Exquisite design of porous carbon microtubule-scaffolding hierarchical In2O3-ZnIn2S4 heterostructures toward efficient photocatalytic conversion of CO2 into CO

Abstract

Porous carbon microtubule (PCMT)-scaffolding semiconductor heterostructures were exquisitely designed through the in situ growth of ZnIn₂S₄ (ZIS) ultrathin nanosheets onto In₂O₃ nanoparticle layers generated on the surface PCMT (abbreviated as PCMT@In₂O₃/ZIS) toward the efficient photocatalytic conversion of CO₂ into CO. The pronounced photocatalytic performance for CO₂ photoreduction into CO is attributed to a synergistic effect of the following factors: (1) the multistage hopping of the charge carriers among In₂O₃, ZIS, and PCMT greatly reduces the charge recombination in In₂O₃ and ZIS. (2) The mesoporous feature of the PCMT renders the large surface area and abundant active sites to accumulate the local concentration of CO₂ in the heterostructures. (3) The existence of a large amount of carbon defects in PCMT promotes the activity of the absorbed CO₂ molecules. (4) The tubular structures with two open ends of PCMT may favor the fast diffusion of the reactants and products, and the optical absorption can also be increased by multi-light scattering/reflection in the interior void. (5) The unique fabrication route leads to an intimate and tight contact among PCMT, In₂O₃, and ZIS, which is also favorable for the charge migration. This work makes a contribution to the development of a complex hollow photocatalysis system for artificial photosynthesis.