Negative apparent kinetic order in steady-state kinetics of the water-gas shift reaction over a Pt-CeO2 catalyst

The kinetics of the water-gas shift reaction Were Studied on a 0.2% Pt/CeO2 catalyst between 177 and 300 degrees C over a range of CO and steam pressures. A rate decrease with increasing partial pressure of CO was experimentally observed over this sample, confirming that a negative order in CO can occur under certain conditions at low temperatures. The apparent reaction order of CO measured at 197 degrees C was about -0.27. This value is significantly larger than that (i.e, -0.03) reported by Ribeiro and co-workers [A.A. Phatak, N. Koryabkina, S. Rai, J.L. Ratts, W. Ruettinger, R.J. Farrauto, G.E. Blau, W.N. Delgass, F.H. Ribeiro, Catal. Today 123 (2007) 224] at a similar temperature. A kinetic peculiarity was also evidenced, i.e. a maximum of the reaction rate as a function of the CO concentration or possibly a kinetic break, which is sometimes observed in the oxidation of simple molecules. These observations support the idea that competitive adsorption of CO and H2O play an essential role in the reaction mechanism. (C) 2008 Elsevier B.V. All rights reserved.

From Empire to Iraq and the "War on Terror": The Transplanation and Commodification of the (Northern) Irish Policing Experience

Charting the enduring export appeal of policing models from (Northern) Ireland, this article sheds some light on the processes by which policing models are communicated and actively promoted to the global policing environment. The authors demonstrate how the transplantation of the Irish colonial model (ICM) represents an early example of the globalization of policing. The legacy of counterinsurgency expertise embedded within the ICM remains a historical constant and is a key factor in relation to the increasing commodification of the contemporary Northern Irish policing model, a model that successfully blends counterterrorism experience with a template for democratic policing reform. By juxtaposing these models, the authors provide a conceptual framework through which to assess the contemporary substance of policing transfer. The authors conclude by suggesting that the seductiveness of these policing models is largely attributable to lessons in counterinsurgency and notions of "Ireland as the solution" to a host of complex security scenarios.