Hole Transfer Channel of Ferrihydrite Designed between Ti–Fe₂O₃ and CoPi as an Efficient and Durable Photoanode

Abstract

A high-efficient oxygen evolution cocatalyst decorated on α-Fe2O3 has been considered as one of the most prospective approaches to accelerate the charge transport at the interface between photoanode and electrolyte. However, efficient charge transport from the semiconductor to the surface of the cocatalyst is still a challenge in fabricating semiconductor electrodes integrated with cocatalysts. Here, we elaborately introduce ferrihydrite (Fh) as a hole transfer channel between Ti doped α-Fe2O3 (Ti–Fe2O3) and cobalt phosphate (CoPi), which exhibits a superior photocurrent density of 3.0 mA/cm2 at 1.23 VRHE and 100 mV negative shift of the onset potential in contrast to CoPi/Ti–Fe2O3. The outstanding photoelectrochemistry performance is not only ascribed to the accelerated charge transfer from Ti–Fe2O3 to the surface of CoPi, but also beneficial from the fluent injection of photogenerated holes into the electrolyte, when Fh is introduced between Ti–Fe2O3 and CoPi. This work emphasizes the importance of introducing a hole transfer channel between semiconductor and cocatalyst in constructing outstanding photoanodes.

A highly enhanced photoelectrochemical performance of BiVO4 photoanodes modified with CoPi groups by increasing energy band bending, accelerating hole separation and improving water oxidation kinetics

“…4f, the main characteristic peak of P 2p is about 133.4 eV, which corresponds to the phosphate group in PO 4 3− . 40 Combined with the analysis of TEM, XRD, and XPS, it can be seen that the amorphous CoPi is indeed deposited on the surface of BiVO 4 . Table S2† presents the content of each element for BiVO 4 and BiVO 4 /CoPi photoanodes obtained from XPS spectra of the overall survey.…”

Investigation on the Photocatalytic Hydrogen Evolution Properties of Z-Scheme Au NPs/CuInS2/NCN-CNx Composite Photocatalysts

“…0.5CuInS 2 /0.5%NCN-CN x exhibits the best result, 2.43 mmol h –1 g –1 , suggesting that appropriate CuInS 2 NPs could further improve the photocatalytic activity. When Au NPs are further photodeposited on 0.5%NCN-CN x /0.5CuInS 2 to afford z Au/0.5%NCN-CN x /0.5CuInS 2 samples, the influence of Au deposition time ( z = 0, 10, 30, 50 min) on the photocatalytic activity has also been considered, which correspond to different sizes of Au NPs . The deposition time is optimized to be 30 min, which can present a H 2 evolution rate of 10.72 mmol h –1 g –1 , about 20 times higher than that of pure NCN-CN x , as shown in Figure a.…”

Oxygen Evolution Catalysts at Transition Metal Oxide Photoanodes: Their Differing Roles for Solar Water Splitting

“…This work is a good example of the different roles OECs can take, as explained in Section 2. Besides 2D BP, many other materials, such as carbon quantum dots, [ 132 ] ferrihydrite (Fh), [ 133 ] and polyaniline (PANI) [ 134 ] also show excellent hole extraction ability as base layers for OECs.…”