Enhanced Oxygen Evolution Reaction Activity in Hematite Photoanodes: Effect of Sb-Li Co-Doping

Abstract

Co-doping represents a valid approach to maximize the performance of photocatalytic and photoelectrocatalytic semiconductors. Albeit theoretical predictions in hematite suggesting a bulk n-type doping and a surface p-type doping would deliver best results, hematite co-doping with coupled cations possessing low and high oxidation states has shown promising results. Herein, we report, for the first time, Sb and Li co-doping of hematite photoanodes. Particularly, this is also a seminal work for the introduction of the highly reactive Sb 5+ directly into the hematite thin films. Upon co-doping, we have a synergistic effect on the current densities with a 67-fold improvement over the standard. Via a combined investigation with profuse photoelectrochemical measurements, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman analyses, we confirm the two doping roles of Sb 5+ and Li + as the substitutional and interstitial dopant, respectively. The improvements are attributed to a higher charge carrier concentration along with a lower charge transfer resistance at the surface.

Flexible and Dynamic Light-Guided Electrochemiluminescence for Spatiotemporal Imaging of Photoelectrochemical Processes on Hematite

“…47 Two peaks at ∼660 and ∼1300 cm −1 were attributed to the presence of symmetry-broken, disordered structures. 48 Furthermore, Figure 1D depicts photoelectrochemical behavior of hematite electrode with simulated solar light illumination, verifying its sensitivity to light shed on the hematite electrode. The hematite was in contact with a phosphate-buffered electrolyte (pH 7.0) containing 1.0 M Na 2 SO 3 as a hole scavenger.…”

“…It also exhibited the A 1g and E g vibrational modes associated with the movement of Fe atoms along the unit cell c -axis and the breathing modes of O atoms perpendicular to the c -axis, respectively . Two peaks at ∼660 and ∼1300 cm –1 were attributed to the presence of symmetry-broken, disordered structures . Furthermore, Figure D depicts photoelectrochemical behavior of hematite electrode with simulated solar light illumination, verifying its sensitivity to light shed on the hematite electrode.…”