Facile Zn and Ni Co-Doped Hematite Nanorods for Efficient Photocatalytic Water Oxidation

Abstract

In this work, we report the effect of zinc (Zn) and nickel (Ni) co-doping of hydrothermally synthesized hematite nanorods prepared on fluorine-doped tin oxide (FTO) substrates for enhanced photoelectrochemical (PEC) water splitting. Seeded hematite nanorods (NRs) were facilely doped with a fixed concentration of 3 mM Zn and varied concentrations of 0, 3, 5, 7, and 9 mM Ni. The samples were observed to have a largely uniform morphology of vertically aligned NRs with slight inclinations. The samples showed high photon absorption within the visible spectrum due to their bandgaps, which ranged between 1.9–2.2 eV. The highest photocurrent density of 0.072 mA/cm2 at 1.5 V vs. a reversible hydrogen electrode (RHE) was realized for the 3 mM Zn/7 mM Ni NRs sample. This photocurrent was 279% higher compared to the value observed for pristine hematite NRs. The Mott–Schottky results reveal an increase in donor density values with increasing Ni dopant concentration. The 3 mM Zn/7 mM Ni NRs sample produced the highest donor concentration of 2.89 × 1019 (cm−3), which was 2.1 times higher than that of pristine hematite. This work demonstrates the role of Zn and Ni co-dopants in enhancing the photocatalytic water oxidation of hematite nanorods for the generation of hydrogen.

CVD Growth of Hematite Thin Films for Photoelectrochemical Water Splitting: Effect of Precursor-Substrate Distance on Their Final Properties

“…In addition, the large surface area exhibited by the nanostructured semiconductors is important in photoelectrochemical devices due to the large number of catalytic sites [ 3 , 7 , 11 , 12 , 13 ]. Additionally, the nano structuration facilitates the incorporation of other nanomaterials or atoms that improve the catalytic performance [ 14 , 15 , 16 , 17 , 18 ]. Several techniques have been investigated for the synthesis of hematite nanocrystalline thin films: thermal evaporation [ 19 ], aqueous chemical growth [ 20 ], spray-pyrolysis [ 10 , 21 , 22 ], sol-gel [ 23 ], and electrodeposition methods [ 1 , 8 , 13 ].…”

Biomass-derived carbon deposited TiO2 nanotube photocatalysts for enhanced hydrogen production

“…5 Among various processes, H 2 production via water splitting can be recognized as the most prominent method. 14,15 The rst reported suitable technology to produce H 2 via water splitting was the photo-assisted electrochemical method. However, it needs sophisticated instrumentations.…”

One-Pot Facile Synthesis of CuO–CdWO4 Nanocomposite for Photocatalytic Hydrogen Production

“…Hydrogen (H 2 ) is one of these attractive possible candidates, and the generation of H 2 from renewable sources does not result in the emission of CO 2 . In this context, H 2 can be considered a clean energy carrier that has the potential to solve currently existing problems in the areas of energy and environment [5][6][7].…”

“…A promising method for producing sustainable H 2 is solar photocatalysis [6,7], which splits water into H 2 gas [9,10]. Recently, Zn-and Ni-Co-doped hematite nanorods [5] and Ni 2 P-Co 2 P [6] photocatalysts were reported to be in use for the process of H 2 production. It is also recognized that the photocatalysts based on semiconductor heterojunctions could enhance water splitting [10].…”