FeNi-MIL53 bimetallic MOFs as a visible light photocatalyst for water oxidation

• FeNi(9:1)-MIL53 with good visible light response were prepared by solvothermal method. • The photocatalytic water oxidation performance of FeNi(9:1)-MIL53 is higher than that of Fe-MIL53. • FeNi(9:1)-MIL53 can reduce the Gibbs free energy barrier and promote electron transfer. Photocatalytic water splitting is an appealing process for solar energy conversions, yet it is often limited by the slow oxidation of water to oxygen half-reaction. Here, a series of Ni (II)-doped Fe-MIL53 to form FeNi(x:1)-MIL53 were synthesized by solvothermal method as water oxidation photocatalysts and their photocatalytic performance was optimized by adjusting the mole ratio of central metal element Fe/Ni. The results showed that the unique bimetallic nanostructure of FeNi(9:1)-MIL53 had been proved to be superior to Fe-MIL53 with a single metal center in photocatalytic water oxidation. The initial quantum yield of FeNi(9:1)-MIL53 reached 47.80%, and its oxygen evolution rate was 0.587mmol/(g.s).The high photocatalytic performance of FeNi(9:1)-MIL53 was mainly due to the good synergistic effect and the charge transfer between Fe and Ni ions, which is expected to be an efficient photocatalyst for water oxidation.