Appropriate strategies for determining the photoconversion efficiency of water photoelectrolysis cells: A review with examples using titania nanotube array photoanodes

Photoeletrochemical generation of hydrogen over carbon-doped TiO2 photoanode

“…Therefore, adsorption process happened at the surface of the photocatalyst would affect in part the strength of photocurrent. It has been reported that solvent polarity would affect the dissociative adsorption of the alcohol over a pair of Ti and O, considered as the controlling step of the photoreaction [44]. Yang et al studied the effect of monohydric alcohols on photoelectrochemical generation of hydrogen from water and reported that the generation rate followed the decreasing order: methanol > ethanol > iso-propanol [43].…”

Nanomaterials for renewable energy production and storage

“…A variety of chemical and physical fabrication methods have been developed in achieving these nanomaterials, such as sol-gel, hydrothermal, and electrochemical oxidation. 6, Grimes et al developed TiO 2 nanotubes with tunable size, length and wall thickness by the electrochemical oxidation of titanium foil, [120][121][122][123][124][125][126][127][128][129][130][131][132][133][134] and these nanotubes demonstrated enhanced activity in water splitting for hydrogen generation. 122,123 For example, titania nanotubes were grown from a starting titanium sheet by potentiostatic anodization in an electrolyte of 0.5% HF + acetic acid mixed in a 7 : 1 ratio using a platinum counter electrode.…”

Nanoscale Effects in Water Splitting Photocatalysis

“…The ideal limiting STH efficiency of a dual absorber configuration is 24.4% (for a combination of absorbers with band gaps of 2.25 and 1.77 eV). This is nearly twice that of the Schottky junction catalysts [11,12]. However, because of the greater complexity (two absorbers instead of one), functional tandem PCs have only been known for about 15 years [16].…”

“…1) [9]. PECs can reach efficiencies of up to 12.4% [10], about half of the theoretical efficiency limit for these devices (24.4% for a tandem [11,12] and 30% for a multijunction device [4]). However, issues with stability continue to plague these devices [13,14].…”

“…In type 1 PCs, light absorption and charge separation occur at a single absorber particle connected to one or several co-catalysts to complete the circuit for water electrolysis. The ideal limiting Solar-to-Hydrogen (STH) efficiency of this Schottky-type configuration is η ¼ 14.4%, based on a light absorber with a 2.0 eV band gap and conversion losses of E Loss ¼ 0.8 eV per electron [11,12]. Actual type 1 photocatalysts such as NiO-modified La:KTaO 3 [32] and Cr/Rh- Fig.…”