Fine‐Tuning Surface Properties of Perovskites via Nanocompositing with Inert Oxide toward Developing Superior Catalysts for Advanced Oxidation

Abstract

Cost-effective, stable, and highly efficient heterogeneous catalyst is the key challenge for wastewater treatment based on Fenton-like advanced oxidation processes. Perovskite oxides offer new opportunities because of their versatile compositions and flexible physiochemical properties. Herein, a new strategy is proposed that is different from the frequently used alien-metal doping, to tune surface properties of perovskite oxides by nanocompositing perovskite with inert oxide, resulting in improved activity and stability for catalytic oxidation. By in situ modification of LaFeO 3 with inert La 2 O 3 oxide through one-pot synthesis, several important surface properties such as surface defects, H 2 O 2 adsorption capacity, Fe 2+ concentration, and chargetransfer rate were improved, as well as resistance against iron leaching. In performance evaluation, among the various materials, La 1.15 FeO 3 (L 1.15 FO) composite shows the highest Fenton activity (0.0402 min −1 ) for activating H 2 O 2 to oxidize methyl orange, 2.5 times that of the pristine LaFeO 3 . Notably, in situ electron paramagnetic resonance analysis and radical scavenging tests unveil a faster generation of singlet oxygen as the dominant reactive species over L 1.15 FO, consequently a novel non-radical activation mechanism is proposed. Such improved performance is assigned to the strong coupling effect between the nanosized LaFeO 3 and La 2 O 3 in the hybrids, which fine-tune the surface properties of LaFeO 3 perovskite as superior Fenton catalysts.

Carbon‐Intercalated 0D/2D Hybrid of Hematite Quantum Dots/Graphitic Carbon Nitride Nanosheets as Superior Catalyst for Advanced Oxidation

“…However, further increase of H 2 O 2 concentration to 25 × 10 −3 m did not cause an improvement of degradation efficiency, while it could lead to a decrease in efficiency. As is expected, increasing H 2 O 2 concentration can generate more radical species, on the contrary, superfluous H 2 O 2 will consume generating radical species by the equation of . Figure e shows the degradation efficiency of PNP at different initial pH values.…”

Utilizing ion leaching effects for achieving high oxygen-evolving performance on hybrid nanocomposite with self-optimized behaviors

“…4g). To further verify this standpoint, oxygen-vacancy-sensitive electron paramagnetic resonance (EPR) was conducted, where the higher peak intensity at g = 2 in EPR spectrum demonstrates more oxygen vacancies in materials 46 . EPR results show that the concentration of oxygen vacancies in hybrid BSCF is higher than that in pure BSCF (Fig.…”

Single-phase perovskite oxide with super-exchange induced atomic-scale synergistic active centers enables ultrafast hydrogen evolution

“…5b) and the corresponding deconvolution results ( Supplementary Table 4) demonstrate a much larger number of (O 2 2− /O -) species, which is closely related to the surface oxygen vacancies 30,43,44 , in STRO relative to STO, suggesting the increased OVs. EPR spectra were recorded to provide fingerprint evidence due to its sensitivity to unpaired electrons trapped by oxygen vacancies 45,46 . A strong signal intensity at g = 2.004 was observed for STRO, while STO has a very weak signal (Fig.…”