Ohmic Hetero-Junction of n-Type Silicon and Tungsten Trioxide for Visible-Light Sensitive Photocatalyst

Abstract

Visible light-sensitive photocatalyst was developed by combining n-type silicon (n-Si) and tungsten trioxide (WO 3 , n-Si/WO 3 ), yielding an ohmic contact in between. In this system, the ohmic contact acted as an electron-and-hole mediator for the transfer of electrons and holes in the conduction band (CB) of WO 3 and in the valence band (VB) of n-Si, respectively. Utilizing thusconstructed n-Si/WO 3 , the decomposition of 2-propanolto CO 2 via acetone was achieved under visible light irradiation, by the contribution of holes in the VB of WO 3 to decompose 2-propanol and the consumption of electrons in the CB of n-Si to reduce O 2 .

Optical Properties of Tungsten: A Parametric Study to Characterize the Role of Roughness, Surface Composition and Temperature

“…As seen in Figure 4a,d, the amount of tungsten oxide (WO 3 ), visible at 37.7 and 35.5 eV, was drastically reduced after laser annealing, while "bulk" metallic W peaks (at 33.3 and 31.1 eV) increased. WO 3 is a semiconductor with a band gap of 2.9 eV [23] absorbing for λ > 400 nm [24]. The increase of reflectivity in the visible and the near-infrared domains was likely related to the reduction of the natural oxide film, in agreement with Addab et al [25], who studied the role of the thickness of oxide layers in decreasing the surface reflectivity in the 2.5-5.5 µm wavelength range.…”

In-Depth Understanding of Hardmetal Corrosion Performance Reveals a Path to the Electrochemical Demolition of Scrap

“…In less corrosion-resistant Co-Ni, WC-type reflectivity (Figure 5a) is also found in the whole active corrosion range-with minor differences, not highlighted for brevity-since binder dissolution impacts negligibly the dominant contribution of the ceramic phase. The reflectivity in the pseudopassive range of Co-Ni (Figure 5a) is controlled by a spectral pattern essentially corresponding to WO3, possibly with metal-ion doping and/or some degree of nanostructuring [78]. The optical response of Co-Ni in the transpassive range (Figure 5a) is typical of TMyWO4 compounds [79][80][81], coherent with the SEM analyses which revealed the attack of both binder and WC in this potential range.…”

Boosting the Performance of WO3/n‐Si Heterostructures for Photoelectrochemical Water Splitting: from the Role of Si to Interface Engineering

“…For TiO2/n-Si, Fe2O3/n-Si, and WO3/n-Si, a Z scheme mechanism was invoked to describe the charge transfer at the metal oxide-Si interface, where the electrons from the oxide layer recombine with holes photogenerated in Si. Note that this mechanism should also reduce the electron-hole recombination within the metal-oxide layer [6,21,23,31] .…”