Addressing the Carbonate Issue: Electrocatalysts for Acidic CO2 Reduction Reaction.

Electrochemical CO2 reduction reaction (CO2RR) powered by renewable energy provides a promising route to CO2 conversion and utilization. However, the widely used neutral/alkaline electrolyte consumes a large amount of CO2 to produce (bi)carbonate byproducts, leading to significant challenges at the device level, thereby impeding the further deployment of this reaction. Conducting CO2RR in acidic electrolytes offers a promising solution to address the "carbonate issue"; however, it presents inherent difficulties due to the competitive hydrogen evolution reaction, necessitating concerted efforts toward advanced catalyst and electrode designs to achieve high selectivity and activity. This review encompasses recent developments of acidic CO2RR, from mechanism elucidation to catalyst design and device engineering. This review begins by discussing the mechanistic understanding of the reaction pathway, laying the foundation for catalyst design in acidic CO2RR. Subsequently, an in-depth analysis of recent advancements in acidic CO2RR catalysts is provided, highlighting heterogeneous catalysts, surface immobilized molecular catalysts, and catalyst surface enhancement. Furthermore, the progress made in device-level applications is summarized, aiming to develop high-performance acidic CO2RR systems. Finally, the existing challenges and future directions in the design of acidic CO2RR catalysts are outlined, emphasizing the need for improved selectivity, activity, stability, and scalability.

Unravelling the carbonate issue through the regulation of mass transport and charge transfer in mild acid.

The electrochemical CO2 reduction reaction (CO2RR) triggered by renewable electricity provides a promising route to produce chemical feedstocks and fuels with low-carbon footprints. The intrinsic challenge for the current CO2RR electrolyzer is the carbonate issue arising from the reaction between hydroxide and CO2. Acid CO2RR electrolyzers, in principle, can effectively solve the carbonate formation, but it remains inevitable practically. In this work, we thoroughly investigated the electrode processes of the CO2RR on the benchmark Ag catalyst in mild acid. The root of the carbonate issue arises from the imbalanced supply-consumption rate of protons-the electron transfer vs. mass transport. Regulating the hydrodynamics substantially reduces the proton diffusion length by 80%, increasing the single-pass carbon utilization efficiency of CO2-to-CO to 44% at -100 mA cm-2. The fundamental difference between mass transport and electron transfer on the spatial and temporal scale still leads to unavoidable carbonate formation. Future work to design intrinsically active catalysts in strong acid or metal-cation-free media is critical to solving the carbonate issue.

How to extract kinetic information from Tafel analysis in electrocatalysis.

Electrocatalysis has become increasingly attractive in aiding transformation to green chemical industries. Proper evaluation and in-depth understanding of electrocatalysts are critical to designing high-performance electrocatalysis systems. Tafel analysis is thus of great importance as it allows reliable performance comparison among different reports and provides insight into the reaction mechanism. This Tutorial discusses the Tafel analysis from experimental and theoretical perspectives. The principle of the Tafel analysis is revisited, and the procedure of mechanism investigation based on the Tafel analysis is included.

Acid Etching Strategy: Optimizing Bifunctional Activities of Metal/Nitrogen-doped Carbon Catalysts for Efficient Rechargeable Zn-Air Batteries.

Transition metal-embedded heteroatom carbon composites are regarded as an important branch of bifunctional catalysts for rechargeable Zn-air batteries. The inevitable transition metal particles on the carbon skeleton may affect the availability of the metal-heteroatom-carbon catalytic site. Herein, we propose an acid treatment strategy to remove the bare transition metal particles, thus regulating the electrochemical surface area. The OER activities are highly related to the electrochemical surface area for the catalysts with different acid treatment times. In addition, there exists an optimal acid treatment time to achieve the highest ORR and OER activities with the ΔE value of 0.75 V. Given the superior bifunctional activities after acid treatment, we further assemble the rechargeable Zn-air batteries with the optimal catalyst, which achieves a peak power density of 364 mW cm-2 and long cycling life of 500 h at 10 mA cm-2 . This work affords an efficient strategy to enhance the ORR/OER activities and may guide the design of transition metal/heteroatom carbon composites.

Preparation of asymmetric Janus hollow silica microparticle and its application on oily wastewaters.

Janus nanoparticles have aroused the interest of scholars because of their highly efficient emulsification of spilled oils in wastewater. In this work, interfacially active Janus hollow glass microparticles (J-HGMPs) of asymmetric wettability were designed and synthesized in order to achieve more efficient separation of emulsified oil droplets from oily wastewater. Surface characteristic techniques such as FTIR, SEM, zeta potential and contact angle measurements had been employed to assess the amphiphilic surface properties of J-HGMPs. The oil removal/recovery performance of J-HGMPs in different oil-water systems and their interfacial activities were studied. As a particulate emulsifier, J-HGMPs could remove/recover > 96% oil from oil-water mixed phase. The results showed that J-HGMPs had strong interfacial activities and anchored firmly at oil/water interfaces. This high adsorption energy was also evaluated and verified via the calculation of Gibbs free energy. Overall, this study provided a novel and low-cost oil recovery method via a convenient buoyancy force that could be effectively applied in the treatment of oil spills while achieving the goal of benign and green environmental protection.

TNFα stimulates the proliferation of immature Sertoli cells by attenuating UPS-degradation of cyclin D1 and leads to the delay of BTB maturation in pubertal rats.

BACKGROUNDS: The Sertoli cell that plays a vital role during spermatogenesis is a known target of physiological and pathological factors affecting testicular development. Tumor necrosis factor alpha (TNFα) participates in the blood-testis barrier reconstruction, cell apoptosis, and inflammatory response by recognizing receptors on Sertoli cell. TNFα has also been shown to induce the proliferation of immature Sertoli cell in vitro, yet the mechanism still remains unclarified. OBJECTIVES: This study was designed to investigate the effect of TNFα on blood-testis barrier development during puberty and the underlying mechanisms of TNFα-induced immature Sertoli cell proliferation. MATERIALS AND METHODS: Immature male Sprague-Dawley rats of postnatal day 12 were intraperitoneally injected with TNFα. Biotin-labeled method was used to detect permeability of the developing blood-testis barrier after TNFα treatment, and the distribution of occludin and junctional adhesion molecule-A (JAM-A) were detected by immunofluorescence. Sertoli cells isolated from Sprague-Dawley rats of postnatal day 10 were cultured in vitro and treated with TNFα. Cell proliferation rate was reflected by Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assay. Immunoblot and quantitative polymerase chain reaction were used to detect the expression of proliferating cell nuclear antigen, Fbxo4, and cyclin D1. Immunoprecipitation was used to detect the ubiquitination of cyclin D1 and the interaction between Fbxo4 and cyclin D1. Ammonium pyrrolidinedithiocarbamate (PDTC) was applied to detect the effect of nuclear factor kappaB (NFκB) activity inhibition on TNFα-induced Sertoli cell proliferation. The adenoviral recombinant plasmid containing rat Fbxo4 gene was constructed to investigate the effect of Fbxo4 overexpression on Sertoli cell proliferation promoted by TNFα. RESULTS: The in vivo experiment revealed a significant delay of blood-testis barrier maturation in pubertal rats caused by exogenous TNFα. TNFα (10 ng/ml) treatment in vitro was found to promote the proliferation of immature Sertoli cells, accompanied with increased NFκB activity and cyclin D1 protein level. The level of Fbxo4 and ubiquitination of cyclin D1 were decreased after TNFα treatment. Inhibitor of NFκB or overexpression of Fbxo4 could both reverse the TNFα-induced proliferation of immature Sertoli cells, meanwhile restore the ubiquitin-proteasome system-dependent degradation of cyclin D1. Overexpression of Fbxo4 could not affect the activation of NFκB caused by TNFα. CONCLUSION: These results indicate that TNFα inhibits the ubiquitination and degradation of cyclin D1 through the NFκB pathway, thereby promoting the proliferation of immature Sertoli cell in vitro and inducing the delay of blood-testis barrier maturation in pubertal rats.

Micromechanism Study of Molecular Compatibility of PVDF/PEI Blend Membrane.

In this paper, the compatibility of polyetherimide (PEI) with different contents as a high-performance copolymer and polyvinylidene fluoride (PVDF) was studied, and 5%-20% PEI was prepared by the non-solvent-induced phase inversion method. The compatibility of PVDF and PEI was evaluated by analyzing the physical structure and properties of the blend membrane, the microstructure, the glass transition temperature Tg, the enthalpy, and the mechanism of the polymer blend enthalpy change. The results show that the blend membranes have -NH and C=O-N binding energies at X-ray photoelectron spectroscopy (XPS), which preliminarily proves that fluorine-amine bonds are formed between the polymers, and new spectra appeared by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) peaks, which further proves that the two have the formation of fluorine-amine bonds, the Tg and enthalpy of the mixed membrane was increased, and a scanning electron microscope (SEM) observed that the membrane pores changed from finger-like pores to sponge-like macropores. When the content of PEI is 15%, the performance of the blended membrane is the best, the water contact angle increases to 58.5°, the porosity increases to 17.33%, the maximum force increases to 8.04 N, and the elongation at break decreases to 24.26%, the pure water flux is 1870.292 L/m2·h, and the oil rejection is 87%. In addition, the enthalpy change of polymer blending further proves that PEI and PVDF are compatible systems and have a good performance improvement for PVDF.

Molecular Compatibility and Hydrogen Bonding Mechanism of PES/PEI Blends.

The development of high-performance polymer membranes has sparked a lot of attention in recent years. Polymer blending is a potential method of modification. A limitation, however, is the compatibility of blends at the molecular level. In this investigation, polyethersulfone/polyetherimide hollow fiber membranes were prepared by the solution blending method. Compatibility, hydrogen bonding, crystallinity, microstructure, hydrophilicity, mechanical properties, and transmissibility of blended membranes were also characterized. The compatibility and hydrogen bonding action of the two components were confirmed by DSC, FTIR, XPS, and XRD. The structure exhibits a C-H···O interaction motif with the sulfone group acting as a hydrogen bond acceptor from a methyl C-H donor. The π-π stacking between the two polymers arranged molecules more orderly, resulting in enhanced intermolecular interactions. Compared to polyethersulfone hollow fiber membranes, the hydrophilic, mechanical properties, and rejection rate of the blended membranes are more effectively enhanced. Self-assembly of the host polymer with a polymer capable of forming hydrogen bonds to construct controllable blends is a crucial and proven method.

Interlayer Engineering of α-MoO3 Modulates Selective Hydronium Intercalation in Neutral Aqueous Electrolyte.

Among various charge-carrier ions for aqueous batteries, non-metal hydronium (H3 O+ ) with small ionic size and fast diffusion kinetics empowers H3 O+ -intercalation electrodes with high rate performance and fast-charging capability. However, pure H3 O+ charge carriers for inorganic electrode materials have only been observed in corrosive acidic electrolytes, rather than in mild neutral electrolytes. Herein, we report how selective H3 O+ intercalation in a neutral ZnCl2 electrolyte can be achieved for water-proton co-intercalated α-MoO3 (denoted WP-MoO3 ). H2 O molecules located between MoO3 interlayers block Zn2+ intercalation pathways while allowing smooth H3 O+ intercalation/diffusion through a Grotthuss proton-conduction mechanism. Compared to α-MoO3 with a Zn2+ -intercalation mechanism, WP-MoO3 delivers the substantially enhanced specific capacity (356.8 vs. 184.0 mA h g-1 ), rate capability (77.5 % vs. 42.2 % from 0.4 to 4.8 A g-1 ), and cycling stability (83 % vs. 13 % over 1000 cycles). This work demonstrates the possibility of modulating electrochemical intercalating ions by interlayer engineering, to construct high-rate and long-life electrodes for aqueous batteries.

A Stimulus-Responsive Zinc-Iodine Battery with Smart Overcharge Self-Protection Function.

Zinc-iodine aqueous batteries (ZIABs) are highly attractive for grid-scale energy storage due to their high theoretical capacities, environmental friendliness, and intrinsic non-flammability. However, because of the close redox potential of Zn stripping/platting and hydrogen evolution, slight overcharge of ZIABs would induce drastic side reactions, serious safety concerns, and battery failure. A novel type of stimulus-responsive zinc-iodine aqueous battery (SR-ZIAB) with fast overcharge self-protection ability is demonstrated by employing a smart pH-responsive electrolyte. Operando spectroelectrochemical characterizations reveal that the battery failure mechanism of ZIABs during overcharge arises from the increase of electrolyte pH induced by hydrogen evolution as well as the consequent irreversible formation of insulating ZnO at anode and soluble Zn(IO3 )2 at cathode. Under overcharge conditions, the designed SR-ZIABs can be rapidly switched off with capacity degrading to 6% of the initial capacity, thereby avoiding continuous battery damage. Importantly, SR-ZIABs can be switched on with nearly 100% of capacity recovery by re-adjusting the electrolyte pH. This work will inspire the development of aqueous Zn batteries with smart self-protection ability in the overcharge state.

MiR-142-3p Inhibits TGF-ß3-Induced Blood-Testis Barrier Impairment by Targeting Lethal Giant Larvae Homolog 2.

BACKGROUND/AIMS: Transforming growth factor-ß3 (TGF-ß3) has been proved to perturb the blood-testis barrier (BTB) by accelerating junction protein endocytosis in Sertoli cells (SCs) to accommodate the traversing of preleptotene spermatocytes across the BTB around stage VIII in rat. Yet the molecular network underlying the impairment of TGF-ß3 on BTB integrity is not fully elucidated. Our study herein was designed to investigate the participation of microRNA-142-3p (miR-142-3p), which has been reported to affect TGF-ß3 signaling via different pathways, during BTB dynamics and the corresponding mechanisms. METHODS: MiRNA mimic or agomiRNA was co-administered with or without TGF-ß3 in the cultured SCs or in the rat testis. The SC permeability barrier function was reflected by measuring the transepithelial resistance (TER) and the permeability of the sodium fluorescein (Na-F). The BTB integrity was detected by the permeation of biotin. A luciferase reporter assay was used to testify the potential target of miR-142-3p, lethal giant larvae 2 (Lgl2). Laser capture microdissection (LCM) was applied to acquire cell components of different stages of seminiferious tubules, followed by detection of the expression levels of miR-142-3p, TGF-ß3, and Lgl2 by qPCR. The SC barrier function was also detected as above in the presence of TGF-ß3 after Lgl2 knockdown. RESULTS: We revealed a reversion of TGF-ß3-induced BTB impairment after miR-142-3p treatment both in vitro and in vivo. Meanwhile, the activation of Cdc42 and reduction in occludin aroused by TGF-ß3 were also reversed by miR-142-3p. The predicted binding of miR-142-3p with 3'-untranslated region (3'-UTR) of Lgl2, was verified by the luciferase assay. Moreover, an increased Lgl2 level in TGF-ß3-treated SCs was found and correlated stage-specific expressions of TGF-ß3, miR-142-3p, and Lgl2 were revealed. Knockdown of Lgl2 in SCs was shown to partially antagonize the BTB disruption mediated by TGF-ß3. CONCLUSIONS: Collectively, our results suggest a resistance of miR-142-3p on the BTB impairment caused by TGF-ß3 during the seminiferous epithelial cycle by targeting Lgl2.

Aroclor1254 disrupts the blood-testis barrier by promoting endocytosis and degradation of junction proteins via p38 MAPK pathway.

The blood-testis barrier (BTB) constituted by coexisting junction apparatus between Sertoli cells (SCs) plays an important role in spermatogenesis, which is a known target of various environmental toxicants. The commercial polychlorinated biphenyls mixture, Aroclor1254, has been shown to impair male reproduction by decreasing sperm count and affecting SC metabolism. This study was designed to investigate the effects of Aroclor1254 on the BTB integrity and elucidate the underlying mechanisms. We found that Aroclor1254 treatment in rats (1 or 3 mg/kg per day for 21 consecutive days) and in primary cultured SCs (5 or 10 µg/ml for 48 h) could induce BTB disruption via p38 MAPK pathway, concurrently with increments in junction proteins (JAM-A, N-cadherin, and ß-catenin) endocytosis, and occludin ubiquitination. Either inhibition of caveolin-dependent membrane protein internalization by cholesterol oxidase or silencing E3 ubiquitine ligase Itch by small interfering RNA could partially counteract the effects of Aroclor1254 on the barrier function of cultured SCs. These results demonstrate that Aroclor1254 disrupts the BTB function by promoting the caveolin-dependent endocytosis and ubiquitine-proteasome degradation of junction proteins through the p38 MAPK pathway, which might be the potential reasons for its negative effects on spermatogenesis and male reproduction.

Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability and applicability of the fitted NPP-age relationships. These relationships were used to replace the normalized NPP-age relationship used in the original InTEC (Integrated Terrestrial Ecosystem Carbon) model, to improve the accuracy of estimated carbon balance for China's forest ecosystems. With the revised NPP-age relationship, the InTEC model simulated a larger carbon source from 1950-1980 and a larger carbon sink from 1985-2001 for China's forests than the original InTEC model did because of the modification to the age-related carbon dynamics in forests. This finding confirms the importance of considering the dynamics of NPP related to forest age in estimating regional and global terrestrial carbon budgets.