Qianqian Jiang

Bio: Qianqian Jiang is an academic researcher from Shenzhen University. The author has contributed to research in topics: Lithium & Spinel. The author has an hindex of 10, co-authored 15 publications receiving 1784 citations. Previous affiliations of Qianqian Jiang include Hunan University.

Plasma-Engraved Co3 O4 Nanosheets with Oxygen Vacancies and High Surface Area for the Oxygen Evolution Reaction.

Abstract: Co3O4, which is of mixed valences Co2+ and Co3+, has been extensively investigated as an efficient electrocatalyst for the oxygen evolution reaction (OER). The proper control of Co2+/Co3+ ratio in Co3O4 could lead to modifications on its electronic and thus catalytic properties. Herein, we designed an efficient Co3O4-based OER electrocatalyst by a plasma-engraving strategy, which not only produced higher surface area, but also generated oxygen vacancies on Co3O4 surface with more Co2+ formed. The increased surface area ensures the Co3O4 has more sites for OER, and generated oxygen vacancies on Co3O4 surface improve the electronic conductivity and create more active defects for OER. Compared to pristine Co3O4, the engraved Co3O4 exhibits a much higher current density and a lower onset potential. The specific activity of the plasma-engraved Co3O4 nanosheets (0.055 mA cm−2BET at 1.6 V) is 10 times higher than that of pristine Co3O4, which is contributed by the surface oxygen vacancies.

Facile Synthesis of Black Phosphorus: an Efficient Electrocatalyst for the Oxygen Evolving Reaction

Abstract: Black phosphorus (BP) as a new 2D material has attracted extensive attention because of its unique electronic, optical, and structural properties. However, the difficulties associated with BP synthesis severely hinder the further development of BP for any potential applications. On the other hand, searching for other potential applications of BP is also a big challenge. A facile strategy was developed for preparation of BP supported on Ti foil (BP-Ti) in a thin-film form. Surprisingly, the as-prepared BP shows advanced electrocatalytic activity for the oxygen evolution reaction (OER). To improve the OER activity of the electrocatalyst, BP was grown on a carbon nanotube network (BP-CNT), showing even better activity. The results demonstrate that BP can be prepared by a facile method and may be applied as an electrocatalyst.

ZIF-67-derived Co-NC@CoP-NC nanopolyhedra as an efficient bifunctional oxygen electrocatalyst

Abstract: In this work, a highly efficient bifunctional electrocatalyst, Co/CoP embedded N-doped carbon (Co-NC@CoP-NC) nanopolyhedra, was derived by the thermal pyrolysis of ZIF-67 under an Ar atmosphere and a subsequent phosphidation process. The nanopolyhedra show excellent activity and stability for both the OER and ORR, which are attributed to the production of highly stable active CoP, and the intact protection of the Co by the N-doped carbon layers.

Plasma-Assisted Sulfur Doping of LiMn2O4 for High-Performance Lithium-Ion Batteries

Abstract: Though considered as one of the most promising materials for rechargeable Li-ion batteries, spinel LiMn2O4 suffers from fast capacity fading during cycling due to the structural instability, Jahn–Teller distortion, and Mn dissolution into the electrolyte. In order to improve the electrochemical performance, in this work, we, for the first time, realize the sulfur doping by the plasma-assisted method in LiMn2O4. Physical properties of the synthesized materials LiMn2O4–xSx are measured by XRD, SEM, and EDS, which confirm that S atoms have been successfully doped into the structure of LiMn2O4 (LiMn2O4–xSx) with the high crystalline and uniform morphology. Compared to the pristine LiMn2O4 prepared by the conventional method (800 °C, 8 h), the LiMn2O4–xSx prepared by the plasma-assisted method shows superior performance with higher capacity (125.3 mAh·g–1) and significantly improved cycling stability (maintaining 97.76% of its initial discharge capacity after 60 cycles). In addition, the sulfur-doped LiMn2O4 d...

Oxygen plasma modified separator for lithium sulfur battery

Abstract: To reduce the shuttle effect of lithium sulfur (Li–S) batteries and improve the cycling stability, the surface of the commercial separator in an Li–S battery was modified by the O2 plasma treatment, which generated lots of electronegative oxygenic functional groups such as –COOH and –OH on the surface of the separator. In order to confirm the existence and the effect of the electronegative oxygenic functional groups on the modified separator, the contact angle measurement and Fourier Transform Infrared Spectrometry (FTIR) were investigated. The charge/discharge and electrochemical impedance spectroscopy (EIS) tests of the Li–S battery assembled with the normal and the O2 plasma treated separator were analyzed. The surface characterization demonstrated that the oxygenic functional groups on the surface of the separator by the plasma modification played a critical role in improving the wettability and increasing electrical insulating properties. The cycling performance of Li–S batteries with the plasma treated separator had an obvious improvement owing to the electrostatic repulsion between electronegative oxygenic functional groups on the surface of O2 plasma treated separator and electronegative polysulfide. The battery assembled with O2 plasma treated separator had a higher capacity retention (48.53%) than that of the normal separator (24.51%).

Electrocatalysis for the oxygen evolution reaction: recent development and future perspectives

Abstract: There is still an ongoing effort to search for sustainable, clean and highly efficient energy generation to satisfy the energy needs of modern society. Among various advanced technologies, electrocatalysis for the oxygen evolution reaction (OER) plays a key role and numerous new electrocatalysts have been developed to improve the efficiency of gas evolution. Along the way, enormous effort has been devoted to finding high-performance electrocatalysts, which has also stimulated the invention of new techniques to investigate the properties of materials or the fundamental mechanism of the OER. This accumulated knowledge not only establishes the foundation of the mechanism of the OER, but also points out the important criteria for a good electrocatalyst based on a variety of studies. Even though it may be difficult to include all cases, the aim of this review is to inspect the current progress and offer a comprehensive insight toward the OER. This review begins with examining the theoretical principles of electrode kinetics and some measurement criteria for achieving a fair evaluation among the catalysts. The second part of this review acquaints some materials for performing OER activity, in which the metal oxide materials build the basis of OER mechanism while non-oxide materials exhibit greatly promising performance toward overall water-splitting. Attention of this review is also paid to in situ approaches to electrocatalytic behavior during OER, and this information is crucial and can provide efficient strategies to design perfect electrocatalysts for OER. Finally, the OER mechanism from the perspective of both recent experimental and theoretical investigations is discussed, as well as probable strategies for improving OER performance with regards to future developments.

Plasma-Engraved Co3 O4 Nanosheets with Oxygen Vacancies and High Surface Area for the Oxygen Evolution Reaction.

Abstract: Co3O4, which is of mixed valences Co2+ and Co3+, has been extensively investigated as an efficient electrocatalyst for the oxygen evolution reaction (OER). The proper control of Co2+/Co3+ ratio in Co3O4 could lead to modifications on its electronic and thus catalytic properties. Herein, we designed an efficient Co3O4-based OER electrocatalyst by a plasma-engraving strategy, which not only produced higher surface area, but also generated oxygen vacancies on Co3O4 surface with more Co2+ formed. The increased surface area ensures the Co3O4 has more sites for OER, and generated oxygen vacancies on Co3O4 surface improve the electronic conductivity and create more active defects for OER. Compared to pristine Co3O4, the engraved Co3O4 exhibits a much higher current density and a lower onset potential. The specific activity of the plasma-engraved Co3O4 nanosheets (0.055 mA cm−2BET at 1.6 V) is 10 times higher than that of pristine Co3O4, which is contributed by the surface oxygen vacancies.

Emerging Two-Dimensional Nanomaterials for Electrocatalysis

Abstract: Over the past few decades, the design and development of advanced electrocatalysts for efficient energy conversion technologies have been subjects of extensive study. With the discovery of graphene, two-dimensional (2D) nanomaterials have emerged as some of the most promising candidates for heterogeneous electrocatalysts due to their unique physical, chemical, and electronic properties. Here, we review 2D-nanomaterial-based electrocatalysts for selected electrocatalytic processes. We first discuss the unique advances in 2D electrocatalysts based on different compositions and functions followed by specific design principles. Following this overview, we discuss various 2D electrocatalysts for electrocatalytic processes involved in the water cycle, carbon cycle, and nitrogen cycle from their fundamental conception to their functional application. We place a significant emphasis on different engineering strategies for 2D nanomaterials and the influence these strategies have on intrinsic material performance, ...

A review on fundamentals for designing oxygen evolution electrocatalysts

Abstract: Electricity-driven water splitting can facilitate the storage of electrical energy in the form of hydrogen gas. As a half-reaction of electricity-driven water splitting, the oxygen evolution reaction (OER) is the major bottleneck due to the sluggish kinetics of this four-electron transfer reaction. Developing low-cost and robust OER catalysts is critical to solving this efficiency problem in water splitting. The catalyst design has to be built based on the fundamental understanding of the OER mechanism and the origin of the reaction overpotential. In this article, we summarize the recent progress in understanding OER mechanisms, which include the conventional adsorbate evolution mechanism (AEM) and lattice-oxygen-mediated mechanism (LOM) from both theoretical and experimental aspects. We start with the discussion on the AEM and its linked scaling relations among various reaction intermediates. The strategies to reduce overpotential based on the AEM and its derived descriptors are then introduced. To further reduce the OER overpotential, it is necessary to break the scaling relation of HOO* and HO* intermediates in conventional AEM to go beyond the activity limitation of the volcano relationship. Strategies such as stabilization of HOO*, proton acceptor functionality, and switching the OER pathway to LOM are discussed. The remaining questions on the OER and related perspectives are also presented at the end.