Free-standing, one-dimensional TiO₂ nanotube arrays (TNAs) with disordered surface structure are synthesized on transparent conducting substrates, and their opto-physicochemical properties and photoelectrocatalytic (PEC) performances are examined in detail. TNAs grown on titanium foils are transplanted onto fluorine-doped SnO₂ substrates via a two-step anodization process (denoted W-TNAs), followed by being reduced electrochemically for 20 and 90 s (denoted B-TNAs-20 and 90, respectively). As-transplanted W-TNAs exhibit the low PEC activities in terms of photocurrent, and oxygen evolution reaction (OER), and oxidations of inorganic and organic substrates (iodide and urea, respectively) under simulated sunlight (AM 1.5; 100 mW×cm^-2) primarily because of sluggish charge transfers through low electrical conductive TNAs framework. The quick electrochemical reduction of W-TNAs leads to 8-fold larger photocurrent, while significantly accelerating the OER by three times, and the oxidations of iodide and urea by 2 and ~20 times, respectively. Such enhanced PEC activity of B-TNAs is attributed to creation of Ti³⁺ and associated oxygen vacancy (examined with XPS, EPR, and Raman), strengthening n-type character and thereby increasing electrical conductivity (examined with Mott-Schottky and Nyquist). Time-resolved photoluminescence spectra further reveal that the lifetime (t) of photogenerated charge carriers in B-TNAs (t = 0.33 ns) is an order of magnitude shorter than that of W-TNAs (t = 3.63 ns). The disordered surface exhibits lower Faradaic efficiency for multi-electron transferred oxidation reactions whereas higher Faradaic efficiency for single-electron transfer oxidations compared to W-TNAs. Detailed surface characterization and PEC mechanism are discussed.