Co-modification of amorphous-Ti(IV) hole cocatalyst and Ni(OH) 2 electron cocatalyst for enhanced photocatalytic H 2 -production performance of TiO 2

Abstract Highly efficient TiO 2 photocatalysts co-modified by amorphous-Ti(IV) hole cocatalyst and Ni(OH) 2 electron cocatalyst (referred to as Ni(OH) 2 -Ti(IV)/TiO 2 ) were prepared by facile two-step process which was the initial formation of amorphous Ti(IV) on the TiO 2 surface via hydrolysis method and the following formation of Ni(OH) 2 via precipitation reaction. It was found that the Ni(OH) 2 -Ti(IV)/TiO 2 showed obviously high hydrogen-production performance. When the amount of Ni(OH) 2 and Ti(IV) was 1 wt% and 0.1 wt%, respectively, the hydrogen-production rate of the resultant Ni(OH) 2 -Ti(IV)/TiO 2 reached 7280.04 μmol h −1  g −1 , which was significantly higher than that of TiO 2 , Ti(IV)/TiO 2 and Ni(OH) 2 /TiO 2 by a factor of 215, 63 and 1.8, respectively. Moreover, it was found that Ni(OH) 2 -Ti(IV)/TiO 2 photocatalyst preserved a steady and highly efficient H 2 -production performance during repeated tests and also exhibited a high transient photocurrent density. The enhanced hydrogen-production performance of Ni(OH) 2 -Ti(IV)/TiO 2 can be attributed to the synergistic effect of Ti(IV) hole cocatalyst and Ni(OH) 2 electron cocatalyst to simultaneously accelerate the interfacial transfer of photogenerated holes and electrons. The present surface modification of dual cocatalysts can be regarded as one of the ideal strategies for the preparation of highly efficient hydrogen-production materials in view of their abundance, low cost and facile method.