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

Cooperatively coupling efficient photocatalytic hydrogen (H-2) 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 Ti3C2Tx/g-C3N4 (TC/CN) Schottky junction is developed as an efficient photocatalyst for the simultaneous reduction of water to H-2 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 H-2 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.

Automated summary

Cooperatively coupling efficient photocatalytic hydrogen (H-2) evolution with simultaneous organic transformations into value-added chemicals can effectively address global energy and environmental challenges. By developing a nitrogen-vacancy-rich TC/CN Schottky junction, the directional transfer of carriers is facilitated, leading to enhanced separation of photogenerated electron-hole pairs. The incorporation of nitrogen vacancies into TC/CN also enhances reactant adsorption and activation, resulting in improved photooxidation activity. The optimized TC/CN heterostructure exhibits highly stable photocatalytic activity for H-2 coupled furfural, with significantly higher rates compared to pure g-C3N4.