Methanol steam reformation (MSR) to produce hydrogen (H-2) gas using copper on zinc oxide (Cu/ZnO) supported catalysts is attractive due to the simple and low cost preparation process of the catalyst. H-2 yield from MSR is proportional to total catalyst loading which can be tuned during catalyst preparation. By creating UV-c light induced surface defects on ZnO nanorods, we have shown improved copper (Cu) nano-particle distribution on the ZnO nanorods leading to better H-2 yield. Increase in Cu nanoparticle adsorption is achieved by in situ reduction of Cu ions by photo-generated electrons, facilitated by ZnO surface defects that act as high energy sites favorable for Cu ion adsorption and their subsequent growth into nanoparticles. The modulated Cu/ZnO catalyst increases H-2 selectivity by 57% along with a corresponding increase in CO content, which can be controlled by adjusting H2O:MeOH ratio in the precursor solution.