using urea solution as a source of NH suffers from solid deposit problems in pipelines and poor efficiency during engine startup. Although direct use of high pressure NH is restricted due to safety concerns, which can be overcome by using solid sorbents as NH carrier. Strontium chloride (SrCl) is considered the best sorbent due to its high sorption capacity; however, challenges are associated with the processing of stable engineering structures due to extraordinary volume expansion during the NH sorption.