Solid-state photoelectrochemical cell with TiO2 nanotubes for water splitting

Abstract

We have fabricated and tested a photoelectrochemical (PEC) cell where the aqueous electrolyte has been replaced by a proton conducting hydrated Nafion® polymer membrane. The membrane was sandwiched between a TiO-based photoanode and a Pt/C-based cathode. The performance was tested with two types of photoanode electrodes, a thermally prepared TiO film on Ti foil (T-TiO) and a nanostructured TiO films in the form of highly ordered nanotubes (TNT) of different lengths. Firstly, photovoltammetry experiments were conducted under asymmetric conditions, where the anode was immersed in deionized water, while the cathode was kept in ambient air. The results showed a high incident photon-to-current efficiency (IPCE) of 19% under unassisted conditions (short-circuit, 0 V vs. cathode) with short TNT (ca. 1 μm) under 4 mW cm illumination with UV-A rich light. Secondly, the deionized water was replaced by 0.5 M NaSO and now the performance was higher with longer nanotubes, assigned to increased ionic conductivity inside the tubes. An unassisted (0 V) IPCE of 33% was achieved with nanotubes of ca. 8 μm. The presented solid-state PEC cell minimizes the electrode distance and volume of the device, and provides a way towards compact practical applications in solar water splitting.

Visible-light-promoted gas-phase water splitting using porous WO3/BiVO4 photoanodes

“…and intensity (1.9 mA.cm -2 at the thermodynamic potential) and regarding the photocatalytical onset (+0.4 V vs RHE). This is several orders of magnitude higher than any other visible light activated solid state electrolyte system described in the literature [3,7,[10][11][12] , confirming the strong potential of our reactor and electrodes design.…”

Hydrogen from wet air and sunlight in a tandem photoelectrochemical cell

“…In our previous work [11], we demonstrated a monolithic solid-state photoelectrochemical (SSPEC) water electrolysis cell, in which the photoanode and cathode electrodes were attached to opposite sides of a Nafion-based polymer electrolyte membrane. The role of the membrane is to separate the evolved gaseous products, support and minimize the distance between the electrodes (down to a few μm) and provide protonic conductivity.…”

Cathodic hydrogen production by simultaneous oxidation of methyl red and 2,4-dichlorophenoxyacetate in aqueous solutions using PbO2, Sb-doped SnO2and Si/BDD anodes. Part 2: hydrogen production

“…22) until now; the n-type titanium dioxide (TiO 2 ) with and without modications has been the semiconductor-based electrode more investigated as photocatalysts for hydrogen production. [23][24][25][26][27][28][29] In these cases, the amount of hydrogen gas produced (in mL or mmol units) by photoelectrolysis is very variable so, for instance, in the work of Lee et al 25 a production of 10.2 mL aer 9 h on a 0.1 mol% Zn-TiO 2 NTs photocatalyst was attained; $2.34 mL h À1 cm À2 on Gd 3+ :TiO 2 as reported by Sudhagar et al, 27 or 8.53 mmol g cat À1 as reported by Simamora et al 26 These photoelectrochemical approaches produce H 2 with relative good photoconversion efficiency, but with a low production level yet. From an economic point of view, it is necessary to design electrolytic devices that make water electrolysis a productive and protable process.…”