Dynamic charge collecting mechanisms of cobalt phosphate on hematite photoanodes studied by photoinduced absorption spectroscopy

Abstract

Reaction sites, surface states and surface loaded electrocatalyst are photoinduced charge storage sites and critical to photoelectrochemical (PEC) performance, while the charge transfer mechanisms involved in the three remain poorly...

Determining the Transformation Kinetics of Water Oxidation Intermediates on Hematite Photoanode

“…Reducing film thickness leads to decreasing TA intensity ( I TA ) at 10 μs–1 s. As a result, the thinner Fe 2 O 3 samples (Fe 2 O 3 -28 min and Fe 2 O 3 -20 min) exhibit different dynamics from those of the thicker Fe 2 O 3 samples (Fe 2 O 3 -60 min and Fe 2 O 3 -40 min). Namely, the thicker Fe 2 O 3 samples show normally TA decay profiles as reported previously. − Conversely, the thinner Fe 2 O 3 samples display first increasing and then decreasing dynamics, implying reaction species formation-consumption processes (a detailed analysis is shown in Figure S8). The different TA dynamics of Fe 2 O 3 may result from the different contributions of surface species and photogenerated charges in bulk due to controlling film thickness.…”

“…Thus, a batch of Fe 2 O 3 films with different thickness were prepared by controlling hydrothermal time. 26 According to the hydrothermal time, the obtained Fe 2 O 3 samples are named Fe 2 O 3 -X min. The time-dependent parameters, such as film thickness, loading amount, UV−vis absorbance, PEC performance, and width of space-charge layer were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), UV−vis absorption spectroscopy, PEC measurement, and electrochemical impedance spectroscopy (EIS) (the detailed results and analysis are shown in Figures S1−S6).…”

“…Moreover, because the applied potential can increase band-bending of Fe 2 O 3 photoanode, resulting in surface hole accumulation, decreasing thickness can increase the ratio of surface OER intermediates to photoinduced charges in bulk. Thus, a batch of Fe 2 O 3 films with different thickness were prepared by controlling hydrothermal time . According to the hydrothermal time, the obtained Fe 2 O 3 samples are named Fe 2 O 3 -X min.…”

Mg-Doped Hematite Nanoparticle Arrays Coated with CoPi Thin Films for Solar Water Oxidation

“…They found that the presence of CoPi enhances the separation of holes and promotes their timely injection into the electrolyte for water oxidation. 21 Although CoPi and Mg doping are frequently used for PEC water splitting, the co-decoration of Mg doping and CoPi deposition has not been reported at present. Herein, we constructed a Mg-doped hematite nanoarray with synergistic modification of CoPi by a simple hydrothermal method and immersion.…”

“…Li et al developed CoPi-modified hematite photoanodes. They found that the presence of CoPi enhances the separation of holes and promotes their timely injection into the electrolyte for water oxidation …”