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Author

Jian Zeng

Other affiliations: Central South University
Bio: Jian Zeng is an academic researcher from Jiangxi University of Science and Technology. The author has contributed to research in topics: Water splitting & Heterojunction. The author has an hindex of 9, co-authored 20 publications receiving 261 citations. Previous affiliations of Jian Zeng include Central South University.

Papers
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Journal ArticleDOI
06 Jan 2021-ACS Nano
TL;DR: In this paper, the authors summarized the related background knowledge, motivation and working principle toward next-generation electrochemical energy storage (or conversion) devices, including fuel cells, Zn-air batteries, Al-air battery, Li-air, LiCO2 batteries, LiS batteries, and Na-S batteries.
Abstract: Owing to the energy crisis and environmental pollution, developing efficient and robust electrochemical energy storage (or conversion) systems is urgently needed but still very challenging. Next-generation electrochemical energy storage and conversion devices, mainly including fuel cells, metal-air batteries, metal-sulfur batteries, and metal-ion batteries, have been viewed as promising candidates for future large-scale energy applications. All these systems are operated through one type of chemical conversion mechanism, which is currently limited by poor reaction kinetics. Single atom catalysts (SACs) perform maximum atom efficiency and well-defined active sites. They have been employed as electrode components to enhance the redox kinetics and adjust the interactions at the reaction interface, boosting device performance. In this Review, we briefly summarize the related background knowledge, motivation and working principle toward next-generation electrochemical energy storage (or conversion) devices, including fuel cells, Zn-air batteries, Al-air batteries, Li-air batteries, Li-CO2 batteries, Li-S batteries, and Na-S batteries. While pointing out the remaining challenges in each system, we clarify the importance of SACs to solve these development bottlenecks. Then, we further explore the working principle and current progress of SACs in various device systems. Finally, future opportunities and perspectives of SACs in next-generation electrochemical energy storage and conversion devices are discussed.

144 citations

Journal ArticleDOI
TL;DR: In this article, a comprehensive and deeper understanding of CVD-grown 2D transition metal dichalcogenides (TMDs) for use in energy-related electrocatalysis is urgently needed.
Abstract: Chemical vapor deposition (CVD) is recognized as a powerful tool to synthesize atomically thin two-dimensional (2D) nanomaterials with the merits of high quality and uniform thickness with high efficiency, controllability, and scalability. Benefitting from the intriguing electronic and chemical characteristics, 2D transition metal dichalcogenides (TMDs) have attracted increasing attention with regard to energy-related electrocatalysis, including H2 evolution, CO2 reduction, O2 reduction/evolution, I3− reduction, etc. Atomic-scale tailoring of the surface and interface of CVD-grown TMDs is critical to not only improve the electronic structure and conductivity but also understand the intrinsic nature of the active sites. Therefore, a comprehensive and deeper understanding of CVD-grown 2D TMDs for use in electrocatalysis is urgently needed. In this review, the very recent advances in surface and interface engineering strategies, such as geometric dimensional control, defect engineering, doping modification, phase transition, strain tuning, and heterostructure construction, have been highlighted. Finally, the current challenges and perspectives are discussed. This review aims to provide the profound understanding and design of atomic-scale active sites in 2D TMDs for use in energy electrocatalysis.

139 citations

Journal ArticleDOI
TL;DR: The defect-induced Z-scheme vdW heterojunction is a key for excellent photocatalytic performance compared to perfect hBN/g-C3N4 as mentioned in this paper.

57 citations

Journal ArticleDOI
TL;DR: In this paper, single atom catalysts (SACs) with isolated metal atoms dispersed on supports exhibit distinctive performances for electrocatalysis reactions, and the designable realization of well-dispersed single metal atoms is still a great challenge owing to their ease of aggregation.

55 citations

Journal ArticleDOI
TL;DR: In this article, a type-II heterojunction, C2N/MoSi2N4, is designed and systematically studied based on AIMD simulations and phonon dispersion verification, which shows sufficient thermodynamic stability.
Abstract: Very recently, an important two-dimensional material, MoSi2N4, was successfully synthesized. However, pure MoSi2N4 has some inherent shortcomings when used in photocatalytic water splitting to produce hydrogen, especially a low separation rate of photogenerated electron–hole pairs and a poor visible light response. Interestingly, we find that the MoSi2N4 can be used as a good modification material, and it can be coupled with C2N to form an efficient heterojunction photocatalyst. Here, using density functional theory, a type-II heterojunction, C2N/MoSi2N4, is designed and systematically studied. Based on AIMD simulations and phonon dispersion verification, C2N/MoSi2N4 shows sufficient thermodynamic stability. As well as its perfect interface electronic properties, its large interlayer charge transfer and good visible light response lay the foundation for its excellent photocatalytic performance. In addition, the oxidation and reduction potentials of the C2N/MoSi2N4 heterojunction not only can meet the requirements of water splitting well but can also maintain a delicate balance between oxidation and reduction reactions. More importantly, the |ΔGH*| value of the C2N/MoSi2N4 heterojunction is very close to zero, indicating great application potential in the field of photocatalytic water splitting. In brief, our research paves the way for the design of future MoSi2N4-based efficient heterojunction photocatalysts.

44 citations


Cited by
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TL;DR: In this article, a review summarizes the recent process of heterogeneous supported single atoms, nanoclusters, and nanoparticles catalysts in electrocatalytic reactions, respectively, and figures out the construct strategies and design concepts based on their strengths and weaknesses.
Abstract: Metal-based electrocatalysts with different sizes (single atoms, nanoclusters, and nanoparticles) show different catalytic behaviors for various electrocatalytic reactions. Regulating the coordination environment of active sites with precision to rationally design an efficient electrocatalyst is of great significance for boosting electrocatalytic reactions. This review summarizes the recent process of heterogeneous supported single atoms, nanoclusters, and nanoparticles catalysts in electrocatalytic reactions, respectively, and figures out the construct strategies and design concepts based on their strengths and weaknesses. Specifically, four key factors for enhancing electrocatalytic performance, including electronic structure, coordination environment, support property, and interfacial interactions are proposed to provide an overall comprehension to readers in this field. Finally, some insights into the current challenges and future opportunities of the heterogeneous supported electrocatalysts are provided.

311 citations

Journal Article
TL;DR: In this paper, the authors demonstrate a systematic control of the electronic properties of 2D-TMDs by creating mixed alloys of the intrinsically p-type WSe2 and intrinsically n-type WS2 with variable alloy compositions and show that a series of WS2xSe2-2x alloy nanosheets can be synthesized with fully tunable chemical compositions and optical properties.
Abstract: Two-dimensional (2D) layered transition metal dichalcogenides (TMDs) have recently emerged as a new class of atomically thin semiconductors for diverse electronic, optoelectronic, and valleytronic applications. To explore the full potential of these 2D semiconductors requires a precise control of their band gap and electronic properties, which represents a significant challenge in 2D material systems. Here we demonstrate a systematic control of the electronic properties of 2D-TMDs by creating mixed alloys of the intrinsically p-type WSe2 and intrinsically n-type WS2 with variable alloy compositions. We show that a series of WS2xSe2-2x alloy nanosheets can be synthesized with fully tunable chemical compositions and optical properties. Electrical transport studies using back-gated field effect transistors demonstrate that charge carrier types and threshold voltages of the alloy nanosheet transistors can be systematically tuned by adjusting the alloy composition. A highly p-type behavior is observed in selenium-rich alloy, which gradually shifts to lightly p-type, and then switches to lightly n-type characteristics with the increasing sulfur atomic ratio, and eventually evolves into highly n-doped semiconductors in sulfur-rich alloys. The synthesis of WS2xSe2-2x nanosheets with tunable optical and electronic properties represents a critical step toward rational design of 2D electronics with tailored spectral responses and device characteristics. © 2015 American Chemical Society.

184 citations

01 Sep 2016
TL;DR: Using novel porous (holey) metallic 1T phase MoS2 nanosheets synthesized by a liquid-ammonia-assisted lithiation route, this study systematically investigated the contributions of crystal structure, edges, and sulfur vacancies to the catalytic activity toward HER and revealed that the phase serves as the key role in determining the HER performance.
Abstract: Molybdenum disulfide (MoS2) is a promising nonprecious catalyst for the hydrogen evolution reaction (HER) that has been extensively studied due to its excellent performance, but the lack of understanding of the factors that impact its catalytic activity hinders further design and enhancement of MoS2-based electrocatalysts. Here, by using novel porous (holey) metallic 1T phase MoS2 nanosheets synthesized by a liquid-ammonia-assisted lithiation route, we systematically investigated the contributions of crystal structure (phase), edges, and sulfur vacancies (S-vacancies) to the catalytic activity toward HER from five representative MoS2 nanosheet samples, including 2H and 1T phase, porous 2H and 1T phase, and sulfur-compensated porous 2H phase. Superior HER catalytic activity was achieved in the porous 1T phase MoS2 nanosheets that have even more edges and S-vacancies than conventional 1T phase MoS2. A comparative study revealed that the phase serves as the key role in determining the HER performance, as 1T phase MoS2 always outperforms the corresponding 2H phase MoS2 samples, and that both edges and S-vacancies also contribute significantly to the catalytic activity in porous MoS2 samples. Then, using combined defect characterization techniques of electron spin resonance spectroscopy and positron annihilation lifetime spectroscopy to quantify the S-vacancies, the contributions of each factor were individually elucidated. This study presents new insights and opens up new avenues for designing electrocatalysts based on MoS2 or other layered materials with enhanced HER performance.

175 citations

Journal ArticleDOI
TL;DR: In this article, the authors summarized the recent exciting progress on the non-carbon-supported SACs and their applications in electrocatalytic reactions, and provided perspective insights into the current challenges and the future prospects for NCSACs.
Abstract: Single-atom site catalysts (SACs) have received considerable attention for electrocatalytic applications, owing to their maximum atom-utilization efficiency, well-identified active centers, and tunable supports. Carbon-supported SACs have been widely applied in electrocatalysis, and their progress has been intensively reviewed. Non-carbon-supported SACs have drawn ever-increasing attention recently, and are emerging as an indispensable class of SACs. This review comprehensively summarizes the recent exciting progress on the non-carbon-supported SACs and their applications in electrocatalytic reactions. Eight types of non-carbon-supported SACs are firstly categorized to show their diversity. Subsequently, the anchoring and stabilization mechanisms for each type of non-carbon-supported SACs are systematically unraveled. Furthermore, the advanced characterization techniques for identifying and monitoring the atomic structure of SACs are highlighted. Thereafter, the advances of non-carbon-supported SACs for electrochemical energy conversion are discussed, which emphasizes their applications in the hydrogen evolution reaction, the oxygen evolution reaction, the oxygen reduction reaction, the N2 reduction reaction, and the CO2 reduction reaction. Finally, perspective insights into the current challenges and the future prospects for non-carbon-supported SACs are provided.

155 citations