In-situ surface reconstruction in Pt and P co-treated hematite for enhanced water oxidation

Improved Water Oxidation of Fe2O3/Fe2TiO5 Photoanode by Functionalizing with a Hydrophilic Organic Hole Storage Overlayer

“…Figure b shows the P 2p spectrum of the HEDP-Fe 2 O 3 /Fe 2 TiO 5 photoanode, in which the peaks located at 133.5 and 134.4 eV are well-consistent with the P–C bonds from HEDP and the P–O–metal bonds, respectively. − Figure c depicts the C 1s spectra of both photoanodes. For the Fe 2 O 3 /Fe 2 TiO 5 sample, the C 1s spectrum is deconvoluted into three peaks, attributed to C–C (284.8 eV), C–O (286.4 eV), and CO (288.1 eV) species, respectively. , By comparison, there is an additional fitted peak at 285.4 eV in the C 1s spectrum of the HEDP-Fe 2 O 3 /Fe 2 TiO 5 photoanode, originating from the C–P–O bond of the HEDP molecule. , The O 1s spectra are displayed in Figure d, wherein the Fe 2 O 3 /Fe 2 TiO 5 photoanode exhibits two kinds of oxygen species: lattice oxygen (O 2– ) for Fe 2 O 3 /Fe 2 TiO 5 (529.6 eV) and surface-adsorbed oxygen such as OH – and a water molecule (531.1 eV). , For the HEDP-Fe 2 O 3 /Fe 2 TiO 5 film, three overlapping components at 530.1, 531.3, and 532.9 eV are clearly observed, assigned to the lattice oxygen of Fe 2 O 3 /Fe 2 TiO 5 , P–O bonds, and adsorbed water, respectively. , Obviously, the presence of P–O bonds further declares the successful HEDP deposition. In Figure e, the high-resolution Fe 2P XPS of Fe 2 O 3 /Fe 2 TiO 5 and HEDP-Fe 2 O 3 /Fe 2 TiO 5 photoanodes show two spin–orbit peaks of Fe 2p 2/3 and Fe 2p 1/2 , and their binding energies are in accord with the typical values of Fe 3+ species in hematite. − Regarding the Ti 2p XPS spectra (Figure f), the characteristic peaks of Ti 2p 3/2 and Ti 2p 1/2 of both photoanodes also agree well with those of Ti 4+ species. , More notably, in comparison with the Fe 2 O 3 /Fe 2 TiO 5 sample, the HEDP-Fe 2 O 3 /Fe 2 TiO 5 photoanode exhibits an obvious positive shift in the binding energies of O 1s (O 2– species), Fe 2p, and Ti 2p peaks.…”

“…35,36 For the HEDP-Fe 2 O 3 / Fe 2 TiO 5 film, three overlapping components at 530.1, 531.3, and 532.9 eV are clearly observed, assigned to the lattice oxygen of Fe 2 O 3 /Fe 2 TiO 5 , P−O bonds, and adsorbed water, respectively. 35,36 Obviously, the presence of P−O bonds further declares the successful HEDP deposition. In Figure 3e, the highresolution Fe 2P XPS of Fe 2 O 3 /Fe 2 TiO 5 and HEDP-Fe 2 O 3 / Fe 2 TiO 5 photoanodes show two spin−orbit peaks of Fe 2p 2/3 and Fe 2p 1/2 , and their binding energies are in accord with the typical values of Fe 3+ species in hematite.…”

“…As illustrated in Figure 32,33 The O 1s spectra are displayed in Figure 3d, wherein the Fe 2 O 3 /Fe 2 TiO 5 photoanode exhibits two kinds of oxygen species: lattice oxygen (O 2− ) for Fe 2 O 3 / Fe 2 TiO 5 (529.6 eV) and surface-adsorbed oxygen such as OH − and a water molecule (531.1 eV). 35,36 For the HEDP-Fe 2 O 3 / Fe 2 TiO 5 film, three overlapping components at 530.1, 531.3, and 532.9 eV are clearly observed, assigned to the lattice oxygen of Fe 2 O 3 /Fe 2 TiO 5 , P−O bonds, and adsorbed water, respectively. 35,36 Obviously, the presence of P−O bonds further declares the successful HEDP deposition.…”

“…51 In the meantime, the in situ reconstruction of Fe-based phosphates and phosphides into FeOOH electrocatalysts for efficient water oxidation has also been widely reported. 36,52 Thus, to unravel the underlying cause of the HEDP overlayer for its hole storage function, we performed XPS characterizations for the HEDP-Fe 2 O 3 /Fe 2 TiO 5 photoanode after J-V scans to investigate its structure change. As shown in Figure S10a, the P 2p XPS spectra clearly depict that, after the J-V scans in NaOH electrolyte, the intensity of the P− O−metal bond decreases.…”

Ultrafine platinum nanoparticles supported on N,S-codoped porous carbon nanofibers as efficient multifunctional materials for noticeable oxygen reduction reaction and water splitting performance

“…[1][2][3][4][5][6] The sluggish kinetics of catalysts in the oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are known to govern their performance in energy utilization and power output. [7][8][9][10][11][12][13][14] Generally, platinum (Pt) on carbon materials has been widely used for ORR, [15][16][17] OER, [18][19][20] HER, [21][22][23] and hydrogen storage. [24][25][26][27][28][29] However, these catalysts require relatively large surface area, high electrical conductivity of carbon materials, and high loading density and uniform dispersion of platinum nanoparticles (NPs).…”