Photocatalytic H2 evolution coupled with selective aromatic alcohol oxidation over nitrogen-vacancy-rich Ti3C2Tx/g-C3N4 junctions via interfacial N–Ti bonding

Abstract

Cooperatively coupling efficient photocatalytic hydrogen (H₂) evolution with simultaneous organic transformations into value-added chemicals is a promising strategy for addressing global energy and environmental challenges. Herein, a nitrogen-vacancy-rich Ti₃C₂T_x/g-C₃N₄ (TC/CN) Schottky junction is developed as an efficient photocatalyst for the simultaneous reduction of water to H₂ and oxidation of furfuryl alcohol to furfural by utilizing photogenerated electrons and holes. Experimental results and density functional theory calculations demonstrate that the Schottky junctions created by interfacial N–Ti bonding between CN and TC facilitate efficient directional transfer of carriers while preventing electron backflow, thereby boosting separation of photogenerated electron–hole pairs. Further, the incorporation of nitrogen vacancies into TC/CN can provide active sites to enhance reactant adsorption and activation, thereby facilitating hole-mediated photooxidation activity towards furfuryl alcohol on the valence band of CN. As expected, the optimized TC/CN heterostructure exhibits a highly stable photocatalytic activity for H₂ coupled furfural, with rates of 1.17 and 1.22 mmol g⁻¹ h⁻¹, respectively, which are 3.7 and 3.8 times higher than pure g-C₃N₄. The photocatalytic oxidation mechanism of the carbon-centered radical pathway was confirmed through control experiments, in situ EPR spectra, and theoretical studies. This ingenious work provides insightful guidance for the rational design of a dual-functional photocatalyst that can efficiently reduce water while selectively synthesizing organic compounds.