Elucidating hydrogen oxidation reaction (HOR) mechanisms in alkaline conditions is vital for understanding and improving the efficiency of anion‐exchange‐membrane fuel cells. However, uncertainty ...remains around the alkaline HOR mechanism owing to a lack of direct in situ evidence of intermediates. In this study, in situ electrochemical surface‐enhanced Raman spectroscopy (SERS) and DFT were used to study HOR processes on PtNi alloy and Pt surfaces, respectively. Spectroscopic evidence indicates that adsorbed hydroxy species (OHad) were directly involved in HOR processes in alkaline conditions on the PtNi alloy surface. However, OHad species were not observed on the Pt surface during the HOR. We show that Ni doping promoted hydroxy adsorption on the platinum‐alloy catalytic surface, improving the HOR activity. DFT calculations also suggest that the free energy was decreased by hydroxy adsorption. Consequently, tuning OH adsorption by designing bifunctional catalysts is an efficient method for promoting HOR activity.
HOR on Au@PtNi surfaces in alkaline media has been investigated by in situ surface‐enhanced Raman spectroscopy (see picture). Direct spectroscopic evidence for OHad species was observed and further confirmed by deuterium isotopic experiments and DFT.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The development of efficient and low‐cost bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly desirable for electrochemical energy ...conversion. Herein, this study puts forward a new Co decorated N,B‐codoped interconnected graphitic carbon and carbon nanotube materials (Co/NBC) synthesized by direct carbonization of a cobalt‐based boron imidazolate framework. It is demonstrated that the carbonization temperature can tune the surface structure and component of the resultant materials and optimize the electrochemically active surface area to expose more accessible active sites, effectively boosting the electrocatalytic activity. As a result, the optimized Co/NBC shows superior bifunctional catalytic activity and stability toward OER and HER in 1.0 m KOH solution. Furthermore, the catalyst can serve as both the anode and cathode for water splitting to achieve a current density of 10 mA cm−2 at a cell voltage of 1.68 V. Experimental results and theoretical calculations indicate that the excellent activity of Co/NBC catalyst benefits from the synergistic effect of partial oxidation of metallic cobalt, conductive N,B‐codoped graphitic carbon and carbon nanotube, and the coupled interactions among these components. This work opens a promising avenue toward the exploration of boron imidazolate frameworks as efficient heteroatom‐doped catalysts for electrocatalysis.
Cobalt nanoparticles embedded in N,B‐codoped interconnected graphitic carbon and carbon nanotube (Co/NBC) are developed by direct carbonization of cobalt boron imidazolate framework as efficient bifunctional electrocatalysts for overall water splitting. Benefiting from the synergistic effects between the surface oxidation metallic cobalt and N,B‐codoped nanocarbon, the Co/NBC hybrid presents superior performance toward oxygen evolution reaction and hydrogen evolution reaction.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Facile interconversion between CO2 and formate/formic acid (FA) is of broad interest in energy storage and conversion and neutral carbon emission. Historically, electrochemical CO2 reduction reaction ...to formate on Pd surfaces was limited to a narrow potential range positive of −0.25 V (vs RHE). Herein, a boron-doped Pd catalyst (Pd–B/C), with a high CO tolerance to facilitate dehydrogenation of FA/formate to CO2, is initially explored for electrochemical CO2 reduction over the potential range of −0.2 V to −1.0 V (vs RHE), with reference to Pd/C. The experimental results demonstrate that the faradaic efficiency for formate (ηHCOO– ) reaches ca. 70% over 2 h of electrolysis in CO2-saturated 0.1 M KHCO3 at −0.5 V (vs RHE) on Pd–B/C, that is ca. 12 times as high as that on homemade or commercial Pd/C, leading to a formate concentration of ca. 234 mM mg–1 Pd, or ca. 18 times as high as that on Pd/C, without optimization of the catalyst layer and the electrolyte. Furthermore, the competitive selectivity ηHCOO–/ηCO on Pd–B/C is always significantly higher than that on Pd/C despite a decreases of ηHCOO– and an increases of the CO faradaic efficiency (ηCO) at potentials negative of −0.5 V. The density functional theory (DFT) calculations on energetic aspects of CO2 reduction reaction on modeled Pd(111) surfaces with and without H-adsorbate reveal that the B-doping in the Pd subsurface favors the formation of the adsorbed HCOO*, an intermediate for the FA pathway, more than that of *COOH, an intermediate for the CO pathway. The present study confers Pd–B/C a unique dual functional catalyst for the HCOOH ↔ CO2 interconversion.
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Electrocatalytic reduction of CO
to fuels and chemicals is one of the most attractive routes for CO
utilization. Current catalysts suffer from low faradaic efficiency of a CO
-reduction product at ...high current density (or reaction rate). Here, we report that a sulfur-doped indium catalyst exhibits high faradaic efficiency of formate (>85%) in a broad range of current density (25-100 mA cm
) for electrocatalytic CO
reduction in aqueous media. The formation rate of formate reaches 1449 μmol h
cm
with 93% faradaic efficiency, the highest value reported to date. Our studies suggest that sulfur accelerates CO
reduction by a unique mechanism. Sulfur enhances the activation of water, forming hydrogen species that can readily react with CO
to produce formate. The promoting effect of chalcogen modifiers can be extended to other metal catalysts. This work offers a simple and useful strategy for designing both active and selective electrocatalysts for CO
reduction.
Abstract
Electrocatalytic reduction of CO
2
to fuels and chemicals is one of the most attractive routes for CO
2
utilization. Current catalysts suffer from low faradaic efficiency of a CO
2
...-reduction product at high current density (or reaction rate). Here, we report that a sulfur-doped indium catalyst exhibits high faradaic efficiency of formate (>85%) in a broad range of current density (25–100 mA cm
−2
) for electrocatalytic CO
2
reduction in aqueous media. The formation rate of formate reaches 1449 μmol h
−1
cm
−2
with 93% faradaic efficiency, the highest value reported to date. Our studies suggest that sulfur accelerates CO
2
reduction by a unique mechanism. Sulfur enhances the activation of water, forming hydrogen species that can readily react with CO
2
to produce formate. The promoting effect of chalcogen modifiers can be extended to other metal catalysts. This work offers a simple and useful strategy for designing both active and selective electrocatalysts for CO
2
reduction.
In this paper, we report the synthetic strategy of direct arylation polymerization (DAP) for four 2,2′-bithiophene-based conjugated microporous polymers (the 2,2′-BTh-based CMPs) by coupling ...2,2′-bithiophene with the building blocks containing bromine. Compared to conventional coupling polymerization, this synthetic scheme is simple, facile and atomically efficient owing to neither preactivating the C–H bonds in 2,2′-bithiophene using organometallic reagents nor synthesis of complex thiophene-based building blocks. The resulting 2,2′-BTh-based CMPs exhibit excellent thermal stability, high specific surface areas, and good microporosity. Their specific surface areas are higher than that of other previously reported CMPs prepared with DAP. The four 2,2′-BTh-based CMPs can be utilized for multicolor fluorescence sensing of 2,4-dinitrophenol (DNP) with the high sensitivity and selectivity. The sensitivities appear to increase with the degree of structural distortion.
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•The 2,2′-bithiophene-based CMPs were synthesized by DAP.•The 2,2′-bithiophene-based CMPs can fluorescence sense DNP.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nickel-based metal organic framework (Ni-MOF) and carbon nanotubes composite (Ni-MOF/CNTs) is constructed via in situ self-assembly of Ni-MOF in the presence of functional CNTs solution and can be ...used as an efficient electrocatalytic oxidation material for glucose detection. The obtained Ni-MOF displays porous structure which is in favor of the close contact between the glucose and the active centers. Amperometric study indicates that the glucose sensor displays excellent electrochemical performance, offering a low detection limit (0.82 μM), a high sensitivity of 13.85 mA mM−1 cm−2, and a wide linear range of 1 μM–1.6 mM. Importantly, good reproducibility and repeatability, long-time stability, and excellent selectivity are obtained within the as-fabricated glucose sensor. The detection results of the real samples demonstrate the Ni-MOF/CNTs composite can be a promising candidate in glucose sensing applications.
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•Ni-MOF/CNTs composite with porous structure is fabricated via self-assembly method.•Ni-MOF/CNTs composite is used as sensitive nonenzymatic glucose sensor.•Ni-MOF/CNTs composite displays a low detection limit and a wide linear range.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
Objectives
This randomized, controlled clinical trial aims to compare the efficacy and safety of glucocorticoid combined with MMF and glucocorticoid monotherapy for patients with ...IgG4-related disease.
Methods
Sixty-nine patients newly diagnosed with IgG4-related disease were randomly divided into two groups (35 patients in Group I and 34 patients in Group II). Patients in Group I received glucocorticoid monotherapy (0.6-0.8 mg/(kg·day) and tapered gradually); patients in Group II received glucocorticoid combined with MMF therapy (1-1.5 g/day). All the patients were followed up at 1, 3, 6 and 12 months. The primary endpoint was response rate in 12 months and the secondary endpoints were relapse, remission rate and adverse reactions.
Results
Group I and Group II shared almost the same efficacy at the 1 month treatment, but during the follow-up, the complete response rate in Group II was much higher than that in Group I at different time points, and the cumulative relapse rate during 1 year of therapy was much higher in Group I than that in Group II (40.00 vs 20.59%). The remission rate was lower in Group I (51.42 vs 76.47%). Relapses were more likely to happen in lung, lacrimal gland, salivary gland, paranasal sinus and kidney. MMF could reduce relapse, especially organs recurrence. No serious adverse reactions occurred in the two groups.
Conclusion
Combination treatment with glucocorticoid and MMF was more effective than the monotherapy, and the relapse of IgG4-related disease might be associated with the elevated levels of serum IgG4 and the low glucocorticoid maintenance dose.
Trial registration
ClinicalTrials.gov, www.clinicaltrials.gov, NCT02458196.
Covalent organic frameworks (COFs) hold the potential in converting CO2 with water into value-added fuels and O2 to save the deteriorating ecological environment. However, reaching high yield and ...selectivity is a grand challenge under metal-, photosensitizer-, or sacrificial reagent-free conditions. Here, inspired by microstructures of natural leaves, we designed triazine-based COF membranes with the integration of steady light-harvesting sites, efficient catalytic center, and fast charge/mass transfer configuration to fabricate a novel artificial leaf for the first time. Significantly, a record high CO yield of 1240 μmol g–1 in a 4 h reaction, approximately 100% selectivity, and a long lifespan (at least 16 cycles) were achieved under gas–solid conditions without using any metal, photosensitizer, or sacrificial reagent. Unlike the existing knowledge, the chemical structural unit of triazine-imide-triazine and the unique physical form of the COF membrane are predominant for such a remarkable photocatalysis. This work opens a new pathway to simulating photosynthesis in leaves and may motivate relevant research in the future.
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CXCL3 belongs to the CXC‐type chemokine family and is known to play a multifaceted role in various human malignancies. While its clinical significance and mechanisms of action in uterine cervical ...cancer (UCC) remain unclear. This investigation demonstrated that the UCC cell line HeLa expressed CXCL3, and strong expression of CXCL3 was detected in UCC tissues relative to nontumor tissues. In addition, CXCL3 expression was strongly correlated with CXCL5 expression in UCC tissues. In vitro, HeLa cells overexpressing CXCL3, HeLa cells treated with exogenous CXCL3 or treated with conditioned medium from WPMY cells overexpressing CXCL3, exhibited enhanced proliferation and migration activities. In agreement with these findings, CXCL3 overexpression was also associated with the generation of HeLa cell tumor xenografts in athymic nude mice. Subsequent mechanistic studies demonstrated that CXCL3 overexpressing influenced the expression of extracellular signal‐regulated kinase (ERK) signaling pathway associated genes, including ERK1/2, Bcl‐2, and Bax, whereas the CXCL3‐induced proliferation and migration effects were attenuated by exogenous administration of the ERK1/2 blocker PD98059. The data of the current investigation support that CXCL3 appears to hold promise as a potential tumor marker and interference target for UCC.
CXCL3 was significantly overexpressed in uterine cervical cancer (UCC), and its upregulation was positively related to the clinical stage. In vitro and in vivo, CXCL3 may act as a tumor promoter involved in the malignant processes of UCC through the Bcl‐2/Bax and ERK pathways.
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