Breaking the Activity–Selectivity Trade-Off for Simultaneous Catalytic Elimination of Nitric Oxide and Chlorobenzene via FeVO₄–Fe₂O₃ Interfacial Charge Transfer

Abstract

Removing chlorinated organics (chlorobenzene as a model) by a deNO x unit over a bifunctional catalyst has become the frontier of environmental catalysis. However, it is fundamentally challenging to achieve efficient selective catalytic reduction of NO x and chlorobenzene catalytic oxidation due to the trade-off between activity and selectivity. Herein, we demonstrated to break such trade-off through interfacial charge modulation on a bifunctional catalyst that is fabricated by integrating FeVO 4 and Fe 2 O 3 semiconductor materials. The optimized FeVO 4 −Fe 2 O 3 catalyst exhibited stable bifunctional removal efficiencies (>95%) for NO x and chlorobenzene with high HCl selectivity (>85%), surpassing the state-of-the-art V 2 O 5 −WO 3 /TiO 2 catalyst. It is identified from the experimental and theoretical results that the charge transferred from Fe in Fe 2 O 3 to V and Fe cations in FeVO 4 through the interfacial oxygen atoms. The formed gap states decreased the work function and promoted the redox ability of FeVO 4 , enhancing the bifunctional catalytic activity. Correspondingly, the Fermi level of Fe 2 O 3 shifted to a lower position, which increased the HCl selectivity and inhibited polychlorinated byproducts. The interfacial charge transfer broke the activity−selectivity trade-off and ensured remarkable bifunctional performance, providing an efficient strategy to design advanced catalysts for multipollutant control.

Elimination of NH3 by Interfacial Charge Transfer over the Ag/CeSnOx Tandem Catalyst

“…Hence, electron density was transferred from CSO to AgO, which promotes the oxidation activity of AgO and the reduction performance of CSO with an improved balance between the NH 3 oxidation rate and the NO x reduction rate. Such an improved balance is critical for increased activity and N 2 selectivity . It has been shown that there is a negative correlation between the oxygen vacancy concentration and the work function.…”

“…Such an improved balance is critical for increased activity and N 2 selectivity. 63 It has been shown that there is a negative correlation between the oxygen vacancy concentration and the work function. More oxygen vacancies imply a smaller work function and easier electron spillage from the support surface.…”

Roles of Ru on the V2O5–WO3/TiO2 Catalyst for the Simultaneous Purification of NOx and Chlorobenzene: A Dechlorination Promoter and a Redox Inductor

“…NO x and dioxins are usually emitted simultaneously from stationary sources such as steel sintering, waste incineration, etc., with 1 or 2 orders of magnitude difference. The emission standards are commonly controlled strictly to ultralow limits (NO x <50 mg/Nm 3 , dioxin <0.1 ng I-TEQ/Nm 3 ) to prevent serious intimidation of human health and the ecosystem. − As one of the most effective technologies in the de-NO x system, selective catalytic reduction (SCR) is widely applied in power plants and industrial boilers, in which an essential catalyst is designed to achieve a balance between surface acidity and reducibility for adsorption and activation of reductant NH 3 . − For example, NH 3 prefers to be adsorbed on acid sites primarily provided by TiO 2 of the V 2 O 5 /TiO 2 catalyst and then dehydrogenates on polymeric (fast) or monomeric (slow) VO x species to yield −NH 2 intermediates to reduce NO x . ,, However, it shows low activity in catalytic oxidation of alkane/alkene, toluene, and even dioxins due to its limited reducibility. , Accordingly, it is a big challenge with great importance to reduce NO x and trace the number of dioxins simultaneously using an optimized SCR catalyst in the de-NO x system, which is named multipollutant control (MPC). − …”

Mimicking Photosynthesis: A Natural Z‐Scheme Photocatalyst Constructed from Red Mud Bauxite Waste for Overall Water Splitting

“…Differently, surface treatment can not only tailor the component elements on the surface of RM but also introduce metallic Fe into the Z‐Scheme heterostructures. Considering that the work function of Fe (4.8 eV) usually lies between those of TiO 2 (4.3 eV) and γ‐Fe 2 O 3 (5.5 eV), it can offer a charge flow highway for shuttling the electrons from the CB of γ‐Fe 2 O 3 to the valence band (VB) of TiO 2 [36–38] . This analogous Z‐Scheme process can be further validated by the electron spin resonance (ESR) spin‐trapping of superoxide anion radicals (⋅O 2 − ) using 5,5‐dimethyl‐1‐pyrroline N‐oxide (DMPO).…”

“…Considering that the work function of Fe (4.8 eV) usually lies between those of TiO 2 (4.3 eV) and γ-Fe 2 O 3 (5.5 eV), it can offer a charge flow highway for shuttling the electrons from the CB of γ-Fe 2 O 3 to the valence band (VB) of TiO 2 . [36][37][38] This analogous Z-Scheme process can be further validated by the electron spin resonance (ESR) spin-trapping of superoxide anion radicals ( * O 2 À ) using 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Note that the CB of γ-Fe 2 O 3 is more positive than the formation potential of * O 2 À (EO 2=.O 2 À = À 0.33 V vs. NHE), no signal can be detected for Ti-PS with a possible Type II alignment (Figure 4c).…”