This paper reports experimental and modeling results for a unique, laboratory-scale opposed-flow reactor. As is typical inopposed-flow diffusion flames, counter-flowing oxidizer (air)and fuel (methane) are introduced from planar injection manifolds.The unique aspect of the presentconfiguration is an interior co-planar catalyst (platinum) mesh that can be positioned relative to thefuel and oxidizer manifolds. The objective is to understand the relationship between catalyst meshlocation, reforming chemistry, and product distribution. The catalyst promotes catalytic partial oxidation(CPOx) reforming at lower temperatures and strain rates than are possible with homogeneouschemistry alone. Experimentally, temperature profile and species profiles along the centeraxis of the reactor are measured using thermocouples, Raman Laser Gas Analyzer (RLGA), and gaschromatography (GC), respectively. The catalytic activity and selectivity were studied over a rangeof catalyst mesh axialposition. The experimental results show that the local equivalence ratio atthe mesh greatly influences the reforming performance. The computational model is analogous toa typical one-dimensional opposed-flow diffusion flame model but modified to accommodate catalyticmesh. In addition to incorporating the catalytic chemistry on the mesh, the radial momentumequation is modified to impose a radial no-slip condition. The model is developed using C++ andCANTERA (an open-source software tool for chemical kinetics). The model is applied to help interpretmeasured profiles of axial temperature and species concentrations.