Efficient hydrogen production in a spotlight reactor with plate photocatalyst of TiO₂/NiO heterojunction supported on nickel foam

It is traditionally accepted that photocatalytic reactor with photocatalysts suspended in reaction solution is efficient due to large solid/liquid reaction surface area of the suspension. However, either circulation or separation of slurry is costly and challenging. Herein, we report for the first-time photocatalytic hydrogen production in a steady and recyclable spotlight reactor with titanium dioxide stabilized on nickel foam prepared via simple coating method. Surprisingly, the hydrogen production rate in our reactor is ca. 2.66 times of the suspended system under the equivalent irradiation intensity (mw/cm²). The high energy flux intensity, increased hydrophilicity of the nickel film supported photocatalyst plate and the low reaction fluid viscosity were found to be essential for the high efficiency of the reactor. All these factors have rarely been considered before in the solar photocatalytic rector design. Considering from the material aspect, the light induced flatting effect under high energy flux density and the formation of a direct Z-scheme TiO₂/NiO heterojunction are essential for the high activity. Our work indicates that the use of plate catalysts in small reactors with intensive light irradiation is a very promising strategy for large scale hydrogen production utilizing solar energy.