Abstract
Glucose electrolysis offers a prospect of value-added glucaric acid synthesis and energy-saving hydrogen production from the biomass-based platform molecules. Here we report that ...nanostructured NiFe oxide (NiFeO
x
) and nitride (NiFeN
x
) catalysts, synthesized from NiFe layered double hydroxide nanosheet arrays on three-dimensional Ni foams, demonstrate a high activity and selectivity towards anodic glucose oxidation. The electrolytic cell assembled with these two catalysts can deliver 100 mA cm
−2
at 1.39 V. A faradaic efficiency of 87% and glucaric acid yield of 83% are obtained from the glucose electrolysis, which takes place via a guluronic acid pathway evidenced by in-situ infrared spectroscopy. A rigorous process model combined with a techno-economic analysis shows that the electrochemical reduction of glucose produces glucaric acid at a 54% lower cost than the current chemical approach. This work suggests that glucose electrolysis is an energy-saving and cost-effective approach for H
2
production and biomass valorization.
The oxygen evolution reaction (OER) catalytic activity of a transition metal oxides/hydroxides based electrocatalyst is related to its pseudocapacitance at potentials lower than the OER standard ...potential. Thus, a well‐defined pseudocapacitance could be a great supplement to boost OER. Herein, a highly pseudocapacitive Ni‐Fe‐Co hydroxides/N‐doped carbon nanoplates (NiCoFe‐NC)‐based electrocatalyst is synthesized using a facile one‐pot solvothermal approach. The NiCoFe‐NC has a great pseudocapacitive performance with 1849 F g−1 specific capacitance and 31.5 Wh kg−1 energy density. This material also exhibits an excellent OER catalytic activity comparable to the benchmark RuO2 catalysts (an initiating overpotential of 160 mV and delivering 10 mA cm−2 current density at 250 mV, with a Tafel slope of 31 mV dec−1). The catalytic performance of the optimized NiCoFe‐NC catalyst could keep 24 h. X‐ray photoelectron spectroscopy, electrochemically active surface area, and other physicochemical and electrochemical analyses reveal that its great OER catalytic activity is ascribed to the Ni‐Co hydroxides with modular 2‐Dimensional layered structure, the synergistic interactions among the Fe(III) species and Ni, Co metal centers, and the improved hydrophily endowed by the incorporation of N‐doped carbon hydrogel. This work might provide a useful and general strategy to design and synthesize high‐performance metal (hydr)oxides OER electrocatalysts.
In this work, a highly pseudocapacitive Ni‐Fe‐Co hydroxides/N‐doped carbon nanoplates (NiCoFe‐NC)‐based electrocatalyst is synthesized via a facile one‐pot solvothermal approach. The as‐synthesized NiCoFe‐NC has an excellent pseudocapacitive performance, leading to high oxygen evolution reaction catalytic activity with an overpotential of 160 mV and delivering 10 mA cm−2 current density at 250 mV overpotential.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The development of high‐efficiency bifunctional electrocatalyst for oxygen reduction and evolution reactions (ORR/OER) is critical for rechargeable metal–air batteries, a typical electrochemical ...energy storage and conversion technology. This work reports a general approach for the synthesis of Pd@PdO–Co3O4 nanocubes using the zeolite‐type metal–organic framework (MOF) as a template. The as‐synthesized materials exhibit a high electrocatalytic activity toward OER and ORR, which is comparable to those of commercial RuO2 and Pt/C electrocatalysts, while its cycle performance and stability are much higher than those of commercial RuO2 and Pt/C electrocatalysts. Various physicochemical characterizations and density functional theory calculations indicate that the favorable electrochemical performance of the Pd@PdO–Co3O4 nanocubes is mainly attributed to the synergistic effect between PdO and the robust hollow structure composed of interconnected crystalline Co3O4 nanocubes. This work establishes an efficient approach for the controlled design and synthesis of MOF‐templated hybrid nanomaterials, and provides a great potential for developing high‐performance electrocatalysts in energy storage and conversion.
This work reports a general approach to synthesize Pd@PdO‐Co3O4 nanocubes using the zeolite‐type metal–organic framework (MOF) as a template. The as‐synthesized material exhibits a high electrocatalytic activity toward Oxygen evolution and reduction reactions (OER and ORR). Synergistic effects between PdO and the robust hollow structure crystalline Co3O4 nanocubes are the main contributions to the catalyst's excellent performance.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Controllable integration of metallic nanoparticles and metal-organic frameworks (MOFs) may create a new material with multifunctional applications. In this work, an emerging type of core-shell ...nanostructure, in which metallic Pd nanoparticle cores were encapsulated by MOF (ZIF-67) shells, was facilely synthesized through an impregnation-reduction process. The as-synthesized PdatZIF-67 material, with highly dispersed Pd nanoparticles encapsulated in the porous ZIF-67 structure, exhibited favorable catalytic performance towards the formic acid (HCOOH)-induced reduction of highly toxic hexavalent chromium (Cr(vi)). In this process Cr(vi) was converted to Cr(iii) within 5 min, and the material could be reused 10 times without significant loss of its catalytic activity. The highly hydrophilic and swellable nature of the ZIF-67 was proposed to be responsible mainly for the favorable durability of the PdatZIF-67. The results provided in this work may pave a way for the concise preparation of nano-hybrid catalysts with high performance and durability for pollutant elimination.
Abstract
Hydrogen peroxide (H
2
O
2
) has the wide range of applications in industry and living life. However, the development of the efficient heterogeneous catalyst in the direct H
2
O
2
synthesis ...(DHS) from H
2
and O
2
remains a formidable challenge because of the low H
2
O
2
producibility. Herein, we develop a two-step approach to prepare PdSn nanowire catalysts, which comprises Pd oxide layered on PdSn nanowires (Pd
L
/PdSn-NW). The Pd
L
/PdSn-NW displays superior reactivity in the DHS at zero Celcius, presenting the H
2
O
2
producibility of 528 mol kg
cat
−1
·h
−1
and H
2
O
2
selectivity of >95%. A layer of Pd oxide on the PdSn nanowire generates bi-coordinated Pd, leading to the different adsorption behaviors of O
2
, H
2
and H
2
O
2
on the Pd
L
/PdSn-NW. Furthermore, the weak adsorption of H
2
O
2
on the Pd
L
/PdSn-NW contributes to the low activation energy and high H
2
O
2
producibility. This surface engineering approach, depositing metal layer on metal nanowires, provides a new insight in the rational designing of efficient catalyst for DHS.
In October 2020, Dr. Emmanuelle Charpentier and Dr. Jennifer Doudna won the Nobel Prize in Chemistry for their pioneering work in precise genome editing using the CRISPR technology. Although CRISPR ...technology has developed rapidly in the last decade, there are still many uncertainties before eventual use in clinical settings. In this mini review, we summarize the current efforts in addressing the limitations of CRISPR technology and future directions.
As common clinical screening tests cannot effectively predict a difficult airway, and unanticipated difficult laryngoscopy remains a challenge for physicians. We herein used ultrasound to develop ...some point-of-care predictors for difficult laryngoscopy.
This prospective observational study included 502 patients who underwent laryngoscopy and a detailed sonographic assessment. Patients under 18 years old, or with maxillofacial deformities or fractures, limited mouth opening, limited neck movement or history of neck surgery were excluded from the study. Laryngoscopic views of all patients were scored and grouping using the modified Cormack-Lehane (CL) scoring system. The measurements acquired comprised tongue width, the longitudinal cross-sectional area of the tongue, tongue volume, the mandible-hyoid bone distance, the hyoid bone-glottis distance, the mandible-hyoid bone-glottis angle, the skin-thyrohyoid membrane distance, the glottis-superior edge of the thyroid cartilage distance (DGTC), the skin-hyoid bone distance, and the epiglottis midway-skin distance. ANOVA and Chi-square were used to compare differences between groups. Logistic regression was used to identify risk factors for difficult laryngoscopy and it was visualized by receiver operating characteristic curves and nomogram. R version 3.6.3 and SPSS version 26.0 were used for statistical analyses.
Difficult laryngoscopy was indicated in 49 patients (CL grade Ⅲ – Ⅳ) and easy laryngoscopy in 453 patients (CL grade Ⅰ – Ⅱ). The ultrasound-measured mandible-hyoid bone-glottis angle and DGTC significantly differed between the 2 groups (p < 0.001). Difficult laryngoscopy was predicted by an area under the curve (AUC) of 0.930 with a threshold mandible-hyoid bone-glottis angle of 125.5° and by an AUC of 0.722 with a threshold DGTC of 1.22 cm. The longitudinal cross-sectional area of the tongue, tongue width, tongue volume, the mandible-hyoid distance, and the hyoid-glottis distance did not significantly differ between the groups.
Difficult laryngoscopy may be anticipated in patients in whom the mandible-hyoid bone-glottis angle is smaller than 125.5° or DGTC is larger than 1.22 cm.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To assess the value of the driving pressure variation rate (ΔP%) in predicting the outcome of weaning from invasive mechanical ventilation in patients with acute respiratory distress syndrome.
In ...this case-control study, a total of 35 patients with moderate-severe acute respiratory distress syndrome were admitted to the intensive care unit between January 2022 and December 2022 and received invasive mechanical ventilation for at least 48 h were enrolled. Patients were divided into successful weaning group and failed weaning group depending on whether they could be removed from ventilator support within 14 days. Outcome measures including driving pressure, PaO2:FiO2, and positive end-expiratory pressure, etc. were assessed every 24 h from day 0 to day 14 until successful weaning was achieved. The measurement data of non-normal distribution were presented as median (Q1, Q3), and the differences between groups were compared by Wilcoxon rank sum test. And categorical data use the Chi-square test or Fisher's exact test to compare. The predictive value of ΔP% in predicting the outcome of weaning from the ventilator was analyzed using receiver operating characteristic curves.
Of the total 35 patients included in the study, 17 were successful vs. 18 failed in weaning from a ventilator after 14 days of mechanical ventilation. The cut-off values of the median ΔP% measured by Operator 1 vs. Operator 2 in the first 4 days were ≥ 4.17% and 4.55%, respectively (p < 0.001), with the area under curve of 0.804 (sensitivity of 88.2%, specificity of 64.7%) and 0.770 (sensitivity of 88.2%, specificity of 64.7%), respectively. There was a significant difference in mechanical ventilation duration between the successful weaning group and the failure weaning group (8 (6, 13) vs. 12 (7.5, 17.3), p = 0.043). The incidence of ventilator-associated pneumonia in the successful weaning group was significantly lower than in the failed weaning group (0.2‰ vs. 2.3‰, p = 0.001). There was a significant difference noted between these 2 groups in the 28-day mortality (11.8% vs. 66.7%, p = 0.003).
The median ΔP% in the first 4 days of mechanical ventilation showed good predictive performance in predicting the outcome of weaning from mechanical ventilation within 14 days. Further study is needed to confirm this finding.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Although fully mechanized caving mining technology has been widely used in China for thick seam mining, the support mechanism for a gob-side entry roof remains unclear under this condition. Taking ...the No. 3304 mining face of Dongtan Coal Mine as the engineering background, this paper seeks to solve this problem. First, the coordinate support mechanism of a bolt-single anchor cable for a gob-side entry roof is analyzed from two aspects: the bearing capacity of single anchor cable and prestress coordination of a bolt-angle anchor cable. Then, the anchoring parameters are optimized combined with FLAC3D numerical simulation followed by field practice. Results of the field practice show that the coordinate support effect was fully utilized when applying bolt-single anchor cable support. The deformation of roadway surrounding rock was effectively controlled.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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