Ceramic membranes offer an attractive option for separating gases to produce high purity oxygen, or as part of synthesis gas production, developing transportable fuels (CO+H2). In these devices the transport of oxygen from high oxygen partial pressure (pO2) to low pO2 is a key driver.  Devices operate with atmospheric air at the high pO2 side of the device. Recent developments have focussed on dual phase membranes with an oxide ion conducting component matched with an electronic phase. Our work has focussed on the transport properties of each phase, synergies between these and more recently the effect of humidity on the surface exchange and diffusion processes in the electronic phase, La1-xSrxFe1-yCryO3-d.