To overcome the limitations of active component aggregation and uncontrolled facet exposure typical of impregnation methods， we report a chloride-mediated engineering strategy to precisely tailor the morphology and electronic structure of Fe/MgO-CaO catalysts. Structural characterizations reveal that the gas-etching effect during NH₄Cl pyrolysis creates a porous architecture. Acting as a morphological modifier， NH₄Cl induces the directional growth of MgO-CaO from disordered sheets into a rod-like structure with preferentially exposed（200） facets. At the microstructural level， Cl⁻ doping strengthens the interaction between Fe species and the MgO lattice. This effectively inhibits the agglomeration of active components and promotes the formation of a highly dispersed Mg-Fe-O solid solution， while generating uniformly distributed Lewis acid sites on the catalyst surface. Consequently， the unique rod-like solid solution exhibits excellent structural stability during the catalytic reaction， successfully preventing framework collapse. Consequently， the optimized catalyst（Fe-Cl=1.00） boosted glycerol conversion from 60% to 90% relative to the Cl- free benchmark. This chloride-mediated engineering strategy provides a blueprint for valorizing natural minerals and rationally designing robust non-noble metal catalysts.
