New Non-noble Metal Cocatalysts On The Surface Of Titanium Dioxide For Enhanced Photocatalytic Hydrogen Production Performance

In the past decades,TiO₂ has attracted enormous interest in photocatalytic H₂-production due to its good biological and chemical stability,low cost and nontoxicity.Unfortunately,previous studies found that bare TiO₂ exhibited low activity for H₂-production from pure water.Thus,numerous methods have been developed to enhance the photocatalytic H₂-production performance of TiO₂,such as morphologycontrol,compositephotocatalystsbetweenTiO₂andother semiconductors,element doping and cocatalyst modification.Among them,highly efficient cocatalyst-modification is considered as one of the most ideal strategies in the field of photocatalytic hydrogen-production via accelerating transfer of photogenerated charges on the surface and promoting the interfacial photocatalytic reaction.In order to further improve the efficiency of hydrogen evolution of TiO₂photocatalysis,in this paper,our work mainly concentrated in two aspects to modification TiO₂:?1?Co-modification of Ti???hole cocatalyst and Ni?OH?₂electron cocatalyst to enhance the photocatalytic performance of H₂-production of TiO₂;?2?the modification of H₂TiO₃ cocatalyst generated on TiO₂ surface via in situ to enhance photocatalytic H₂-production performance.The main results were summarized as follows:First,the highly efficient TiO₂ photocatalyst with co-modification of Ti???hole cocatalyst and Ni?OH?₂ electron cocatalyst were prepared by a facile two-step method.It was found that the Ni?OH?₂-Ti???/TiO₂ showed obviously high H₂-production performance.When the amount of Ni?OH?₂ and Ti???was 1 wt%and 0.1 wt%,respectively,the H₂-production rate of the resultant Ni?OH?₂-Ti???/TiO₂ reached7280.04?mol h^-1g^-1,which was significantly higher than that of TiO₂,Ti???/TiO₂and Ni?OH?₂/TiO₂ by a factor of 215,63 and 1.8,respectively.The enhanced hydrogen-production performance of Ni?OH?₂-Ti???/TiO₂ could be attributed to the synergistic effect of Ti???hole cocatalyst and Ni?OH?₂ electron cocatalyst to simultaneously accelerate the interfacial transfer of photogenerated holes and electrons.Second,the highly efficient TiO₂ photocatalyst modified by H₂TiO₃ cocatalyst were prepared by controlling the dealing time in a low concentration of NaOH solution and HCl solution.When the dealing time was 60 min,the H₂-production rate of the resultant H₂TiO₃/TiO₂?60 min?reached 86?mol h^-1g^-1,which was significantly higher than that of TiO₂ by a factor of 2.4.The enhanced H₂-production performance of H₂TiO₃/TiO₂ could be attributed to H₂TiO₃ hole cocatalyst to simultaneously accelerate the interfacial transfer of photogenerated holes.Further loading Ni?OH?₂ electronic cocatalyst,the H₂-production performance of Ni?OH?₂-H₂TiO₃/TiO₂ was further improved,the H₂-production rate of the resultant Ni?OH?₂-H₂TiO₃/TiO₂ reached 5102?mol h^-1g^-1.The enhanced hydrogen-production performanceof Ni?OH?₂-H₂TiO₃/TiO₂ could be attributed to the synergistic effect of H₂TiO₃ hole cocatalyst and Ni?OH?₂ electron cocatalyst to simultaneously accelerate the interfacial transfer of photogenerated holes and electrons.