Spatial Distribution of Brønsted Acid Sites Determines the Mobility of Reactive Cu Ions in the Cu-SSZ-13 Catalyst during the Selective Catalytic Reduction of NOx with NH3

The formation of dimer-Cu species, which serve as the active sites of the low-temperature selective catalytic reduction of NOx with NH3 (NH3-SCR), relies on the mobility of CuI species in the channels of the Cu-SSZ-13 catalysts. Herein, the key role of framework Brønsted acid sites in the mobility of reactive Cu ions was elucidated via a combination of density functional theory calculations, in situ impedance spectroscopy, and in situ diffuse reflectance ultraviolet-visible spectroscopy. When the number of framework Al sites decreases, the Brønsted acid sites decrease, leading to a systematic increase in the diffusion barrier for [Cu(NH3)2]+ and less formation of highly reactive dimer-Cu species, which inhibits the low-temperature NH3-SCR reactivity and vice versa. When the spatial distribution of Al sites is uneven, the [Cu(NH3)2]+ complexes tend to migrate from an Al-poor cage to an Al-rich cage (e.g., cage with paired Al sites), which effectively accelerates the formation of dimer-Cu species and hence promotes the SCR reaction. These findings unveil the mechanism by which framework Brønsted acid sites influence the intercage diffusion and reactivity of [Cu(NH3)2]+ complexes in Cu-SSZ-13 catalysts and provide new insights for the development of zeolite-based catalysts with excellent SCR activity by regulating the microscopic spatial distribution of framework Brønsted acid sites.

Efficient Pt/KFI zeolite catalysts for the selective catalytic reduction of NOx by hydrogen

Aiming at purification of NOx from hydrogen internal combustion engines (HICEs), the hydrogen selective catalytic reduction (H2-SCR) reaction was investigated over a series of Pt/KFI zeolite catalysts. H2 can readily reduce NOx to N2 and N2O while O2 inhibited the deNOx efficiency by consuming the reductant H2. The Pt/KFI zeolite catalysts with Pt loading below 0.1 wt.% are optimized H2-SCR catalysts due to its suitable operation temperature window since high Pt loading favors the H2-O2 reaction which lead to the insufficient of reactants. Compared to metal Pt0 species, Ptδ+ species showed lower activation energy of H2-SCR reaction and thought to be as reasonable active sites. Further, Eley-Rideal (E-R) reaction mechanism was proposed as evidenced by the reaction orders in kinetic studies. Last, the optimized reactor was designed with hybrid Pt/KFI catalysts with various Pt loading which achieve a high NOx conversion in a wide temperature range.

Combined Experimental and Density Functional Theory Study on the Mechanism of the Selective Catalytic Reduction of NO with NH3 over Metal-Free Carbon-Based Catalysts

Metal-free carbon-based catalysts are attracting much attention in the low-temperature selective catalytic reduction of NOx with NH3 (NH3-SCR). However, the mechanism of the NH3-SCR reaction on carbon-based catalysts is still controversial, which severely limits the development of carbon-based SCR catalysts. Herein, we successfully reconstructed carbon-based catalysts through oxidation treatment with nitric acid, thereby enhancing their low-temperature activity in NH3-SCR. Combining experimental results and density functional theory (DFT) calculations, we proposed a previously unreported NH3-SCR reaction mechanism over carbon-based catalysts. We demonstrated that C-OH and C-O-C groups not only effectively activate NH3 but also remarkedly promote the decomposition of intermediate NH2NO. This study enhances the understanding of the NH3-SCR mechanism on carbon-based catalysts and paves the way to develop low-temperature metal-free SCR catalysts.

Unexpected Promotion Effect of H2O on the Selective Catalytic Reduction of NOx with NH3 over Cu-SSZ-39 Catalysts

Water molecules commonly inhibit the selective catalytic reduction (SCR) of NOx with NH3 on most catalysts, and water resistance is a long-standing challenge for SCR technology. Herein, by combining experimental measurements and density functional theory (DFT) calculations, we found that water molecules do not inhibit and even promote the NOx conversion to some extent over the Cu-SSZ-39 zeolites, a promising SCR catalyst. Water acting as a ligand on active Cu sites and as a reactant in the SCR reaction significantly improves the O2 activation performance and reduces the overall energy barrier of the catalytic cycle. This work unveils the mechanism of the unexpected promotion effect of water on the NH3-SCR reaction over Cu-SSZ-39 and provides fundamental insight into the development of zeolite-based SCR catalysts with excellent activity and water resistance.

Uncovering the Dinuclear Mechanism of NO2-Involved NH3-SCR over Supported V2O5/TiO2 Catalysts

Commercial vanadium oxide catalysts exhibit high efficiency for the selective catalytic reduction (SCR) of NO with NH3, especially in the presence of NO2 (i.e., occurrence of fast NH3-SCR). The high-activity sites and their working principle for the fast NH3-SCR reaction, however, remain elusive. Here, by combining in situ spectroscopy, isotopic labeling experiments, and density functional theory (DFT) calculations, we demonstrate that polymeric vanadyl species act as the main active sites in the fast SCR reaction because the coupling effect of the polymeric structure alters the elementary reaction step and effectively avoids the high energy barrier of the rate-determining step over monomeric vanadyl species. This study unveils the high-activity dinuclear mechanism of the NO2-involved SCR reaction over vanadia-based catalysts and provides a fundamental basis for developing high-efficiency and low V2O5-loading SCR catalysts.

Enhanced Hydrosaturation Selectivity and Electron Transfer for Electrocatalytic Chlorophenols Hydrogenation on Ru Sites

Electrocatalytic hydrogenation is acknowledged as a promising strategy for chlorophenol dechlorination. However, the widely used Pd catalysts exhibit drawbacks, such as high costs and low selectivity for phenol hydrosaturation. Herein, we demonstrate the potential and mechanism of Ru in serving as a Pd substitute using 2,4,6-trichlorophenol (TCP) as a model pollutant. Up to 99.8% TCP removal efficiency and 99% selectivity to cyclohexanol, a value-added compound with an extremely low toxicity, were achieved on the Ru electrode. In contrast, only 66% of TCP was removed on the Pd electrode, with almost no hydrosaturation selectivity. The superiority of Ru over Pd was especially noteworthy in alkaline conditions or the presence of interfering species such as S2-. The theoretical simulation demonstrates that Ru possesses a hydrodechlorination energy barrier of 0.72 eV, which is comparable to that on Pd. Meanwhile, hydrosaturation requires an activation energy of 0.69 eV on Ru, which is much lower than that on Pd (0.92 eV). The main reaction mechanism on Ru is direct electron transfer, which is distinct from that on Pd (indirect pathway via atomic hydrogen, H*). This work thereby provides new insights into designing cost-effective electrocatalysts for halogenated phenol detoxification and resource recovery.

A Study of CeSnOx and Pd/CeSnOx as Low-Temperature NOx Adsorbers with Excellent Hydrothermal Stability

In the present work, we report on two passive NOx adsorber (PNA) material candidates: the novel support CeSnOx with and without Pd loading. The NOx adsorption and storage capacities of fresh and hydrothermally aged CeSnOx and Pd/CeSnOx were investigated. The results show that CeSnOx exhibits a rather large NOx uptake and storage capacity (28.9 μmol/g), while the loading of Pd on CeSnOx can further increase the storage capacity to 37.6 μmol/g and affect the desorption temperature of NOx. It was found that the NOx desorption temperature of Pd/CeSnOx was compatible with the efficient operating window of selective catalytic reduction (SCR) catalysts. After a hydrothermal aging treatment at 800 °C for 12 h, the NOx adsorption and storage capacities of CeSnOx and Pd/CeSnOx increased, indicating excellent hydrothermal stability. The interaction of Pd with CeSnOx, the state of Pd species, and the structure of CeSnOx and Pd/CeSnOx are studied by combination of the characterization results.

Unveiling the Origin of Selectivity in the Selective Catalytic Reduction of NO with NH3 over Oxide Catalysts

The trade-off between activity and selectivity is a century-old puzzle in catalysis. In the selective catalytic reduction of NO with NH₃ (NH₃-SCR), various typical oxide catalysts exhibit distinct characteristics of activity and selectivity: Mn-based catalysts show outstanding low-temperature activity and poor N₂ selectivity, mainly caused by N₂O formation, while Fe- and V-based catalysts possess inverse characteristics. The underlying mechanism, however, has remained elusive. In this study, by combining experimental measurements and density functional theory calculations, we demonstrate that the distinct difference in the selectivity of oxide catalysts is determined by the gap in the energy barriers between N₂ formation and N₂O formation from the consumption of the key intermediate NH₂NO. The gaps in the energy barriers follow the order of α-MnO₂ < α-Fe₂O₃ < V₂O₅/TiO₂, in correspondence with the order of N₂ selectivity of the catalysts. This work discloses the intrinsic link between the target reaction and side reactions in the selective catalytic reduction of NO, providing fundamental insights into the origin of selectivity.

Effects of Si/Al Ratio on Passive NOx Adsorption Performance over Pd/Beta Zeolites

In the current article, the effect of Si/Al ratio on the NO_x adsorption and storage capacity over Pd/Beta with 1 wt% Pd loading was investigated. The XRD, ²⁷Al NMR and ²⁹Si NMR measurements were used to determine the structure of Pd/Beta zeolites. XAFS, XPS, CO-DRIFT, TEM and H₂-TPR were used to identify the Pd species. The results showed that the NO_x adsorption and storage capacity on Pd/Beta zeolites gradually decreased with the increase of Si/Al ratio. Pd/Beta-Si (Si-rich, Si/Al~260) rarely has NO_x adsorption and storage capacity, while Pd/Beta-Al (Al-rich, Si/Al~6) and Pd/Beta-C (Common, Si/Al~25) exhibit excellent NO_x adsorption and storage capacity and suitable desorption temperature. Pd/Beta-C has slightly lower desorption temperature compared to Pd/Beta-Al. The NO_x adsorption and storage capacity increased for Pd/Beta-Al and Pd/Beta-C by hydrothermal aging treatment, while the NO_x adsorption and storage capacity on Pd/Beta-Si had no change.

Hydrothermal Aging Alleviates the Phosphorus Poisoning of Cu-SSZ-39 Catalysts for NH3-SCR Reaction

As a new type of catalyst with the potential for commercial application in NO_x removal from diesel engine exhausts, Cu-SSZ-39 catalysts must have excellent resistance to complex and harsh conditions. In this paper, the effects of phosphorus on Cu-SSZ-39 catalysts before and after hydrothermal aging treatment were investigated. Compared with fresh Cu-SSZ-39 catalysts, phosphorus poisoning significantly decreased the low-temperature NH₃-SCR catalytic activity. However, such activity loss was alleviated by further hydrothermal aging treatment. To reveal the reason for this interesting result, a variety of characterization techniques including NMR, H₂-TPR, X-ray photoelectron spectroscopy, NH₃-TPD, and in situ DRIFTS measurements were employed. It was found that Cu-P species produced by phosphorus poisoning decreased the redox ability of active copper species, resulting in the observed low-temperature deactivation. After hydrothermal aging treatment, however, Cu-P species partly decomposed with the formation of active CuO_x species and a release of active copper species. As a result, the low-temperature NH₃-SCR catalytic activity of Cu-SSZ-39 catalysts was recovered.

Insights into SO2 Poisoning Mechanisms of Fresh and Hydrothermally Aged Cu-KFI Catalysts for NH3-SCR Reaction

The complex poisoning of Cu-KFI catalysts by SO₂ and hydrothermal aging (HTA) was investigated. The low-temperature activity of Cu-KFI catalysts was restrained by the formation of H₂SO₄ and then CuSO₄ after sulfur poisoning. Hydrothermally aged Cu-KFI exhibited better SO₂ resistance than fresh Cu-KFI since HTA significantly reduced the number of Brønsted acid sites, which were considered to be the H₂SO₄ storage sites. The high-temperature activity of SO₂-poisoned Cu-KFI was basically unchanged compared to the fresh catalyst. However, SO₂ poisoning promoted the high-temperature activity of hydrothermally aged Cu-KFI since it triggered CuOx into CuSO₄ species, which was considered as an important role in the NH₃-SCR reaction at high temperatures. In addition, hydrothermally aged Cu-KFI catalysts were more easily regenerated after SO₂ poisoning than fresh Cu-KFI on account of the instability of CuSO₄.

Economical and Sustainable Synthesis of Small-Pore Chabazite Catalysts for NOx Abatement by Recycling Organic Structure-Directing Agents

The application of small-pore chabazite-type SSZ-13 zeolites, key materials for the reduction of nitrogen oxides (NO_x) in automotive exhausts and the selective conversion of methane, is limited by the use of expensive N,N,N-trimethyl-1-ammonium adamantine hydroxide (TMAdaOH) as an organic structure-directing agent (OSDA) during hydrothermal synthesis. Here, we report an economical and sustainable route for SSZ-13 synthesis by recycling and reusing the OSDA-containing waste liquids. The TMAdaOH concentration in waste liquids, determined by a bromocresol green colorimetric method, was found to be a key factor for SSZ-13 crystallization. The SSZ-13 zeolite synthesized under optimized conditions demonstrates similar physicochemical properties (surface area, porosity, crystallinity, Si/Al ratio, etc.) as that of the conventional synthetic approach. We then used the waste liquid-derived SSZ-13 as the parent zeolite to synthesize Cu ion-exchanged SSZ-13 (i.e., Cu-SSZ-13) for ammonia-mediated selective catalytic reduction of NO_x (NH₃-SCR) and observed a higher activity as well as better hydrothermal stability than Cu-SSZ-13 by conventional synthesis. In situ infrared and ultraviolet-visible spectroscopy investigations revealed that the superior NH₃-SCR performance of waste liquid-derived Cu-SSZ-13 results from a higher density of Cu²⁺ sites coordinated to paired Al centers on the zeolite framework. The technoeconomic analysis highlights that recycling OSDA-containing waste liquids could reduce the raw material cost of SSZ-13 synthesis by 49.4% (mainly because of the higher utilization efficiency of TMAdaOH) and, meanwhile, the discharging of wastewater by 45.7%.

Advances in emission control of diesel vehicles in China

Diesel vehicles have caused serious environmental problems in China. Hence, the Chinese government has launched serious actions against air pollution and imposed more stringent regulations on diesel vehicle emissions in the latest China VI standard. To fulfill this stringent legislation, two major technical routes, including the exhaust gas recirculation (EGR) and high-efficiency selective catalytic reduction (SCR) routes, have been developed for diesel engines. Moreover, complicated aftertreatment technologies have also been developed, including use of a diesel oxidation catalyst (DOC) for controlling carbon monoxide (CO) and hydrocarbon (HC) emissions, diesel particulate filter (DPF) for particle mass (PM) emission control, SCR for the control of NOx emission, and an ammonia slip catalyst (ASC) for the control of unreacted NH₃. Due to the stringent requirements of the China VI standard, the aftertreatment system needs to be more deeply integrated with the engine system. In the future, aftertreatment technologies will need further upgrades to fulfill the requirements of the near-zero emission target for diesel vehicles.

Si/Al Ratio Determines the SCR Performance of Cu-SSZ-13 Catalysts in the Presence of NO2

A comparative study was performed to investigate the NH₃-selective catalytic reduction (SCR) reaction activity of Cu-SSZ-13 zeolites having Si/Al ratios (SARs) of 5, 18, and 30. Remarkably, the Cu-SSZ-13 zeolite catalysts exhibited completely opposite behaviors as a function of SAR under standard SCR (SSCR) and fast SCR (FSCR) reaction atmospheres. Under SSCR conditions, the NO_x conversion increased as expected with the decreasing SAR. Under FSCR conditions, however, the NO_x conversion decreased as the SAR decreased, contrary to expectations. In this study, based on characterization of the catalysts by X-ray diffraction, transmission electron microscopy, electron paramagnetic resonance, H₂-temperature-programmed reduction, temperature-programmed desorption, and diffuse reflectance infrared Fourier transform spectroscopy, together with theoretical calculations, the authors found that the amount of Brønsted acid sites goes up while the SAR goes down, leading to an increase in the accumulation of NH₄NO₃ under FSCR reaction conditions. Moreover, the accumulated NH₄NO₃ is of greater stability for those low SAR Cu-SSZ-13 catalysts. These two reasons cause the FSCR performance of Cu-SSZ-13 to decrease with a decrease in SAR. As a result, the NO₂ effect on SCR activity changes from promotion to inhibition as the SAR decreases.

POS0535 OUTCOMES IN PATIENTS WITH RHEUMATOID ARTHRITIS INITIATING THERAPY WITH ETANERCEPT, ADALIMUMAB, OR JANUS KINASE INHIBITORS

Background

Ongoing debate exists regarding the optimal sequence of tumor necrosis factor inhibitors and Janus kinase inhibitors (JAKis) in patients with rheumatoid arthritis (RA) as first-line biologic or targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) therapy following conventional therapies.

Objectives

To describe baseline characteristics, effectiveness, persistency, and treatment patterns among first-line b/tsDMARD-naive initiators of etanercept (ETN), adalimumab (ADA), or JAKis (tofacitinib, baricitinib, and upadacitinib).

Methods

Data on patients who initiated b/tsDMARD from 11/2012 to 6/2021 were obtained from the CorEvitas RA Registry, a prospective, multicenter, observational, disease-based registry. Patients ≥18 years with rheumatologist-diagnosed RA and 6- and/or 12-months’ (M) follow-up were included. We report descriptive statistics at baseline, persistency on therapy, escalation/de-escalation of therapy, details on patterns of drug switching, and effectiveness outcomes using regression models adjusted for baseline covariates (demographic/socioeconomic/lifestyle characteristics, comorbidities, medication history, disease activity, and patient-reported outcomes). Outcomes were evaluated at 6M and 12M follow-up.

Results

First-line initiators of ETN, ADA, and JAKis with baseline and follow-up visits were identified: 803, 984, and 361 patients at 6M, respectively; 589, 749, and 264 patients at 12M, respectively. Baseline characteristics were similar among ETN, ADA, and JAKi initiators with the exception of disease duration, which was longer among first-line JAKi initiators (mean, 8.6 y) versus ETN (5.9 y) and ADA (5.8 y) initiators. Unadjusted mean improvement in Clinical Disease Activity Index (CDAI) was generally similar between groups at 6M and 12M (Table 1). Adjusted effectiveness results were similar at 6M and 12M (Figure 1). At 6M, 68% of ETN, 69% of ADA, and 67% of JAKi initiators remained on the same therapy; at 12M, 53% of ETN, 57% of ADA, and 57% of JAKi initiators remained on the same therapy. The frequency of switching to another b/tsDMARD was similar across initiators.

Table 1.

Patient Description at Time of Initiation and Unadjusted Disease Activity Results

ETNADAJAKisAge, years54.4 (12.8)55.5 (12.1)60.9 (12.5)Female, n (%)666 (77)843 (76)303 (77)BMI, kg/m230.4 (7.6)31.3 (7.9)30.8 (7.6)Duration of RA, years5.9 (7.6)5.8 (7.3)8.6 (10.0)BL disease activitya CDAI19.9 (14.3)18.9 (12.7)18.8 (13.2) mHAQ0.5 (0.5)0.5 (0.5)0.5 (0.5) Patient painb48.0 (28.8)49.2 (28.5)45.2 (29.2)Disease activity decrease from BL at 6M CDAI6.9 (13.6)6.4 (12.1)4.7 (12.3) mHAQ0.1 (0.4)0.1 (0.4)0.1 (0.4) Patient painb9.7 (30.2)10.6 (28.4)8.9 (29.5)Disease activity decrease from BL at 12M CDAI7.4 (13.5)6.1 (13.0)5.1 (13.0) mHAQ0.1 (0.4)0.1 (0.4)0.1 (0.4) Patient painb8.8 (29.7)8.7 (30.1)7.5 (28.6)Achievement of LDAc, % 6M43.441.932.5 12M41.039.638.3

aBaseline for combined population with 6M and 12M follow-up. b(range: 0–100). cCDAI ≤10 among those with moderate or high disease activity at baseline.

Data are mean (SD) unless otherwise specified.

ADA, adalimumab; BL, baseline; CDAI, Clinical Disease Activity Index; ETN, etanercept; JAKis, Janus kinase inhibitors; LDA, low disease activity; M, months; mHAQ, modified Health Assessment Questionnaire; RA, rheumatoid arthritis; SD, standard deviation.

Conclusion

In this real-world study in patients initiating first-line b/tsDMARD therapy with ETN, ADA, or JAKis, we did not observe differences in clinical effectiveness/patient-reported outcomes and treatment persistency at 6M and12M after treatment initiation.

Acknowledgements

This study is sponsored by CorEvitas, LLC. CorEvitas has been supported through contracted subscriptions in the last two years by AbbVie, Amgen Inc., Arena, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Chugai, Eli Lilly and Company, Genentech, Gilead, GSK, Janssen, LEO, Novartis, Ortho Dermatologics, Pfizer Inc., Regeneron, Sanofi, Sun, and UCB. Writing support was funded by Amgen Inc. and provided by Su Cappello, PharmD, of Peloton Advantage, LLC, an OPEN Health company, and Julie Wang, DPM, of Amgen Inc.

Disclosure of Interests

Dimitrios A Pappas Shareholder of: Officer or Board Member for Corrona Research Foundation, Speakers bureau: Speaker/Honoraria for AbbVie, Novartis, Roche Hellas, Sanofi, Consultant of: Consultant for AbbVie, Roche Hellas; Advisor for Sanofi, Employee of: Employment by, ownership interest, and stock options in CorEvitas, LLC, Jacqueline O’Brien Employee of: Employment by CorEvitas, LLC., Lin Guo Employee of: Employment by CorEvitas, LLC., Ying Shan Employee of: Employment by CorEvitas, LLC., Joshua Baker Consultant of: Received consulting fees from Bristol Myers Squibb, Pfizer, CorEvitas LLC, and Burns-White, LLC., Greg Kricorian Shareholder of: Employment by and stock ownership in Amgen Inc., Employee of: Employment by and stock ownership in Amgen Inc., Scott Stryker Shareholder of: Employment by and stock ownership in Amgen Inc., Employee of: Employment by and stock ownership in Amgen Inc., David Collier Shareholder of: Employment by and stock ownership in Amgen Inc., Employee of: Employment by and stock ownership in Amgen Inc.

[Analysis of clinical phenotype and genotype of Chinese children with disorders of sex development]

Objective: To explore the heterogeneity and correlation of clinical phenotypes and genotypes in children with disorders of sex development (DSD). Methods: A retrospective study of 1 235 patients with clinically proposed DSD in 36 pediatric medical institutions across the country from January 2017 to May 2021. After capturing 277 DSD-related candidate genes, second-generation sequencing was performed to analyzed the heterogeneity and correlation combined with clinical phenotypes. Results: Among 1 235 children with clinically proposed DSD, 980 were males and 255 were females of social gender at the time of initial diagnosis with the age ranged from 1 day of age to 17.92 years. A total of 443 children with pathogenic variants were detected through molecular genetic studies, with a positive detection rate of 35.9%. The most common clinical phenotypes were micropenis (455 cases), hypospadias (321 cases), and cryptorchidism (172 cases) and common mutations detected were in SRD5A2 gene (80 cases), AR gene (53 cases) and CYP21A2 gene (44 cases). Among them, the SRD5A2 mutation is the most common in children with simple micropenis and simple hypospadias, while the AMH mutation is the most common in children with simple cryptorchidism. Conclusions: The SRD5A2 mutation is the most common genetic variant in Chinese children with DSD, and micropenis, cryptorchidism, and hypospadias are the most common clinical phenotypes. Molecular diagnosis can provide clues about the biological basis of DSD, and can also guide clinicians to perform specific clinical examinations. Target sequence capture probes and next-generation sequencing technology can provide effective and economical genetic diagnosis for children with DSD.

Promotion of the selective catalytic reduction of NOx with NH3 over microporous Cu-SSZ-13 by H2O and OH group at low temperatures: a density functional theory study

The successful commercialization of microporous Cu-SSZ-13 catalysts in the selective catalytic reduction (SCR) of NOx with NH3 has attracted extensive attention and debate on the mechanism of their excellent activity...

Reaction Pathways of Standard and Fast Selective Catalytic Reduction over Cu-SSZ-39

Cu-SSZ-39 exhibits excellent hydrothermal stability and is expected to be used for NO_x purification in diesel vehicles. In this work, the selective catalytic reduction (SCR) activities in the presence or absence of NO₂ were tested over Cu-SSZ-39 catalysts with different Cu contents. The results showed that the NO_x conversion of Cu-SSZ-39 was improved by NO₂ when NO₂/NO_x = 0.5, especially for the catalysts with low Cu loadings. The kinetic studies showed two kinetic regimes for fast SCR from 150 to 220 °C due to a change in the rate-controlling mechanism. The activity test and diffuse reflectance infrared Fourier transform spectra demonstrated that the reduction of NO mainly occurred on the Cu species in the absence of feed NO₂, and when NO₂/NO = 1, NO could react with NH₄NO₃ on the Brønsted acid sites in addition to undergoing reduction on Cu species. Thus, NO₂ can promote the SCR reaction over Cu-SSZ-39 by facilitating the formation of surface nitrate species.

Selective catalytic reduction of NO x with NH3: opportunities and challenges of Cu-based small-pore zeolites

Zeolites, as efficient and stable catalysts, are widely used in the environmental catalysis field. Typically, Cu-SSZ-13 with small-pore structure shows excellent catalytic activity for selective catalytic reduction of NO _x with ammonia (NH₃-SCR) as well as high hydrothermal stability. This review summarizes major advances in Cu-SSZ-13 applied to the NH₃-SCR reaction, including the state of copper species, standard and fast SCR reaction mechanism, hydrothermal deactivation mechanism, poisoning resistance and synthetic methodology. The review gives a valuable summary of new insights into the matching between SCR catalyst design principles and the characteristics of Cu²⁺-exchanged zeolitic catalysts, highlighting the significant opportunity presented by zeolite-based catalysts. Principles for designing zeolites with excellent NH₃-SCR performance and hydrothermal stability are proposed. On the basis of these principles, more hydrothermally stable Cu-AEI and Cu-LTA zeolites are elaborated as well as other alternative zeolites applied to NH₃-SCR. Finally, we call attention to the challenges facing Cu-based small-pore zeolites that still need to be addressed.

Photoluminescence and magnetism integrated multifunctional black phosphorus probes through controllable PO bond orbital hybridization

Biological probes with integrated photoluminescence and magnetism characteristics play a critical role in modern clinical diagnosis and surgical protocols combining fluorescence optical imaging (FOI) with magnetic resonance imaging (MRI) technology. However, traditional magnetic semiconductors can easily generate a spin splitting at the Fermi level and half-metallic electronic occupation, which will sharply reduce the radiation recombination efficiency of photogenerated carriers. To overcome this intrinsic contradiction, we propose a controllable oxidation strategy to introduce some particular PO bonds into black phosphorus nanosheets, in which the p orbital hybridization between P and O atoms not only provides some carrier recombination centers but also leads to a room-temperature spin polarization. As a result, the coexistence of photoluminescence and magnetism is realized in multifunctional black phosphorus probes with excellent biocompatibility. This work provides a new insight into integrating photoluminescence and magnetism together by intriguing atomic orbital hybridization.

Salvage mandibular reconstruction: multi-institutional analysis of 17 patients

Unsuccessful mandibular reconstruction occasionally occurs, leaving the patient with undesirable function and contours. In such cases, second- or third-time corrective operations are challenging. However, published studies on the complicated retreatment of such patients are scarce. A retrospective analysis covering the years 2015-2019 was conducted in three centers. All 17 patients included had undergone prior failed mandibular reconstructions in other institutions. Salvage secondary or tertiary reconstructive surgeries were attempted and the results are presented. Major factors for these failed reconstructions included exposed non-vascularized bone grafts (n = 7, 41.2%), flap loss (n = 4, 23.5%), exposed artificial joint (n = 3, 17.6%), skewed occlusion with deformity (n = 1, 5.9%), non-union (n = 1, 5.9%), and recurrence (n = 1, 5.9%). Fibula flaps were transferred in 15 patients, while iliac flaps were used in two patients for mandibular re-do reconstructions. Virtual surgical designs were conducted in nine (52.9%) patients, with navigation-guided approaches performed in three cases. Postoperative functions were relatively favorable in these complicated mandibular re-do reconstruction cases. Mandibular symmetry (mandibular length and height; P = 0.002) and condylar position (P < 0.001) were regained after these re-do attempts. Secondary or tertiary mandibular re-do reconstruction can still achieve good functional outcomes with appropriate preoperative selection and well-conceived designs, especially with the aid of virtual surgery and navigation.

AB0202 IMPROVEMENT IN CLINICAL DISEASE ACTIVITY AND PATIENT-REPORTED OUTCOMES AFTER 6 MONTHS OF TREATMENT WITH ABATACEPT, STRATIFIED BY LINE OF THERAPY, IN PATIENTS WITH RA: RESULTS FROM A LARGE, US, NATIONAL OBSERVATIONAL STUDY

Background:

RA is more responsive to treatment in the early stages of disease, and early treatment may lead to better long-term outcomes.1,2 Data on the effectiveness of specific drugs as first or later lines of therapy will help inform treatment sequencing.

Objectives:

Data from patients enrolled in the Corrona RA Registry were used to compare the effectiveness of abatacept across lines of therapy overall (primary cohort) and in a subset of patients who were anti-citrullinated protein antibody positive (ACPA+).

Methods:

Patients with RA who initiated abatacept (January 2006 to October 2020), had 6 months’ follow-up (within 4−9 months of starting abatacept), had baseline (BL) and follow-up CDAI scores available, and had BL CDAI >2.8 were included. Outcomes were compared for first-, second- and third or higher-line therapy: 0, 1 or ≥2 prior biologic DMARDs or Janus kinase inhibitors, respectively. Continuous outcomes included change from BL to 6 months in mean CDAI and patient-reported pain, fatigue, and HAQ. Binary outcomes included rate of achieving minimal clinically important difference (MCID) in CDAI or modified ACR20/50/70 at 6 months. Continuous and binary outcomes were analysed using multiple linear and logistic regression, respectively. The models included line of therapy, age, sex, disease duration, work status, SC nodules, history of hypertension and depression, BL CDAI, BL patient-reported pain and BL fatigue. Additional subgroup analyses were carried out in patients with moderate/high disease activity (CDAI >10) at BL.

Results:

In total, 2876 patients (2327 with BL CDAI >10; 890 ACPA+) were included; 442, 911, and 1523 patients initiated first-, second- or third/higher-line abatacept, respectively. Compared with patients on second/third/higher-line abatacept therapy, those on first-line abatacept were significantly older, had shorter disease duration, and had lower BL CDAI, pain and fatigue (all p<0.001). In adjusted analyses, patients receiving abatacept as earlier lines of therapy had significantly greater improvement from BL in mean CDAI and in patient-reported fatigue and HAQ (Table 1). There was no significant difference between lines of therapy in change in patient-reported pain. Patients receiving first-line abatacept had significantly higher odds of achieving a MCID in CDAI or modified ACR20/50/70 response (Figure 1). Similar patterns were seen when the sample was limited to patients with moderate/high disease activity or in patients who were ACPA+.

Conclusion:

There were significant differences in improvement in clinical disease activity and patient-reported outcomes across lines of therapy. Better treatment responses were observed with earlier lines of abatacept therapy in the overall population, in patients who were ACPA+ and in those with moderate/high BL disease activity.

References:

[1]Harrold LR, et al. Clin Rheumatol 2017;36:1215−1220.

[2]Monti S, et al. RMD Open 2015;1(Suppl 1):e000057.

Table 1.

Adjusted mean change in CDAI and patient-reported outcomes from BL to 6 months after initiation of abatacept by line of therapy (primary cohort)

Adjusted outcome, mean change (SE)First-line (n=440)Second-line (n=898)Third/higher-line (n=1515)p valueaCDAI−7.96 (0.33)−7.49 (0.27)−5.74 (0.19)<0.001Patient-reported pain (VAS 0–100)−9.43 (0.69)−7.98 (0.47)−7.70 (0.35)0.074Patient-reported fatigue (VAS 0–100)−7.49 (0.71)−5.87 (0.51)−4.81 (0.36)0.002Patient-reported HAQ−0.16 (0.01)−0.12 (0.01)−0.08 (0.01)<0.001

aEstimated by multiple linear regression model adjusted for age, sex, disease duration, work status, SC nodules, history of hypertension and depression, BL CDAI, BL patient-reported pain and BL fatigue (factors that were identified a priori based on clinical experience or that differed significantly by line of therapy); p values reflect ANOVA overall test of differences across lines of therapy.

VAS=visual analogue scale.

Acknowledgements:

Professional medical writing and editorial assistance was provided by Claire Line, PhD, at Caudex and was funded by Bristol Myers Squibb. The poster was a collaborative effort between Corrona and Bristol Myers Squibb, with financial support provided by Bristol Myers Squibb. This study was sponsored by Corrona, LLC. Corrona is supported through contracted subscriptions with multiple pharmaceutical companies.

Disclosure of Interests:

Leslie Harrold Consultant of: AbbVie, Bristol Myers Squibb, Genentech/Roche, Grant/research support from: Pfizer, Keith Wittstock Employee of: Bristol Myers Squibb, Sheila Kelly Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Sang Hee Park Employee of: Bristol Myers Squibb, Xue Han Employee of: Bristol Myers Squibb, Ying Shan: None declared, Carla Roberts-Toler: None declared, Nicole Middaugh: None declared, Vadim Khaychuk Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb

Distinct NO2 Effects on Cu-SSZ-13 and Cu-SSZ-39 in the Selective Catalytic Reduction of NOx with NH3

Cu-SSZ-13 and Cu-SSZ-39, with similar structures, are both highly active and hydrothermally stable in the selective catalytic reduction of NO_x with NH₃ (NH₃-SCR), attracting great attention for applications on diesel vehicles. In this study, it was interestingly found that NO₂ has distinct effects on the NO_x conversion over Cu-SSZ-13 and Cu-SSZ-39, with an inhibiting effect for Cu-SSZ-13 but a promoting effect for Cu-SSZ-39. The distinct NO₂ effects were found to be associated with the differences in the reactivity of surface NH₄NO₃, a key intermediate for NH₃-SCR, on these two Cu-based small-pore zeolites. Cu-SSZ-13 has excellent standard SCR activity, but the reactivity of surface NH₄NO₃ with NO is relatively low, which would induce the accumulation of NH₄NO₃ on the surface and thus inhibit NO_x conversion. Surface Brønsted acid sites play key roles in the reduction of surface NH₄NO₃ by NO, and Cu-SSZ-39 showed much higher surface acidity than Cu-SSZ-13. Compared with Cu-SSZ-13, the intrinsic standard SCR activity of Cu-SSZ-39 was lower but NH₄NO₃ could be reduced by NO rapidly on Cu-SSZ-39, even faster than the reduction of NO by the adsorbed NH₃ on Cu active sites; thus, NO_x conversion was promoted by NO₂ on Cu-SSZ-39. This work provides an improved understanding of fast SCR on Cu-based small-pore zeolites.

Investigation of the common intermediates over Fe-ZSM-5 in NH3-SCR reaction at low temperature by in situ DRIFTS

The surface species formed in the reaction of NO and NO₂ with pre-adsorbed NH₃ over a Fe-ZSM-5 catalyst (1.27 wt.% Fe, SiO₂/Al₂O₃ = 25) at low temperature (140°C) were studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Through using a background spectrum of NH₃-saturated Fe-ZSM-5, we clearly observed the formation of common intermediates resulting from the reaction of NO₂ or NO + O₂ with pre-adsorbed NH₃. This presents strong evidence that the oxidation of NO to form surface nitrates and nitrites is the key step for standard SCR at low temperature. In addition, the results suggest that in the SCR reaction at low temperature, the NH₄⁺ ions absorbed on Brønsted acid sites are less active than NH₃ adsorbed on Lewis acid sites related to Fe species.

Investigation of Suitable Templates for One-Pot-Synthesized Cu-SAPO-34 in NOx Abatement from Diesel Vehicle Exhaust

The control of NO_x emission from diesel vehicles is of great importance to the environment, and Cu-SAPO-34 is considered to be an effective catalyst for the abatement of NO_x from diesel vehicles. Along with catalytic activity, hydrothermal stability is a key property for NO_x abatement catalysts. The attack of Cu species and framework atoms by H₂O may result in activity loss under both low/high temperature humid conditions, which are inevitable in practical application. Therefore, apart from good catalytic activity, hydrothermal stability under both low/high temperatures for Cu-SAPO-34 is also critical for NO_x control in diesel vehicles. Three Cu-SAPO-34 samples were prepared by a one-pot hydrothermal method using propylamine, triethylamine, and morpholine, with Cu-TEPA (tetraethylenepentamine) as the cotemplate. The NH₃-SCR activity and the effects of hydrothermal aging at 70 and 800 °C on these Cu-SAPO-34 samples were investigated. The type of cotemplate can affect the Si and Cu species in one-pot-synthesized Cu-SAPO-34 catalysts, so that the catalytic activity as well as the low/high temperature hydrothermal stability is affected by the choice of template. Generally speaking, Cu-SAPO-34 prepared using PA as cotemplate showed superior catalytic activity and hydrothermal stability under low/high temperatures compared with the other two catalysts, which makes PA a more suitable template for one-pot-synthesized Cu-SAPO-34 for use in NO_x abatement from diesel vehicle exhaust.

FRI0100 COMPARISON OF PATIENTS (PTS) WITH RHEUMATOID ARTHRITIS (RA) AMONG DISEASE ACTIVITY CATEGORIES AFTER 6 MONTHS OF TREATMENT WITH A TUMOUR NECROSIS FACTOR INHIBITOR (TNFI): RESULTS FROM THE CORRONA® RA REGISTRY

Background:

Targeting remission (REM) or low disease activity (LDA) is a widely accepted treatment strategy for RA. However, there are limited data on the proportion of pts who achieve these targets, or remain in moderate (MDA) or high disease activity (HDA) following advanced therapy.

Objectives:

To estimate the proportion of RA pts in disease activity states (REM, LDA, MDA, and HDA) who were biologic-naïve at initiation and had continuous treatment with a TNFi for 6–12 months in the Corrona RA registry.

Methods:

Eligible pts were aged ≥18 years, biologic-naïve, initiated TNFi treatment between January 1, 2010 and July 31, 2019, and had continuous use of a TNFi for 6–12 months. Disease activity was defined based on Clinical Disease Activity Index (CDAI) at the visit closest to 6-month follow-up: REM, ≤2.8; LDA, >2.8–10; MDA, >10–22; and HDA, >22. Disease characteristics, disease activity measures, and pt-reported outcomes (PROs) were reported at TNFi initiation and at the 6-month follow-up visit.

Results:

2586 biologic-naïve pts who initiated a TNFi and had continuous use for 6–12 months were included. At TNFi initiation, 167 (6%) were in REM, 479 (19%) had LDA, 907 (35%) had MDA, and 1033 (40%) had HDA. After 6–12 months of treatment, 563 (21.8%) were in REM, 923 (35.7%) had LDA, 674 (26.1%) had MDA, and 426 (16.5%) had HDA. Pts with HDA/MDA at 6–12 months were more likely to have a history of hypertension (32.7% HDA; 34.0% MDA; vs 23.6% REM) and had higher mean body mass index (BMI) (30.9 HDA; 31.1 MDA; vs 29.0 REM) at baseline compared with pts in REM. Disease activity measures and PROs were worse in pts with MDA and HDA vs LDA and REM after 6–12 months (Table). Pt Global Assessment was higher than Physician Global Assessment across all groups.

Conclusion:

While 57.4% of pts who initiated a TNFi experienced a favorable outcome, >40% required additional or alternative intervention to achieve REM/LDA. Pts who remained in MDA/HDA continued to have an inadequate response to TNFi (as measured by disease activity measures and PROs) after 6–12 months of treatment compared with those who achieved REM/LDA.

Table

Summary of disease activity measures and PROs in previously biologic-naïve pts at the 6–12-month follow-up visit, stratified by disease activity category at the 6–12-month follow-up visit

Characteristics at 6–12 months, mean (standard deviation)Disease activity category at 6–12 monthsREM (n=563)LDA (n=923)MDA (n=674)HDA (n=426)CDAI1.2 (0.8)6.2 (2.1)15.4 (3.4)32.7 (9.2)Tender joint count (28)0.1 (0.3)1.0 (1.3)4.3 (3.3)13.4 (7.0)Swollen joint count (28)0.1 (0.3)1.1 (1.6)4.0 (3.6)9.1 (5.9)C-reactive protein6.4 (22.7)7.0 (10.6)11.1 (19.9)12.6 (22.1)Modified health assessment questionnaire0.1 (0.2)0.3 (0.4)0.5 (0.5)0.8 (0.5)Pt global assessment6.6 (6.8)28.6 (20.9)43.7 (25.7)58.0 (22.7)Physician global assessment3.6 (4.3)12.1 (10.4)27.4 (15.9)44.9 (19.8)Pt pain assessment8.7 (11.0)30.3 (23.5)46.1 (27.0)59.9 (24.4)Pt fatigue assessment15.7 (19.2)34.5 (26.6)48.3 (28.0)59.4 (27.5)Morning stiffness (min)16.5 (36.5)55.4 (146.3)96.9 (197.5)143.6 (260.0)

Disclosure of Interests:

Joel M Kremer Shareholder of: May own stocks and opinions, Grant/research support from: Research and consulting fees from AbbVie Inc., Consultant of: AbbVie, Amgen, BMS, Genentech, Inc., Gilead, GSK, Lilly, Pfizer, Regeneron and Sanofi, Employee of: Corrona, LLC employee, Anne Winkler Consultant of: AbbVie, Pfizer, and Novratis, Speakers bureau: AbbVie, Janssen, Sanofi, Genentech, Celgene, Eli Lilly, and Novartis., Laura Anatale-Tardiff Employee of: Corrona, LLC employee, Robert McLean Employee of: Corrona, LLC, Ying Shan Employee of: Corrona, LLC employee, Page Moore Employee of: Corrona, LLC employee, Namita Tundia Shareholder of: May own stocks and options, Employee of: AbbVie employee, Jessica Suboticki Shareholder of: AbbVie Inc., Employee of: AbbVie Inc., John Tesser Consultant of: Sanofi/Regeneron, Speakers bureau: Sanofi/Regeneron

P-type laser-doped WSe2/MoTe2 van der Waals heterostructure photodetector

Van der Waals heterostructures (vdWHs) based on two-dimensional (2D) materials are being studied extensively for their prospective applications in photodetectors. As the pristine WSe₂/MoTe₂ heterostructure is a type I (straddling gap) structure, it cannot be used as a photovoltaic device theoretically, although both WSe₂ and MoTe₂ have excellent photoelectric properties. The Fermi level of p-doped WSe₂ is close to its valence band. The p-doped WSe₂/MoTe₂ heterostructure can perform as a photovoltaic device because a built-in electric field appears at the interface between MoTe₂ and p-doped WSe₂. Here, a 633 nm laser was used for scanning the surface of WSe₂ in order to obtain the p-doped WSe₂. x-ray photoelectron spectroscopy (XPS) and electrical measurements verified that p-type doping in WSe₂ is produced through laser treatment. The p-type doping in WSe₂ includes substoichiometric WO_x and nonstoichiometric WSe_x. A photovoltaic device using p-doped WSe₂ and MoTe₂ was successfully fabricated. The band structure, light-matter reactions, and carrier-transport in the p-doped WSe₂/MoTe₂ heterojunction were analyzed. The results showed that this photodetector has an on/off ratio of ≈10⁴, dark current of ≈1 pA, and response time of 72 μs under the illumination of 633 nm laser at zero bias (V _ds = 0 V). The proposed p-doping method may provide a new approach to improve the performance of nanoscale optoelectronic devices.

The effect of crystallite size on low-temperature hydrothermal stability of Cu-SAPO-34

Two Cu-SAPO-34 catalysts with different crystallite sizes were obtained, and catalyst with smaller crystallite size had better low-temperature hydrothermal stability because of less Cu²⁺ species on the surface.

Effects of SO2 on Cu-SSZ-39 catalyst for the selective catalytic reduction of NOx with NH3

The impact of SO₂ on Cu-SSZ-39 was firstly investigated, and sulfation mechanism at different temperature was proposed.

Quantitative determination of the Cu species, acid sites and NH3-SCR mechanism on Cu-SSZ-13 and H-SSZ-13 at low temperatures

The NH₃-SCR mechanism and the number of acid sites and various Cu species on Cu-SSZ-13 and H-SSZ-13 were quantitatively determined.

Interfacial structure-governed SO2 resistance of Cu/TiO2 catalysts in the catalytic oxidation of CO

Different types of Cu–Ti interfacial structures determine different tolerance abilities of catalysts towards SO₂ poisoning during CO oxidation at 250 °C.

Promotion effect of cerium doping on iron–titanium composite oxide catalysts for selective catalytic reduction of NOx with NH3

Doping with a suitable amount of Ce enhances the SCR performance of FeTi catalysts.

MOTS-c accelerates bone fracture healing by stimulating osteogenesis of bone marrow mesenchymal stem cells via positively regulating FOXF1 to activate the TGF-β pathway

OBJECTIVE

To elucidate the function of MOTS-c in accelerating bone fracture healing by inducing BMSCs differentiation into osteoblasts, as well as its potential mechanism.

MATERIALS AND METHODS

Primary BMSCs were extracted from rats and induced for osteogenesis. The highest dose of MOTS-c that did not affect BMSCs proliferation was determined by CCK-8 assay. After 7-day osteogenesis, the relative levels of ALP, Bglap, and Runx2 in MOTS-c-treated BMSCs influenced by FOXF1 were examined. ALP staining and alizarin red S staining in BMSCs were performed as well. The interaction between FOXF1 and TGF-β was analyzed by ChIP assay. At last, rescue experiments were performed to uncover the role of FOXF1/TGF-β axis in MOTS-c-induced osteogenesis.

RESULTS

1 μM MOTS-c was the highest dose that did not affect BMSCs proliferation. MOTS-c treatment upregulated the relative levels of ALP, Bglap, and Runx2, and stimulated mineralization ability in BMSCs, which were attenuated by the silence of FOXF1. TGF-β was proved to interact with FOXF1, and its level was positively mediated by FOXF1. The silence of FOXF1 attenuated the accelerated osteogenesis and TGF-β upregulation in BMSCs because of MOTS-c induction, and these trends were further reversed by the overexpression of TGF-β.

CONCLUSIONS

MOTS-c treatment markedly induces osteogenesis in BMSCs. During MOTS-c-induced osteogenic progression, the upregulated FOXF1 triggers the activation of TGF-β pathway, thus accelerating bone fracture healing.

Atomic-scale insights into zeolite-based catalysis in N2O decomposition

Nitrous oxide (N₂O) has been the most serious ozone-depleting species throughout the 21st century. Zeolite-based catalysis is a highly promising method for N₂O removal in large-scale industrial applications. However, the exchanged transition metal species in zeolites greatly influence the performance of catalysts. The primary factor governing the catalytic activity is a fiercely debated topic and remains highly uncertain. Here we synthesize a series of transition-metal ion (Fe, Co, Ni, Cu)-exchanged ZSM-5 zeolite catalysts. Both experiments and density functional theory (DFT) calculations demonstrate that the activity for N₂O decomposition follows the order Fe ≈ Co > Ni > Cu. Analysis of the electronic structure properties reveals that the catalytic activity of the transition-metal ion-exchanged ZSM-5 zeolites is governed by the local softness of active sites and the composition of their HOMOs. The higher the local softness and the proportion of 4s orbitals in the HOMO, the higher the catalytic activity, which facilitates electron transfer in the redox process and thereby reduces the reaction barriers for N₂O decomposition into N₂ and O₂. Clarification of the nature of catalytic activity advances the understanding of the principles of zeolite-based catalysis, and is helpful for the design of highly efficient zeolite catalysts for pollutant removals.