A dip coating process for large area silicon-doped high performance hematite photoanodes

Abstract

A facile and low-cost dip-coating process for the deposition of silicon doped hematite films (Si:a-Fe 2 O 3) for hydrogen production by solar water splitting in photo-electrochemical cells (PEC) is presented. The precursors include iron nitrate, oleic acid, tetraethyl orthosilicate (TEOS) and tetrahydrofuran as dispersion agent. Sequential dip coating on transparent conducting oxides glass substrates with heat treatment steps at 500 C and 760 C yields mesoporous Si:a-Fe 2 O 3 with a roughness factor of 17 and photocurrent densities >1 mA/cm 2 at 1.23 V vs. reversible hydrogen electrode with SiO x underlayer and surface modification. A PEC demonstrator with 80 cm 2 active area in 1 M potassium hydroxide yields a photocurrent of 35 mA at 1.

Influence of anodization time on the surface modifications on α-Fe2O3photoanode upon anodization

“…Although a significant improvement has been made on conductivity of a-Fe 2 O 3 by elemental doping 5,[22][23][24][25] and nanostructuring, [26][27][28][29] the influence of the anodizing process on the photocatalytic performance of a-Fe 2 O 3 photoanode in a PEC cell has not been extensively studied. However, a detailed research on the surface molecular structure of anodized a-Fe 2 O 3 photoanode has been conducted and reported transformation of Fe 21 to Fe 31 states at the surface upon subject to anodizing conditions and the findings were attributed to filling of oxygen vacancies due to increasing oxygen content at the surface.…”

Fabrication of silicon doped hematite photoelectrode with enhanced photocurrent density via solution processing of an in-situ TEOS modified precursor

“…The thought of using TEOS during the iron oleic acid precursor synthesis is to use it as a source of silicon. In an earlier method adopted by Hu et al [22], Si doped hematite photoelectrode been fabricated with the help of following a similar route. However the photocurrent obtained during the study is around 1 mA/cm 2 while in the current study with a slightly modified protocol, the photocurrent density can be improved further upto 2 mA/cm 2 .…”

“…The dip coating process can similarly be used beside these strategies for making silicon doped hematite thin film. Staying with the dip coating approach, a method has been developed recently for depositing Si doped hematite film with a photocurrent density of 1.18 mA/cm 2 [22]. A comparison of the photocurrent density of hematite film doped with silicon is shown in Table 1 along with the one made in this work.…”

Biological Components and Bioelectronic Interfaces of Water Splitting Photoelectrodes for Solar Hydrogen Production

“…Hematite photoanodes can easily be coated and with low-cost processes on large scale panels. [38] Concomitantly, we use algal CPC because it is a low-cost resource directly harvested from algae. As mentioned above, the efficiency of the charge transfer between proteins and electrode is of crucial importance.…”