Revitalizing interface in protonic ceramic cells by acid etch.

Protonic ceramic electrochemical cells hold promise for operation below 600 °C (refs. 1,2). Although the high proton conductivity of the bulk electrolyte has been demonstrated, it cannot be fully used in electrochemical full cells because of unknown causes3. Here we show that these problems arise from poor contacts between the low-temperature processed oxygen electrode-electrolyte interface. We demonstrate that a simple acid treatment can effectively rejuvenate the high-temperature annealed electrolyte surface, resulting in reactive bonding between the oxygen electrode and the electrolyte and improved electrochemical performance and stability. This enables exceptional protonic ceramic fuel-cell performance down to 350 °C, with peak power densities of 1.6 W cm-2 at 600 °C, 650 mW cm-2 at 450 °C and 300 mW cm-2 at 350 °C, as well as stable electrolysis operations with current densities above 3.9 A cm-2 at 1.4 V and 600 °C. Our work highlights the critical role of interfacial engineering in ceramic electrochemical devices and offers new understanding and practices for sustainable energy infrastructures.

Synergistic Effects of In-Situ Exsolved Ni-Ru Bimetallic Catalyst on High-Performance and Durable Direct-Methane Solid Oxide Fuel Cells.

Direct-methane solid oxide fuel cells (CH4-SOFCs) have gained significant attention as methane, the primary component of natural gas (NG), is cheap and widely available and the natural gas infrastructures are relatively mature. However, at intermediate temperatures (e.g., 600-650 °C), current CH4-SOFCs suffer from low performance and poor durability under a low steam-to-carbon ratio (S/C ratio), which is ascribed to the Ni-based anode that is of low catalytic activity and prone to coking. Herein, with the guidance of density functional theory (DFT) studies, a highly active and coking tolerant steam methane reforming (SMR) catalyst, Sm-doped CeO2-supported Ni-Ru (SCNR), was developed. The synergy between Ni and Ru lowers the activation energy of the first C-H bond activation and promotes CHx decomposition. Additionally, Sm doping increases the oxygen vacancy concentration in CeO2, facilitating H2O adsorption and dissociation. The SCNR can therefore simultaneously activate both CH4 and H2O molecules while oxidizing the CH* and improving coking tolerance. We then applied SCNR as the CH4-SOFC anode catalytic reforming layer. A peak power density of 733 mW cm-2 was achieved at 650 °C, representing a 55% improvement compared to that of pristine CH4-SOFCs (473 mW cm-2). Moreover, long-term durability testing, with >2000 h continuous operation, was performed under almost dry methane (5% H2O). These results highlight that CH4-SOFCs with a SCNR catalytic layer can convert NG to electricity with high efficiency and resilience.

An Unbalanced Battle in Excellence: Revealing Effect of Ni/Co Occupancy on Water Splitting and Oxygen Reduction Reactions in Triple-Conducting Oxides for Protonic Ceramic Electrochemical Cells.

Porous electrodes that conduct electrons, protons, and oxygen ions with dramatically expanded catalytic active sites can replace conventional electrodes with sluggish kinetics in protonic ceramic electrochemical cells. In this work, a strategy is utilized to promote triple conduction by facilitating proton conduction in praseodymium cobaltite perovskite through engineering non-equivalent B-site Ni/Co occupancy. Surface infrared spectroscopy is used to study the dehydration behavior, which proves the existence of protons in the perovskite lattice. The proton mobility and proton stability are investigated by hydrogen/deuterium (H/D) isotope exchange and temperature-programmed desorption. It is observed that the increased nickel replacement on the B-site has a positive impact on proton defect stability, catalytic activity, and electrochemical performance. This doping strategy is demonstrated to be a promising pathway to increase catalytic activity toward the oxygen reduction and water splitting reactions. The chosen PrNi0.7 Co0.3 O3- δ oxygen electrode demonstrates excellent full-cell performance with high electrolysis current density of -1.48 A cm-2 at 1.3 V and a peak fuel-cell power density of 0.95 W cm-2 at 600 °C and also enables lower-temperature operations down to 350 °C, and superior long-term durability.

MicroRNA-146a and microRNA-146b deficiency correlates with exacerbated disease activity, and their longitude increment relates to etanercept response in psoriasis patients.

BACKGROUND: MicroRNA (miR)-146a and miR-146b regulate autoimmunity, inflammation, and keratinocytes proliferation to engage in psoriasis pathology. The current study aimed to investigate their correlation with disease risk and clinical features, and the linkage of their longitudinal changes with clinical response to etanercept in psoriasis patients. METHODS: Plasma samples were collected from 84 moderate-to-severe psoriasis patients who underwent etanercept treatment (at baseline (M0), 1 month (M1), 3 months (M3), and 6 months (M6)), 80 disease controls and 80 health controls (both after enrollment); afterward, miR-146a and miR-146b expressions were detected by RT-qPCR. Furthermore, PASI75 and PASI90 responses were assessed in psoriasis patients. RESULTS: Both miR-146a and miR-146b were decreased in psoriasis patients compared with disease controls and health controls (all p < 0.001), which also distinguished psoriasis patients from disease controls and health controls by receiver-operating characteristic analyses. Furthermore, miR-146a positively correlated with miR-146b in psoriasis patients (p < 0.001) and disease controls (p = 0.005) but not in healthy controls (p = 0.062). In psoriasis patients, miR-146a negatively related to psoriatic body surface area (p = 0.011) and PASI score (p = 0.003); miR-146b negatively linked with PASI score (p = 0.020). At M1, M3, and M6 after etanercept treatment, PASI75 response rate was 14.3%, 32.1%, and 69.0%, respectively; PASI90 response rate was 1.2%, 17.9%, and 36.9%, respectively. During etanercept treatment, both miR-146a and miR-146b elevated gradually over time and their longitude increments were associated with PASI75 response (all p < 0.001). CONCLUSION: MiR-146a and miR-146b might serve as indicators for optimizing etanercept application and improving treatment outcomes in psoriasis patients.

High-Performance Reversible Solid Oxide Cells for Powering Electric Vehicles, Long-Term Energy Storage, and CO2 Conversion.

The rapid population growth coupled with rising global energy demand underscores the crucial importance of advancing intermittent renewable energy technologies and low-emission vehicles, which will be pivotal toward carbon neutralization. Reversible solid oxide cells (RSOCs) hold significant promise as a technology for high-efficiency power generation, long-term chemical energy storage, and CO2 conversion. Herein, RSOCs were, for the first time, studied to power electric vehicles. Based on our experimental results, an ideal RSOC stack was established with reasonable assumptions. Subsequently, through analysis and comparison of important merits, such as power densities, energy densities, charging/refueling time, and fuel economy of RSOC-based electric vehicles (RSOCEVs), conventional internal combustor vehicles (ICEVs), and battery-based electric vehicles (BEVs), the advantages and prospects of RSOCEVs were highlighted. Our H2-H2O RSOCs exhibit high electrochemical performances in both fuel cell (peak power density = 1.6 W cm-2 at 750 °C) and electrolysis modes (current density = 2.0 A cm-2 at 1.3 V and 750 °C), along with durable reversible operation under a wide range of conditions. In CO-CO2, our RSOCs achieved excellent performance in fuel cell mode (peak power density = 0.68 cm-2 at 700 °C). Furthermore, a world record current density of 3.4 A cm-2 at 1.5 V and 750 °C was achieved in the CO2 electrolysis mode. Moreover, an assessment of the CO2 electrolysis efficiency was conducted, offering insights for establishing energy storage strategies and mitigating CO2 emissions. Therefore, the RSOC technology has the potential to assume a central role in a future energy system with abundant renewable power generation while mitigating the CO2 released from fossil fuels.

Direct conversion of methane to aromatics and hydrogen via a heterogeneous trimetallic synergistic catalyst.

Non-oxidative methane dehydro-aromatization reaction can co-produce hydrogen and benzene effectively on a molybdenum-zeolite based thermochemical catalyst, which is a very promising approach for natural-gas upgrading. However, the low methane conversion and aromatics selectivity and weak durability restrain the realistic application for industry. Here, a mechanism for enhancing catalysis activity on methane activation and carbon-carbon bond coupling has been found to promote conversion and selectivity simultaneously by adding platinum-bismuth alloy cluster to form a trimetallic catalyst on zeolite (Pt-Bi/Mo/ZSM-5). This bimetallic alloy cluster has synergistic interaction with molybdenum: the formed CH3* from Mo2C on the external surface of zeolite can efficiently move on for C-C coupling on the surface of Pt-Bi particle to produce C2 compounds, which are the key intermediates of oligomerization. This pathway is parallel with the catalysis on Mo inside the cage. This catalyst demonstrated 18.7% methane conversion and 69.4% benzene selectivity at 710 °C. With 95% methane/5% nitrogen feedstock, it exhibited robust stability with slow deactivation rate of 9.3% after 2 h and instant recovery of 98.6% activity after regeneration in hydrogen. The enhanced catalytic activity is strongly associated with synergistic interaction with Mo and ligand effects of alloys by extensive mechanism studies and DFT calculation.

Tri-Doped BaCeO3-BaZrO3 as a Chemically Stable Electrolyte with High Proton-Conductivity for Intermediate Temperature Solid Oxide Electrolysis Cells (SOECs).

Solid oxide electrolysis cells (SOECs) are devices that enable economically viable production of clean fuel such as hydrogen gas, which can be used in many industrial applications and serving as an energy carrier for renewable energy sources. Operation of SOEC at intermediate temperature (IT) range (400 to 600 °C) is highly attractive because many unexploited heat sources from industries can be utilized. Proton conducting SOECs based on barium-zirconium-cerate electrolytes show great potential for operating at this temperature range due to their high proton conductivity at reduced temperatures. In this study, a new tridoped BaCe0.5Zr0.2Y0.1Yb0.1Gd0.1O3-δ (BCZYYbGd) electrolyte with very high chemical stability and proton conductivity is coupled with a PrNi0.5Co0.5O3-δ steam electrode and a Ni-BCYYbGd hydrogen electrode for IT-SOEC operation. The dopants of the electrolyte were carefully designed to obtain the optimum stability and conductivity for IT-SOEC. The BCYYbGd electrolyte was stable over 200 h at 50 vol % steam in argon and at 600 °C, and a very high electrolysis current density of 2.405 A cm-2 was obtained at 600 °C and 1.6 V at 20 vol % of steam in argon. This system was also found to be highly reversible, exhibiting very high performance in SOFC mode and suggesting a potential candidate for next generation proton conducting electrolyte.

Self-sustainable protonic ceramic electrochemical cells using a triple conducting electrode for hydrogen and power production.

The protonic ceramic electrochemical cell (PCEC) is an emerging and attractive technology that converts energy between power and hydrogen using solid oxide proton conductors at intermediate temperatures. To achieve efficient electrochemical hydrogen and power production with stable operation, highly robust and durable electrodes are urgently desired to facilitate water oxidation and oxygen reduction reactions, which are the critical steps for both electrolysis and fuel cell operation, especially at reduced temperatures. In this study, a triple conducting oxide of PrNi0.5Co0.5O3-δ perovskite is developed as an oxygen electrode, presenting superior electrochemical performance at 400~600 °C. More importantly, the self-sustainable and reversible operation is successfully demonstrated by converting the generated hydrogen in electrolysis mode to electricity without any hydrogen addition. The excellent electrocatalytic activity is attributed to the considerable proton conduction, as confirmed by hydrogen permeation experiment, remarkable hydration behavior and computations.

3D Self-Architectured Steam Electrode Enabled Efficient and Durable Hydrogen Production in a Proton-Conducting Solid Oxide Electrolysis Cell at Temperatures Lower Than 600 °C.

Hydrogen production via water electrolysis using solid oxide electrolysis cells (SOECs) has attracted considerable attention because of its favorable thermodynamics and kinetics. It is considered as the most efficient and low-cost option for hydrogen production from renewable energies. By using proton-conducting electrolyte (H-SOECs), the operating temperature can be reduced from beyond 800 to 600 °C or even lower due to its higher conductivity and lower activation energy. Technical barriers associated with the conventional oxygen-ion conducting SOECs (O-SOECs), that is, hydrogen separation and electrode instability that is primarily due to the Ni oxidation at high steam concentration and delamination associated with oxygen evolution, can be remarkably mitigated. Here, a self-architectured ultraporous (SAUP) 3D steam electrode is developed for efficient H-SOECs below 600 °C. At 600 °C, the electrolysis current density reaches 2.02 A cm-2 at 1.6 V. Instead of fast degradation in most O-SOECs, performance enhancement is observed during electrolysis at an applied voltage of 1.6 V at 500 °C for over 75 h, attributed to the "bridging" effect originating from reorganization of the steam electrode. The H-SOEC with SAUP steam electrode demonstrates excellent performance, promising a new prospective for next-generation steam electrolysis at reduced temperatures.

A High-Performing Sulfur-Tolerant and Redox-Stable Layered Perovskite Anode for Direct Hydrocarbon Solid Oxide Fuel Cells.

Development of alternative ceramic oxide anode materials is a key step for direct hydrocarbon solid oxide fuel cells (SOFCs). Several lanthanide based layered perovskite-structured oxides demonstrate outstanding oxygen diffusion rate, favorable electronic conductivity, and good oxygen surface exchange kinetics, owing to A-site ordered structure in which lanthanide and alkali-earth ions occupy alternate (001) layers and oxygen vacancies are mainly located in [LnOx] planes. Here we report a nickel-free cation deficient layered perovskite, (PrBa)0.95(Fe0.9Mo0.1)2O5 + δ (PBFM), for SOFC anode, and this anode shows an outstanding performance with high resistance against both carbon build-up and sulfur poisoning in hydrocarbon fuels. At 800 °C, the layered PBFM showed high electrical conductivity of 59.2 S cm(-1) in 5% H2 and peak power densities of 1.72 and 0.54 W cm(-2) using H2 and CH4 as fuel, respectively. The cell exhibits a very stable performance under a constant current load of 1.0 A cm(-2). To our best knowledge, this is the highest performance of ceramic anodes operated in methane. In addition, the anode is structurally stable at various fuel and temperature conditions, suggesting that it is a feasible material candidate for high-performing SOFC anode.