Blue‐light‐excited NaCe(MoO ₄ ) ₂ microcrystals for photoelectrochemical water splitting

Abstract We report the structural, morphological, and optical characterization, and the application of sodium‐cerium molybdate (NaCe(MoO 4 ) 2 ) as a promising photoelectroactive material for water splitting. Information on these several properties was obtained by X‐ray diffraction, Raman spectroscopy, scanning electron microscopy, and UV–Vis–NIR diffuse reflectance. For the photoelectrochemical tests, NaCe(MoO 4 ) 2 microcrystals were deposited on conductive indium‐tin oxide (ITO) glass substrate by drop coating, and the activity of the as‐prepared photoanode toward oxygen evolution reaction was investigated in the absence and presence of blue light‐emitting diode irradiation. Studies carried out by linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy attested to a significant photoelectroactivity of molybdate associated with the fast electron‐hole pairs generation. The steady‐state photocurrent density recorded under irradiation achieved a remarkable increase, varying from 1.5 µA cm −2 (light off) to 44.1 µA cm −2 (light on), in addition, it presents high stability after on–off cycles, what proves the proper performance of NaCe(MoO 4 ) 2 /ITO as photoanode for water splitting.