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  • REVIEW ARTICLE
    Exploring 2D perovskite chemistry for advancing efficient and stable solar cells
    Xinyu Zhao, Jiajun Li, Jinzhan Cheng, Xuezheng Liu, Xiaoming Zhao

    Perovskite-based photovoltaic devices have garnered significant interest owing to their remarkable performance in converting light into electricity. Recently, the focus in the field of perovskite solar cells (PSCs) has shifted towards enhancing their durability over extended periods. One promising strategy is the incorporation of two-dimensional (2D) perovskites, known for their ability to enhance stability due to the large organic cations that act as a barrier against moisture. However, the broad optical bandgap and limited charge transport properties of 2D perovskites hinder their efficiency, making them less suitable as the sole light-absorbing material when compared to their three-dimensional (3D) counterparts. An innovative approach involves using 2D perovskite structures to modify the surface properties of 3D perovskite. This hybrid approach, known as 2D/3D perovskites, while enhancing their performance. Beyond solar energy applications, 2D perovskites offer a flexible platform for chemical engineering, allowing for significant adjustments to crystal and thin-film configurations, bandgaps, and charge transport properties through the different organic ligands and halide mixtures. Despite these advantages, challenges remain in integration of 2D perovskites into solar cells without compromising device stability. This review encapsulates the latest developments in 2D perovskite research, focusing on their structural, optoelectronic, and stability attributes, while delving into the challenges and future potential of these materials.

  • MINI REVIEW
    Nanomaterials-based enzymatic biofuel cells for wearable and implantable bioelectronics
    Jingyao Wang, Jiwei Ma, Hongfei Cheng

    Enzymatic biofuel cells (EBFCs), which generate electricity through electrochemical reactions between metabolites and O2/air, are considered a promising alternative power source for wearable and implantable bioelectronics. However, the main challenges facing EBFCs are the poor stability of enzymes and the low electron transfer efficiency between enzymes and electrodes. To enhance the efficiency of EBFCs, researchers have been focusing on the development of novel functional nanomaterials. This mini-review first introduces the working principles and types of EBFCs, highlighting the key roles of nanomaterials, such as enzyme immobilization and stabilization, promotion of electron transfer and catalytic activity. It then summarizes the recent advancements in their application in wearable and implantable devices. Finally, it explores future research direction and the potential of high-performance EBFCs for practical applications.

  • RESEARCH ARTICLE
    A carbon dioxide energy storage system with high-temperature graded heat storage structure: Thermodynamic intrinsic cycle construction and performance analysis
    Jiahao Hao, Pingyang Zheng, Yanchang Song, Zhentao Zhang, Junling Yang, Yunkai Yue

    Carbon dioxide energy storage (CES) is an emerging compressed gas energy storage technology which offers high energy storage efficiency, flexibility in location, and low overall costs. This study focuses on a CES system that incorporates a high-temperature graded heat storage structure, utilizing multiple heat exchange working fluids. Unlike traditional CES systems that utilize a single thermal storage at low to medium temperatures, this system significantly optimizes the heat transfer performance of the system, thereby improving its cycle efficiency. Under typical design conditions, the round-trip efficiency of the system is found to be 76.4%, with an output power of 334 kW/(kg·s‒1) per unit mass flow rate, through mathematical modeling. Performance analysis shows that increasing the total pressure ratio, reducing the heat transfer temperature difference, improving the heat exchanger efficiency, and lowering the ambient temperature can enhance cycle efficiency. Additionally, this paper proposes a universal and theoretical CES thermodynamic intrinsic cycle construction method and performance prediction evaluation method for CES systems, providing a more standardized and accurate approach for optimizing CES system design.

  • RESEARCH ARTICLE
    Gas-particle flow and rapid load-up characteristics of a novel deep peak regulation burner
    Chunchao Huang, Zhengqi Li, Yue Lu, Huacai Liu, Zhichao Chen, Xiangjun Long

    Existing swirling combustion technology, which relies on faulty coal, is unable to meet deep peak shaving demands without auxiliary methods. This paper developed a deep peak regulation burner (DPRB) to achieve stable combustion at 15%–30% of the boiler’s rated load without auxiliary support. Gas-particle tests, industrial trials, and transient numerical simulations were conducted to evaluate the burner’s performance. At full rated load, the DPRB formed a central recirculation zone (RZ) with a length of 1.5d and a diameter of 0.58d (where d represents the outlet diameter). At 40%, 20%, and 15% rated loads, the RZ became annular, with diameters of 0.30d, 0.40d, and 0.39d, respectively, with a length of 1.0d. At 20% and 15% rated loads, the recirculation peak and the range of particle volume flux were comparable to those at 40% rated load. The prototype burner demonstrated that, without oil support, the gas temperature within 0 to 1.8 m from the primary air outlet remained below 609 °C, insufficient to ignite faulty coal. As the load rate increased from 20% to 30%, the prototype’s central region temperature remained low, with a maximum of 750 °C between 0 and 2.0 m. In contrast, the DPRB’s central region temperature reached 750 °C at around 0.65–0.70 m. At a 3%·min‒1 load-up rate, when the load increased from 20% to 30%, the prototype burner extinguished after 30 s. However, the DPRB maintained stable combustion throughout the process.

  • NEWS
    Intramolecular junction for methane photooxidation to ethanol
    Li Li, Yongfu Sun
  • RESEARCH ARTICLE
    Bird skeleton-inspired 3D hollow diamond-enhanced PEG composite PCM for photothermal conversion and thermal management
    Zihao Zhao, Xurui Feng, Daili Feng, Chengming Li, Yanhui Feng, Junjun Wei

    The use of porous skeletons for encapsulating phase change materials (PCMs) is an effective approach to addressing issues such as leakage, low thermal conductivity, and poor photothermal conversion efficiency. Inspired by the hollow skeletal structure found in birds in nature, high-quality 3D interconnected hollow diamond foam (HDF) was fabricated using a series of processes, including microwave plasma chemical vapor deposition (CVD), laser perforation, and acid immersion. This HDF was then used as a scaffold to encapsulate PEG2000. The results demonstrate that HDF significantly reduces the supercooling degree and latent heat discrepancy of PEG2000. Compared to pure PEG2000, the thermal conductivity of the HDF/PEG increased by 378%, while its latent heat reached 111.48 J/g, accompanied by a photothermal conversion efficiency of up to 86.68%. The significant performance improvement is mainly attributed to the combination of the excellent properties of the diamond with the inherent advantages of the 3D interconnected structure in HDF, which creates a high-conductivity transport network inside. Moreover, the HDF/PEG composite extends the temperature cycling time of electronic components by 4 times for heating and 2.3 times for cooling, thereby prolonging the operational lifetime of electronic devices. HDF/PEG offers an integrated solution for solar energy collection, photothermal conversion, heat dissipation in electronic components, and thermal energy transfer/storage. This innovative approach provides innovative ideas for the design and fabrication of composite PCMs and has great application potential, such as solar energy utilization, thermal management, and thermal energy storage.

  • RESEARCH ARTICLE
    Performance evaluation and optimization of a novel compressed CO2 energy storage system based on gas–liquid phase change and cold-electricity cogeneration
    Ding Wang, Jiahua Wu, Shizhen Liu, Dongbo Shi, Yonghui Xie

    Compressed CO2 energy storage (CCES) system has received widespread attention due to its superior performance. This paper proposes a novel CCES concept based on gas–liquid phase change and cold-electricity cogeneration. Thermodynamic and exergoeconomic analyses are performed under simulation conditions, followed by an investigation of the impacts of various decision parameters on the proposed system. Next, a multi-objective optimization is conducted with the total energy efficiency and total product unit cost as the objective functions. Finally, brief comparisons are made between the proposed system and existing systems. The results indicate that the total energy efficiency of the proposed system reaches 79.21% under the given simulation conditions, outperforming the electrical efficiency of 61.27%. Additionally, the total product unit cost of the system is 25.61 /GJ.Akeycomponent,T1,playsanimportantroleduetoitslargeexergydestructionrate(1.0591MW)andtotalinvestmentcostrate(154.85/h). Despite this, the exergoeconomic factors of T1 is only 41.08%, indicating that investing in T1 to improve the efficiency is practicable. The analysis shows that a lower CO2 condensation temperature benefits the proposed system performance. While improving the isentropic efficiencies of the compressors and turbines enhances total energy efficiency, excessive isentropic efficiencies can lead to a significant increase in total product unit cost. Through multi-objective optimization, an optimal favorable operating condition is identified, yielding a compromise result with a total energy efficiency of 111.91% and a total product unit cost of 28.35 $/GJ. The proposed CCES system efficiently delivers both power and cooling energy, demonstrating clear superiorities over previous systems.

  • RESEARCH ARTICLE
    Bifunctional Pt/TiO2-Ov catalysts for enhanced electron transfer and CO tolerance in acidic HOR and ORR
    Bianyong Lian, Jinghong Chen, Lingfei Li, Shuqi Deng, Kaili Wang, Wei Yan, Jiujun Zhang

    The development of anti-corrosion and anti-poison electrocatalysts for both the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) is of great importance for effective applications of proton exchange membrane fuel cells (PEMFCs). In this study, a non-carbon supported catalyst, Pt/TiO2-Ov, enriched with oxygen vacancies (Ov), is successfully synthesized using a microwave-assisted method. This catalyst is developed as a bifunctional electrocatalyst with superior contamination tolerance, enabling efficient HOR and ORR performance. The electronic metal-support interaction (EMSI) is leveraged to facilitate electron transfer between Pt and Ti atoms, induced by the formation of oxygen vacancy channels in the small-sized, high surface area TiO2-Ov support. Notably, TiO2-Ov has a lower bandgap than commercial TiO2, enhancing its catalytic properties. In a 0.1 mol/L HClO4 electrolyte, the normalized Pt mass activity (jk,m) and specific activity (j0,s) of Pt/TiO2-Ov are 1.24 times higher than those of commercial Pt/C. Furthermore, Pt/TiO2-Ov catalyst exhibits minimal current density decay after a prolonged durability testing under hydrogen and oxygen atmospheres. Remarkably, under a H2/(1000×10–6) CO atmosphere, the relative retention rate of Pt/TiO2-Ov significantly exceeds that of Pt/C catalyst, demonstrating its superior CO tolerance and promising potential for practical applications in PEMFCs. This study highlights the critical role of the strong metal-support interaction between the reducible oxide support and the noble metal Pt in improving long-term performance and CO poisoning resistance.

  • RESEARCH ARTICLE
    In situ construction of Cs3Bi2I9/WO3 0D/1D Z-scheme heterojunction photocatalyst for photochemical CO2 reduction under visible light
    Yan Ding, Yihao Zhang, Fei Zhang, Pei Tian, Yiduo Wang, Shaohua Shen, Jinjia Wei, Jie Chen

    The photocatalytic efficiency of lead-free Bi-based halide perovskites, such as Cs3Bi2X9 (X = Br, I) for CO2 reduction is often hindered by self-aggregation and insufficient oxidation ability. In this work, a visible-light-driven (λ > 420 nm) Z-scheme heterojunction photocatalyst composed of 0D Cs3Bi2I9 nanoparticles on 1D WO3 nanorods for photocatalytic CO2 reduction and water oxidation is synthesized using an in situ growing approach. The resulting 0D/1D Cs3Bi2I9/WO3 Z-scheme heterojunction photocatalyst exhibits a visible-light-driven photocatalytic CO2 reduction performance for selective CO production, achieving a selectivity of 98.7% and a high rate of 16.5 μmol/(g·h), approximately three times that of pristine Cs3Bi2I9. Furthermore, it demonstrates decent stability in the gas-solid photocatalytic CO2 reduction system. The improved performance of Cs3Bi2I9/WO3 is attributed to the formation of the 0D/1D Z-scheme heterojunction, which facilitates charge transfer, reduces charge recombination, and maintains the active sites of both 0D Cs3Bi2I9 for CO2 reduction and 1D WO3 for water oxidation. This work provides valuable insights into the potential of morphological engineering and the design of simultaneous Z-scheme heterojunction for lead-free halide perovskites.

  • RESEARCH ARTICLE
    Recent trends in CO2 reduction through various catalytic methods to achieve carbon-neutral goals: A comprehensive bibliometric analysis
    Xuxu Guo, Hangrang Zhang, Yang Su, Yingtang Zhou

    The extensive utilization of fossil fuels has led to a significant increase in carbon dioxide (CO2) emissions, contributing to global warming and environmental pollution, which pose major threats to human survival. To mitigate these effects, many researchers are actively employing state-of-the-art technologies to convert CO2 into valuable chemicals and fuels, thereby supporting sustainable development. However, few studies have employed bibliometric methods to systematically analyze research trends in CO2 reduction reaction (CO2RR), resulting in limited macroscopic insights into this field. This study aims to conduct a scientometric analysis of academic literature on electrocatalytic, photocatalytic, and thermocatalytic CO2RR from 2015 to 2023. Utilizing bibliometric analysis tools Citespace, Bibliometrix, and Vosviewer for data visualization, it establishes a knowledge framework for catalytic CO2RR. The results show that China, the United States, and India are the top three countries with the highest number of published papers in this field, with China and the United States having the highest levels of collaboration. The journal Applied Catalysis B-Environmental published the most articles and received the highest citation count, with 3.4% of the articles in this field appearing in the journal and a total of 62526 citations. Keyword analysis revealed that terms like “CO2RR,” “CO2,” “conversion,” and “reduction” are the most frequently occurring, indicating key areas of focus. Additionally, “selectivity” and “heterojunction” emerged as prominent research hotspots. The discussion section highlights the current challenges in the field and proposes potential strategies to address these obstacles, providing valuable insights for research in the field of catalytic CO2RR.