• Energy Research

AbstractMixed ionic‐electronic conducting (MIEC) membranes have gained growing interest recently for various promising environmental and energy applications, such as H2and O2production, CO2reduction, O2and H2separation, CO2separation, membrane reactors for production of chemicals, cathode development for solid oxide fuel cells, solar‐driven evaporation and energy‐saving regeneration as well as electrolyzer cells for power‐to‐X technologies. The purpose of this roadmap, written by international specialists in their fields, is to present a snapshot of the state‐of‐the‐art, and provide opinions on the future challenges and opportunities in this complex multidisciplinary research field. As the fundamentals of using MIEC membranes for various applications become increasingly challenging tasks, particularly in view of the growing interdisciplinary nature of this field, a better understanding of the underlying physical and chemical processes is also crucial to enable the career advancement of the next generation of researchers. As an integrated and combined article, it is hoped that this roadmap, covering all these aspects, will be informative to support further progress in academics as well as in the industry‐oriented research toward commercialization of MIEC membranes for different applications.

This study aims to investigate the kinetic compensation effects (KCE) and gain insights into the mechanisms, during gasification of Loy Yang brown coal char with steam, in an in-situ fluidized bed gasification operation for two-particle size ranges (106–150 and 180–212 µm). The instantaneous rate of char gasification and CO, CO₂, and H₂ formation was measured by continuous monitoring of product gas composition through a quadrupole mass spectrometer. Gasification of the smaller particle size range (106–150 µm) in kinetics-controlled regime shows less importance of char-catalyzed element on the WGS reaction, as revealed by the apparent activation energy and apparent frequency factor for CO and CO₂ formation. However, the study of kinetic parameters of char consumption on gasification using coal char with larger particle sizes (180–212 µm) indicated the limitations of intraparticle diffusion. That potentially affects the CO₂ formation by catalyzed WGS through re-adsorption of CO on catalytic char surface at a higher conversion level (> 0.3) as revealed by the difference in the extent of KCE for CO and CO₂ formation. The difference in the extent of KCE for char consumption and H₂ formation for bigger particles indicates the intraparticle diffusion limitations also appear to affect the route of H₂ formation, i.e., significantly produced through adsorption on catalytical active site with less involving the carbon active sites on char surface.

Study aims to experimentally investigate the physical significance of continuously evolved kinetic parameters i.e.lnAapp and Eapp including the importance of parameters, i.e., m and c, in the kinetic compensation effect (KCE) lnAapp = mEapp + c during steam gasification of char. To gain further insights into the char gasification mechanism in the steam atmosphere, an understanding of KCE is desirable. Two low-rank coals, viz., Loy Yang brown coal and Collie sub-bituminous coal samples of particle sizes 106150 µm and 180212 µm, are selected for fluidized bed gasification. The high-sensitive, quadrupole mass spectrometer (QMS) is used to measure the product gas composition for determining the instantaneous rate of char-H₂O reactions. Results suggest that the difference in Eapp with the change in coal sample at fixed conversion level, signifies the relative condensation of residual char, whereas the respective differences in lnAapp reflects the difference in the relative proportion of active sites consumed during char gasification under the reaction controlled by the chemical reactivity of char. However, the continuous variation in Eapp with conversion in the event of char gasification of any coal sample, displays the change in the rate of surface reaction following surface desorption with conversion and the variation of lnAapp potentially presents the change in the rate of adsorption of gasifying agents with conversion. In the subsequent KCE, the slope ‘m’ shows the reactiveness of char by displaying the impact of change in the rate of surface reaction with the desorption on the rate of surface adsorption during char gasification. The degree of deviation in char reactivity due to the evolution of KCE from a foreseeable condition of having non-KCE is indicated by intercept ‘c’.

Abstract This work characterizes the hydrogen permeation fluxes of dual-phase SrCe0.9Y0.1O3-Ce0.8Sm0.2O2 (SCY-SDC) laminated membrane that contains regular and independent transport channels made of alternating films of SCY and SDC phases. Such membrane was synthesized via combined tape casting, co-pressing, and sintering route. The hydrogen flux of the dual-phase SCY-SDC laminated membrane reached 0.163 mL min−1 cm−2 at 900 °C when 100 mL min−1 of 20 vol% H2 in He and 100 mL min−1 of N2 were passed in the feed side and the permeate side, respectively. Such flux is significantly larger than the flux of the conventional SCY-SDC dual-phase membrane made by mixing SCY-SDC powder mixture and subsequent sintering at the same operation condition. The enhanced flux for the dual-phase laminated membrane relative to the conventional dual-phase membrane is attributed to the shorter diffusion paths for protons and electrons and the lower amount of the phase interfaces. The dual-phase SCY-SDC laminated membrane also displayed stable hydrogen permeation flux of around 0.15 mL min−1 cm−2 during 166-hour continuous operation at 850 °C in the presence of carbon dioxide in the permeate gas stream. Such stable performance highlights its chemical stability. Another attractive advantage of the dual-phase SCY-SDC laminated membrane lies in the minor discrepancy of the thermal expansion coefficient of SCY (α = 1.12·10−5 K−1) to that of SDC (α = 1.28·10−5 K−1) as obtained by dilatometry from room temperature to 1500 °C, which ensures its mechanical integrity during repeated thermal cycles.

Abstract Hydrogen is considered a fuel of the future due to its diversified supply and zero greenhouse gas emission. The application of advanced membrane technology for hydrogen separation within the larger hydrogen production process context can substitute the use of more expensive and energy intensive cryogenic distillation and pressure swing adsorption technologies. This review overviews the basic aspects and progresses in perovskite-based proton conducting hydrogen separation membranes. Different configurations such as symmetric, asymmetric, hollow fiber, and surface modified perovskite membranes with various compositions are discussed and summarized. The challenges and future directions of such membranes are also elaborated.

Reversible storage of carbon dioxide in dolomite using a catalyst allows viable thermal energy storage technology.

Here we report the production of novel high performance BaBi0.05Sc0.1Co0.85O3−δ (BaBiScCo) hollow fibres delivering oxygen fluxes of 11.4 ml cm−2 min−1 at 950 °C. The doping of bismuth, a highly ionic conductor, at the B-site of a barium based perovskite overcame oxygen ionic transport limitations even at temperatures as low as 600 °C.

La pandémie sans cesse croissante et les catastrophes naturelles pourraient se chevaucher spatio-temporellement pour déclencher des catastrophes composées qui perturbent la vie urbaine, y compris les mouvements humains. Dans cette étude, nous avons proposé un cadre pour des analyses fondées sur des données sur la résilience de la mobilité afin de découvrir les effets composés de la COVID-19 et des événements météorologiques extrêmes sur la reprise de la mobilité dans des villes aux contextes socio-économiques variés. Le concept de risque de suppression (SR) est introduit pour quantifier le risque relatif de réduction de la mobilité en dessous de la ligne de base pré-pandémique lorsque certaines variables s'écartent de leurs valeurs normales. En analysant les données quotidiennes sur la mobilité dans et entre 313 villes chinoises, nous avons constamment observé que les SR les plus élevés lors d'épidémies se produisaient à des températures élevées et à des niveaux de précipitations anormaux, quels que soient le type de voyage, les incidences et le moment. Plus précisément, des températures extrêmement élevées (à 35 °C) ont augmenté la SR pendant les épidémies de 12,5 % à 120 %, mais ont raccourci le temps de récupération de la mobilité. L'augmentation des précipitations (à 20 mm/jour) a ajouté des SR de 12,5 %à 300 %, avec des effets retardés reflétés dans les mouvements interurbains. Ces impacts composés, avec des réponses décalées variables, ont été aggravés dans les villes à forte densité de population et à faibles niveaux de PIB. Nos résultats fournissent des preuves quantitatives pour éclairer la conception de stratégies de préparation et de réponse pour améliorer la résilience urbaine face aux futures pandémies et catastrophes complexes. La pandemia cada vez mayor y los desastres naturales podrían superponerse espacio-temporalmente para desencadenar desastres compuestos que interrumpen la vida urbana, incluidos los movimientos humanos. En este estudio, propusimos un marco para los análisis basados en datos sobre la resiliencia de la movilidad para descubrir los efectos compuestos de la COVID-19 y los fenómenos meteorológicos extremos en la recuperación de la movilidad en ciudades con contextos socioeconómicos variados. El concepto de riesgo de supresión (RS) se introduce para cuantificar el riesgo relativo de que la movilidad se reduzca por debajo de la línea de base prepandémica cuando ciertas variables se desvían de sus valores normales. Al analizar los datos de movilidad diaria dentro y entre 313 ciudades chinas, observamos consistentemente que la RS más alta bajo brotes ocurrió a altas temperaturas y niveles de precipitación anormales, independientemente del tipo de viaje, las incidencias y el tiempo. En concreto, las temperaturas extremadamente altas (a 35 °C) aumentaron la RS durante los brotes en un 12,5%-120%, pero acortaron el tiempo de recuperación de la movilidad. El aumento de las precipitaciones (a 20 mm/día) añadió SR en un 12,5%-300%, con efectos retardados reflejados en los movimientos entre ciudades. Estos impactos compuestos, con respuestas rezagadas variables, se agravaron en ciudades con alta densidad de población y bajos niveles de PIB. Nuestros hallazgos proporcionan evidencia cuantitativa para informar el diseño de estrategias de preparación y respuesta para mejorar la resiliencia urbana frente a futuras pandemias y desastres compuestos. The ever-increasing pandemic and natural disasters might spatial-temporal overlap to trigger compound disasters that disrupt urban life, including human movements. In this study, we proposed a framework for data-driven analyses on mobility resilience to uncover the compound effects of COVID-19 and extreme weather events on mobility recovery across cities with varied socioeconomic contexts. The concept of suppression risk (SR) is introduced to quantify the relative risk of mobility being reduced below the pre-pandemic baseline when certain variables deviate from their normal values. By analysing daily mobility data within and between 313 Chinese cities, we consistently observed that the highest SR under outbreaks occurred at high temperatures and abnormal precipitation levels, regardless of the type of travel, incidences, and time. Specifically, extremely high temperatures (at 35°C) increased SR during outbreaks by 12.5%-120% but shortened the time for mobility recovery. Increased rainfall (at 20mm/day) added SRs by 12.5%-300%, with delayed effects reflected in cross-city movements. These compound impacts, with varying lagged responses, were aggravated in cities with high population density and low GDP levels. Our findings provide quantitative evidence to inform the design of preparedness and response strategies for enhancing urban resilience in the face of future pandemics and compound disasters. قد تتداخل الجائحة والكوارث الطبيعية المتزايدة باستمرار مع المكان والزمان لإحداث كوارث مركبة تعطل الحياة الحضرية، بما في ذلك التحركات البشرية. في هذه الدراسة، اقترحنا إطارًا للتحليلات القائمة على البيانات حول مرونة التنقل للكشف عن الآثار المركبة لـ COVID -19 والظواهر الجوية القاسية على تعافي التنقل عبر المدن ذات السياقات الاجتماعية والاقتصادية المتنوعة. يتم تقديم مفهوم مخاطر القمع (SR) لتحديد المخاطر النسبية لتقليل التنقل إلى ما دون خط الأساس قبل الجائحة عندما تنحرف بعض المتغيرات عن قيمها الطبيعية. من خلال تحليل بيانات التنقل اليومية داخل 313 مدينة صينية وبينها، لاحظنا باستمرار أن أعلى معدل استجابة تحت تفشي المرض حدث في درجات حرارة عالية ومستويات هطول أمطار غير طبيعية، بغض النظر عن نوع السفر والحوادث والوقت. على وجه التحديد، زادت درجات الحرارة المرتفعة للغاية (عند 35 درجة مئوية) ريال سعودي أثناء تفشي المرض بنسبة 12.5٪ -120 ٪ ولكنها قللت من وقت التعافي من التنقل. أدت زيادة هطول الأمطار (عند 20 مم/يوم) إلى زيادة معدل المقاومة بنسبة 12.5٪ -300 ٪، مع انعكاس التأثيرات المتأخرة في التحركات عبر المدن. وقد تفاقمت هذه الآثار المركبة، مع تباين الاستجابات المتأخرة، في المدن ذات الكثافة السكانية العالية ومستويات الناتج المحلي الإجمالي المنخفضة. توفر النتائج التي توصلنا إليها أدلة كمية لتوجيه تصميم استراتيجيات التأهب والاستجابة لتعزيز المرونة الحضرية في مواجهة الأوبئة والكوارث المركبة في المستقبل.