Spatially Controlled Photogenerated Charge Carriers Induced by SrTiO₃-Architectured Heterojunction Nanocubes for a Photocatalytic Hydrogen Evolution Reaction

Abstract

Effective charge separation and transfer of photoinduced electron (e − )−hole (h + ) pairs in a perovskite photocatalyst, namely, SrTiO 3 (STO), are crucial factors for a highly effective and durable photocatalytic hydrogen evolution reaction (HER). Herein, we develop a highly efficient pathway based on a semiconductor−metal heterostructured photocatalyst, in which Ir-doped (STO) nanocubes loaded with Ag nanoparticles are prepared by two facile approaches for water splitting driven by visible-light irradiation. This strategy was easily accessible to highly enhanced photocatalytic HER activities by (i) Ir 3+ doping in the forbidden gap of STO nanocubes for broadening the light absorption wavelengths up to 730 nm and (ii) incorporating Ag nanoparticles for controlling the electron−hole transportation at the interface and developing active reaction sites. Remarkably, the as-synthesized Ag/Ir/STO showed apparent quantum efficiencies of up to 0.17% and 0.06% under UV light and 420 nm illumination, respectively, which are 7.4-, 2-, and 1.6-fold higher than those of bare STO, binary Ag/STO, and Ir/STO, respectively. It also possessed outstanding stability in the photocatalytic process after four cycling tests. This work provides a rational design of a metal cocatalyst−semiconductor channel for enhancing the photocatalytic HER under visible light.

Development of Sustainable Catalyst Coating of Ni2P Engineered SrTiO3 Nanocubes for Hydrogen Generation

“…Further, XRD and XPS studies are performed on the as-obtained SrTiO 3 –Ni 2 P5 photocatalyst coating after 20 runs in order to find the reason for the drop in the activity after the repeated runs. The results obtained with the present work are compared with other recently reported similar catalyst systems in this area (Table S6), ,,,,,,, and it shows that the developed catalyst system is highly competent in activity for generating hydrogen by solar water splitting. Notably, the retained stability of the SrTiO 3 –Ni 2 P5 coating catalyst nearly up to 15 runs is outstanding compared to the 4 to 5 runs of other recently reported catalysts in their powdered forms.…”

“…However, tunable morphologies and photochemical properties for optimizing the band gap makes it suitable for water splitting applications . Numerous works have been already reported for altering the photocatalytic properties of SrTiO 3 : for example, morphological tailoring for influencing the active surface area, heteroatom/group doping for tuning the effective band gaps, introducing defects for influencing the absorption spectrum in the visible region, and cocatalyst loading for reducing the electron–hole recombination rates. , Even though the formation of the heterojunction with metal phosphides is one such effective technology, it is not widely explored in altering the band gap of SrTiO 3 . The presence of negatively charged phosphorus atoms can stimulate proton reduction at the catalyst surface .…”