3D-printed graphene-anatase TiO2 photoanode with well-interconnected hierarchical channels for integrated self-floating photofuel cell powered by seawater pollutants

Photoelectrode architecture with well-interconnected oriented micro- and nanochannels is essential and critical for photofuel cell (PFC) to high-performance energy conversion of pollutants. However, challenges remain pertaining to manufacturing consistency and scalability, high efficiency in pollutant trapping and remarkable light absorption. Herein, a novel photoelectrode featuring porous microlattice structure was constructed via a scalable and controllable extrusion-based 3D printing strategy, with well-interconnected oriented channels as well as enriched hierarchical and open pores built by jointing tortuous photoactive graphene sheets. The unique architectural features facilitated high light absorption, and meanwhile guaranteed unimpeded channels acting as “superhighways” for rapid seawater pollutant diffusion and trapping. An integrated PFC assembled with 3D-printed photoelectrode demonstrated impressive photoelectric conversion capability for seawater pollutants under persistent self-floating and sunlight, with exceptional cycling stability and maximum power density of 0.09 mW cm−2. This work has shed light on new strategies for fabricating rational photoelectrode architectures toward high-performance PFC devices.