Effective transformation of hydrothermally grown TiO2 nanorods to nanotube arrays for improved PEC hydrogen evolution

Innovative green and renewable energy solutions to achieve carbon neutrality could be achieved using advanced functional materials. For the commercial realization of PEC water-splitting technology, low-cost, high active surface area, and high-performance catalyst is required. To do so, engineering the structure of the catalyst, controlling morphology and synthesis method becomes essential. So herein insightful design of experiments was carried out to synthesize in-situ growth of facet-controlled, vertically oriented rutile titanium dioxide (TiO2) nanorod (TNR) arrays and subsequent conversion to nanotubes (TNT) arrays using a facile hydrothermal approach. The photoelectrochemical (PEC) measurements at 1.23 V vs. RHE reveal a high photocurrent density of 976.8 µA cm−2 and a high theoretical H2 production of 7.4 µl min−1 cm−2 for FTO-grown TNTs. The increased exposed active surface area, improved light penetration, and uniformly oriented structures are responsible for higher response of TNTs over TNRs. Thus, present study offers a one-step conversion of nanorods to nanotubes and the corresponding improvement in PEC performances.