Influence of photo-deposited pt and pd onto chromium doped tio2 nanotubes in photo-electrochemical water splitting for hydrogen generation

Abstract

Hydrogen (H2) is considered as an ideal fuel for the future. The photo-electrochemical (PEC) water splitting employing semiconducting materials and induced irradiation, preferably of solar spectrum, presents a viable route for H2 production. In this work, self-ordered chromium-doped TiO2 nanotube (CT) was fabricated using in-situ electro-anodization. CT surface modification was then performed by photo-deposition of Pt and Pd particles, producing Pt-CT and Pd-CT cata-lysts, respectively. Their morphological features, crystallinity, surface composition, and optical absorption have been inspected by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman, and UV–vis absorption spectroscopy. Linear sweep voltammetry, chronoamperometry, and open circuit potential methods have been applied to study PEC activities of Pt-CT and Pd-CT catalysts in a form of electrodes. It was found that Pt-CT and Pd-CT electrodes possess excellent photo-generated electron/hole (e−/h+) separation and transport properties. The enhanced photocurrent responses of 4 and 3 times more than that of CT are revealed for Pt-CT and Pd-CT, respectively. The activity of as-prepared Pt-CT and Pd-CT catalysts was then tested for H2 generation. The maximum amount of the evolved H2 followed decreas-ing order: 1.08 ˃ 0.65 ˃ 0.26 mL cm−2 h−1 for Pt-CT, Pd-CT, and CT electrodes, respectively, clearly showing the positive contribution of photo-deposited (nano)particles onto CT surface.