A novel Ti³⁺-mediated approach for supporting palladium on anodic TiO2 nanotubes: Toward efficient and recyclable catalysis in the heck reaction

A simple electrochemical reduction technique was employed to generate Ti3+ with strong reducing property on the anodic TiO2 nanotubes (ATNTs). Utilizing Ti3+ as the reducing agent, Pd2+ was successfully reduced in situ to Pd0 on the anodic TiO2 nanotubes (Pd@ATNTs). Various characterization methods were employed to confirm that the proportion of Ti3+ and the size of Pd nanoparticles could be controlled by adjusting the electrochemical reduction voltage. The obtained Pd@ATNTs-2.5 exhibited satisfactory catalytic efficiency (TOF: 1302 h−1) in the Heck reaction between various aryl halides and olefins. Furthermore, Pd@ATNTs-2.5 demonstrated high stability, with no significant loss of catalytic activity observed even after six cycles. [Display omitted] •Ti3+ ions introduced into anodic TiO2 nanotubes (ATNTs) by electrochemical reduction.•The proportion of Ti3+ was effectively controlled by adjusting reduction voltage.•Pd NPs were uniformly dispersed on ATNTs by the reducing property of Ti3+.•Pd@ATNTs exhibited satisfactory catalytic efficiency for Heck reaction.•Pd@ATNTs showed high stability, maintaining catalytic activity after six cycles.