Abstract:
Herein, hydrothermally synthesized hematite nanorods (NRs) co-doped with
erbium and titanium, using titanium tetrachloride and erbium(III) nitrate pentahydrate
as the dopant sources, are presented. The effect of varied volumes of
the erbium/titanium surface co-dopants on the morphology, structural, optical,
and photoelectrochemical (PEC) properties of hematite NRs is investigated. The
pristine hematite, 40 μL-Er, and 40 μL-Er/20 μL-Ti-doped NRs samples present a
similar surface morphology of vertically aligned NRs. The NRs are randomly
oriented with an increase in titanium dopant for the 40 μL-Er/30 μL-Ti-doped
NRs and later coalesced for the 40 μL-Er/40 μL-Ti-doped NRs. The structural
analysis based on X-ray diffraction and Raman analysis present a uniform, pure
hematite phase for all the prepared NRs. The samples exhibit high photon
absorbance with peaks in the 400–450 nm wavelength range of the visible
spectrum. The 40 μL-Er/40 μL-Ti-doped NRs sample present the highest
photocurrent density of 83.9 μA cm 2 at 1.4 V vs reversible hydrogen electrode
(RHE) and is attributed to the lowest flat band potential ( 0.76 V vs RHE) that
enhances charge mobility at the electrode–electrolyte interface. These results
reveal the facile erbium/titanium doping of hematite NRs as a viable strategy for
enhancing their PEC water-splitting performance.
