Ga-Promoted Photocatalytic H₂ Production over Pt/ZnO Nanostructures

Abstract

Photocatalytic H2 generation is investigated over a series of Ga-modified ZnO photocatalysts that were prepared by hydrothermal methods. It is found that the structural, textural, and optoelectronic properties remarkably depend on the Ga content. The photocatalytic activity is higher in samples with Ga content equal to or lower than 5.4 wt %, which are constituted by Zn1-xGaxO phases. Structural, textural, and optoelectronic characterization, combined with theoretical calculations, reveals the effect of Ga in the doped ZnO structures. Higher Ga incorporation leads to the formation of an additional ZnGa2O4 phase with spinel structure. The presence of such a phase is detrimental for the textural and optoelectronic properties of the photocatalysts, leading to a decrease in H2 production. When Pt is used as the cocatalyst, there is an increase of 1 order of magnitude in the activity with respect to the bare photocatalysts. This is a result of Pt acting as an electron scavenger, decreasing the electron-hole recombination rate and boosting the H2 evolution reaction.

Ferrite Materials for Photoassisted Environmental and Solar Fuels Applications

“…Using ethanol as sacrificial agent, Tijare and co-workers reported a relatively similar hydrogen evolution rate (even if the usual difficulties to quantitatively compare different works must be considered) that could be further boosted by using platinum as co-catalyst [167]. However, in this case the improvement caused by platinum was considerably low if compared to its effect on other semiconducting catalysts [157]. Indeed, Iervolino and co-workers studied LaFeO3 as a promising noble-metal-free hydrogen evolution photocatalyst [168].…”

“…In photocatalytic hydrogen evolution reactions, the presence of a co-catalyst, most generally a noble metal, improves the hydrogen yield by boosting charge separation and acting as catalytic sites for H-H bond formation [157]. In addition, in the case of some metals with appropriate particle size, the localized surface plasmon resonance effect may enhance light absorption in the visible range [114].…”

Photocatalyst for High‐Performance H2 Production: Ga‐Doped Polymeric Carbon Nitride

“…Other than transition metals, post‐transition metal is rarely paid close attention. Ga has been widely used in the fields of optical materials to achieve regional enrichment of photogenerated electrons [6b, 12] . The main reason for long afterglow luminescence is due to the excited electron can be stored at the empty p orbital of Ga sites.…”

“…In terms of photocatalysis, Víctor A. de la Peña O'Shea et al. found that Ga doping on Pt/ZnO can maximize the photocatalytic hydrogen evolution efficiency [6b] . Cabot's group [12] reported that a certain amount of photogenerated electrons can be injected at the Ga site in the Ga doping CuInS 2 , which improves the separation efficiency of photogenerated carriers and maximizes the photocatalytic efficiency.…”

Highly efficient nanostructured CoFe2O4 thin film electrodes for electrochemical degradation of rhodamine B

“…These organic compounds can be degraded photocatalytically under UV light or electrocatalycally by applying a current density at the anode material (Baddouh et al, ; Garcia‐Segura & Brillas, ; Holkar, Jadhav, Pinjari, Mahamuni, & Pandit, ; Martínez‐Huitle & Brillas, ). Different semiconductor photocatalysts have been explored, including metal oxides (Núñez et al, ; Yu et al, ), phosphates (Chennah et al, , ; Naciri et al, ; Zeng et al, ), etc. However, most of these materials still suffer from the rapid recombination of photo‐induced carriers, and the poor light utilization, which limits their photocatalytic efficiency and thus their practical application.…”