Rational design of versatile 1D Ti–O-based core–shell nanostructures for efficient pollutant removal and solar fuel production

Abstract

The rational design of Ti–O-based nanocomposites is of great importance for achieving efficient solar energy conversion and storage. Herein, novel one-dimensional (1D) K₂Ti₆O₁₃/TiO₂ core–shell nanobelt composites were fabricated by a controlled hydrothermal method using 1D K₂Ti₆O₁₃ nanobelts as precursors. The K₂Ti₆O₁₃ derived TiO₂ shells with a thickness of 5 nm were in situ grown on the K₂Ti₆O₁₃ NBs with closely connected interfaces, which resulted in remarkably enhanced photoactivities for pollutant degradation, hydrogen production and CO₂ reduction. Interestingly, the porous carbon paper supported K₂Ti₆O₁₃/TiO₂ nanocomposites could be used for efficient water purification via synergistic adsorption and photothermal catalysis. Moreover, such a 1D conformal core–shell nanobelt photoanode also showed higher photoelectrochemical water-splitting performance than pure K₂Ti₆O₁₃, and impressively the significantly accelerated and stable H₂ production was achieved due to the thermodynamically favorable glycerol oxidation reaction. Importantly, the high value-added formate was produced along with cathodic H₂ generation, revealing a sustainable way for concurrent solar hydrogen generation and green biomass upgrading. It was demonstrated that the enhanced photoactivities of K₂Ti₆O₁₃/TiO₂ nanocomposites could be mainly attributed to their higher light absorption, increased surface reactive sites and especially the promoted charge separation over the S-scheme heterojunction. This work paves a new avenue to rationally design versatile and high-performance Ti–O-based nanostructure photocatalysts for environmental remediation and solar fuel production.