Lattice-strained nanotubes facilitate efficient natural sunlight-driven CO₂ photoreduction

Photocatalytic reduction of CO₂ holds tremendous promise for alleviating the energy crisis. Despite the progress that has been made, there are still some challenges to overcome, such as the realization under real sunlight rather than the simulation condition. In this work, ultrathin Ni₂(OH)(PO₄) nanotubes (NTs) prepared through hydrothermal route are applied as a novel catalyst for photocatalytic reduction of CO₂ under real sunlight. The prepared Ni₂(OH)(PO₄) NTs exhibit a 11.3 µmol·h^-1 CO production rate with 96.1% CO selectivity. Interestingly, Ni₂(OH)(PO₄) NTs have a positive impact on the facilitation of photoreduction in diluted CO₂. Notably, when the system is performed under real sunlight, Ni₂(OH)(PO₄) NTs afford an accumulated CO of ca. 26.8 μmol with 96.9% CO selectivity, exceeding most previous inorganic catalysts under simulated irradiation in the laboratory. Our experimental results demonstrate that the multisynergetic effects induced by surface-OH and the lattice strain serve as highly active sites for CO₂ molecular adsorption and activation as well as electron transfer, hence enhancing photoreduction activity. Therefore, this work provides experimental basis that CO₂ photocatalysis can be put into practical use.