The batch liquid phase hydrogenation of p-chloronitrobenzene over MO2N resulted in the sole formation of p-chloroaniline. Incorporation of Au nanoparticles (mean size = 8 nm) enhanced hydrogen uptake with a fourfold increase in rate, retention of ultraselectivity with stability over repeated reaction cycles. Reaction exclusivity to p-chloroaniline extended to continuous gas phase operation where Au/MO2N outperformed Au/Al2O3 as a benchmark. Under the same conditions, Pd/MO2N was non-selective, generating nitrobenzene and aniline via combined hydrodechlorination and hydrogenation. These results demonstrate the viability of Au/MO2N as a new catalyst formulation in selective substituted nitroarene hydrogenation. (C) 2012 Elsevier B.V. All rights reserved.