Fundamental Understanding of Nonaqueous and Hybrid Na-CO2 Batteries: Challenges and Perspectives.

Alkali metal-CO2 batteries, which combine CO2 recycling with energy conversion and storage, are a promising way to address the energy crisis and global warming. Unfortunately, the limited cycle life, poor reversibility, and low energy efficiency of these batteries have hindered their commercialization. Li-CO2 battery systems have been intensively researched in these aspects over the past few years, however, the exploration of Na-CO2 batteries is still in its infancy. To improve the development of Na-CO2 batteries, one must have a full picture of the chemistry and electrochemistry controlling the operation of Na-CO2 batteries and a full understanding of the correlation between cell configurations and functionality therein. Here, recent advances in CO2 chemical and electrochemical mechanisms on nonaqueous Na-CO2 batteries and hybrid Na-CO2 batteries (including O2 -involved Na-O2 /CO2 batteries) are reviewed in-depth and comprehensively. Following this, the primary issues and challenges in various battery components are identified, and the design strategies for the interfacial structure of Na anodes, electrolyte properties, and cathode materials are explored, along with the correlations between cell configurations, functional materials, and comprehensive performances are established. Finally, the prospects and directions for rationally constructing Na-CO2 battery materials are foreseen.

Efficient Organic Solar Cells Enabled by Simple Non-Fused Electron Donors with Low Synthetic Complexity.

Fused-ring electron donors boost the efficiency of organic solar cells (OSCs), but they suffer from high cost and low yield for their large synthetic complexity (SC > 30%). Herein, the authors develop a series of simple non-fused-ring electron donors, PF1 and PF2, which alternately consist of furan-3-carboxylate and 2,2'-bithiophene. Note that PF1 and PF2 present very small SC of 9.7% for their inexpensive raw materials, facile synthesis, and high synthetic yield. Compared to their all-thiophene-backbone counterpart PT-E, two new polymers feature larger conjugated plane, resulting in higher hole mobility for them, especially a value up to ≈10-4 cm2 V-1 ·s for PF2 with longer alkyl side chain. Meanwhile, PF1 and PF2 exhibit larger dielectric constant and deeper electronic energy level versus PT-E. Benefiting from the better physicochemical properties, the efficiencies of PF1- and PF2-based devices are improved by ≈16.7% and ≈71.3% relative to that PT-E-based devices, respectively. Furthermore, the optimized PF2-based devices with introducing PC71 BM as the third component deliver a higher efficiency of 12.40%. The work not only indicates that furan-3-carboxylate is a simple yet efficient building block for constructing non-fused-ring polymers but also provides a promising electron donor PF2 for the low-cost production of OSCs.

Carbon-Free Crystal-like Fe1-xS as an Anode for Potassium-Ion Batteries.

Potassium-ion batteries (PIBs) as a new electrochemical energy storage system have been considered as a desirable candidate in the post-lithium-ion battery era. Nevertheless, the study on this realm is in its infancy; it is urgent to develop electrode materials with high electrochemical performance and low cost. Iron sulfides as anode materials have aroused wide attention by virtue of their merits of high theoretical capacities, environmental benignity, and cost competitiveness. Herein, we constructed carbon-free crystal-like Fe1-xS and demonstrated its feasibility as a PIB anode. The unique structural feature endows the prepared Fe1-xS with plentiful active sites for electrochemical reactions and short transmission pathways for ions/electrons. The Fe1-xS electrode retained capacities of 420.8 mAh g-1 after 100 cycles at 0.1 A g-1 and 212.9 mAh g-1 after 250 cycles at 1.0 A g-1. Even at a high rate of 5.0 A g-1, an average capacity of 167.6 mAh g-1 was achieved. In addition, a potassium-ion full cell is assembled by employing Fe1-xS as an anode and potassium Prussian blue as a cathode; it delivered a discharge capacity of 127.6 mAh g-1 at 100 mA g-1 after 50 cycles.

Bismuth Nanoparticles Confined in Carbonaceous Nanospheres as Anodes for High-Performance Potassium-Ion Batteries.

Bismuth (Bi) has been considered as a promising alloying-type anode for potassium-ion batteries (PIBs), owing to its high theoretical capacity and suitable working voltage plateaus. However, Bi suffers from dramatic volume fluctuation and significant pulverization during the discharge/charge processes, resulting in fast capacity decay. Herein, we synthesize Bi nanoparticles confined in carbonaceous nanospheres (denoted as Bi@C) for PIBs by first utilizing BiOCl nanoflakes as a hard template and a Bi precursor. The construction of the loose structure buffers the mechanical stresses resulting from the volume expansion of Bi during the alloying reaction and avoids the fracture of the electrode structure, thus improving the cycling performance. Moreover, the carbonaceous layers increase the electronic conductivity and disperse the Bi nanoparticles, enhancing the charge transportation and ionic diffusion, which further promotes the rate capability of Bi@C. It exhibits a superior capacity (389 mAh g-1 at 100 mA g-1 after 100 cycles), excellent cycling stability (206 mAh g-1 at 500 mA g-1 over 1000 cycles), and an improved rate capability (182 mAh g-1 at 2.0 A g-1). This work provides a new structuring strategy in alloying materials for boosting reversible and stable potassium-ion storage.

Polyimide@Ketjenblack Composite: A Porous Organic Cathode for Fast Rechargeable Potassium-Ion Batteries.

Potassium-ion batteries (PIBs) configurated by organic electrodes have been identified as a promising alternative to lithium-ion batteries. Here, a porous organic Polyimide@Ketjenblack is demonstrated in PIBs as a cathode, which exhibits excellent performance with a large reversible capacity (143 mAh g-1 at 100 mA g-1 ), high rate capability (125 and 105 mAh g-1 at 1000 and 5000 mA g-1 ), and long cycling stability (76% capacity retention at 2000 mA g-1 over 1000 cycles). The domination of fast capacitive-like reaction kinetics is verified, which benefits from the porous structure synthesized using in situ polymerization. Moreover, a renewable and low-cost full cell is demonstrated with superior rate behavior (106 mAh g-1 at 3200 mA g-1 ). This work proposes a strategy to design polymer electrodes for high-performance organic PIBs.

The optimization of optical modes in Ni-BiVO4 nanoarrays for boosting photoelectrochemical water splitting.

The full utilization of incident light is vitally important for boosting the photoelectrochemical activity of photoelectrodes. Herein, we introduce Ni-BiVO4 nanoarrays for mediating the photoelectrochemical water splitting by optimizing the optical modes. Highly ordered Ni-BiVO4 nanoarrays were fabricated using a nanoimprinted AAO templating technique. By controlling the thickness of BiVO4, we efficiently regulate the photoelectrochemical activity, and the photocurrent was up to 0.91 mA cm-2 at 1.4 V versus Ag/AgCl under 100 mW cm-2 in the visible light, which is 3.25 times that of a flat Ni-BiVO4 electrode with the same deposition cycles of BiVO4. The optimal efficiency of a Ni-BiVO4 nanoarrray-based photoelectrode can be attributed to the optimal morphology, which has the lowest reflection, the strongest scattering and the induced strongest absorption for the incident light among the nanoarrays samples with different thickness of BiVO4. This work demonstrates the importance of the optimization of optical modes in the nanoarray photoelectrode in order to boost photoelectrochemical activity.

Bismuth oxychloride nanoflake assemblies as a new anode for potassium ion batteries.

This work reports the first demonstration of bismuth oxyhalides as anode materials in potassium-ion batteries. BiOCl nanoflake assemblies deliver high capacities of 367 mA h g-1 at 50 mA g-1 and 175 mA h g-1 at 1 A g-1. The formation of K-Bi alloys at an early stage of potassiation is observed.

Insights into the Crystallinity of Layer-Structured Transition Metal Dichalcogenides on Potassium Ion Battery Performance: A Case Study of Molybdenum Disulfide.

Layer-structured transition metal dichalcogenides (LS-TMDs) are being heavily studied in K-ion batteries (KIBs) owing to their structural uniqueness and interesting electrochemical mechanisms. Synthetic methods are designed primarily focusing on high capacities. The achieved performance is often the collective results of several contributing factors. It is important to decouple the factors and understand their functions individually. This work presents a study focusing on an individual factor, crystallinity, by taking MoS2 as a demonstrator. The performance of low and high-crystallized MoS2 is compared to show the function of crystallinity is dependent on the electrochemical mechanism. Lower crystallinity can alleviate diffusional limitation in 0.5-3.0 V, where intercalation reaction takes charge in storing K-ions. Higher crystallinity can ensure the structural stability of the MoS2 layers and promote surface charge storage in 0.01-3.0 V, where conversion reaction mainly contributes. The low-crystallized MoS2 exhibits an intercalation capacity (118 mAh g-1 ), good cyclability (85% over 100 cycles), and great rate capability (41 mAh g-1 at 2 A g-1 ), and the high-crystallized MoS2 delivers a high capacity of 330 mAh g-1 at 1 A g-1 and retains 161 mAh g-1 at 20 A g-1 , being one of the best among the reported LS-TMDs in KIBs.

Gold nanochestnut arrays as ultra-sensitive SERS substrate for detecting trace pesticide residue.

In comparison to conventional spectroscopic techniques based on chromatography, surface-enhanced Raman spectroscopy (SERS) enables the rapid identification and detection of trace pesticide residues present in trace amounts in the environment and foods. Herein, a facile approach to fabricate unique gold nanochestnuts (GNCs) as an ultra-sensitive SERS substrate for detecting trace pesticide residues has been developed based on anodic aluminum oxide (AAO) templates. The GNCs are synthesized through the galvanic replacement of Ag on the top of Ni nanorod arrays. The as-prepared GNCs have well-controlled structural parameters, and importantly have unique anisotropic morphologies that benefit the enhancement in SERS performance. As a result, rhodamine 6 G (R6G) can be efficiently detected with GNCs as the SERS substrate even with a concentration of only 10-12 M, and the Raman enhancement factor reaches up to 5.4 × 109 at this concentration. Further SERS measurement of thiram indicates a remarkable SERS-active sensitivity of the as-prepared GNCs with a detection limit of thiram up to 10-14 M. The GNCs also exhibit a high signal-to-noise ratio.

Urinary monohydroxylated metabolites of polycyclic aromatic hydrocarbons in children living in city and rural residences in Southern China.

Urinary 2-hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, 1-hydroxypyrene and 3-hydroxybenz[a]pyrene concentrations in 179 randomly selected voluntary students were determined in the Southern China, aged 14-16 and living in four areas with different levels of polycyclic aromatic hydrocarbons (PAHs) in soil, water and ambient air. The excretion of 1-hydroxypyrene is significantly higher in students of the urban than in students of the rural, while there are no significant differences of urinary 2-hydroxynaphthalene, 2-hydoxyfluorene and 9-hydroxyphenanthrene between urban and rural children. Mean concentrations of 1-hydroxypyrene (0.54-0.80 µmol/mol creatinine) in the study are much higher than those in the children of Denmark, Germany, Spain, USA, Korea, Japan and Taiwan, and a little higher than those in the children of Ukraine and Thailand. Urinary 2-hydroxynaphthalene concentrations in the study are a little higher than those in the children of USA, and similar to that in non-occupational exposure residences in Korea. Urinary 9-hydroxyphenanthrene concentrations in China are much higher than those in the children of USA. Differences between children with smoking parents and non-smoking parents are not significant in the study.

Isolation and structure determination of anti-influenza component from Mahonia bealei.

The fraction possessing anti-influenza activity, which is obtained from the roots of Mahonia bealei (Fort), has been studied regarding its chemical compositions and molecular structure. The previous experiment on this fraction in vitro suggested that the anti-influenza effect was due to the existence of alkaloids in M. bealei (Fort), and mainly from one bisbenzylisoquinoline alkaloid. In this paper the structure of this bisbenzylisoquinoline alkaloid has been determined as 1R, 1'S-(+)-isotetrandrine by means of MS, 1H NMR, 13C NMR, FT-IR and HPLC analyses.

Analysis of single nucleotide polymorphism sites in exon 4 of the p53 gene using high-performance liquid chromatography electrospray ionization mass spectrometry tandem mass spectrometry.

Three groups of four oligonucleotides with special single nucleotide polymorphisms (SNP) sites in exon 4 of the p53 gene were analyzed with ion-pair reversed-phase high-performance liquid chromatography electrospray ionization mass spectrometry tandem mass spectrometry. The retention order of four oligonucleotides with SNPs was C < G < A < T, regardless of whether the polymorphisms were at the 3' end, the 5' end, or the middle of the oligonucleotides. The charge state of the molecular ion affects the MS/MS spectra of the oligonucleotides. SNPs at the 3' end can be easily identified from the fragmentation pattern of the 2- charge state, but not from the 3- charge state, especially from the w1 fragment. The single base may be taken as the symbol of the 5' end SNP site derived from [M3H]2, but not from the [M3H]2 charge state. The oligonucleotides with SNPs in the middle were also determined from the [M2H]2 precursor ion.

Fast simultaneous determination of urinary 1-hydroxypyrene and 3-hydroxybenzo[a]pyrene by liquid chromatography-tandem mass spectrometry.

A fast analysis method using liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry was developed for the simultaneous determination of the 1-hydroxypyrene (1-OHP) and 3-hydroxybenzo[a]pyrene (3-OHBaP) in urine. Mass transitions were monitored at m/z 219.3-200.0 for 1-OHP and m/z 269.2-252.2 for 3-OHBaP. Only 10 min was needed for the analysis. The recovery was 60% for 3-OHBaP and 91% for 1-OHP, respectively. And the method detection limits were 0.49 microg/L for 1-OHP and 1.03 microg/L for 3-OHBaP. The inter- and intra-day relative standard deviations were in the range of 2.8-8.9% for 1-OHP and 9.7-20.8% for 3-OHBaP, respectively. The developed method was successfully used to measure urinary PAH metabolites of student volunteers in a high school.

Quantification of several monohydroxylated metabolites of polycyclic aromatic hydrocarbons in urine by high-performance liquid chromatography with fluorescence detection.

A high-performance liquid chromatographic method with fluorescence detection has been developed to determine the urinary polycyclic aromatic hydrocarbon metabolites 2-hydroxynaphthalene, 2-hydroxyfluorene, 9-hydroxyphenanthrene, 1-hydroxypyrene and 3-hydroxybenz[a]pyrene. Solid phase extraction (SPE) was used to clean up the samples, and washing with 30% methanol was found to be the best way to remove interferences in the matrix. The method detection limits ranged from 0.044 microg/L for 1-hydroxypyrene to 1.615 microg/L for 3-hydroxybenz[a]pyrene, and the recoveries ranged between 40% for 3-hydroxybenz[a]pyrene and 99% for 2-hydroxynaphthalene. The within-day relative standard deviation was lowest for 2-hydroxynaphthalene at 0.67% and went up to 2.42% for 3-hydroxybenz[a]pyrene, and the between-day relative standard deviation ranged from 3.84% for 9-hydroxyphenanthrene to 10.42% for 2-hydroxyfluorene. The correlation coefficients were between 0.9962 and 0.9998. The developed method was successfully used to analyze samples from student volunteers in a high school.

Comparison of A+T-rich oligonucleotides with and without self-complementary sequence using ion-pair reversed-phase high-performance liquid chromatography/tandem electrospray ionization mass spectrometry.

Both A+T-rich oligonucleotides with and without self-complementary sequences were analyzed using ion- pair reversed-phase liquid chromatography/electrospray ionization mass spectrometry (IP-RP-HPLC/ESI-MS) by tryethylammonium acetate (TEAA) and hexafluoroisopropanol (HFIP) buffer systems to study the characteristics of their retention behavior and electrospray ionization tandem mass spectrometry (ESI-MS/MS) response. The results indicated that the chain length had the same effect on the retention of A+T-rich oligonucleotides in both of TEAA and HFIP buffer systems but the sequence had a different impact on the retention in the two buffer systems. A+T- rich oligonucleotides with a self-complementary sequence were much shorter than those without in the TEAA buffer system whereas a slight difference was observed in the HFIP buffer system. Similar total ion current (TIC) intensity was observed both in oligonucleotides with or without self-complementary sequence. The opposite trend of a change in the TIC intensities with increasing chain length were observed in both the TEAA and HFIP buffer systems. A lower charge state was predominant in the TEAA buffer system whereas a higher charge state was mainly distributed in the HFIP buffer system. The oligonucleotides without self-complementary sequences had a higher charge state than those with self-complementary sequences. A- and T- are more esily formed at a higher charge state whereas the sequence fragments will be formed more easily at a lower charge state in both A+T-rich oligonucleotides with and without self-complementary sequences.

Characterization of G-rich and T-rich oligonucleotides using ion-pair reversed-phase high-performance liquid chromatography/tandem electrospray ionization mass spectrometry.

Characteristics of G-rich and T-rich oligonucleotides were investigated to compare their retention time, total ion current (TIC) intensity, charge-state distribution and product ion using ion-pair reversed-phase high- performance liquid chromatography/tandem electrospray ionization mass spectrometry (IP-RP-HPLC/ESI-MS) at room temperature. Three commonly used mobile phases for the analysis of oligonucleotides, triethylammonium acetate (TEAA), triethylammonium bicarbonate (TEAB) and triethylammonium hexafluoroisopropanol (HFIP) have been utilized. Retention time of G-rich and T-rich oligonucleotides was significantly different in TEAA and TEAB buffer systems, while in the HFIP buffer system it was affected more by the length of oligonucleotides. On the other hand, the ESI-MS ion abundance in the HFIP buffer system was higher than that in both TEAA and TEAB buffers. The TIC intensity of T-rich oligonucleotides was much higher than that of G-rich oligonucleotides in all mobile phases. In addition, much higher charge-state fragments were observed in HFIP buffer system than that in the case of TEAA and TEAB buffer systems. Product ions of both G-rich and T-rich oligonucleotides were affected by charge state of parent ions and collision energy.

[Study on anti-influenza effect of alkaloids from roots of Mahonia bealei in vitro].

Anti-influenza effect of alkaloids from roots of Mahonia bealei (Fort.) Carr. was studied in vitro. The experiment in embryo indicated that the alkaloids at concentration of 0.25 mg/ml obviously inhibited the proliferation of influenza virus Al, and at concentration of 20 mg/ml showed no side-effect on embryo.