Dual templating fabrication of hierarchical porous three-dimensional ZnO/carbon nanocomposites for enhanced photocatalytic and photoelectrochemical activity

•Hierarchical porous ZnO/C nanocomposite at different length scales was synthesized via ice and micelle templation.•The ZnO/C showed 2.2 and 7.0 times reactivity of the control for methylene blue degradation under UV and visible light.•The sample exhibited the excellent photoelectrochemical performance with the photocurrent density of 1.5 mA cm−2 at the potential of 0.99 V.•Ultrasonic-assisted photocatalytic reactivity enhancement is confirmed for ZnO/C nanocomposites.

Herein, a novel fabrication strategy to synthesize the ZnO/C nanocomposite with hierarchical porous structure was proposed with dual templating method that combines both ice and micelle templating. The composite material annealed at 900 °C showed the best photocatalytic reactivity for organic dye degradation compared with samples annealed at other temperatures, which is 2.2/7.0 times of the control ZnO + C sample under UV and visible light irradiation. The sample also showed superior photoelectrochemical performance while ultrasonic assisted photodegradation of methylene blue was also observed. This work demonstrates a novel and feasible approach for processing ZnO based photocatalysts with enhanced reactivity, which can be extended to the design of a broad series of functional metal oxide composites with high electrochemical performance for energy applications.

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