• Energy Research

AbstractIn recent years, the development of photocatalysts based on noncovalent strategies has shown an important role in medical and organic materials. Herein, an organic fluorescent dye benzothiazole derivative (2‐(N,N‐diethylanilin‐4‐yl)‐4,6‐bis(3‐methylpyrazol‐1‐yl)‐1,3,5‐triazine [MPBT]) was designed and synthesized. It was encapsulated in the cavity of cucurbit[8]uril (CB[8]) to form a supramolecular dimer through host–guest interaction, which converted the dye into a highly efficient photocatalyst. With the formation of 2MPBT‐CB[8] supramolecular dimer, the emergence of host‐enhanced charge transfer interactions could significantly facilitate singlet to triplet through intersystem crossing. At the same time, the alternating structure of 2MPBT‐CB[8] facilitated the triplet states for further energy transfer and electron transfer. In addition, the electron transfer process with electron donor generated cationic free radical and photocatalyst negative ion free radical (), which in turn reacted with oxygen (O2) to form superoxide anion radical (). The generated could be used to catalyze the oxidative hydroxylation of aryl boronic acid. Therefore, the 2MPBT‐CB[8] had become a highly efficient photocatalyst for the oxidative hydroxylation of aryl boronic acid. This strategy of supramolecular dimerization provides a new strategy for the development of new photocatalysts based on noncovalent interactions.

The fabrication art of the membrane electrode assembly (MEA) in a proton exchange membrane (PEM) fuel cell strongly correlates to the cell performance. It has been recognized that defects, for exam...

AbstractDue to the fact that traditional heavy metal‐based catalysts toward wastewater treatment could cause the problem of secondary contamination, it is imperative to seek for more eco‐friendly catalysts to address this tricky issue. Recently, numerous novel metal‐based heterogeneous catalysts, especially perovskite oxides, have been widely investigated for the activation of peroxymonosulfate (PMS), which is significant in the removal of organic pollutants. Here, we report a novel perovskite oxide (La0.7Sr0.3)CoO3‐δ (LSC)‐based 3D ceramic hollow fiber catalyst for aqueous‐phase advanced oxidation. Through it cooperating with PMS, the methylene blue (20 ppm) can be completely degraded only about 30 minutes. The mechanism of advanced oxidation process is explored via the electron paramagnetic resonance test on the active species. In addition, it also displays high activity for the degradation of other pollutes, such as tetrabromobisphenol A and rhodamine B. This study provides a new strategy to effectively degrade contaminant via introducing 3D ceramic catalysts.image

AbstractThe electrochemical oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are fundamental processes in a range of energy conversion devices such as fuel cells and metal–air batteries. ORR and OER both have significant activation barriers, which severely limit the overall performance of energy conversion devices that utilize ORR/OER. Meanwhile, ORR is another very important electrochemical reaction involving oxygen that has been widely investigated. ORR occurs in aqueous solutions via two pathways: the direct 4-electron reduction or 2-electron reduction pathways from O2 to water (H2O) or from O2 to hydrogen peroxide (H2O2). Noble metal electrocatalysts are often used to catalyze OER and ORR, despite the fact that noble metal electrocatalysts have certain intrinsic limitations, such as low storage. Thus, it is urgent to develop more active and stable low-cost electrocatalysts, especially for severe environments (e.g., acidic media). Theoretically, an ideal oxygen electrocatalyst should provide adequate binding to oxygen species. Transition metals not belonging to the platinum group metal-based oxides are a low-cost substance that could give a d orbital for oxygen species binding. As a result, transition metal oxides are regarded as a substitute for typical precious metal oxygen electrocatalysts. However, the development of oxide catalysts for oxygen reduction and oxygen evolution reactions still faces significant challenges, e.g., catalytic activity, stability, cost, and reaction mechanism. We discuss the fundamental principles underlying the design of oxide catalysts, including the influence of crystal structure, and electronic structure on their performance. We also discuss the challenges associated with developing oxide catalysts and the potential strategies to overcome these challenges.

Dense oxygen ion–conducting ceramic membranes with CO2 resistance can promote many advanced applications such as membrane reactors for green chemical synthesis and oxy‐fuel combustion for clean energy delivery. The state‐of‐the‐art perovskite oxide membranes are characterized by their high O2 flux but low stability in a CO2‐containing atmosphere. To solve this problem, dual‐phase membranes have captured the imagination of researchers. Herein, a novel dual‐phase hollow fiber membrane with a composition of 40 wt% Ce0.9Gd0.1O2–δ (GDC)–60 wt% La2NiO4+δ (LNO) is developed via a combined phase inversion sintering process. During the high temperature treatment, La‐doping behavior is observed with La leaching out from the LNO phase and diffusing into the GDC phase. This dual phase membrane displays the O2 flux of 1.47 at 950 °C, which is reduced by 10% to 1.31 mL min−1 cm−2 when the sweep gas is switched from helium to pure CO2. Such minor O2 flux reduction is due to the strong CO2 adsorption on membrane surface occupying the O2 vacancies without permanent membrane damage, which is fully eliminated by an inert gas purge. Such a robust dual‐phase membrane exhibits the potential to overcome the low stability problem under the CO2‐containing atmosphere.

Kiln is a prime need in the ceramics industry, where energy loss is a major part which consumes about 60% production cost through thermal energy for different applications. Higher density of fired and tunnel kiln refractory material lowers the thermal diffusivity and the proper selection of fired material minimizes the energy loss along the kiln. In particular, this research analysed the results of a heat recovery system comprised of a metallic recuperator which gives around 8% energy savings in natural gas consumption. In this work, detailed power quality analysis of low-power factor motors of a tunnel kiln was carried out and a power factor improvement solution was suggested to save electrical energy with payback period of 0.8 y. The motor operating at a low-power factor consumes more reactive power which does not produce beneficial work. A low-power factor around 0.4 causes network power loss, increases in transformer loss and voltage drops. The solution with accumulative capacitance power of 148.05 uF was installed to achieve the power factor to 0.9. Flu gas analyzer was installed to monitor the range of O2 in pre-heating, oxidation, and firing zones of the kiln which should be ≥8% and 3%, respectively. Regression analysis for thermal energy consumption of a tunnel kiln is done to find the forecast thermal energy consumption. This analysis can be used to find operational efficiency, supporting decisions regarding dependent variable of thermal energy consumption and independent variable of production. This research is very helpful for the ceramics industry to mitigate the energy loss at SMEs as well as in mass production level.

Despite the abundance of carbon in nature, a significant portion of the existing biomass carbon materials in livestock, agriculture, and marine fishery industry are currently being wasted. Utilizing sustainable carbon materials as an alternative to noble Pt-based catalysts is crucial step to convert widely available and low-cost biomass resources into clean energy systems. Therefore, the rational synthesis of carbon-based catalysts for oxygen reduction reaction (ORR) has become a hot research focus in the field of electrochemistry. In this study, the recent progress in the synthesis of ORR electrocatalysts using sustainable biomass resources was reviewed; the activation and synthesis strategies of various biomass resources, as well as the microstructure and oxygen reduction performance of the prepared carbon-based catalysts were investigated. It is hoped that this review article will promote the understanding of various parameters from biomass as precursors for catalyst preparation and make contribute to the transition of biomass resources from the wasted carbon materials to the main catalysts in future energy devices.