Rationally designed ultrathin Ni(OH)2/titanate nanosheet heterostructure for photocatalytic CO2 reduction

Abstract

Dye-sensitized photocatalysis has been extensively studied for photocatalytic solar energy conversion due to the advantage in capturing long-wavelength photons with a high absorption coefficient. The rational integration of photosensitizer with semiconductor and cocatalyst to collaboratively operate in one system is highly desired. Here, we fabricate a Ni(OH) 2 -loaded titanate nanosheet (Ni(OH) 2 /H 2 Ti 6 O 13 ) composite for high-performance dye-sensitized photocatalytic CO 2 reduction. The ultrathin H 2 Ti 6 O 13 nanosheets with negative surface charge provide an excellent support to anchor the dye photosensitizer, while the loaded Ni(OH) 2 serves as an adsorbent of CO 2 and electron sink of photoelectrons. As such, the photoelectrons derived from the [Ru(bpy) 3 ]Cl 2 sensitizer can be targeted transfer to the Ni(OH) 2 active sites via the H 2 Ti 6 O 13 nanosheets linker. A high CO production rate of 1801 μmol g -1 h -1 is obtained over the optimal Ni(OH) 2 /H 2 Ti 6 O 13 , while the pure H 2 Ti 6 O 13 shows significantly lower CO 2 reduction performance. The work is anticipated to trigger more research attention on the rational design and synthesis of earth-abundant transition metal-based cocatalysts decorated on ultrathin 2D platforms for artificially photocatalytic CO 2 reduction. • 2D ultrathin Ni(OH) 2 /H 2 Ti 6 O 13 catalysts are successfully fabricated. • The alkaline sites of Ni(OH) 2 effectively bind and activate acidic CO 2 molecules. • The H 2 Ti 6 O 13 with negative surface charge strongly interact with homogeneous light absorber. • The composite synergistically improves adsorption, charge separation, and active sites for CO 2 reduction. • High-performance photocatalytic CO 2 reduction to CO is achieved over the dye-sensitized catalyst system.