Hydrophobic Ni@N‐Doped TiO2 Nanosheet Arrays‐Carbon Paper Photocatalyst for CO2 Photoreduction at Tri‐Phase Interfaces

Abstract Rational interphase reaction provides a feasible method to overcome the matters of insufficient adsorption of CO 2 molecules at the catalytic sites and competitive hydrogen evolution reaction (HER), which can increase the formation rate and selectivity of carbon derivatives in photocatalytic CO 2 reduction. Herein, a hydrophobic photocatalyst with TiO 2 nanosheet arrays grown on hydrophobic carbon paper (TiO 2 ‐HCP) is fabricated using a combination of magnetron sputtering and hydrothermal method, and its unique structure not only endows it excellent light absorption and effective carrier spatial separation but also avoids the hydrophobic reagent covering reactive sites. When the interphase reaction shifts from solid–liquid diphase to gas‐liquid‐solid tri‐phase, the photocatalytic CO 2 reduction over TiO 2 ‐HCP mainly generates CO molecules and effectively suppresses HER due to the HCP suppressing the mass transfer of H 2 O molecules to active sites. Notably, amounts of H 2 byproduct can further react with CO 2 /CO to produce high value‐added CH 4 resultant by modifying the N‐doped TiO 2 ‐HCP with nickel/nickel oxide species. In the tri‐phase interfacial CO 2 photoreduction system, the CH 4 formation rate of Ni@N‐doped TiO 2 ‐HCP reaches 134.17 µmol m −2 h −1 (about 74.6% selectivity) and total carbon derivatives selectivity is about 93%.