Bandgap energy controlling and electrochemical performances of quaternary metal oxide combined graphene-TiO2 nanocomposite and its photocatalytic hydrogen evolution

[Display omitted] •Successfully synthesis of a quaternary metal oxide (BiZnSb2O4) combined graphene-TiO2 nanocomposite for high hydrogen production.•New test methods with cyclic voltammetry test, LSV, and Tafel data with standard three-probe electrode systems.•Three different types of nanocomposites with bandgap energy control.•Hydrogen production amounts of 95.5 μmol/g without ultrasonic and 112.6 μmol/g with ultrasonic during 4 h, respectively. A quaternary metal oxide (BiZnSb2O4) combined graphene-TiO2 nanocomposite could be used to control band gap energy using a heterojunction for high hydrogen production by photocatalytic activity. Here, we designed a BiZnSb2O4 combined graphene-TiO2 heterostructure using a high-power sonic synthesis process. The photocatalyst prepared in this way was coated on a nickel foam in the form of a thin film. Various techniques were then used to characterize the nanoscale composite hybrid. Standard three-probe electrode systems were used for cyclic voltammetry test, LSV, and Tafel data. Finally, we obtained good hydrogen evolution results using three different types of nanocomposites with bandgap energy control. To check photoreaction characteristics of the synthesized sample, more current generation reactions were confirmed in the photocatalyst because light existed in the evaluation of electrochemical characteristics depending on the presence or absence of light. Among these three samples, the BZSB-G-T photocatalyst showed the highest hydrogen production amount (95.5 μmol/g without ultrasonic and 112.6 μmol/g with ultrasonic during 4 h). In addition, BZSB-G-T had a lower band-value energy effect with a heterojunction effect compared to the other two types of photocatalysts owing to its synergetic effects.