Ammonia (NH3)-based selective catalytic reduction (SCR) is a mainstream flue gas denitration technology for stationary and mobile sources, but NH3 slip remains a critical challenge from mismatches between stoichiometric reaction requirements and fluctuating nitrogen oxides (NOx) concentrations. Herein, we show organic amines (e.g., n-butylamine, n-B) act as smart reductants for SCR systems. Unlike NH3, n-B reacts stoichiometrically with NOx and undergoes NO-accelerated self-elimination when overdosed over TiO2-supported VOx catalysts. Mechanistic studies reveal Ti─OH sites on the catalyst facilitate n-B adsorption and activation, with the *NH3 intermediate driving NOx reduction. *NH2 from excess n-B oxidizes to nitrites and NO2 under NO+O2, which further react with *NH3 via an internal SCR pathway, avoiding free NH3 formation and slip. We propose a hybrid reductants system (NH3 + n-B) enabling efficient NH3 slip suppression over a reductant/NOx molar ratio of 1.2, providing a promising strategy without modifying existing SCR hardware or structures.

The synergistic catalytic removal of multipollutants, such as nitrogen oxides and volatile organic compounds, has emerged as a transformative strategy for air pollution control. It directly tackles the interconnected challenges of PM2.5 and ozone formation. This mini review summarizes recent breakthroughs in this field, encompassing the design of novel catalysts with multifunctional active sites, the elucidation of the kinetic mechanisms underlying synergistic reactions, and the development of anti-poisoning strategies to maintain activity under complex flue gas conditions. We further examine how tailored acid-redox bifunctionality and dynamic active-site cooperation can overcome inherent issues such as temperature-window mismatches and competitive adsorption between pollutant molecules. Finally, by integrating advances in operando characterization and artificial intelligence, we propose a forward-looking roadmap for synergistic catalysis. This roadmap aligns with carbon neutrality goals and highlights the critical role of catalytic innovations in enabling clean and efficient environmental protection.

Passive NOx adsorber (PNA) captures NOx during cold-start phases and then releases it at operating conditions of the SCR catalyst, allowing NOx elimination of diesel vehicle exhaust efficiently. The Pd/CeO2 catalyst exhibits excellent PNA performance in the cold-start stage of diesel vehicles. An insightful understanding of the mechanism by which different Pd species mediate NOx adsorption and desorption is crucial but still unclear. This study systematically studied the PNA performance of Pd/CeO2 catalysts having distinct Pd loadings. The 3.0%Pd/CeO2, on which the aggregated Pd species (Pdn) and highly dispersed single atoms (Pd1) coexist on the CeO2 surface, exhibited the highest low-temperature NOx adsorption capacity. The structure-performance relationship governing NOx storage and release behaviors on Pd sites with distinct dispersion states was thoroughly studied. It revealed that the synergy of Pdn and Pd1 sites contributed to optimal PNA performance of 3.0%Pd/CeO2. At low temperature, Pdn species supplied adequate sites for NOx adsorption, and Pd1 site in PdxCe1-xO2-σ solid solutions mainly promoted interfacial active oxygen to activate NOx to monodentate nitrite via the MvK mechanism. At high temperature, part of the unstable nitrites readily decomposes into NOx on Pdn sites, and the remaining part is further oxidized to nitrate species by Pd1 promoted active oxygen and then decomposed. Both the NOx storage and release process were facilitated through the synergy between Pdn and Pd1 sites of Pd/CeO2. These findings provide a theoretical guideline for the controlled design of novel Pd/CeO2 based PNA materials via interfacial structural regulation.

Abstract Consistently arranging molecules within single‐walled carbon nanotube (SWCNT) templates shows promise for creating advanced 1D heterostructures, but diameter variations in raw SWCNTs pose a significant challenge. In this work, a precise synthesis of C70 fullerene‐filled SWCNTs (C70@SWCNTs) is achieved through vapor‐phase filling followed by polymer sorting. As the SWCNT diameter increases, C70 molecules first stack in a single chain, then form unusual configurations, including staggered double chains and double helices—configurations not observed in bulk C70 crystals. SWCNT deformation, which is often overlooked in previous theoretical works, is found to significantly alter the C70 stacking configuration. C70‐SWCNT electronic interactions, particularly charge transfer, allow selective extraction of C70@SWCNTs with narrowly distributed diameters and good semiconducting purity. The sorted C70@SWCNTs have diameters of 1.3–1.4 nm, corresponding to C70‐SWCNT distances of ca. 0.34 nm, where the strongest electronic interactions occur. An on/off current ratio of 10⁴ is achieved in their field‐effect transistors. The synthesis and separation strategy sheds light on the preparation and application of 1D heterostructures.

The synergistic catalytic removal of nitrogen oxides (NOx) and chlorinated volatile organic compounds (CVOC) is in significant demand from both ecological and economic perspectives. Breaking the trade-off between synergistic catalytic activity and selectivity is a big challenge. In this study, we developed a catalyst named MnCeOx/ MMT-Ti, which features an atomically dispersed MnCeOx supported on montmorillonite. It exhibited superior performance from 260 to 330 degrees C, achieving over 80 % conversion of NOx and chlorobenzene (CB), as well as over 80 % selectivity for N2 and CO2. Atomically dispersed asymmetric Mn-O-Ce sites were constructed and evidenced. The isolated asymmetric Mn-O-Ce sites in MnCeOx/MMT-Ti stimulated exceptional O2 adsorption and activation, facilitating CB oxidation through a variant Mars-van Krevelen mechanism while improving the N2 selectivity of NOx reduction. In addition, the abundant Br & Oslash;nsted acid sites from montmorillonite ensured the Clresistance and high stability of the catalyst. This study presents a novel approach for the synergistic removal of NOx and VOCs via tailoring atomically dispersed active sites of synergistic catalysts composed of complex oxides.

Chlorobenzene is a model molecule for researching harmful chlorinated volatile organic compounds. Designing the chemical adsorption site for complex molecules such as chlorobenzene is challenging without a large dataset and reasonable descriptors. Here, the adsorption of chlorobenzene on a phosphorylated CeO2 catalyst was analyzed using density functional theory calculations. Three different surface phosphate (HxPO4) models were constructed and used to adsorb chlorobenzene. An orbital interaction with fully occupied antibonding is found in one of three physical adsorptions. Based on this, the surface sites of a tri-cluster (M3) located at the CeO2 surface have been suggested to activate chlorobenzene. Three different clusters have been tested, namely Fe3, Ru3, and B3. All these clusters can activate and twist chlorobenzene by donating electrons. Fe3 and Ru3 form bonds with weak covalent and strong ionic characters, while B3 forms strong covalent bonds between boron and carbon. This work not only predicts a class of sites for chlorobenzene activation that may prevent polychlorinated by-products but also gives a template for catalyst rational design according to fundamental catalytic theory.

The synergistic catalytic abatement of nitrogen oxides (NOx) and chlorinated aromatic pollutants remains a significant challenge. The matching of the active temperature window and the trade-off between catalytic activity and selectivity are two principal issues to be concerned with. In this context, adding niobium oxide into the titania-supported cerium oxide (CeNbTi) catalyst markedly enhanced the synergistic catalytic activity and stability. The asymmetrical Ce-O-Nb structure was verified to be constructed on the CeNbTi catalyst. Nb demonstrated a dual modulation of redox and acidity, enabling a balance of dual sites for two cycles. This led to a simultaneous improvement in NH3-SCR and chlorobenzene oxidation performance. In situ DRIFTS indicated a synergistic promotion mechanism that chlorobenzene oxidation utilizes highly reactive oxidizing species, reducing NH3 excessive oxidation and lowering N2O production from the NH3-SCR pathway. This study offers a strategy via designing asymmetrical sites to develop catalysts for controlling multiple pollutants.

Multi-pollutant control of nitrogen oxides (NOx) and chlorinated aromatics in industrial flue by synergistic catalysis is still a huge challenge. Tailoring well-defined interfacial structures of multi-component heterogeneous catalysts has become an effective strategy for facilitating reactions involving multiple reactants. Here, a coupling of copper and tin oxide with particle-particle heterostructure supported on H-ZSM5 is designed to achieve a high-performance catalyst for NOx and chlorobenzene synergistic elimination. Experimental and theoretical calculation (DFT) studies show that the particle-particle coupling Janus heterostructure induced Sn-O-Cu interfaces. The strong electronic interaction improves the interfacial charge redistribution and mediates the activated interfacial oxygen, supporting redox (R) sites for the redox reaction cycle. Together with the abundant intrinsic Lewis (L) acid sites from CuOx and Brønsted (B) acid sites from the H-ZSM-5 interface, a combination punch of ideal L-B-R sites was constructed for the synergistic catalysis of NOx reduction and chlorobenzene oxidation. The designed Sn-Cu/H-ZSM5 catalyst exhibits significant low-temperature synergistic catalytic activity, a wide temperature window, robust long-term stability, and excellent water resistance, which outperforms Sn/H-ZSM5 and Cu/H-ZSM5. Moreover, in situ infrared spectra of serial transient reactions evidenced that the NOx reduction reaction promotes chlorobenzene oxidation. This novel strategy of regulating the overall L acid, B acid, and redox properties to fabricate balanced L-B-R sites via interfacial engineering provides a distinct strategy for facilitating the synergistic abatement of NOx and chlorinated aromatics.

Synergistic catalytic removal (SyCR) of NOx and chlorinated volatile organic compound (CVOCs) emission from nonelectric industries is effective to suppress PM2.5 and ozone complex air pollution. Catalysts with balanced competence to reduce NOx and oxidize CVOCs, as well as the resistance to chlorine poisoning, are critical to SyCR. Here, neighboring effects over SmMn2O5 mullite (SMO) modified by HZSM-5 composite catalysts (SMO-Z) were demonstrated in the Cl-resistant SyCR of NOx and chlorobenzene (CB, a representative CVOCs). Characterizations demonstrated that HZSM-5 modification did not alter the crystal structure of SMO and retained Mn-O-Mn-Mn active sites for the SyCR of NOx and CB. HZSM-5 regulated the redox ability of SMO-Z to reduce the formation of inert nitrate species and to promote the N2 selectivity. Acidic HZSM-5 acted as dechlorination sites to promote the breakage of the C-Cl bond via the nucleophilic substitution reaction and accelerated the formation of HCl to avoid Cl poisoning on catalysts. The fine-tuned compensation of surface acidity by HZSM-5 suppressed the competitive adsorption of NH3 and CB on SMO-Z, which promoted NOx reduction at high temperatures, whereupon neighboring effects between HZSM-5 acidic dechlorination sites and SMO active redox sites on SMO-Z capitally promoted the SyCR efficiency and antichlorination poisoning performance.

Synergistic control of nitrogen oxides (NOx) and nitrogen-containing volatile organic compounds (NVOCs) from industrial furnaces is necessary. Generally, the elimination of n-butylamine (n-B), a typical pollutant of NVOCs, requires a catalyst with sufficient redox ability. This process induces the production of nitrogen-containing byproducts (NO, NO2, N2O), leading to lower N-2 selectivity of NH3 selective catalytic reduction of NOx (NH3-SCR). Here, synergistic catalytic removal of NOx and n-B via spatially separated cooperative sites was originally demonstrated. Specifically, titania nanotubes supported CuOx-CeO2 (CuCe-TiO2 NTs) catalysts with spatially separated cooperative sites were creatively developed, which showed a broader active temperature window from 180 to 340 degrees C, with over 90% NOx conversion, 85% n-B conversion, and 90% N-2 selectivity. A synergistic effect of the Cu and Ce sites was found. The catalytic oxidation of n-B mainly occurred at the Cu sites inside the tube, which ensured the regular occurrence of the NH3-SCR reaction on the outer Ce sites under the matching temperature window. In addition, the n-B oxidation would produce abundant intermediate NH2*, which could act as an extra reductant to promote NH3-SCR. Meanwhile, NH3-SCR could simultaneously remove the possible NOx byproducts of n-B decomposition. This novel strategy of constructing cooperative sites provides a distinct pathway for promoting the synergistic removal of n-B and NOx.

The synergistic removal of NOx and chlorinated volatile organic compounds (CVOCs) has become the hot topic in the field of environmental catalysis. However, due to the trade-off effects between catalytic reduction of NOx and catalytic oxidation of CVOCs, it is indispensable to achieve well-matched redox property and acidity. Herein, synergistic catalytic removal of NOx and chlorobenzene (CB, as the model of CVOCs) has been originally demonstrated over a Co-doped SmMn2O5 mullite catalyst. Two kinds of Mn-Mn sites existed in Mn-O-Mn-Mn and Co-O-Mn-Mn sites were constructed, which owned gradient redox ability. It has been demonstrated that the cooperation of different active sites can achieve the balanced redox and acidic property of the SmMn2O5 catalyst. It is interesting that the d band center of Mn-Mn sites in two different sites was decreased by the introduction of Co, which inhibited the nitrate species deposition and significantly improved the N2 selectivity. The Co-O-Mn-Mn sites were beneficial to the oxidation of CB and it cooperates with Mn-O-Mn-Mn to promote the synergistic catalytic performance. This work paves the way for synergistic removal of NOx and CVOCs over cooperative active sites in catalysts.

The presence of alkali metals in exhaust gas from stationary resources causes a grand challenge for the practical application of selective catalytic reduction (SCR) of NOx with NH3. Here, alkali-resistant NOx reduction has been successfully implemented via tailoring the electron transfer over Fe and V species on FeVO4/TiO2 catalysts. The strong interaction between Fe and V induced electron transfer from V to Fe and strengthened the adsorption and activation of NH3 and NO over active VOx sites. In the presence of K2O, the strong electron withdrawing effect of Fe offset the electron donating effect of K on the VOx species, thus protecting the active species VOx to maintain the NOx reduction ability. The enhanced adsorption and activation of NH3 allowed SCR reaction to proceed via E-R mechanism even after K2O poisoning. This work elucidated the electronic effects on the alkali metals resistance of traditional ferric vanadate SCR catalysts and provided a promising strategy to design SCR catalysts with superior alkali resistance.

The development of efficient technologies for the synergistic catalytic elimination of NOx and chlorinated volatile organic compounds (CVOCs) remains challenging. Chlorine species from CVOCs are prone to catalyst poisoning, which increases the degradation temperature of CVOCs and fails to balance the selective catalytic reduction of NOx with the NH3 (NH3-SCR) performance. Herein, synergistic catalytic elimination of NOx and chlorobenzene has been originally demonstrated by using phosphotungstic acid (HPW) as a dechlorination agent to collaborate with CeO2. The conversion of chlorobenzene was over 80% at 270 degrees C, and the NOx conversion and N-2 selectivity reached over 95% at 270-420 degrees C. HPW not only allowed chlorine species to leave as inorganic chlorine but also enhanced the Bronsted acidity of CeO2. The NH4+ produced in the NH3-SCR process can effectively promote the dechlorination of chlorobenzene at low temperatures. HPW remained structurally stable in the synergistic reaction, resulting in good water resistance and long-term stability. This work provides a cheaper and more environmentally friendly strategy to address chlorine poisoning in the synergistic reaction and offers new guidance for multipollutant control.

Metal oxides have been used as the supports for heterogeneous catalysis for many years, but they still suffer from coking in some high-temperature applications. The main reasons for coking are the uncontrollable dissociation of C-H and the overbalance between carbon deposition and removal. Herein, we find a boron nitride (BN)-immobilized Ni catalyst shows unprecedented coking resistance in dry reforming of methane via the incomplete decomposition of methane. Unlike the Ni-based catalysts supported by traditional metal oxides, BN-supported Ni accelerates the first C-H dissociation while inhibiting the breaking of the final C-H bond; hence, the suppression of the complete decomposition of methane thoroughly addresses the coking issue. This work reveals the fundamental reason for the coking resistance over BN-supported Ni catalysts is selective activation of the C-H bond, which can provide an inspiring idea for other applications.

Selective catalytic reduction (SCR) of NH3 is a widely used technology for eliminating NOx, but alkali metals, heavy metals, SO2, and other flue gas contaminants can drastically reduce the service life of catalysts and increase the cost of environmental protection. This study demonstrates that the TiOSO4/CeO2 catalyst exhibits natural resistance to multipoisons for NOx reduction. Despite being poisoned with 1 wt% K2O and 3 wt% PbO, the catalyst retained a NOx conversion rate of over 95% across a wide temperature range of 225-450 degrees C and showed excellent tolerance to SO2. The catalyst's interfacial structure is composed of cross-linked TiO6-SO4-Ce-O units. When K & Pb were deposited on the TiOSO4/CeO2 catalyst, the SO42- ions distributed on the catalyst surface preferentially combined with K & Pb to protect the Ce active sites. Additionally, the cross-linked TiO6 layer structure on the catalyst surface effectively blocked the adsorption of SO2. This anti-poison strategy enhances NOx reduction and resistance by modifying intrinsic active sites, rather than constructing additional sacrificial sites traditionally. These findings have significant implications for the development of effective NOx reduction catalysts with excellent resistance to multipoisons for practical applications.

Coupling NH_3-SCR denitration and VOCs purification in flue gas treatment of typical industries such as waste incineration and steel smelting, developing multi-pollutants synergistic control theory and technology to collaboratively remove NO_x and VOCs is of great importance. It possesses important scientific significance, ecological and economic benefits. At present, the synergistic catalytice limination of NO_x and VOCs has attracted wide attentions, and relevant studies mainly focus on the catalytic performance of synergistic catalysts. These current studies are still preliminary. Further research efforts are needed to develop more effective synergistic catalyst and investigate the interaction mechanism of SCR and VOCs oxidation. The construction and regulation of the acid/redox dual-core active site of the synergistic catalyst, the understanding of the mechanism of the acid/redox dual-cycle reaction pathway, and the improvement of anti-poisoning ability of the catalyst are three key issues needed to be considered in the following researches. The first step to solve these key scientific problems is still to design and prepare catalysts with high activity, stability and anti-poisoning ability. The next step is to investigate the chemical composition and structural properties of the catalyst and illustrate the microchemical environment of dual-core sites. Further, the efficient synergistic mechanism of the catalytic process and the anti-poisoning effect of catalyst are to be studied by in situ technology and theoretical calculation. This review summarizes the current research progress of NO_x and VOCs synergic catalytic purification technology, proposes the technical bottleneck, analyzes the key scientific issues, and puts forward corresponded strategic solutions, aiming to shed light on developing multi-pollutant removal in future.

Unraveling the dynamics of the active sites upon CeO2-based catalysts in selective catalytic reduction of nitrogen oxides by ammonia (NH3-SCR) is challenging. In this work, we prepared tungsten-acidified and sulfated CeO2 catalysts and used operando spectroscopy to reveal the dynamics of acid sites and redox sites on catalysts during NH3-SCR reaction. We found that both Lewis and Brønsted acid sites are needed to participate in the catalytic reaction. Notably, Brønsted acid sites are the main active sites after a tungsten-acidified or sulfated treatment, and the change of Brønsted acid sites significantly affects the NOx removal. Moreover, acid functionalization promotes the cerium species cycle between Ce4+ and Ce3+ for the NOx reduction. This work is critical to deeply understanding the natural properties of active sites, and it also provides new insights into the mechanism for NH3-SCR over CeO2-based catalysts.

In the flue gas of stationary NOx emission source, HCl was deemed to be one of the poisons of NOx reduction catalysts since it can react with ammonia to form NH4Cl and adhere to oxide surface, reducing the redox property and blocking the active sites of catalysts for selective catalytic reduction of NOx with NH3 (NH3-SCR). Herein, unexpected promotional effects of HCl over CeO2-based catalysts for NOx reduction against alkali poisoning have been unraveled. The modification of gaseous HCl on the surface of CeO2 constructed Cl-Ce-O-Ce-OH and Cl-Ce-O-Ce3+ sites, providing additional Bronsted and Lewis acid sites to facilitate ammonia adsorption. It is worth noting that HCl can not only directly neutralize alkali metal to reduce alkalinity, but also increase the acidity to offset the encroachment of acid sites by alkali metal poisoning. The lower NO adsorption energy and weaker oxidation property of Cl-Ce-O-Ce3+ sites also prevented the accumulation of inert nitrate on the surface of alkali metal poisoned catalyst. This work unveils multi-promotion mechanisms for the enhanced catalytic activity and anti -alkali poisoning of gaseous HCl modified cerium-based NOx reduction catalysts, providing a new thinking based on pollutant interaction for further development of highly efficient NOx reduction catalysts in multipollutant flue gas.

Mn-basedcatalysts are promising for selective catalytic reduction(SCR) of NO x with NH3 at lowtemperatures due to their excellent redox capacity. However, the N-2 selectivity of Mn-based catalysts is an urgent problem forpractical application owing to excessive oxidizability. To solve thisissue, we report a Mn-based catalyst using amorphous ZrTiO x as the support (Mn/ZrTi-A) with both excellent low-temperatureNO( x ) conversion and N-2 selectivity.It is found that the amorphous structure of ZrTiO x modulates the metal-support interaction for anchoringthe highly dispersed active MnO x speciesand constructs a uniquely bridged Mn3+ bonded with thesupport through oxygen linked to Ti4+ and Zr4+, respectively, which regulates the optimal oxidizability of theMnO( x ) species. As a result, Mn/ZrTi-A isnot conducive to the formation of ammonium nitrate that readily decomposesto N2O, thus further increasing N-2 selectivity.This work investigates the role of an amorphous support in promotingthe N-2 selectivity of a manganese-based catalyst and shedslight on the design of efficient low-temperature deNO( x ) catalysts.

Herein, we synthesize Fe‐based nanocatalysts supported on the composites composed of hollow carbon spheres (HCSs) and metal–organic frameworks (MOFs) by a facile pyrolysis method. The composites with different ratios of HCSs and MOFs present an interesting phenomenon: the oxygen reduction reaction (ORR) limiting current increases along with the HCSs content, while the onset potential and half‐wave potential show the highest values when the ratio between HCSs and MOFs is optimized. The composite catalysts exhibit superior ORR electrocatalytic performance than Pt/C in alkaline and neutral media. Even in the acidic media, these composite catalysts still present a close catalytic activity to Pt/C. For the oxygen evolution reaction (OER) test, the prepared Fe‐NC@NHCS‐600 shows a reduced overpotential to that of the benchmark IrO 2 . The rechargeable Zn‐air battery using Fe‐NC@NHCS‐600 as the catalyst of air electrode exhibits superior discharge capability with an open‐circuit voltage of 1.620 V and a maximum power density of 278.97 mW cm −2 in alkaline electrolyte, as well as an open‐circuit voltage of 1.457 V and a maximum power density of 114.96 mW cm −2 in neutral electrolyte. The battery also exhibits steady cycling stability for more than 90 and 70 h at 5 and 10 mA cm −2 , respectively.