Full-spectrum utilization of diffusive solar energy by a photocatalyst for environmental remediation and fuel generation has long been pursued. In contrast to tremendous efforts in the UV-to-VIS ...light regime of the solar spectrum, the NIR and IR areas have been barely addressed although they represent about 50% of the solar flux. Here we put forward a biomimetic photocatalyst blueprint that emulates the growth pattern of a natural plant—a peapod—to address this issue. This design is exemplified via unidirectionally seeding core-shell Au@Nb nanoparticles in the cavity of semiconducting HxK1−xNbO3 nanoscrolls. The biomimicry of this nanopeapod (NPP) configuration promotes near-field plasmon–plasmon coupling between bimetallic Au@Nb nanoantennas (the peas), endowing the UV-active HxK1−xNbO3 semiconductor (the pods) with strong VIS and NIR light harvesting abilities. Moreover, the characteristic 3D metal-semiconductor junction of the Au@Nb@HxK1−xNbO3 NPPs favors the transfer of plasmonic hot carriers to trigger dye photodegradation and water photoelectrolysis as proofs-of-concept. Such broadband solar spectral response renders the Au@Nb@HxK1−xNbO3 NPPs highly promising for widespread photoactive devices.
Metal oxides are widely evaluated as high‐capacity anode candidates for practical lithium ion battery applications, owing to their attractive volumetric and gravimetric capacities compared with the ...traditional graphite anode. Synergistic effects on improving electrochemical performance of binary metal oxide anodes have been increasingly reported via different working mechanisms for lithium storage instead of simple combination of two single components. Herein, we report on exploring lithium storage mechanism in Bi2Mo3O12 binary metal oxide for the first time as an anode material. In‐situ synchrotron X‐ray diffraction measurements are performed on this exotic material to elucidate lithium storage behaviors, coupled with voltage‐resolved cyclic voltammetry and ex‐situ X‐ray photoelectron spectroscopy analyses. The Bi2Mo3O12 anode undergoes an irreversible initial conversion reaction, resulting in metallic Bi and Li2MoO4 components through electrochemical lithiation. During successive cycling, these two components reversibly uptake and release Li ions through alloying/de‐alloying and intercalation/de‐intercalation reactions, by forming corresponding Li3Bi alloy and excessively‐lithiated Li2+xMoO4 derivative, respectively. Cycling stability of the Bi2Mo3O12 anode material is considerably enhanced by in‐situ composition with Ti3C2‐based MXene nanosheets. The Bi2Mo3O12@Ti3C2 composite anode material can deliver an initial charge capacity of approximately 846 mAh g−1 at 50 mA g−1 and retain at 227 mAh g−1 upon prolonged 1000 cycles at 2.5 A g−1 high charge/discharge current density. This work offers some insights into lithium storage mechanism and composite nanostructure design in Bi−Mo−O binary metal oxide anode towards enhanced electrochemical performance.
Supplementary mechanisms: Lithium storage mechanism is explored on binary metal oxide Bi2Mo3O12 as anode material. In situ synchrotron XRD examination reveals that capacity contribution originates from reversible reactions of Li ion alloying with Bi and intercalating into Li2MoO4 components during charge/discharge cycles. The composition of Ti3C2 MXene with Bi2Mo3O12 significantly improves cycle stability and rate capability performance.
In this work, we have fabricated a highly sensitive direct irradiating X-ray photodetector (DXPD) based on Zinc Gallium Oxide (ZnGa2O4) epilayers with a metal-semiconductor-metal structure. The ...ZnGa2O4 epilayers were grown on a c-plane sapphire substrate by metalorganic chemical vapor deposition (MOCVD). To test the DXPD's capabilities, we subjected it to a synchrotron hard X-ray source with an energy of 10 keV, and measured incident radiation flux ranging from 5.7✕107 to 4.6 ✕1011 counts/sec. The effect of changing the applied bias voltage on the time response of the DXPD was investigated. The sensitivity of hard XPDs was compared using gallium oxide (β-Ga2O3) epilayer grown by MOCVD. The results showed that ZnGa2O4 DXPD had approximately 104 times greater sensitivity than the β-Ga2O3 based XPD. ZnGa2O4 based detectors also exhibited remarkable sensitivity of 2.87 × 109 μC Gyair−1cm−2 for the incident flux of 5.7✕107 counts/sec at 15 V. Additionally, the sensitivity was examined in terms of applied bias and dose rate. Based on these observations, it can be concluded that ZnGa2O4 epilayers grown by MOCVD hold immense potential for use in high-performance hard XPDs.
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Developing efficient oxygen evolution reaction (OER) electrocatalysts can greatly advance the commercialization of proton exchange membrane (PEM) water electrolysis. However, the unclear and disputed ...reaction mechanism and structure-activity relationship of OER pose significant obstacles. Herein, the active site and intermediate for OER on AuIr nanoalloys are simultaneously identified and correlated with the activity, through the integration of in situ shell-isolated nanoparticle-enhanced Raman spectroscopy and X-ray absorption spectroscopy. The AuIr nanoalloys display excellent OER performance with an overpotential of only 246 mV to achieve 10 mA cm
and long-term stability under strong acidic conditions. Direct spectroscopic evidence demonstrates that
OO adsorbed on IrO
sites is the key intermediate for OER, and it is generated through the O-O coupling of adsorbed oxygen species directly from water, providing clear support for the adsorbate evolution mechanism. Moreover, the Raman information of the
OO intermediate can serve as a universal "in situ descriptor" that can be obtained both experimentally and theoretically to accelerate the catalyst design. It unveils that weakening the interactions of
OO on the catalysts and facilitating its desorption would boost the OER performance. This work deepens the mechanistic understandings on OER and provides insightful guidance for the design of more efficient OER catalysts.
We report the first demonstration of cobalt phosphate (Co‐Pi)‐assisted molybdenum‐doped zinc oxide nanorods (Zn1−xMoxO NRs) as visible‐light‐sensitive photofunctional electrodes to fundamentally ...improve the performance of ZnO NRs for photoelectrochemical (PEC) water splitting. A maximum photoconversion efficiency as high as 1.05 % was achieved, at a photocurrent density of 1.4 mA cm−2. More importantly, in addition to achieve the maximum incident photon to current conversion efficiency (IPCE) value of 86 %, it could be noted that the IPCE of Zn1−xMoxO photoanodes under monochromatic illumination (450 nm) is up to 12 %. Our PEC performances are comparable to those of many oxide‐based photoanodes in recent reports. The improvement in photoactivity of PEC water splitting may be attributed to the enhanced visible‐light absorption, increased charge‐carrier densities, and improved interfacial charge‐transfer kinetics due to the combined effect of molybdenum incorporation and Co‐Pi modification, contributing to photocatalysis. The new design of constructing highly photoactive Co‐Pi‐assisted Zn1−xMoxO photoanodes enriches knowledge on doping and advances the development of high‐efficiency photoelectrodes in the solar‐hydrogen field.
Molybdenum and Co: A photocatalytic system comprising an array of zinc oxide nanorods (NRs) doped with molybdenum is reported. The addition of cobalt phosphate (Co‐Pi) further enhances the performance of the Zn1−xMoxO NR‐array photoanodes. The results demonstrate that the system can serve as visible‐light‐sensitive photofunctional electrodes to fundamentally improve the performance of ZnO‐based photoanodes for photoelectrochemical water oxidation.
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•A procedure to remove CO2 gas and convert it to biofuel (methanol) is developed.•CuO cluster is deposited with femtosecond pulsed-laser irradiation on ZnO particle.•Photocatalyst ...CuO/ZnO is embedded in a chitosan (CS) film to be CO2 adsorber.•The conversion efficiency is maximum 2.16 mmol/g(catalyst)) for 6 h reaction.•Amine in CS is vital to adsorb CO2 with a CuO/ZnO catalyst for CO2 conversion.
A procedure that diminishes carbon dioxide in the atmosphere and converts it to alternative biofuels was reported. On zinc oxide (ZnO) nanoparticles synthesized in ethandiol, copper oxide (CuO) nanoclusters were deposited by femtosecond pulsed-laser irradiation. CuO-deposited ZnO was chemically bound with amine-terminated poly(amido amine) dendrimer using 3-glycidyloxypropyltrimethoxysilan, mixed with TEMPO-oxidized cellulose nanofibril, and molded to a film (CuO/ZnO-Den-TOCNF film). CuO/ZnO was also embedded in a chitosan (CS) matrix and molded to a film. Both films were used for adsorption and conversion of gaseous carbon dioxide. The amine groups in dendrimer loaded on TOCNF and in CS act as adsorption sites of carbon dioxide, and CuO/ZnO is a photocatalyst. On photocatalytic conversion, a composite film converted gaseous carbon dioxide to methanol (maximum 2.42 and 2.16 mmol/g(catalyst) on CuO/ZnO-Den-TOCNF and CuO/ZnO-CS films, respectively) and produced less acetaldehyde (0.030 and 0.037 mmol/g(catalyst), respectively) on irradiation with ultraviolet light for 6 h. The results indicate that the amine group is the vital component to adsorb carbon dioxide besides the catalyst (CuO/ZnO) for the conversion of carbon dioxide. Moreover, TOCNF and CS-based catalytic films are preferable with the objectives of easily removable systems from reaction vessels and of convenient environmentally compatible resources.
We report on calcium containing iron oxide thin films (CaFeO x ), prepared by spin-coating and a follow-up annealing process under mild condition, as an efficient and robust catalyst in ...electrocatalytic and photoelectrocatalytic water oxidation at neutral pH. Thin films prepared without calcium are essentially crystalline γ-Fe 2 O 3 , but those prepared with calcium are amorphous, and with optimal calcium content, the resultant film consists of a short-range order γ-Fe 2 O 3 domain embedded in an amorphous Ca 2 Fe 2 O 5 matrix. CaFeO x prepared with optimal calcium content decomposes upon exposure to phosphate, resulting in the leaching of surface calcium and formation of redox-active iron phosphate, which prevents the loss of active iron species from etching by protons released from the water oxidation process. The amorphous nature and in situ formation of iron phosphate render CaFeO x with high activity and stability under high turnover conditions, reaching 10 mA cm −2 at an overpotential ( η ) of ∼650 mV with a small increase in η (∼30 mV) over 2 h electrolysis in phosphate buffer (1.0 M, pH 7). When being integrated onto a BiVO 4 photoanode, CaFeO x greatly improves the kinetics of the OER and interfacial hole transfer at BiVO 4 , resulting in remarkable enhancement in its photocurrent response and photostability.
Pathologic complete remission after neoadjuvant chemotherapy has a role in guiding the management of breast cancer. The present meta-analysis examined the accuracy of contrast-enhanced magnetic ...resonance imaging (CE-MRI) and diffusion-weighted magnetic resonance imaging (DW-MRI) in detecting the response to neoadjuvant chemotherapy and compared CE-MRI with ultrasonography, mammography, and positron emission tomography/computed tomography (PET/CT). Medical subject heading terms and related keywords were searched to generate a compilation of eligible studies. The pooled sensitivity, specificity, diagnostic odds ratio, area under summary receiver operating characteristic curve (AUC), and Youden index (Q* index) were used to estimate the diagnostic efficacy of CE-MRI, DW-MRI, ultrasonography, mammography, and PET/CT. A total of 54 studies of CE-MRI and 8 studies of DW-MRI were included. The overall AUC and the Q* index values for CE-MRI and DW-MRI were 0.88 and 0.94 and 0.80 and 0.85, respectively. According to the summary receiver operating characteristic curves, CE-MRI resulted in a higher AUC value and Q* index compared with ultrasonography and mammography but had values similar to those of DW-MRI and PET/CT. CE-MRI accurately assessed pathologic complete remission in specificity, and PET/CT and DW-MRI accurately assessed pathologic complete remission in sensitivity. The present meta-analysis indicates that CE-MRI has high specificity and DW-MRI has high sensitivity in predicting pathologic complete remission after neoadjuvant chemotherapy. CE-MRI is more accurate than ultrasonography or mammography. Additionally, PET/CT is valuable for predicting pathologic complete remission. CE-MRI, combined with PET/CT or DW-MRI, might allow for a more precise assessment of pathologic complete remission.
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•FeCo-NP (1000A900) is developed for hydrogen capture in NaBH4/EtOH mixture.•Catalyst prepared by self-assembly of N-doped carbon shell and FeCo-alloy core.•This catalyst shows good ...performance for both H2 and O2 capture applications.
Hydrogen energy storage and transportation are critical issues that must be addressed to ensure the development of alternatives to fossil fuel energy in the future. Herein, the poly(Schiff base) strategy is used to explore the carbon substrate, which is enclosed with binary metal Fe and Co as precursors. After the calcination and acid treatment steps, one of the FeCo alloy, termed FeCoNC-1000A900, was assembled with porous carbon skeleton as a shell and enclosed with FeCo alloy as a core. The FeCoNC-1000A900 exhibits outstanding H2 capture properties from NaBH4/EtOH mixtures circumstance owing to its large average particle size of 45 nm and high specific surface area of 462.07 m2/g. Notably, the FeCoNC-1000A900 acquires bi-functional catalysis efficacy, one is for chemoselectivity in the hydrogenation of nitroarene substrates and shows a high turnover frequency in 690 h−1 within the overall conversion yield. The other one is the O2 capture performance toward the oxygen reduction reaction with the excellent onset potential of 0.89 V, the half-wave potential of 0.77 V, and limiting current density of − 5.56 mA cm−2, which are comparable to those of the commercial Pt/C catalyst. In addition, the Tafel slope of 79.6 mV dec−1 is lower than those for other catalysts. Consequently, the development of the novel FeCoNC-1000A900 catalyst has two functional applications.
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