Figure shows this mechanism quantitatively by computing the peak intensity ratio changes with and without light illumination. The intensity ratio between the peak of Ni/FeOOH (at 682.1 cm -1 ) and the peak of Ni-O A 1g stretching vibrations (at 556.1 cm -1 ) enhances a factor more significant than 200% compared to the pristine NiFe alloy film, from 0.13 to 0.29 (Fig. , left panel). We observe the same enhancement in intensity ratio between the peak of Ni/FeOOH at 322.9 cm -1