Yaqiong Gong

Bio: Yaqiong Gong is an academic researcher from North University of China. The author has contributed to research in topics: Electrocatalyst & Overpotential. The author has an hindex of 16, co-authored 40 publications receiving 858 citations. Previous affiliations of Yaqiong Gong include Northeast Normal University & Nanjing University.

Controlled synthesis of Ni(OH)2/Ni3S2 hybrid nanosheet arrays as highly active and stable electrocatalysts for water splitting

Abstract: The efficiency and stability of electrocatalysts are the key factors influencing the process of overall water splitting. In the research reported in this paper, the universal two-step method of co-precipitation and sulfuration is used to directly grow hierarchical nickel(II) hydroxide/trinickel disulfide [Ni(OH)2/Ni3S2] hybrid on nickel foam. The results show that the Ni(OH)2/Ni3S2-12h material used as the three-dimensional (3D) substrate electrode can maximize the synergy between the Ni(OH)2 and Ni3S2, and it also exhibits high efficiency and persistent stability of the oxygen evolution reaction. The lower overpotential of only 270 mV at 20 mA cm−2 compared to the benchmark of iridium(IV) oxide electrodes (300 mV of overpotential at 20 mA cm−2) benefited from the particular hybrid structure of Ni(OH)2/Ni3S2-12h with large voids and volume and rapid charge transfer. In addition, the Ni(OH)2/Ni3S2-12h material also shows a remarkable improved hydrogen evolution reaction activity compared to that of Ni(OH)2, Ni(OH)2/Ni3S2-9h and Ni(OH)2/Ni3S2-15h individual catalysts, with which a low overpotential of only 211 mV is achieved at 20 mA cm−2. Remarkably, Ni(OH)2/Ni3S2-12h is used as a bifunctional water splitting catalyst, with which an overpotential of ∼340 mV is acquired at a very low cell voltage of 1.57 V with 10 mA cm−2 in 1.0 M potassium hydroxide. These results demonstrate that most hydroxide/sulfide-based materials can be used as a electrocatalyst candidate and provide a superior synergy strategy, which provides a new way for robust water splitting electrochemical fabrication of high-performance and inexpensive electrode materials.

Hierarchical heterostructure NiCo2O4@CoMoO4/NF as an efficient bifunctional electrocatalyst for overall water splitting

Abstract: The design of efficient and economical noble-metal-free bifunctional electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is needed to fulfil the promise of hydrogen production technologies through overall water splitting. Herein, hierarchical NiCo2O4@CoMoO4 on Ni foam (NF) was synthesized via a facile two-step method which involved hydrothermal and calcination processes. In addition, to explore the mechanism for the growth of hierarchical NiCo2O4@CoMoO4/NF nanostructures, variable time-dependent experiments were carried out. The results showed that the optimal NiCo2O4@CoMoO4/NF-7 electrode exhibits superior electrocatalytic performance and excellent durability for OER, HER and overall water splitting, which presents a low overpotential of 265 mV at a current density of 20 mA cm−2 for OER and 121 mV at a current density of 10 mA cm−2 for HER in 1.0 M KOH. Meanwhile, when used as an electrocatalyst electrode for overall water splitting, NiCo2O4@CoMoO4/NF-7 shows a quite low cell voltage of 1.55 V at 10 mA cm−2, and long-term durability during a 12 h stability test at a current density of 10 mA cm−2 in 1.0 M KOH. The study demonstrates that synergistic effects between NiCo2O4 and CoMoO4 in NiCo2O4@CoMoO4/NF heterostructures can effectively enhance electrochemical performance and provides a wide range of possibilities for the further development of inexpensive electrode materials for overall water splitting.

Hierarchical Ni3S2 nanosheets coated on Co3O4 nanoneedle arrays on 3D nickel foam as an efficient electrocatalyst for the oxygen evolution reaction

Abstract: The controlled storage and release of hydrogen are still pivotal issues for upcoming hydrogen economy due to the imminent depletion of energy from traditional sources. The synthesis of water oxidation electrocatalysts which are low-cost, earth-abundant and highly efficient is an important prerequisite for the release of hydrogen from water under mild conditions for practical applications. In this article, we have designed and investigated a 3D hybrid Co3O4@Ni3S2/NF composite via successive hydrothermal and calcination methods for the first time, in which Ni3S2 nanosheets coated on Co3O4 nanoneedle arrays with unique hierarchically porous morphology were directly grown on nickel foam. Due to the positive synergistic effect of the 1D Co3O4 nanoneedles and the 2D Ni3S2 nanosheets, the hybrid Co3O4@Ni3S2/NF composite can be considered to be an efficient oxygen evolution reaction (OER) catalyst with an overpotential of 260 mV at a current density of 20 mA cm−2 in 1.0 M KOH. The combination of Co3O4 and in situ formed α-Ni(OH)2 on the surface of Ni3S2 nanosheets during the OER resulted in dramatic electrocatalyst performance and excellent stability, providing a novel approach for the design of an effective and efficient OER electrode.

A 3D well-matched electrode pair of Ni–Co–S//Ni–Co–P nanoarrays grown on nickel foam as a high-performance electrocatalyst for water splitting

Abstract: Seeking out new methodologies to assemble low-cost, highly efficient and stable oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrocatalysts continues to be a great impetus and significant challenge for designing renewable energy systems. In this paper, brush-like Ni–Co–M (M = O, S, Se and P) samples on three-dimensional (3D) hierarchically porous nickel foams (NF) were synthesized via thermolysis, sulfuration, selenylation and phosphorization, respectively, of the Ni–Co–precursor under an Ar atmosphere. Ni–Co–S/NF demonstrated an overpotential of 270 mV@40 mA cm−2 toward the OER and Ni–Co–P/NF demonstrated one of 156 mV@10 mA cm−2 toward the HER in 1.0 M KOH electrolyte. What’s more, considering the beneficial superior activity of Ni–Co–S/NF for the OER and Ni–Co–P/NF for the HER, an electrode pairing of Ni–Co–SOER//Ni–Co–PHER was assembled for overall water splitting and the result was that only 1.57 V was needed to afford a current density of 20 mA cm−2. Ni–Co–S//Ni–Co–P also demonstrated long-term durability during a 20 h stability test without obvious deactivation in 1.0 M KOH. The novelty of choosing the highest activity catalyst for the OER and HER from Ni–Co–M (M = O, S, Se and P) to construct a well-matched electrode pair and thus enhance the overall water splitting performance presents a wide range of possibilities for the further development of earth-abundant and highly efficient electrode pairs.

State of the Art and Prospects in Metal-Organic Framework (MOF)-Based and MOF-Derived Nanocatalysis.

Abstract: Metal-organic framework (MOF) nanoparticles, also called porous coordination polymers, are a major part of nanomaterials science, and their role in catalysis is becoming central. The extraordinary variability and richness of their structures afford engineering synergies between the metal nodes, functional linkers, encapsulated substrates, or nanoparticles for multiple and selective heterogeneous interactions and activations in these MOF-based nanocatalysts. Pyrolysis of MOF-nanoparticle composites forms highly porous N- or P-doped graphitized MOF-derived nanomaterials that are increasingly used as efficient catalysts especially in electro- and photocatalysis. This review first briefly summarizes this background of MOF nanoparticle catalysis and then comprehensively reviews the fast-growing literature reported during the last years. The major parts are catalysis of organic and molecular reactions, electrocatalysis, photocatalysis, and views of prospects. Major challenges of our society are addressed using these well-defined heterogeneous catalysts in the fields of synthesis, energy, and environment. In spite of the many achievements, enormous progress is still necessary to improve our understanding of the processes involved beyond the proof-of-concept, particularly for selective methane oxidation, hydrogen production, water splitting, CO2 reduction to methanol, nitrogen fixation, and water depollution.

Nanoarchitectonics for Transition-Metal-Sulfide-Based Electrocatalysts for Water Splitting.

Abstract: Heterogenous electrocatalysts based on transition metal sulfides (TMS) are being actively explored in renewable energy research because nanostructured forms support high intrinsic activities for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, it is described how researchers are working to improve the performance of TMS-based materials by manipulating their internal and external nanoarchitectures. A general introduction to the water-splitting reaction is initially provided to explain the most important parameters in accessing the catalytic performance of nanomaterials catalysts. Later, the general synthetic methods used to prepare TMS-based materials are explained in order to delve into the various strategies being used to achieve higher electrocatalytic performance in the HER. Complementary strategies can be used to increase the OER performance of TMS, resulting in bifunctional water-splitting electrocatalysts for both the HER and the OER. Finally, the current challenges and future opportunities of TMS materials in the context of water splitting are summarized. The aim herein is to provide insights gathered in the process of studying TMS, and describe valuable guidelines for engineering other kinds of nanomaterial catalysts for energy conversion and storage technologies.

Metal–Organic Frameworks in Heterogeneous Catalysis: Recent Progress, New Trends, and Future Perspectives

Abstract: More than 95% (in volume) of all of today’s chemical products are manufactured through catalytic processes, making research into more efficient catalytic materials a thrilling and very dynamic rese...

"Clicking" polymers or just efficient linking: What is the difference?

Abstract: The "click" trick: Many reactions are classified as click reactions even though some are limited to certain applications. Thus, there is danger that the term "click" will become meaningless over time and simply a synonym for "successful". To prevent this, the original click criteria are evaluated in this Essay specifically for the synthetic polymer field and a set of criteria are specified that distinguishes click from other efficient reactions. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.