Photoelectrochemical properties of an active site working on Fe‐SBA‐15 catalyst: Application to the water reduction under visible light irradiation

Iron‐substituted mesoporous silica, Santa Barbara Amorphous (Fe‐SBA‐15) molecular sieve with Si/Fe ratio of 50 is prepared by microwave‐hydrothermal method. The photoelectrochemistry reveals a metal deficiency and the oxide exhibits P type conductivity with activation energy of 20 meV. The flat band potential, determined from the capacitance measurements, is found to be −0.61 V SCE . Hence, the conduction band, made up of 3d orbital (∼4 eV), permits a good position of H 2 O/H 2 level (−0.88 V/SCE), thus allowing a thermodynamically feasible H 2 liberation under visible light. In neutral medium, the photocatalyst shows a high H 2 evolution with a rate of 115 μmol g −1 min −1 in presence of SO 3 2− as hole scavenger. The initial performance of the PEC system is restored when the solution is bubbled with nitrogen, a deactivation effect of <2% is observed. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 141–146, 2014