Hydrodechlorination (HDC) of CCl4 to CHCl3 is an economically and environmentally attractive alternative for CCl4 disposal. Commercially available 0.3 wt% egg-shell Pt/Al2O3 pellet catalysts from several catalyst vendors were evaluated for CCl4 HDC. In all cases, the catalysts were rapidly deactivated during reaction at 90 degrees C; the CCl4 conversion dropped from 90% to 2% within an hour. A remarkably durable catalyst was obtained by treating the as-received commercial Pt/Al2O3 catalyst with a solution of NH4Cl. The treated catalyst showed excellent CCl4 HDC performance for over 2000 h without deactivation. Treatment with NH4Cl resulted in an increased Pt particle size, which is crucial for a Pt catalyst to resist HCl poisoning.