Phosphotungstic Acid as a Dechlorination Agent Collaborates with CeO2 for Synergistic Catalytic Elimination of NOx and Chlorobenzene.

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 °C, and the NOx conversion and N2 selectivity reached over 95% at 270-420 °C. HPW not only allowed chlorine species to leave as inorganic chlorine but also enhanced the BroÌ·nsted 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.

The CRISPR-Cas13a Gemini System for noncontiguous target RNA activation.

Simultaneous multi-target detection and multi-site gene editing are two key factors restricting the development of disease diagnostic and treatment technologies. Despite numerous explorations on the source, classification, functional features, crystal structure, applications and engineering of CRISPR-Cas13a, all reports use the contiguous target RNA activation paradigm that only enables single-target detection in vitro and one-site gene editing in vivo. Here we propose a noncontiguous target RNA activation paradigm of Cas13a and establish a CRISPR-Cas13a Gemini System composed of two Cas13a:crRNA binary complexes, which can provide rapid, simultaneous, highly specific and sensitive detection of two RNAs in a single readout, as well as parallel dual transgene knockdown. CRISPR-Cas13a Gemini System are demonstrated in the detection of two miRNAs (miR-155 and miR-375) for breast cancer diagnosis and two small RNAs (EBER-1 and EBER-2) for Epstein-Barr virus diagnosis using multiple diagnostic platforms, including fluorescence and colorimetric-based lateral flow systems. We also show that CRISPR-Cas13a Gemini System can knockdown two foreign genes (EGFP and mCherry transcripts) in mammalian cells simultaneously. These findings suggest the potential of highly effective and simultaneous detection of multiple biomarkers and gene editing of multiple sites.

Tunable Surface Wettability via Terahertz Electrowave Controlled Vicinal Subnanoscale Water Layer.

Achieving timely, reversible, and long-range remote tunability over surface wettability is highly demanded across diverse fields, including nanofluidic systems, drug delivery, and heterogeneous catalysis. Herein, using molecular dynamic simulations, we show, for the first time, a theoretical design of electrowetting to achieve remotely controllable surface wettability via using a terahertz wave. The key idea driving the design is the unique terahertz collective vibration identified in the vicinal subnanoscale water layer, which is absent in bulk water, enabling efficient energy transfer from the terahertz wave to the rotational motion of the vicinal subnanoscale water layer. Consequently, a frequency-specific alternating terahertz electric field near the critical strength can significantly affect the local hydrogen-bonding network of the contact water layer on the solid surface, thereby achieving tunable surface wettability.

Synergistic catalytic removal of NOx and chlorinated organics through the cooperation of different active sites.

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.

Development of plasma technology for the preparation and modification of energy storage materials.

The development of energy storage material technologies stands as a decisive measure in optimizing the structure of clean and low-carbon energy systems. The remarkable activity inherent in plasma technology imbues it with distinct advantages in surface modification, functionalization, synthesis, and interface engineering of materials. This review systematically expounds upon the principles, classifications, and application scenarios of plasma technology, while thoroughly discussing its unique merits in the realm of modifying electrode materials, solid-state electrolytes, and conductive carbon materials, which are widely used in lithium-ion batteries, sodium ion batteries, metal air batteries and other fields. Finally, considering the existing constraints associated with lithium-ion batteries, some application prospects of plasma technology in the energy storage field are suggested. This work is of great significance for the development of clean plasma technology in the field of energy storage.

Strong metal oxide-zeolite interactions during selective catalytic reduction of nitrogen oxides.

In response to the stricter EU VII emission standards and the "150 â„ƒ challenge", selective catalytic reduction by ammonia (NH3-SCR) catalysts for motor vehicles are required to achieve high NO conversion below 200 °C. Compounding metal oxides with zeolites is an important strategy to design the low-temperature SCR catalysts. Here, we original prepared Cu-SSZ-13 @ MnGdOx (Cu-Z @ MGO), which achieved over 90% NO conversion and 95% N2 selectivity at 150 â„ƒ. It has been demonstrated that a uniform mesoporous loaded layer of MGO grows on Cu-Z, and a recrystallization zone appears at the MGO-Cu-Z interface. We discover that the excellent low-temperature SCR activity derives from the strong metal oxide-zeolite interaction (SMZI) effects. The SMZI effects cause the anchor and high dispersion of MGO on the surface of Cu-Z. Driven by the SMZI effects, the Mn3+/Mn4+ redox cycle ensures the low and medium temperature-SCR activity and the Cu2+/Cu+ redox cycle guarantees the medium and high temperature-SCR activity. The introduction of MGO improves the reaction activity of -NH2 species adsorbed at Mn sites at 150 â„ƒ, achieving a cycle of reduction and oxidation reactions at low temperatures. This strategy of inducing SMZI effects of metal oxides and zeolites paves a way for development of high-performance catalysts.

Selective Synergistic Catalytic Elimination of NOx and CH3SH via Engineering Deep Oxidation Sites against Toxic Byproducts Formation.

NOx and CH3SH as two typical air pollutants widely coexist in various energy and industrial processes; hence, it is urgent to develop highly efficient catalysts to synergistically eliminate NOx and CH3SH. However, the catalytic system for synergistically eliminating NOx and CH3SH is seldom investigated to date. Meanwhile, the deactivation effects of CH3SH on catalysts and the formation mechanism of toxic byproducts emitted from the synergistic catalytic elimination reaction are still vague. Herein, selective synergistic catalytic elimination (SSCE) of NOx and CH3SH via engineering deep oxidation sites over Cu-modified Nb-Fe composite oxides supported on TiO2 catalyst against toxic CO and HCN byproducts formation has been originally demonstrated. Various spectroscopic and microscopic characterizations demonstrate that the sufficient chemisorbed oxygen species induced by the persistent electron transfer from Nb-Fe composite oxides to copper oxides can deeply oxidize HCOOH to CO2 for avoiding highly toxic byproducts formation. This work is of significance in designing superior catalysts employed in more complex working conditions and sheds light on the progress in the SSCE of NOx and sulfur-containing volatile organic compounds.

Promoting C-F bond activation via proton donor for CF4 decomposition.

Tetrafluoromethane (CF4), the simplest perfluorocarbons, is a permanently potent greenhouse gas due to its powerful infrared radiation adsorption capacity. The highly symmetric and robust C-F bond structure makes its activation a great challenge. Herein, we presented an innovated approach that efficiently activates C-F bond utilizing protonated sulfate (-HSO4) modified Al2O3@ZrO2 (S-Al2O3@ZrO2) catalyst, resulting in highly efficient CF4 decomposition. By combining in situ infrared spectroscopy tests and density function theory simulations, we demonstrate that the introduced -HSO4 proton donor has a stronger interaction on the C-F bond than the hydroxyl (-OH) proton donor, which can effectively stretch the C-F bond for its activation. Consequently, the obtained S-Al2O3@ZrO2 catalyst achieved a stable 100% CF4 decomposition at a record low temperature of 580 °C with a turnover frequency value of ~8.3 times higher than the Al2O3@ZrO2 catalyst without -HSO4 modification, outperforming the previously reported results. This work paves a new way for achieving efficient C-F bond activation to decompose CF4 at a low temperature.

Improving Electrocatalytic Oxygen Evolution through Local Field Distortion in Mg/Fe Dual-site Catalysts.

Transition metal single atom electrocatalysts (SACs) with metal-nitrogen-carbon (M-N-C) configuration show great potential in oxygen evolution reaction (OER), whereby the spin-dependent electrons must be allowed to transfer along reactants (OH- /H2 O, singlet spin state) and products (O2 , triplet spin state). Therefore, it is imperative to modulate the spin configuration in M-N-C to enhance the spin-sensitive OER energetics, which however remains a significant challenge. Herein, we report a local field distortion induced intermediate to low spin transition by introducing a main-group element (Mg) into the Fe-N-C architecture, and decode the underlying origin of the enhanced OER activity. We unveil that, the large ionic radii mismatch between Mg2+ and Fe2+ can cause a FeN4 in-plane square local field deformation, which triggers a favorable spin transition of Fe2+ from intermediate (dxy 2 dxz 2 dyz 1 dz2 1 , 2.96 µB ) to low spin (dxy 2 dxz 2 dyz 2 , 0.95 µB ), and consequently regulate the thermodyna-mics of the elementary step with desired Gibbs free energies. The as-obtained Mg/Fe dual-site catalyst demonstrates a superior OER activity with an overpotential of 224 mV at 10 mA cm-2 and an electrolysis voltage of only 1.542 V at 10 mA cm-2 in the overall water splitting, which outperforms those of the state-of-the-art transition metal SACs.

Prussian blue analogues derived magnetic FeCo@GC material as high-performance metallic peroxymonosulfate activators to degrade tetrabromobisphenol A over a wide pH range.

Metal-organic frame (MOF) materials can effectively degrade organic pollutants, whereas the MOF is rapidly hydrolysed in water and has poor stability and low reusability. However, in the current advanced oxidation process (AOP) system, the removal effect of pollutants under alkaline condition is not ideal. In this study, a magnetic composite material derived from MOF was synthesised and used as a new catalyst for rapid degradation of tetrabromobisphenol A (TBBPA). Compared to precarbonisation, FeCo@GC formed a conductive graphite carbon skeleton, retained the complete rhombododecahedron structure, had a larger specific surface area and provided more active sites for peroxymonosulfate (PMS) activation. The target pollutant TBBPA (20 mg/L) was completely degraded within 30 min, and the mineralisation rate reached 40.98% in the FeCo@GC (150 mg/L) and PMS (1 mM) systems, owing to the synergistic interaction between Fe, Co and graphite carbon. The reactive oxygen species (ROS) involved in the reaction were determined to be SO4•-, ·OH, 1O2 and O2•- by electron paramagnetic resonance and free radical scavenging experiments, and the 1O2 played a dominant role. Based on the results of LC-MS analysis results, the main degradation pathways of TBBPA involve three mechanisms: the debromination reaction, hydroxylation and cleavage of the benzene ring. In addition, compared with previous AOP systems, FeCo@GC/PMS overcomes the disadvantage of poor degradation effect of TBPPA under alkaline conditions, has a wide range pH (3-11) application and has the best effect on TBBPA degradation under alkaline conditions. FeCo@GC has an excellent cycle performance, with a removal rate of re-calcined material of 88.52% after five cycles. Therefore, FeCo@GC can be used as a promising and efficient catalyst for removing environmental organic pollutants.

Ultrahighly Alkali-Tolerant NOx Reduction over Self-Adaptive CePO4/FePO4 Catalysts.

Catalyst deactivation caused by alkali metal poisoning has long been a key bottleneck in the application of selective catalytic reduction of NOx with NH3 (NH3-SCR), limiting the service life of the catalyst and increasing the cost of environmental protection. Despite great efforts, continuous accumulation of alkali metal deposition makes the resistance capacity of 2 wt % K2O difficult to enhance via merely loading acid sites on the surface, resulting in rapid deactivation and frequent replacement of the NH3-SCR catalyst. To further improve the resistance of alkali metals, encapsulating alkali metals into the bulk phase could be a promising strategy. The bottleneck of 2 wt % K2O tolerance has been solved by virtue of ultrahigh potassium storage capacity in the amorphous FePO4 bulk phase. Amorphous FePO4 as a support of the NH3-SCR catalyst exhibited a self-adaptive alkali-tolerance mechanism, where potassium ions spontaneously migrated into the bulk phase of amorphous FePO4 and were anchored by PO43- with the generation of Fe2O3 at the NH3-SCR reaction temperature. This ingenious potassium storage mechanism could boost the K2O resistance capacity to 6 wt % while maintaining approximately 81% NOx conversion. Besides, amorphous FePO4 also exhibited excellent resistance to individual and coexistence of alkali (K2O and Na2O), alkali earth (CaO), and heavy metals (PbO and CdO), providing long durability for CePO4/FePO4 catalysts in flue gas with multipollutants. The cheap and accessible amorphous FePO4 paves the way for the development and implementation of poisoning-resistant NOx abatement.

Revealing the Dynamic Behavior of Active Sites on Acid-Functionalized CeO2 Catalysts for NOx Reduction.

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.

Improved N2 Selectivity of MnOx Catalysts for NOx Reduction by Engineering Bridged Mn3+ Sites.

Mn-based catalysts are promising for selective catalytic reduction (SCR) of NOx with NH3 at low temperatures due to their excellent redox capacity. However, the N2 selectivity of Mn-based catalysts is an urgent problem for practical application owing to excessive oxidizability. To solve this issue, we report a Mn-based catalyst using amorphous ZrTiOx as the support (Mn/ZrTi-A) with both excellent low-temperature NOx conversion and N2 selectivity. It is found that the amorphous structure of ZrTiOx modulates the metal-support interaction for anchoring the highly dispersed active MnOx species and constructs a uniquely bridged Mn3+ bonded with the support through oxygen linked to Ti4+ and Zr4+, respectively, which regulates the optimal oxidizability of the MnOx species. As a result, Mn/ZrTi-A is not conducive to the formation of ammonium nitrate that readily decomposes to N2O, thus further increasing N2 selectivity. This work investigates the role of an amorphous support in promoting the N2 selectivity of a manganese-based catalyst and sheds light on the design of efficient low-temperature deNOx catalysts.

Triggering High Capacity and Superior Reversibility of Manganese Oxides Cathode via Magnesium Modulation for Zn//MnO2 Batteries.

Aqueous zinc-ion batteries (ZIBs) have attracted extensive attention in recent years because of its high volumetric energy density, the abundance of zinc resources, and safety. However, ZIBs still suffer from poor reversibility and sluggish kinetics derived from the unstable cathodic structure and the strong electrostatic interactions between bivalent Zn2+ and cathodes. Herein, magnesium doping into layered manganese dioxide (Mg-MnO2 ) via a simple hydrothermal method as cathode materials for ZIBs is proposed. The interconnected nanoflakes of Mg-MnO2 possess a larger specific surface area compared to pristine δ-MnO2 , providing more electroactive sites and boosting the capacity of batteries. The ion diffusion coefficients of Mg-MnO2 can be enhanced due to the improved electrical conductivity by doped cations and oxygen vacancies in MnO2 lattices. The assembled Zn//Mg-MnO2 battery delivers a high specific capacity of 370 mAh g-1 at a current density of 0.6 A g-1 . Furthermore, the reaction mechanism confirms that Zn2+ insertion occurred after a few cycles of activation reactions. Most important, the reversible redox reaction between Zn2+ and MnOOH is found after several charge-discharge processes, promoting capacity and stability. It believes that this systematic research enlightens the design of high-performance of ZIBs and facilitates the practical application of Zn//MnO2 batteries.

Boosting Ozone Catalytic Oxidation of Toluene at Room Temperature by Using Hydroxyl-Mediated MnOx/Al2O3 Catalysts.

Ozone catalytic oxidation (OZCO) has gained great interest in environmental remediation while it still faces a big challenge during the deep degradation of refractory volatile organic compounds (VOCs) at room temperature. Hydroxylation of the catalytic surface provides a new strategy for regulating the catalytic activity to boost VOC degradation. Herein, OZCO of toluene at room temperature over hydroxyl-mediated MnOx/Al2O3 catalysts was originally demonstrated. Specifically, a novel hydroxyl-mediated MnOx/Al2O3 catalyst was developed via the in situ AlOOH reconstruction method and used for toluene OZCO. The toluene degradation performance of MnOx/Al2O3 was significantly superior to those of most of the state-of-the-art catalysts, and 100% toluene was removed with an excellent mineralization rate (82.3%) and catalytic stability during OZCO. ESR and in situ DRIFTs results demonstrated that surface hydroxyl groups (HGs) greatly improved the reactive oxygen species generation, thus dramatically accelerating the benzene ring breakage and deep mineralization. Furthermore, HGs provided anchoring sites for uniformly dispersing MnOx and greatly enhanced toluene adsorption and ozone activation. This work paves a way for deep decomposition of aromatic VOCs at room temperature.

Atomically Local Electric Field Induced Interface Water Reorientation for Alkaline Hydrogen Evolution Reaction.

The slow water dissociation process in alkaline electrolyte severely limits the kinetics of HER. The orientation of H2 O is well known to affect the dissociation process, but H2 O orientation is hard to control because of its random distribution. Herein, an atomically asymmetric local electric field was designed by IrRu dizygotic single-atom sites (IrRu DSACs) to tune the H2 O adsorption configuration and orientation, thus optimizing its dissociation process. The electric field intensity of IrRu DSACs is over 4.00×1010  N/C. The ab initio molecular dynamics simulations combined with in situ Raman spectroscopy analysis on the adsorption behavior of H2 O show that the M-H bond length (M=active site) is shortened at the interface due to the strong local electric field gradient and the optimized water orientation promotes the dissociation process of interfacial water. This work provides a new way to explore the role of single atomic sites in alkaline hydrogen evolution reaction.

Expediting Toluene Combustion by Harmonizing the Ce-O Strength over Co-Doped CeZr Oxide Catalysts.

Low-temperature catalytic degradation of volatile organic compounds (VOCs) by enhancing the activity of non-precious metal catalysts has always been the focus of attention. The mineralization of aromatic VOCs requires the participation of a large number of oxygen atoms, so the activation of oxygen species is crucial in the degradation reaction. Herein, we originally adjust the Ce-O bond strength in CeZr oxide catalysts by cobalt doping to promote the activation of oxygen species, thus improving the toluene degradation performance while maintaining high stability. Subsequent characterizations and theoretical calculations demonstrate that the weakening of the Ce-O bond strength increases the oxygen vacancy content, promotes the activation of oxygen species, and enhances the redox ability of the catalysts. This strategy also promotes the activation of toluene and accelerates the depletion of intermediate species. This study will contribute a strategy to enhance the activation ability of oxygen species in non-noble metal oxide catalysts, thereby enhancing the degradation performance of VOCs.

Balancing acid and redox sites of phosphorylated CeO2 catalysts for NOx reduction: The promoting and inhibiting mechanism of phosphorus.

The role of phosphorus in metal oxide catalysts is still controversial. The precise tuning of the acidic and redox properties of metal oxide catalysts for the selective catalytic reduction in NOx using NH3 is also a great challenge. Herein, CeO2 catalysts with different degrees of phosphorylation were used to study the balance between the acidity and redox property by promoting and inhibiting effects of phosphorus. CeO2 catalysts phosphorylated with lower phosphorus content (5 wt%) exhibited superior NOx reduction performance with above 90% NOx conversion during 240-420 °C due to the balanced acidity and reducibility derived from the highest content of Brønsted acid sites on PO43- to adsorb NH3 and surface adsorbed oxygen species. Plenty of PO3- over CeO2 catalysts phosphorylated with the higher phosphorus content (≥ 10 wt%) significantly disrupted the balance between the acidity and the redox property due to the reduced acid/redox sites, which resulted in the less active NOx species. The mechanism of different structural phosphorus species (PO43- and PO3-) in promoting or inhibiting the NOx reduction over CeO2 catalysts was revealed. This work provides a novel method for qualitative and quantitative study of the relationship between acidity/redox property and activity of catalysts for NOx reduction.

Compensation or Aggravation: Pb and SO2 Copoisoning Effects over Ceria-Based Catalysts for NOx Reduction.

Severe catalyst deactivation caused by multiple poisons, including heavy metals and SO2, remains an obstinate issue for the selective catalytic reduction (SCR) of NOx by NH3. The copoisoning effects of heavy metals and SO2 are still unclear and irreconcilable. Herein, the unanticipated differential compensated or aggravated Pb and SO2 copoisoning effects over ceria-based catalysts for NOx reduction was originally unraveled. It was demonstrated that Pb and SO2 exhibited a compensated copoisoning effect over the CeO2/TiO2 (CT) catalyst with sole active CeO2 sites but an aggravated copoisoning effect over the CeO2-WO3/TiO2 (CWT) catalyst with dual active CeO2 sites and acidic WO3 sites. Furthermore, it was uniquely revealed that Pb preferred bonding with CeO2 among CT while further being combined with SO2 to form PbSO4 after copoisoning, which released the poisoned active CeO2 sites and rendered the copoisoned CT catalyst a recovered reactivity. In comparison, Pb and SO2 would poison acidic WO3 sites and active CeO2 sites, respectively, resulting in a seriously degraded reactivity of the copoisoned CWT catalyst. Therefore, this work thoroughly illustrates the internal mechanism of differential compensated or aggravated deactivation effects for Pb and SO2 copoisoning over CT and CWT catalysts and provides effective solutions to design ceria-based SCR catalysts with remarkable copoisoning resistance for the coexistence of heavy metals and SO2.

In Celebration of the 100th Anniversary of Shanghai University.

To celebrate the 100th anniversary of Shanghai University, Chemistry - An Asian Journal worked closely with Prof. Hongbin Zhao, Prof. Dengsong Zhang, Prof. Yang Yu, Prof. Liqiang Luo and Prof. Jiaqiang Xu from Shanghai University to launch this special collection. More than 30 contributions were assembled, covering topics in organic chemistry, inorganic chemistry, physical chemistry, analytical chemistry and environmental chemistry to highlight the significant contributions that chemists connected with Shanghai University made.