Manipulating the active species and improving the structural stabilization of sulfur‐containing catalysts during the OER process remain a tremendous challenge. Herein, we constructed NiO/NiS2 and ...Fe−NiO/NiS2 as catalyst models to study the effect of Fe doping. As expected, Fe−NiO/NiS2 exhibits a low overpotential of 270 mV at 10 mA cm−2. The accumulation of hydroxyl groups on the surface of materials after Fe doping can promote the formation of highly active NiOOH at a lower OER potential. Moreover, we investigated the level of corrosion of M−S bonds and compared the stability variation of M−S bonds with Fe at different locations. Interestingly, Fe bonded with S in the bulk as the sacrificial agent can alleviate the oxidation corrosion of partial Ni−S bonds and thus endow Fe−NiO/NiS2 long‐term durability. This work could motivate the community to focus more on resolving the corrosion of sulfur‐containing materials.
Bulk doped Fe not only accelerates the surface reconstruction of NiO/NiS2 into the active NiOOH phase at a lower oxygen evolution reaction (OER) overpotential but also alleviates the oxidation corrosion of partial Ni−S bonds to provide a promising way to balance the activity and stability of sulfur‐containing materials in the OER process.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Arabidopsis mutants produced by constitutive overexpression of the CRISPR/Cas9 genome editing system are usually mosaics in the T1 generation. In this study, we used egg cell-specific promoters to ...drive the expression of Cas9 and obtained non-mosaic T1 mutants for multiple target genes with high efficiency. Comparisons of 12 combinations of eight promoters and two terminators found that the efficiency of the egg cell-specific promoter-controlled CRISPR/Cas9 system depended on the presence of a suitable terminator, and the composite promoter generated by fusing two egg cell-specific promoters resulted in much higher efficiency of mutation in the T1 generation compared with the single promoters.
The proton exchange membrane (PEM) water electrolysis is one of the most promising hydrogen production techniques. The oxygen evolution reaction (OER) occurring at the anode dominates the overall ...efficiency. Developing active and robust electrocatalysts for OER in acid is a longstanding challenge for PEM water electrolyzers. Most catalysts show unsatisfied stability under strong acidic and oxidative conditions. Such a stability challenge also leads to difficulties for a better understanding of mechanisms. This review aims to provide the current progress on understanding of OER mechanisms in acid, analyze the promising strategies to enhance both activity and stability, and summarize the state‐of‐the‐art catalysts for OER in acid. First, the prevailing OER mechanisms are reviewed to establish the physicochemical structure–activity relationships for guiding the design of highly efficient OER electrocatalysts in acid with stable performance. The reported approaches to improve the activity, from macroview to microview, are then discussed. To analyze the problem of instability, the key factors affecting catalyst stability are summarized and the surface reconstruction is discussed. Various noble‐metal‐based OER catalysts and the current progress of non‐noble‐metal‐based catalysts are reviewed. Finally, the challenges and perspectives for the development of active and robust OER catalysts in acid are discussed.
Developing proton exchange membrane water electrolyzers requires a fundamental understanding of the oxygen evolution reaction (OER) in acid, which is the primary focus of this review. The water electrolyzer in alkaline and acid are compared; and the recent advances in OER mechanisms, the strategies for enhancing activity and stability of electrocatalysts, surface reconstruction, and the state‐of‐the‐art electrocatalysts are discussed.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
The demand for sustainable energy has motivated the development of artificial photosynthesis. Yet the catalyst and reaction interface designs for directly fixing permanent gases (e.g. CO
2
, ...O
2
, N
2
) into liquid fuels are still challenged by slow mass transfer and sluggish catalytic kinetics at the gas-liquid-solid boundary. Here, we report that gas-permeable metal-organic framework (MOF) membranes can modify the electronic structures and catalytic properties of metal single-atoms (SAs) to promote the diffusion, activation, and reduction of gas molecules (e.g. CO
2,
O
2
) and produce liquid fuels under visible light and mild conditions. With Ir SAs as active centers, the defect-engineered MOF (e.g. activated NH
2
-UiO-66) particles can reduce CO
2
to HCOOH with an apparent quantum efficiency (AQE) of 2.51% at 420 nm on the gas-liquid-solid reaction interface. With promoted gas diffusion at the porous gas-solid interfaces, the gas-permeable SA/MOF membranes can directly convert humid CO
2
gas into HCOOH with a near-unity selectivity and a significantly increased AQE of 15.76% at 420 nm. A similar strategy can be applied to the photocatalytic O
2
-to-H
2
O
2
conversions, suggesting the wide applicability of our catalyst and reaction interface designs.
The oxygen reduction reaction (ORR) has been demonstrated as a critical technology for both energy conversion technologies and hydrogen peroxide intermediate production. Herein, an in situ oxygen ...evolution reaction (OER) surface evolution strategy is applied for changing the surface structure of MnCo2O4 oxide with tetrahedral and octahedral cations vacancies to realize reaction pathway switching from 2e− ORR and 4e− ORR. Interestingly, the as‐synthesized MnCo2O4‐pristine (MnCo2O4‐P) with the highest surficial Mn/Co octahedron occupation favors two electrons reaction routes exhibiting high H2O2 selectivity (≈80% and reaches nearly 100% at 0.75 V vs RHE); after surface atoms reconstruction, MnCo2O4‐activation (MnCo2O4‐A) with the largest Mn/Co tetrahedron occupation present excellent ORR performance through the four‐electron pathway with an ultrahigh onset potential and half‐wave potential of 0.78 and 0.92 V, ideal mass activity (MA), and turnover frequencies (TOF) values. Density functional theory (DFT) calculations reveal the concurrent modulations of both Co and Mn by the surface reconstructions, which improve the electroactivity of MnCo2O4‐A toward the 4e− pathway. This work provides a new perspective to building correlation of OER activation–ORR property, bringing detailed understating for reaction route transformation, and thus guiding the development of certain electrocatalysts with specific purposes.
The oxygen reduction reaction (ORR) is crucial for both energy conversion technologies and hydrogen peroxide intermediate production, which proceeds via four‐electron or two‐electron pathways, respectively. Special electrocatalysts to promote either the 4e− or the 2e− reaction route are important. The surficial metals occupation of partially inverse MnCo2O4 can be tuned to realize this reaction mechanism switching.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Herein, a strategy is reported for the fabrication of NiCo2O4‐based mesoporous nanosheets (PNSs) with tunable cobalt valence states and oxygen vacancies. The optimized NiCo2.148O4 PNSs with an ...average Co valence state of 2.3 and uniform 4 nm nanopores present excellent catalytic performance with an ultralow overpotential of 190 mV at a current density of 10 mA cm−2 and long‐term stability (700 h) for the oxygen evolution reaction (OER) in alkaline media. Furthermore, Zn–air batteries built using the NiCo2.148O4 PNSs present a high power and energy density of 83 mW cm−2 and 910 Wh kg−1, respectively. Moreover, a portable battery box with NiCo2.148O4 PNSs as the air cathode presents long‐term stability for 120 h under low temperatures in the range of 0 to −35 °C. Density functional theory calculations reveal that the prominent electron exchange and transfer activity of the electrocatalyst is attributed to the surface lower‐coordinated Co‐sites in the porous region presenting a merging 3d–eg–t2g band, which overlaps with the Fermi level of the Zn–air battery system. This favors the adsorption of the *OH, and stabilized *O radicals are reached, toward competitively lower overpotential, demonstrating a generalized key for optimally boosting overall OER performance.
Optimized NiCo2.148O4 mesoporous nanosheets with an average Co valence state of 2.3 and uniform 4 nm mesopores demonstrate exceptional performance for Zn–air batteries under a wide temperature range from 80 to −35 °C, which arises from the high activities of electron exchange and transfer by the surface lower‐coordinated Co‐sites within the porous region.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Atomic‐thick interfacial dominated bifunctional catalyst NiO/CoO transition interfacial nanowires (TINWs) with abundant defect sites display high electroactivity and durability in the oxygen ...evolution reaction (OER) and the oxygen reduction reaction (ORR). Density functional theory (DFT) calculations show that the excellent OER/ORR performance arises from the electron‐rich interfacial region coupled with defect sites, thus enabling a fast‐redox rate with lower activation barrier for fast electron transfer. When assembled as an air‐electrode, NiO/CoO TINWs delivered the high specific capacity of 842.58 mAh gZn−1, the large energy density of 996.44 Wh kgZn−1 with long‐time stability of more than 33 h (25 °C), and superior performance at low (−10 °C) and high temperature (80 °C).
An oxygen removing and re‐doping process applied to NiCo2O4 nanowires (NW) gives so‐called NiO/CoO transition interfacial nanowires (TINWs) with an abundance of interfacial defects. The atomic‐thick interface makes NiO/CoO TINWs highly efficient and stable bifunctional oxygen evolution/oxygen reduction reaction (OER/ORR) catalysts, and gives a wide working temperature range (−10 to 80 °C) for portable Zn–air batteries.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
While quasi‐two‐dimensional (quasi‐2D) perovskites have emerged as promising semiconductors for light‐emitting diodes (LEDs), the broad‐width distribution of quantum wells hinders their efficient ...energy transfer and electroluminescence performance in blue emission. In particular, the underlying mechanism is closely related to the crystallization kinetics and has yet to be understood. Here for the first time, the influence of bifunctional zwitterions with different coordination affinity on the crystallization kinetics of quasi‐2D perovskites is systematically investigated. The zwitterions can coordinate with Pb2+ and also act as co‐spacer organic species in quasi‐2D perovskites, which collectively inhibit the aggregation of colloidal precursors and shorten the distance of quantum wells. Consequently, restricted nucleation of high‐n phases and promoted growth of low‐n phases are achieved with moderately coordinated zwitterions, leading to the final film with a more concentrated n distribution and improved energy transfer efficiency. It thus enables high‐efficiency blue LEDs with a recorded external quantum efficiency of 15.6% at 490 nm, and the operation stability has also been prolonged to 55.3 min. These results provide useful directions for tuning the crystallization kinetics of quasi‐2D perovskites, which is expected to lead to high‐performance perovskite LEDs.
In this work, a facile strategy base on bifunctional zwitterions is proposed that effectively modulates the crystallization kinetics of quantum wells—both suppressing the formation of low‐n phases and restricting the growth of high‐n phases—contributing to a narrow n distribution. Accordingly, high‐performance sky‐blue PeLEDs at 490 nm with a recorded EQE of 15.6% are realized.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Anti-angiogenic therapy combined with chemotherapy could improve the outcomes of patients with platinum-resistant ovarian cancer. Apatinib is an oral tyrosine kinase inhibitor that selectively ...inhibits VEGF receptor 2. We assessed the efficacy and safety of the combination therapy of apatinib and oral etoposide, considering the potential advantage of home administration without hospital admission, in patients with platinum-resistant or platinum-refractory ovarian cancer.
In this phase 2, single-arm, prospective study, we recruited patients aged 18–70 years with platinum-resistant or platinum-refractory ovarian cancer at the Sun Yat-sen University Cancer Center (China). The treatment consisted of apatinib at an initial dose of 500 mg once daily on a continuous basis, and oral etoposide at a dose of 50 mg once daily on days 1–14 of a 21-day cycle. Oral etoposide was administered for a maximum of six cycles. Treatment was continued until disease progression, patient withdrawal, or unacceptable toxic effects. The primary endpoint was the proportion of patients achieving an objective response according to Response Evaluation Criteria in Solid Tumors, version 1.1. We used Simon's two-stage design, and analysed efficacy in the intention-to-treat and per-protocol populations. Safety analyses included enrolled patients who had received at least one dose of study medication, but excluded those without any safety data. This study is registered with ClinicalTrials.gov, number NCT02867956.
Between Aug 10, 2016, and Nov 9, 2017, we screened 38 and enrolled 35 patients. At the data cutoff date (Dec 31, 2017), 20 (57%) patients had discontinued the study, and 15 (43%) patients remained on treatment. Objective responses were achieved in 19 (54%; 95% CI 36·6–71·2) of 35 patients in the intention-to-treat population and in 19 (61%; 42·2–78·2) of 31 patients in the per-protocol population. The most common grade 3 or 4 adverse events were neutropenia (17 50%), fatigue (11 32%), anaemia (ten 29%), and mucositis (eight 24%). Serious adverse events were reported in two patients who were admitted to hospital (one patient had anaemia and anorexia; the other patient had increased ascites due to disease progression). No treatment-related deaths were recorded.
The combination of apatinib with oral etoposide shows promising efficacy and manageable toxicities in patients with platinum-resistant or platinum-refractory ovarian cancer, and further study in phase 3 trials is warranted.
None.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
To accelerate the application of the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/ CRISPR-associated protein 9) system to a variety of plant species, a toolkit with ...additional plant selectable markers, more gRNA modules, and easier methods for the assembly of one or more gRNA expression cassettes is required.
We developed a CRISPR/Cas9 binary vector set based on the pGreen or pCAMBIA backbone, as well as a gRNA (guide RNA) module vector set, as a toolkit for multiplex genome editing in plants. This toolkit requires no restriction enzymes besides BsaI to generate final constructs harboring maize-codon optimized Cas9 and one or more gRNAs with high efficiency in as little as one cloning step. The toolkit was validated using maize protoplasts, transgenic maize lines, and transgenic Arabidopsis lines and was shown to exhibit high efficiency and specificity. More importantly, using this toolkit, targeted mutations of three Arabidopsis genes were detected in transgenic seedlings of the T1 generation. Moreover, the multiple-gene mutations could be inherited by the next generation.
We developed a toolkit that facilitates transient or stable expression of the CRISPR/Cas9 system in a variety of plant species, which will facilitate plant research, as it enables high efficiency generation of mutants bearing multiple gene mutations.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK