An attractive strategy to improve the performance of water ox- idation catalysts would be to anchor a homogeneous molecu- lar catalyst onto a heterogeneous solid surface to create a hybrid catalyst. The idea of this combined system is to take advantage of the individual properties of each of the two cata- lyst components. We use DFT calculations to determine the stability and activity of a model hybrid water oxidation catalyst that consists of a dimeric Ir complex attached on the IrO2(110) surface through two oxygen atoms. We find that homogene- ous catalysts can be anchored to oxide surfaces without a sig- nificant loss of activity. Hence, the design of hybrid systems that benefit from both the high tunability of the activity of ho- mogeneous catalysts and the stability of heterogeneous sys- tems seems feasible.