Template-Free Nanostructured Fluorine-Doped Tin Oxide Scaffolds for Photoelectrochemical Water Splitting

Abstract

The synthesis and characterization of highly stable and conductive F:SnO2 (FTO) nanopyramid arrays are investigated, and their use as scaffolds for water splitting is demonstrated. Current densities during the oxygen evolution reaction with a NiFeOx catalyst at 2 V vs reversible hydrogen electrode were increased 5-fold when substituting commercial FTO (TEC 15) by nanostructured FTO scaffolds. In addition, thin α-Fe2O3 films (∼50 nm thick) were employed as a proof of concept to show the effect of our nanostructured scaffolds during photoelectrochemical water splitting. Double-layer capacitance measurements showed a drastic increase of the relative electrochemically active surface area for the nanostructured samples, in agreement with the observed photocurrent enhancement, whereas UV–vis spectroscopy indicates full absorption of visible light at wavelengths below 600 nm.

Recent advances on interfacial engineering of hematite photoanodes for viable photo‐electrochemical water splitting

“…Source: Images adapted with permission. Copyright 2019, 71‐73,79,98 2020, 76,96,97,102,104 (American Chemical Society); 2019, 74,75,87,92,93 2020, 77 (Royal Society of Chemistry), 2019, 78 licensed under a Creative Commons Attribution 4.0 International License; 2018, 99 2019, 85,86,90,100,101 (Elsevier Ld. ); 2019, 81‐83,88,89,91 2020, 95,103 (John Wiley and Sons); 2018, 94 (Materials Research Society), 2019, 80,84 licensed under a Creative Commons Attribution‐NonCommercial License, respectively.…”

“…The photoanodes exhibited leaflet type structures that were oriented perpendicular to the FTO substrate, and generated photocurrent density of 1.3 mA cm −2 at 1.23 V RHE , and 16% of IPCE at 375 nm illumination. Furthermore, owing to the high reproducibility, this method also provided valuable fundamental studies on dopants 117 and substrate effects 73,118 . For example, Garcia‐Torregrosa and co‐workers 73 reported a thin α‐Fe 2 O 3 film that was coated on nanostructure of 3D‐FTO scaffolds by ultrasonic spray pyrolysis (USP), as shown in Figure 7(A),(B).…”

“…Furthermore, owing to the high reproducibility, this method also provided valuable fundamental studies on dopants 117 and substrate effects 73,118 . For example, Garcia‐Torregrosa and co‐workers 73 reported a thin α‐Fe 2 O 3 film that was coated on nanostructure of 3D‐FTO scaffolds by ultrasonic spray pyrolysis (USP), as shown in Figure 7(A),(B). The hematite photoanodes showed 4.5‐fold improvement of the photocurrent density at 1.23 V RHE compared to the planar version hematite film (Figure 7(B)).…”

“…(B) Chopped light sweep voltammograms of various morphology hematite photoanode. Source: Reprinted with permission from Reference 73 copyright (2019) American Chemical Society. (C) SEM images of Ti‐doped Fe 2 O 3 on NTO nanobowls substrate.…”

Efficient Oxygen Evolution and Gas Bubble Release Achieved by a Low Gas Bubble Adhesive Iron–Nickel Vanadate Electrocatalyst

“…The difference in pH of the precursor solutions (pH metal =2.6, pH vanadate =12.3) etches the unreacted and agglomerated precipitates during each cycle but leaves fine nanoparticles on NF. The following reaction betides for a layer-by-layer assembly at nucleation sites in each ionic layer and eventually deposition of a nanoparticulate film over NF without the need for additives, reducing/structure-directing agents, and temperature: [36][37][38][39][40] ( )…”