Construction and characterization of visible light active Pd nano-crystallite decorated and C-N-S-co-doped TiO2 nanosheet array photoelectrode for enhanced photocatalytic degradation of acetylsalicylic acid

• Pd/C-N-S-TiO2 NS were prepared by hydrothermal and photo-deposition strategies.
• The physicochemical properties of Pd/C-N-S-TiO2 NS photoelectrode were studied.
• Pd/C-N-S-TiO2 NS photoelectrode displayed excellent PC and PEC activity.
• Contribution of active species for degrading acetylsalicylic acid was investigated.
• The enhanced PEC mechanism of Pd/C-N-S-TiO2 NS photoelectrode was proposed.

A photo-assisted deposition technique was adopted to construct highly dispersed Pd nano-crystallites on C-N-S-co-doped TiO2 nanosheets (Pd/C-N-S-TiO2 NS) arrays photoelectrodes prepared by one-step hydrothermal synthesis. The morphology, elemental composition, crystal structure, light absorption capability and photoelectrochemical (PECH) property of as-obtained Pd/C-N-S-TiO2 NS electrodes were determined and investigated through the various characterizations. The photocatalytic (PC) and photoelectrocatalytic (PEC) activity of the Pd/C-N-S-TiO2 NS electrode was evaluated through the degradation of acetylsalicylic acid and the formation of OH radicals. Compared with pristine TiO2 NS, Pd/TiO2 NS and C-N-S-TiO2 NS, Pd/C-N-S-TiO2 NS electrode displayed greatly enhanced PC and PEC activity towards the degradation of acetylsalicylic acid under visible light (λ > 420 nm) or Xenon light irradiation. The synergy effect of interfacial transfer of photoinduced electrons between Pd nanoparticles and TiO2 NS as well as the external potential and intense visible light absorption induced by C, N and S co-doing promoted the effective charge separation and transfer and more visible photons to participate in the catalytic process on obtained Pd/C-N-S-TiO2 NS, which were evidenced by a series of characterizations, resulting in highly efficient and stable PC and PEC activity. Moreover, the probable visible light PEC mechanism was proposed.

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