TiO₂-coated window for facilitated gas evolution in PEC solar water splitting

Abstract

Photoelectrochemical (PEC) cells for water splitting generally have a transparent front window for the sunlight to reach the surface of the photoelectrode or tandem photoelectrode. The overall efficiency of a PEC system for solar hydrogen production is strongly affected by the evolved gases that get trapped in the front window. This negative effect is clearly observed when the PEC cells are placed in tilted positions to maximize light harvesting. Titanium dioxide coatings become superhydrophilic when exposed to UV light, facilitating the gas bubbles to slip up. The present study focuses on the development of a thin TiO 2 coating to minimize the adhesion of the evolved bubbles in the front window of PEC cells, thereby maximizing its transparency. Highly transparent, crack-free, and stable thin films of TiO 2 were prepared by spin coating followed by sintering at 465 C for 45 min. A water contact angle (WCA) of 0 was obtained after irradiating the surface of the sample for 30 min with UV-light (365 nm, 2 W m À2), confirming the superhydrophilic behaviour. The irradiance loss during the evolution of H 2 /O 2 was assessed using a silicon PV cell; the cell, tilted at 45 and equipped with a TiO 2 -coated glass window, showed ca. 10% higher irradiance as compared to the uncoated glass window cell for both hydrogen and oxygen evolutions, whereas no significant differences were observed when the cells were vertically placed.

Process analysis of solar steam reforming of methane for producing low-carbon hydrogen

“…(4) Correlation between the effective aperture area of the solar eld and DNI can be considered as a key parameter affecting the investment cost of the solar eld with a central receiver system. (5) The variation of DNI is a stronger impact on the operation performance of the solar SRM process.…”

The route for commercial photoelectrochemical water splitting: a review of large-area devices and key upscaling challenges

“…This design is quite similar to the well-known alkaline electrolysers (AEC), comprising a reservoir for the electrolyte wherein the electrodes are immersed and physically separated by an ion-exchange membrane. Over the past decade, different approaches were reported for scaling up this family of devices: (i) in 2011, a 100 cm 2 “stacked” PEC reactor was reported for the first time by the Imperial College of London; 215,216 (ii) in 2014 UPORTO developed the 100 cm 2 “PortoCell”, which was further improved in 2016; 39,217 (iii) in 2015, the European Union (EU) project ArtipHyction developed the largest PEC prototype to date, with an irradiated surface area of 1.6 m 2 ; 218 and (iv) in 2019, EPFL patented an integrated PEC (IPEC) device, whose concept was validated experimentally using a close electronic integration between the III–V-based photoabsorber (4 cm 2 ) and the IrRuOx-Pt-based electrocatalyst. 17 Holmes-Gentle et al .…”

“…The upgraded version of the “PortoCell” was the first PEC design that included an optimized flow pattern and simultaneously addressed ohmic losses across the electrolyte reservoir; still, this design presents some disadvantages under real operating conditions. 217 On the other hand, the ArtipHyction prototype was the first device that validated the transfer from lab-scale cells to pilot-scale units; however, its viability was compromised by the low overall PEC performance: STH conversion efficiency of ca. 2% with a 5% decrease over 1000 h of continuous operation.…”

A Facile Preparation of Transparent Ultrahydrophobic Glass via TiO2/Octadecyltrichlorosilane (ODTS) Coatings for Self‐Cleaning Material

“…The spectra of TNC shows a wide absorption band at 900–950 cm −1 , which is attributed to the Si‐O−Ti stretching vibration (Figure a). This result confirms that TiO 2 film was coated on the surface of sodalime glass . After the TiO 2 coated glass being modified with ODTS, a new absorption band was observed at 1025 cm −1 , which is assigned to asymmetric Si‐O−Si stretching vibration (Figure b).…”