| 1. |
|
|
| 2. |
- Chng, Kern Rei, et al.
(author)
-
Cartography of opportunistic pathogens and antibiotic resistance genes in a tertiary hospital environment
- 2020
-
In: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 26, s. 941-951
-
Journal article (peer-reviewed)abstract
- Although disinfection is key to infection control, the colonization patterns and resistomes of hospital-environment microbes remain underexplored. We report the first extensive genomic characterization of microbiomes, pathogens and antibiotic resistance cassettes in a tertiary-care hospital, from repeated sampling (up to 1.5 years apart) of 179 sites associated with 45 beds. Deep shotgun metagenomics unveiled distinct ecological niches of microbes and antibiotic resistance genes characterized by biofilm-forming and human-microbiome-influenced environments with corresponding patterns of spatiotemporal divergence. Quasi-metagenomics with nanopore sequencing provided thousands of high-contiguity genomes, phage and plasmid sequences (>60% novel), enabling characterization of resistome and mobilome diversity and dynamic architectures in hospital environments. Phylogenetics identified multidrug-resistant strains as being widely distributed and stably colonizing across sites. Comparisons with clinical isolates indicated that such microbes can persist in hospitals for extended periods (>8 years), to opportunistically infect patients. These findings highlight the importance of characterizing antibiotic resistance reservoirs in hospitals and establish the feasibility of systematic surveys to target resources for preventing infections. Spatiotemporal characterization of microbial diversity and antibiotic resistance in a tertiary-care hospital reveals broad distribution and persistence of antibiotic-resistant organisms that could cause opportunistic infections in a healthcare setting.
|
|
| 3. |
- Franchi, Daniele, et al.
(author)
-
Effect of the Ancillary Ligand on the Performance of Heteroleptic Cu(I) Diimine Complexes as Dyes in Dye-Sensitized Solar Cells
- 2022
-
In: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 5:2, s. 1460-1470
-
Journal article (peer-reviewed)abstract
- A series of heteroleptic Cu(I) diimine complexes with different ancillary ligands and 6,6'-dimethyl-2,2'-bipyridine-4,4'-dibenzoic acid (dbda) as the anchoring ligand were selfassembled on TiO2 surfaces and used as dyes for dye-sensitized solar cells (DSSCs). The binding to the TiO2 surface was studied by hard X-ray photoelectron spectroscopy for a brominecontaining complex, confirming the complex formation. The performance of all complexes was assessed and rationalized on the basis of their respective ancillary ligand. The DSSC photocurrent-voltage characteristics, incident photon-to-current conversion efficiency (IPCE) spectra, and calculated lowest unoccupied molecular orbital (LUMO) distributions collectively show a push-pull structural dye design, in which the ancillary ligand exhibits an electron-donating effect that can lead to improved solar cell performance. By analyzing the optical properties of the dyes and their solar cell performance, we can conclude that the presence of ancillary ligands with bulky substituents protects the Cu(I) metal center from solvent coordination constituting a critical factor in the design of efficient Cu(I)-based dyes. Moreover, we have identified some components in the I-/I-3(-)-based electrolyte that causes dissociation of the ancillary ligand, i.e., TiO2 photoelectrode bleaching. Finally, the detailed studies on one of the dyes revealed an electrolyte-dye interaction, leading to a dramatic change of the dye properties when adsorbed on the TiO2 surface.
|
|
| 4. |
- Li, Jiayuan, et al.
(author)
-
Dye-sensitized photoanode decorated with pyridine additives for efficient solar water oxidation
- 2021
-
In: Cuihuà xuébào. - : Elsevier BV. - 0253-9837 .- 1872-2067. ; 42:8, s. 1352-1359
-
Journal article (peer-reviewed)abstract
- Splitting water into hydrogen and oxygen by dye-sensitized photoelectrochemical cell (DSPEC) is a promising approach to solar fuels production. In this study, a series of pyridine derivatives as surface additives were modified on a molecular chromophore and water oxidation catalyst co-loaded TiO2 photoanode, TiO2 vertical bar RuP, 1 (RuP = Ru(4,4'-(PO3H2)(2)-2,2'-bipyridine)(2,2'-bipyridine)2, 1 = Ru(bda)(L)(2), (bda = 2,2'-bipyridine-6,6'-dicarboxylate, L = 10-(pyridin-4-yloxy)decyl)phosphonic acid). The addition of pyridine additives was found to result in up to 42% increase in photocurrent. Under simulated sun-light irradiation, TiO2 vertical bar RuP, 1, P-1 (P-1 = 4-Hydroxypyridine) produced a photo-current density of 1 mA/cm(2) at a bias of 0.4 V vs. NHE in acetate buffer. Moreover, the observed photocurrents are correlated with the electron-donating ability of the substituent groups on pyridine ring. Transient absorption measurements and electrochemical impedance spectroscopy revealed that surface-bound pyridine can effectively retard the back-electron transfer from the TiO2 conduction band to the oxidized dye, which is a major process responsible for energy loss in DSPECs.
|
|
| 5. |
- Li, Xiansheng, et al.
(author)
-
A Multifunctional Small-Molecule Hole- Transporting Material Enables Perovskite QLEDs with EQE Exceeding 20%
- 2023
-
In: ACS Energy Letters. - : AMER CHEMICAL SOC. - 2380-8195. ; 8:3, s. 1445-1454
-
Journal article (peer-reviewed)abstract
- Hole-transporting materials (HTMs) play critical roles in the device performance and stability of perovskite quantum dot light-emitting diodes (Pe-QLEDs). However, the development of small-molecule HTMs for achieving high-performance Pe-QLEDs has proven to be very challenging because of their low hole mobility and poor solvent resistance. Herein, we tailor-made a multifunc-tional small-molecule HTM, termed X10, with methoxy as the substituents, for application in Pe-QLEDs. X10 features high hole mobility, good film-forming ability, and strong solvent resistance ability as well as defect passivation effect. Subsequently, Pe-QLEDs employing X10 as HTM presented a promising external quantum efficiency (EQE) of 20.18%, which is 7-fold higher than that of the reference HTM-TCTA-based ones (EQE approximate to 2.88%). To the best of our knowledge, this is the first case in which a small-molecule HTM displays a high EQE over 20% in Pe-QLEDs. Our work provides important guidance for the rational design of multifunctional small-molecule HTMs for high-performance Pe-QLEDs.
|
|
| 6. |
- Liu, Guoquan, et al.
(author)
-
Photocatalytic Water Oxidation by Surface Modification of BiVO4 with Heterometallic Polyphthalocyanine
- 2023
-
In: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 13:13, s. 8445-8454
-
Journal article (peer-reviewed)abstract
- Developing efficient photocatalysts for water oxidation is among the central challenges of solar energy conversion. Here, we report semiconductor-molecular photocatalysts by integration of heteronuclear bimetallic polyphthalocyanine (PPc) catalysts with particulate bismuth vanadate (BiVO4) as the photosensitizer. Their photocatalytic activity for water oxidation was modulated by tuning the Fe/Co ratio of polyphthalocyanines. At an optimal Fe/Co ratio of 3:1, the resulting Fe3CoPPc-BiVO4 hybrid exhibits an excellent oxygen evolution rate of 4557 μmol g-1 h-1 in the presence of iodate under visible light irradiation, which is nearly two orders of magnitude greater than that of pristine BiVO4 and superior to those of the corresponding homometallic counterparts. Both experimental and theoretical methods suggest that the presence of a large population of high-valent Fe/Co molecular species due to the favorable interfacial charge transfer and upshift of the d-band centers of metal sites toward Fermi level lead to a lower energy barrier for the O-O bond formation and eventually promote the oxidation of water.
|
|
| 7. |
- Liu, Tianqi, et al.
(author)
-
Isolation and Identification of Pseudo Seven-Coordinate Ru(III) Intermediate Completing the Catalytic Cycle of Ru-bda Type of Water Oxidation Catalysts
- 2022
-
In: CCS Chemistry. - : Chinese Chemical Society. - 2096-5745. ; 4:7, s. 2481-2490
-
Journal article (peer-reviewed)abstract
- Isolation of RuIII-bda (17-electron specie) complex with an aqua ligand (2-electron donor) is challenging due to violation of the 18-electron rule. Although considerable efforts have been dedicated to mechanistic studies of water oxidation by the Ru-bda family, the structure and initial formation of the RuIII-bda aqua complex are still controversial. Herein, we challenge this often overlooked step by designing a pocket-shape Ru-based complex 1. The computational studies showed that 1 possesses the crucial hydrophobicity at the RuV(O) state as well as similar probability of access of terminal O to solvent water molecules when compared with classic Ru-bda catalysts. Through characterization of single-crystal structures at the RuII and RuIII states, a pseudo seven-coordinate “ready-to-go” aqua ligand with RuIII...O distance of 3.62 Å was observed. This aqua ligand was also found to be part of a formed hydrogen-bonding network, providing a good indication of how the RuIII-OH2 complex is formed.
|
|
| 8. |
- Liu, Tianqi, et al.
(author)
-
Promoting Proton Transfer and Stabilizing Intermediates in Catalytic Water Oxidation via Hydrophobic Outer Sphere Interactions
- 2022
-
In: Chemistry - A European Journal. - : Wiley-VCH Verlagsgesellschaft. - 0947-6539 .- 1521-3765. ; 28:24
-
Journal article (peer-reviewed)abstract
- The outer coordination sphere of metalloenzyme often plays an important role in its high catalytic activity, however, this principle is rarely considered in the design of man-made molecular catalysts. Herein, four Ru-bda (bda=2,2 '-bipyridine-6,6 '-dicarboxylate) based molecular water oxidation catalysts with well-defined outer spheres are designed and synthesized. Experimental and theoretical studies showed that the hydrophobic environment around the Ru center could lead to thermodynamic stabilization of the high-valent intermediates and kinetic acceleration of the proton transfer process during catalytic water oxidation. By this outer sphere stabilization, a 6-fold rate increase for water oxidation catalysis has been achieved.
|
|
| 9. |
- Liu, X., et al.
(author)
-
Bromide-Mediated Photoelectrochemical Epoxidation of Alkenes Using Water as an Oxygen Source with Conversion Efficiency and Selectivity up to 100%
- 2022
-
In: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 144:43, s. 19770-19777
-
Journal article (peer-reviewed)abstract
- In a photoelectrochemical (PEC) cell, the production of solar fuels such as hydrogen is often accompanied either by the oxidation of water or by the oxidation of organic substrates. In this study, we report bromide-mediated PEC oxidation of alkenes at a mesoporous BiVO4 photoanode and simultaneous hydrogen evolution at the cathode using water as an oxygen source. NaBr as a redox mediator was demonstrated to play a dual role in the PEC organic synthesis, which facilitates the selective oxidation of alkenes into epoxides and suppresses the photocorrosion of BiVO4 in water. This method enables a near-quantitative yield and 100% selectivity for the conversion of water-soluble alkenes into their epoxides in H2O/CH3CN solution (v/v, 4/1) under simulated sunlight without the use of noble metal-containing catalysts or toxic oxidants. The maximum solar-to-electricity efficiency of 0.58% was obtained at 0.39 V vs Ag/AgCl. The obtained epoxide products such as glycidol are important building blocks of the chemical industry. Our results provide an energy-saving and environment-benign approach for producing value-added chemicals coupled with solar fuel generation.
|
|
| 10. |
- Luo, Xin, et al.
(author)
-
Spiro[fluorene-9,9′-xanthene]-Based Hole-Transporting Materials for Photovoltaics : Molecular Design, Structure-Property Relationship, and Applications
- 2024
-
In: ACCOUNTS OF MATERIALS RESEARCH. - : American Chemical Society (ACS). - 2643-6728. ; 5:2, s. 220-235
-
Journal article (peer-reviewed)abstract
- Organic hole-transporting materials (HTMs) are of importance in the progress of new-generation photovoltaics, notably in perovskite solar cells (PSCs), solid-state dye-sensitized solar cells (sDSCs), and organic solar cells (OSCs). These materials play a vital role in hole collection and transportation, significantly impacting the power conversion efficiency (PCE) and overall stability of photovoltaic devices. The emergence of spiro(fluorene-9,9 '-xanthene) (SFX) as a novel building block for organic HTMs has gained considerable attention in the field of photovoltaics. Its facile one-pot synthetic approach, straightforward purification, and physiochemical properties over the prototype HTM spiro-OMeTAD have positioned SFX as a highly attractive alternative. In this Account, we present a comprehensive and in-depth summary of our research work, focusing on the advancements in SFX-based organic HTMs in photovoltaic devices with a particular emphasis on PSCs and sDSCs. Several key objectives of our research have been focused on exploring strategies to improve the properties of SFX-based HTMs. (i) One of the critical aspects we have addressed is the improvement of film quality. By carefully designing the molecular structure and employing suitable synthetic approaches, we have achieved HTMs with excellent film-forming ability, resulting in uniform and smooth films over large areas. This achievement is pivotal in ensuring the reproducibility and efficiency of photovoltaic devices. Furthermore, (ii) our investigations have led to an improvement in hole mobility within the HTMs. Through molecular engineering, such as increasing the molecular conjugation and introducing multiple SFX units, we have demonstrated enhanced charge-carrier mobility. This advancement plays a crucial role in minimizing charge recombination losses and improving the overall device efficiency. Additionally, (iii) we have explored the concept of defect passivation in SFX-based HTMs. By incorporating Lewis base structures, such as pyridine groups, we have successfully coordinated to Pb2+ in the perovskite layer, resulting in a passivation of surface defects. This defect passivation contributes to better stability and enhanced device performance. Throughout our review, we highlighted the potential and opportunities achieved through these steps. The combination of enhanced film quality, improved hole mobility, and defect passivation resulted in remarkable photovoltaic performance. Our findings have demonstrated promising short-circuit current densities, open-circuit voltages, fill factors, and PCEs, with some HTMs even outperforming the widely used spiro-OMeTAD. We believe that this review will not only provide a better understanding of SFX-based HTMs but also open new avenues for enhancing the performance of organic HTMs in photovoltaic and other organic electronic devices. By providing unique perspectives and exploring different strategies, we aim to inspire ongoing advancements in photovoltaic technologies and organic electronics. Meanwhile, the success of SFX-based HTMs in improving photovoltaic device performance holds great promise for the continued development of efficient and stable photovoltaic devices in the years to come.
|
|
| 11. |
- Shang, Yu, et al.
(author)
-
Pyrrolic N or pyridinic N : The active center of N-doped carbon for CO2 reduction
- 2022
-
In: Cuihuà xuébào. - : Elsevier BV. - 0253-9837 .- 1872-2067. ; 43:9, s. 2405-2413
-
Journal article (peer-reviewed)abstract
- Pyridinic N is widely regarded as the active center while pyrrolic N has low-activity in metal-free N-doped carbon for electrocatalytic CO2 reduction reaction (CO2RR) to CO, but this viewpoint remains open to question. In this study, through density functional theoretical calculations, we first illustrate that the intrinsic activity of pyrrolic N is high enough for effectively catalyzing CO2RR, however, due to the interplay with the neighboring pyridinic N sites, the activity of pyrrolic N is dramatically suppressed. Then, experimentally, metal-free N-doped carbon spheres (NCS) electrocatalysts without significant pyridinic N content are prepared for CO2RR. The pyrrolic N in NCS shows a direct-positive correlation with the performance for CO2RR, representing the active center with high activity. The optimum NCS could produce syngas with a wide range of CO/H-2 ratio (0.09 to 12) in CO2RR depending on the applied potential, meanwhile, the best selectivity of 71% for CO can be obtained. Intentionally adding a small amount of pyridinic N to the optimum NCS dramatically decreases the activity for CO2RR, further verifying the suppressed activity of pyrrolic N sites by the neighboring pyridinic N sites. This work reveals the interaction between a variety of N species in N-doped carbon, and the potential of pyrrolic N as the new type of active site for electrocatalysts, which can improve our understanding of the electrocatalysis mechanism and be helpful for the rational design of high-efficient electrocatalysts.
|
|
| 12. |
- Wang, Guanqun, et al.
(author)
-
Predictability of Vehicle Fuel Consumption Using LSTM: Findings from Field Experiments
- 2023
-
In: Journal of Transportation Engineering Part A: Systems. - 2473-2893 .- 2473-2907. ; 149:5
-
Journal article (peer-reviewed)abstract
- It has been well-recognized that driving behaviors significantly impact the fuel consumption of vehicles. To explore how well deep learning methods can predict fuel consumption precisely and efficiently and then guide drivers to go in an energy-saving way, we propose a fuel consumption prediction model, namely FuelNet, based on long short-term memory (LSTM) neural networks in this study. First, we develop the proposed FuelNet model with numerous vehicle kinematics data and corresponding fuel consumption data collected in the test field and real-world scenarios. And we analyze the relationship between the prediction accuracy and different combinations of input variables, training set size, and the sampling interval of the raw data. Second, we conduct intensive field tests to demonstrate the applicability of our model to fuel consumption prediction for different speed conditions and vehicle types. Furthermore, the superior prediction performance of FuelNet is shown by comparing it with five other types of models, such as the physical model, statistical and regression model, conventional neural networks model, and other deep learning models. Finally, we apply it to three real case studies, which verify that FuelNet can precisely predict fuel consumption for different driving trajectories in many scenarios such as signalized intersection (average value of RE is 0.049), campus environments (RE is 0.030), urban roads (RE is 0.077), and highways (RE is 0.097), as well as can contribute to detecting abnormal fuel consumption.
|
|
| 13. |
- Wang, Linqin, et al.
(author)
-
A crosslinked polymer as dopant-free hole-transport material for efficient n-i-p type perovskite solar cells
- 2021
-
In: Journal of Energy Chemistry. - : Elsevier BV. - 2095-4956 .- 2096-885X. ; 55, s. 211-218
-
Journal article (peer-reviewed)abstract
- A new crosslinked polymer, called P65, with appropriate photo-electrochemical, opto-electronic, and thermal properties, has been designed and synthesized as an efficient, dopant-free, hole-transport material (HTM) for n-i-p type planar perovskite solar cells (PSCs). P65 is obtained from a low-cost and easily synthesized spiro[fluorene-9,9′-xanthene]-3′,6′-diol (SFX-OH)-based monomer X65 through a free-radical polymerization reaction. The combination of a three-dimensional (3D) SFX core unit, hole-transport methoxydiphenylamine group, and crosslinked polyvinyl network provides P65 with good solubility and excellent film-forming properties. By employing P65 as a dopant-free hole-transport layer in conventional n-i-p type PSCs, a power conversion efficiency (PCE) of up to 17.7% is achieved. To the best of our knowledge, this is the first time a 3D, crosslinked, polymeric dopant-free HTM has been reported for use in conventional n-i-p type PSCs. This study provides a new strategy for the future development of a 3D crosslinked polymeric dopant-free HTM with a simple synthetic route and low-cost for commercial, large-scale applications in future PSCs.
|
|
| 14. |
- Wang, Tiantian, et al.
(author)
-
Microstructural probing of phosphonium-based ionic liquids on a gold electrode using colloid probe AFM
- 2022
-
In: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 24:41, s. 25411-25419
-
Journal article (peer-reviewed)abstract
- Atomic force microscopy (AFM) with a gold colloid probe modeled as the electrode surface is employed to directly capture the contact resonance frequency of two phosphonium-based ionic liquids (ILs) containing a common anion [BScB]− and differently lengthened cations ([P6,6,6,14]+ and [P4,4,4,8]+). The comparative interfacial studies are performed by creating IL films on the surface of gold, followed by measuring the wettability, thickness of the films, adhesion forces, surface morphology and AFM-probed contact resonance frequency. In addition, the cyclic voltammetry and impedance spectroscopy measurements of the neat ILs are measured on the surface of the gold electrode. The IL with longer cation alkyl chains exhibits a well-defined thin film on the electrode surface and enhanced the capacitance than the shorter chain IL. The AFM contact resonance frequency and force curves reveal that the longer IL prefers to form stiffer ion layers at the gold electrode surface, suggesting the “…anion–anion–cation–cation…” bilayer structure, in contrast, the shorter-chain IL forms the softer cation–anion alternating structure, i.e., “…anion–cation–anion–cation…”.
|
|
| 15. |
- Wen, Zhibing, et al.
(author)
-
Aqueous CO2 Reduction on Si Photocathodes Functionalized by Cobalt Molecular Catalysts/Carbon Nanotubes
- 2022
-
In: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 61:24
-
Journal article (peer-reviewed)abstract
- Photoelectrochemical reduction of CO2 is a promising approach for renewable fuel production. We herein report a novel strategy for preparation of hybrid photocathodes by immobilizing molecular cobalt catalysts on TiO2-protected n+-p Si electrodes (Si|TiO2) coated with multiwalled carbon nanotubes (CNTs) by π–π stacking. Upon loading a composite of CoII(BrqPy) (BrqPy=4′,4′′-bis(4-bromophenyl)-2,2′ : 6′,2′′ : 6′′,2′′′-quaterpyridine) catalyst and CNT on Si|TiO2, a stable 1-Sun photocurrent density of −1.5 mA cm−2 was sustained over 2 h in a neutral aqueous solution with unity Faradaic efficiency and selectivity for CO production at a bias of zero overpotential (−0.11 V vs. RHE), associated with a turnover frequency (TOFCO) of 2.7 s−1. Extending the photoelectrocatalysis to 10 h, a remarkable turnover number (TONCO) of 57000 was obtained. The high performance shown here is substantially improved from the previously reported photocathodes relying on covalently anchored catalysts.
|
|
| 16. |
- Xu, Guodong, et al.
(author)
-
Reducing Energy Loss and Morphology Optimization Manipulated by Molecular Geometry Engineering for Hetero-junction Organic Solar Cells
- 2020
-
In: Chinese journal of chemistry. - : WILEY-V C H VERLAG GMBH. - 1001-604X .- 1614-7065. ; 38:12, s. 1553-1559
-
Journal article (peer-reviewed)abstract
- A Summary of main observation and conclusion Molecular geometry engineering is an effective strategy to control the micromorphology and molecular energy level in organic photovoltaics (OPVs). Two novel copolymers based on alkylsilyl- and chloride-functionalized benzodithiophene (BDT) were designed and synthesized for wide bandgap copolymer donor materials in OPVs. It was found that the two copolymers exhibited distinctly different properties in active layer when blended with fullerene-free acceptor IT-4F. The chloride-functionalized copolymer PBDTCl-TZ with deeper molecular energy level and better coplanar structure induced more ordered aggregation in blend film. Thus, the device based on PBDTCl-TZ exhibits better energy alignment with IT-4F and smaller radiative recombination. Furthermore, the non-radiative recombination of PBDTCl-TZ:IT-4F based device is about 45 mV lower than the PBDTSi-TZ:IT-4F based device, contributing to a lower energy loss (E-loss), and a higher open-circut voltage (V-OC). As a result, the devices based on the blend of PBDTCl-TZ:IT-4F exhibit a high power conversion efficiency (PCE) of up to 12.2% with a highV(OC)of 0.837 V, higher than that of PBDTSi-TZ:IT-4F, of which the PCE is 11.2% with a V-OC of 0.781 V.
|
|
| 17. |
- Xu, Suxian, et al.
(author)
-
Immobilization of Iron Phthalocyanine on Pyridine-Functionalized Carbon Nanotubes for Efficient Nitrogen Reduction Reaction
- 2022
-
In: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 12:9, s. 5502-5509
-
Journal article (peer-reviewed)abstract
- An electrochemical nitrogen reduction reaction (NRR) under mild conditions offers a promising alternative to the traditional Haber-Bosch process in converting abundant nitrogen (N2) to high value-added ammonia (NH3). In this work, iron phthalocyanine (FePc) was homogeneously immobilized on pyridine-functionalized carbon nanotubes to form a well-tuned electrocatalyst with an FeN5 active center (FePc-Py-CNT). Synchrotron X-ray absorption and Fourier transform infrared spectroscopy proved the presence of an Fe-N coordination bond between FePc and surface-bound pyridine. The resulting hybrid exhibited notably enhanced electrocatalytic NRR performance compared to FePc immobilized on CNTs based on pi-pi stacking interactions (FePc-CNT), resulting in doubled NH3 yield (21.7 mu g 1 h mgcat-1h-1) and Faradaic efficiency (22.2%). Theoretical calculations revealed that the axial coordination on FePc resulted in partial electron transfer from iron to pyridine, which efficiently suppresses the adsorption of H+ and improves the chemisorption of N2 at Fe sites. Meanwhile, the interfacial electron transfer was facilitated by pyridine as an electron transfer relay between FePc and CNTs. This work provides a unique strategy for the design of highly efficient NRR electrocatalysts at the molecular level.
|
|
| 18. |
- Xu, Suxian, et al.
(author)
-
Nickel-selenide templated binary metal-organic frameworks for efficient water oxidation
- 2020
-
In: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 8:33, s. 16908-16912
-
Journal article (peer-reviewed)abstract
- The development of highly active and stable non-precious metal electrocatalysts is of great significance for energy conversion with the oxygen evolution reaction (OER) being a rate-determining step. Herein, we report a hybrid material bearing a three-dimensional (3D) core-shell hierarchical structure, in which binary metal-organic framework nanosheets (NiFe-MOF NSs) are rationally decorated on NiSe(x)nanosheet (NS) arrays supported on Ni foam (NF). With this approach, the highly conductive NiSe(x)NSs ensure rapid charge transfer, the NiFe-MOF NSs provide a large number of exposed active sites, and the 3D hierarchical structure benefits gas release and electrolyte diffusion. As a result the NiFe-MOF/NiSex/NF electrode delivers current densities of 10 and 100 mA cm(-2)at overpotentials of 198 and 230 mV and reveals a low Tafel slope of 30.6 mV dec(-1)toward the OER. When NiFe-MOF/NiSex/NF was used as both the anode and cathode for overall water splitting, the potential to deliver a current density of 10 mA cm(-2)was 1.59 V, lower than that for the benchmark IrO2/NF(+)||Pt/C/NF(-) system (1.66 V at 10 mA cm(-2)).
|
|
| 19. |
- Xu, Suxian, et al.
(author)
-
Polystyrene spheres-templated mesoporous carbonous frameworks implanted with cobalt nanoparticles for highly efficient electrochemical nitrate reduction to ammonia
- 2023
-
In: Applied Catalysis B. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 323
-
Journal article (peer-reviewed)abstract
- Electrocatalytic nitrate reduction reaction (eNO3RR) to ammonia (NH3) provides an intriguing approach for both environmental denitrification and sustainable NH3 synthesis. Herein, we report the fabrication of hierarchically mesoporous Co nanoparticles decorated N-doped carbon composites as a highly efficient electrocatalyst for eNO3RR by using monodispersed polystyrene spheres (PS) as sacrificial templates (MR Co-NC). By taking advantage of the large specific area of the pore-rich structures and the high intrinsic activity of metallic Co, the MR Co-NC shows remarkable activity toward eNO3RR, which achieves a partial current density of 268 mA cm-2 with a Faradaic efficiency (FE) of 95.35 +/- 1.75 % and a generation rate of 1.25 +/- 0.023 mmol h-1 cm-2 for NH3 production under the optimal conditions. The porous carbon skeleton was found to play a dual role by simul-taneously protecting the active sites from oxidation and facilitating long-range charge and mass transfer. Theoretical calculations reveal a lower energy barrier of the rate-determining step (*NO2 + H2O + 2e- -> *NO + 2OH-) on the metallic Co of MR Co-NC over beta-Co(OH)2 formed by the reconstruction of carbon-free Co nanoparticles.
|
|
| 20. |
- Zhang, Wei, et al.
(author)
-
Organic Salts as p-Type Dopants for Efficient LiTFSI-Free Perovskite Solar Cells
- 2020
-
In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:30, s. 33751-33758
-
Journal article (peer-reviewed)abstract
- Despite the ubiquity and importance of organic hole-transport materials in photovoltaic devices, their intrinsic low conductivity remains a drawback. Thus, chemical doping is an indispensable solution to this drawback and is essentially always required. The most widely used p-type dopant, FK209, is a cobalt coordination complex. By reducing Co(III) to Co(II), Spiro-OMeTAD becomes partially oxidized, and the film conductivity is initially increased. In order to further increase the conductivity, the hygroscopic co-dopant LiTFSI is typically needed. However, lithium salts are normally quite hygroscopic, and thus, water absorption has been suggested as a significant reason for perovskite degradation and therefore limited device stability. In this work, we report a LiTFSI-free doping process by applying organic salts in relatively high amounts. The film conductivity and morphology have been studied at different doping amounts. The resulting solar cell devices show comparable power conversion efficiencies to those based on conventional LiTFSI-doped Spiro-OMeTAD but show considerably better long-term device stability in an ambient atmosphere.
|
|
| 21. |
- Zhang, Wei, 1989-, et al.
(author)
-
Single crystal structure and opto-electronic properties of oxidized Spiro-OMeTAD
- 2020
-
In: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 56:10, s. 1589-1592
-
Journal article (peer-reviewed)abstract
- Single crystals of Spiro(TFSI)2 were grown, the optical and electronic properties were characterized and compared with neutral Spiro-OMeTAD. Density-functional theory was used to get insights into binding and band structure properties. The flat valence bands indicate a rather limited orbital overlap in Spiro(TFSI)2.
|
|
