Toward CO₂ utilization for direct power generation using an integrated system consisting of CO₂ photoreduction with 3D TiO₂/Ni-foam and a photocatalytic fuel cell

Carbon dioxide (CO₂) significantly contributes to global warming. To effectively remedy the CO₂ emission and simultaneously meet the global energy demand, CO₂ photoreduction to solar fuels has been considered as one of the promising approaches. However, the post-use of the hydrocarbons generated by the CO₂ photoreduction usually suffers from low yield and poor selectivity. In this work, therefore, we develop an integrated system consisting of CO₂ photoreduction with 3D TiO₂/Ni-foam and a photocatalytic fuel cell for direct power generation. Such an integration allows the generated hydrocarbons by the CO₂ photoreduction to be directly used as fuels for the photocatalytic fuel cell, realizing direct power by generation using CO₂. Moreover, the 3D TiO₂/Ni-foam as the photocatalyst for the CO₂ photoreduction can provide a large surface area for loading the photocatalyst and its highly porous structure can significantly enhance mass transport and avail light scattering, both of which facilitate the photocatalytic reaction of CO₂ and thereby enhance power output. The results confirm that the use of CO₂ for direct power generation is successfully enabled by this integrated system. This work not only demonstrates the feasibility of the integrated system for direct power generation but also provides a new avenue for effective CO₂ utilization.