We employ the photoanodes deposited with a 10 nm NiFe alloy layer to get appreciable GIXRD patterns, directly focusing on the NiFe layer. Both GIXRD patterns before and after the PEC reaction show peaks at 44.3 • and 51.9 • , corresponding to the characteristic (111) and (200) lattice planes of NiFe alloy , respectively. When increasing the ω H value, peaks at 38.1 • and 55.4 • get sharper, indicating the more dense crystalline structure inside the NiFe layer and the formation of more substantial amorphous features in the top surface of the NiFe layer . After 20 h CA reaction, peaks corresponding to (111) and ( ) planes appreciably broaden, demonstrating the surface amorphization induced by the PEC process.