Influence of ruthenium doping on UV- and visible-light photoelectrocatalytic color removal from dye solutions using a TiO2 nanotube array photoanode

Turning Carbon Dioxide and Ethane into Ethanol by Solar-Driven Heterogeneous Photocatalysis over RuO2- and NiO-co-Doped SrTiO3

“…Figure 2 depicts the UV-Vis DRS spectra (Figure 2a-c) and the optical band gap energy (Eg) (Figure 2d) of the SrTiO 3 , SrTiO 3 :Ru and SrTiO 3 :RuO 2 :NiO samples, where it is possible to verify that: (i) the pristine SrTiO 3 presented a characteristic absorption band in the UV light region and the highest Eg value of ca. 3.2 eV (estimated through the application of Kubelka-Munk method [24]) in accordance with the literature [25], with an absorption edge around 380-390 nm, corroborating the need towards a spectral red-shift; (ii) the decoration of the SrTiO 3 with Ru nanoparticles indeed increased the response against the visible irradiation since the Eg values decreased by about 8-14%, compared to SrTiO 3 , resulting in a wide absorption band between 400-800 nm due to the RuO 2 plasmon band, as also recorded Mateo et al [21]; (iii) the impregnation with nickel further increased the visible light harvest, mainly after 520 nm through the ion transition level [26], and narrowed the Eg between 14-20%, compared to SrTiO 3 ; (iv) the global spectrum intensity progressively increased as the dopant concentration raised; (v) the Eg values did not follow a gradual decay pattern as the metal oxides' concentration increase, since the presence of excessive ions can induce intrinsic point defects, or oxygen vacancies, on the surface of metal-doped semiconductors, which may act as recombination centers [27,28]; and (vi) the double doping approach led to a partial suppression of the higher energy ions, resulting in a photocatalyst with weaker UV light absorption between 200-400 nm, when compared to Ru-doped SrTiO 3 , as similarly reported for the co-doping of SrTiO 3 with Ni and Ta/La [17,20,29].…”

A critical review on surface-modified nano-catalyst application for the photocatalytic degradation of volatile organic compounds

“…Noble metal elements such as platinum (Pt) 132 , palladium (Pd) 133 , ruthenium (Ru) 134 , silver (Ag) 135 . Because of noble metals, the recombination of carriers is reduced, which improve the photoactivity of the catalyst 136 .…”

Zinc oxide/graphene nanocomposite as efficient photoelectrode in dye‐sensitized solar cells: Recent advances and future outlook

“…Moreover, the 2D graphene bridge also acts as an electron transfer channel or pathway in the ZnO/graphene nanocomposite. 87 Figure 8 presents the schematic illustration of the electron transfer process in (A) ZnO and (B) ZnO/ graphene photoelectrodes, whereby the essential principle operation of ZnO/graphene-based DSSCs can be explained as follows 52,88 : i. The dye sensitizer absorbs the incident light, giving rise to positive and negative charge carriers in the DSSCs.…”

“…Therefore, the interaction between these two materials may enhance the photoelectrode's electron transport capability and hinder electron–hole recombination inside the DSSCs. Moreover, the 2D graphene bridge also acts as an electron transfer channel or pathway in the ZnO/graphene nanocomposite 87 …”