2024-02-20 2024, Volume 2 Issue 2

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  • PERSPECTIVE
    Yang Li , Suhua Wang , Xiangke Wang
    2024, 2(2): 205-219. https://doi.org/10.1002/ece2.35

    With the fast development of nuclear energy peaceful utilization, large amounts of U(VI) are not only required to be extracted from solutions for sustainable nuclear fuel supply but also inevitably released into the environment to result in pollution, which is hazardous to human health. Thereby, the selective extraction of U(VI) from aqueous solutions is crucial to U(VI) pollution treatment and also to nuclear industry sustainable development. In this minireview, we summarized the selective extraction of U(VI) from solutions by porous nanomaterials (i.e., porous carbon nanomaterials, covalent organic frameworks, metal organic frameworks, and other nanomaterials) using different techniques, that is, sorption, electrocatalysis, photocatalysis, and other strategies. The efficient high extraction ability is dependent on the properties of porous nanomaterials and the used techniques. The high surface areas, abundant active sites, and functional groups are efficient for the high sorption of U(VI), but the special functional groups such as amidoxime groups are more critical for high selective extraction. The electrocatalytic extraction is related to the active sites, especially the single atom sites, of the porous nanomaterials as electrode. The special functional groups, bandgap, electron transfer pathway and electron donor-acceptor structures of photocatalysts contribute the high photocatalytic extraction of U(VI). The interaction mechanisms are discussed from spectroscopic analysis and computational simulation at molecular level. In the end, the challenges and prospectives for the efficient extraction of U(VI) are described.

  • PERSPECTIVE
    Baisheng Nie , Liangliang Jiang , Xianfeng Liu , Bozhi Deng , Peng Liu , Hao Zhang , Suihong Song , Ke Yan , Jiansheng Zhang , Ke Liu , Zhangxin Chen , S. M. Farouq Ali
    2024, 2(2): 220-228. https://doi.org/10.1002/ece2.46

    The global shift toward cleaner energy sources, driven by carbon neutrality goals and climate change urgency, faces a paradoxical rise in coal consumption despite efforts to expand alternative energies. Economic disparities drive reliance on coal, particularly in underdeveloped regions where affordability and accessibility dictate energy choices. To address this, innovative approaches such as harnessing controlled pulverized coal detonation for in situ clean power plants are proposed. These plants offer compact, efficient, and sustainable energy generation with reduced emissions and minimal environmental impact. In addition, a comparison of costs, efficiency, and environmental impact with conventional methods showcases the potential of this novel technology to transform coal-based energy into a green and viable solution.

  • REVIEW
    Li An , Zhaoyan Zhang , Guohua Liu , Wenning Liu , Yajie Fu , Dan Qu , Yichang Liu , Pu Hu , Zaicheng Sun
    2024, 2(2): 229-257. https://doi.org/10.1002/ece2.39

    As one of the world’s largest chemical products, ammonia (NH3) plays a vital role in the industry, agricultural production, and national defense. In modern industry, NH3 is produced primarily through the high-temperature highpressure Haber-Bosch process, which consumes large amounts of energy and releases large amounts of greenhouse gases. Electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions has been widely considered among many nitrogen fixation methods, which can be produced using renewable energy. However, the main challenge is to achieve both high NH3 yield and Faraday efficiency, which is attributed to the strong N ≡ N bond and serious hydrogen evolution reaction. Based on the key problems, this review discussed the transition metal (TM) catalysts, including alloys, TM oxides, TM sulfides, TM carbides, and strategies for tuning the electronic structure, regulating the morphology, and bimetallic synergistic effect on improving the NRR performance. Moreover, this review also summarized the NH3 detection methods and the reliable control experimental parameters in the NRR process to obtain accurate experimental results. Finally, the challenges and future directions of TM catalysts for NRR are considered, emphasizing the available opportunities by following the giving principles.

  • RESEARCH ARTICLE
    Yi Tan , Yijin Zhao , Xiaokang Chen , Shengliang Zhai , Xiao Wang , Le Su , Hongyan Yang , Wei-Qiao Deng , Ghim Wei Ho , Hao Wu
    2024, 2(2): 258-267. https://doi.org/10.1002/ece2.33

    The electroreduction of nitrate (NO3RR) to ammonia (NH3) provides a promising solution to enable environmental remediation caused by NO3containing waste and also allows for energy-saving NH3 generation. Adsorption of *NO2 intermediate may be strengthened to decrease byproducts (e.g., NO2) and favor the eight-electron NO3RR into NH3. In this work, copperincorporated O-vacancy containing Ti3C2 MXene (Cu@Ti3C2Ov) is reported, which cooperatively inhibits NO2 production and facilitates hydrogenation, leading to approximately 100% Faradaic efficiencies of NH3 and high yield rates at various potentials. Density functional theory calculations show that NO3 and the *NO2 intermediates have a significant interaction with the Cu@Ti3C2Ov catalyst. Moreover, the formation of NO2 has a high energy barrier, which explains the appealing catalytic performance of the Cu@Ti3C2Ov toward NO3RR with suppressed NO2 and elevated NH3 selectivity. This work would motivate the prudent design of new catalysts for highperformance NO3RR to NH3 by elucidating the significance of stabilizing the *NO2 intermediate.

  • RESEARCH ARTICLE
    Qingdong Ruan , Dan Li , Chaoling Wu , Chao Huang , Paul K. Chu
    2024, 2(2): 268-277. https://doi.org/10.1002/ece2.36

    The rational design of electronic and vacancy structures is crucial to regulating and enhancing electrocatalytic water splitting. However, creating novel vacancies and precisely controlling the number of vacancies in existing materials systems pose significant challenges. Herein, a novel approach to optimize the concentration of the CN vacancy (VCN) in the NiFe Prussian blue analog (PBA) nanocubes is designed by incorporating the H2 or O2 plasma treatment. The relationship between the VCN and catalysis is analyzed, and results show that a moderate concentration of VCN (6.5%) can enormously enhance oxygen evolution reaction (OER) activity of NiFe PBA. However, an excessive amount of VCN disrupts the crystal structure and hinders the transportation of charge carriers, consequently leading to inferior OER. Furthermore, the VCN significantly activates the activity of Fe sites, inducing preferential adsorption of OH on Fe sites, followed by adsorption on Ni sites, thereby optimizing the reaction pathway and significantly promoting OER performance. In addition, VCN also suppresses Fe leaching, giving the catalyst excellent durability. This study reveals the feasibility of creating unconventional defects in nanomaterials and precisely controlling the number of vacancies for diverse catalytic and energy applications.

  • RESEARCH ARTICLE
    Pooran Koli , Rajendra Kumar , Yashodhara Dayma , Dheerata , Meenakshi Jonwal
    2024, 2(2): 278-298. https://doi.org/10.1002/ece2.37

    An optimization, photo-stability, and hysteresis property of the Graphite counter electrode-modified Tropaeolin-O (TPO) photo-sensitized photogalvanic (PG) cells has been investigated. A complex H-shaped cell design, a costly and delicate saturated calomel electrode (counter electrode), and a heavy sensitizer molecule (dye having high molecular weight, low diffusivity, and low photo-stability) have been exploited for fabricating most of the PG cells so far. All these factors are not suitable for the fabrication of durable and cheap PG cells. Therefore, in the present study, the highly conductive/catalytically active robust graphite electrode with TPO dye photosensitizer (having a low molecular weight, higher diffusivity, and higher photo-stability) has been exploited with diffusion-friendly low cost and a simple transparent cylindrical glass tube. The cheap and robust graphite counter electrode has been exploited for optimization and long-term study of the TPO photo-sensitized PG cells. The observed electrical output is potential 676 mV, current 2000 µA, and power 340.0 µW. The power, current, and efficiency, have been found quite independent of the illumination window size. The potential and current have been observed to be quite stable over a long time during illumination, and the same has been supported by the hysteresis study.

  • RESEARCH ARTICLE
    Yu Wu , Fei Ma , Ziheng Zhang , Daiqian Chen , Hesheng Yu , Xiaojuan Zhang , Fei Ding , Lin Zhang , Yuanfu Chen
    2024, 2(2): 299-310. https://doi.org/10.1002/ece2.38

    Lithium metal batteries (LMBs) are recognized to be crucial for secondary battery technology targeting electric vehicles and portable electronic devices. However, the undesirable growth of lithium dendrites would result in reduced capacity, short-circuit, and overheating, seriously hindering the practical applications of LMBs. To address this issue, a neoteric lithiophilic interlayer on a commercial polypropylene separator is presented for the first time, which is constructed by amorphous CoB nanoparticles decorated reduced graphene oxide nanosheets (CoB@rGO). Density Functional Theory calculations and experimental analysis reveal remarkable lithiophilicity features for CoB@rGO and provide multiple Li deposition sites and improved electrolyte wettability, which facilitates the formation of durable solid electrolyte interphase (SEI), reduces side reactions, and improves Li+ flux regulation for long-term cycling stability in LMBs. Taking advantage of these merits, the symmetric Li//Li cell with CoB@rGO/PP separator exhibits stable cycling for up to 1600 h at 1 mA cm−2 with 1 mAh cm−2. Employed with CoB@rGO separator, the Li//LiFePO4 full cell with a high LiFePO4 loading of 11 mg cm−2 delivers a high initial specific capacity of 115.3 mAh g−1 and a low decay rate of 0.08% per cycle after 200 cycles even at a high rate of 2C.

  • RESEARCH ARTICLE
    Dongdong Li , Yue He , Bin Chen , Jun Xu , Qingyi Liu , Shengchen Yang , Wen-Yong Lai
    2024, 2(2): 311-321. https://doi.org/10.1002/ece2.40

    Lithium metal is an attractive anode candidate to enable high-energy lithium battery systems. However, nonideal dendrite growth at the anode/separator interface hinders the safe application of lithium metal batteries (LMBs). Three-dimensional (3D) current collectors (CCs) with high specific surface area could afford a crucial effect on suppressing dendrites, yet still subject to large thickness/weight and limited scalability for large-area fabrication. Here, we show an industry-compatible screenprinting technique to prepare ultrathin (∼1.5 µm) and ultralight (∼0.54 mg cm-2) Cu mesh on commercial Cu foil to realize a long-term safety of LMBs. In contrast to conventional laboratory level techniques, the screen-printed Cu-mesh CCs (∼8.3 mg cm-2), which are even lighter than the original Cu foil (∼8.84 mg cm-2), show a high compatibility for large-area fabrication. Meanwhile, the periodic Cu mesh can be also used to regulate the homogeneous distribution of Li-ion flux and thus, be in favor of realizing self-smoothing anodes at even deep and fast plating/ stripping of lithium. The resulting lithium anodes demonstrate a long-term cyclic life of ∼840 h at 1 mA cm-2 with a high Coulombic efficiency of 97.5%. LMBs with Cu-mesh CCs exhibit outstanding capacity retentions of ∼87% after 350 cycles at 1 C and ∼80% after 200 cycles at 5 C, suggesting a significant step of printable 3D CCs toward practical application of high-energy LMBs.

  • RESEARCH ARTICLE
    Shao-Yu Yuan , Tian-Tian Li , Jun-Yuan Cui , Jian-Kun Sun , Yan-Shang Gong , Artur Braun , Hong Liu , Jian-Jun Wang
    2024, 2(2): 322-335. https://doi.org/10.1002/ece2.41

    Photoelectrochemical (PEC) water splitting offers a promising route for harnessing solar energy to produce clean hydrogen fuel sustainably. A major hurdle has been boosting the performance of photoanode materials within acidic electrolytes—a critical aspect for advancing PEC technology. In response to this challenge, we report a method to augment the efficacy of hematite photoanodes under acidic conditions by anchoring IrOx nanoparticles, replete with hydroxyl groups, onto their surface. A remarkable and steady photocurrent density of 1.71 mA cm−2 at 1.23 V versus RHE was achieved, marking a significant leap in PEC efficiency of hematite in acidic media. The introduction of the IrOx layer notably expanded the electrochemically active surface area for more active sites, fostering improved charge separation and transfer. It also served as an effective hole capture layer, drawing photogenerated holes from hematite to facilitate swift migration to the active sites for the water oxidation process. This advancement has the potential to fully harness the capabilities of hematite photoanodes in acidic environments, thereby smoothing the path toward more effective and sustainable hydrogen production through PEC water splitting.