Kun Rui

Bio: Kun Rui is an academic researcher from Nanjing Tech University. The author has contributed to research in topics: Lithium & Materials science. The author has an hindex of 34, co-authored 78 publications receiving 3315 citations. Previous affiliations of Kun Rui include Center for Advanced Materials & University of Wollongong.

Hybrid 2D Dual-Metal–Organic Frameworks for Enhanced Water Oxidation Catalysis

Abstract: Metal-organic frameworks (MOFs) and MOF-derived nanostructures have recently been emerging as promising catalysts for electrocatalysis applications. Herein, twodimensional (2D) MOFs nanosheets decorated with Fe-MOF nanoparticles are synthesized and evaluated as the catalysts for water oxidation catalysis in alkaline medium. A dramatic enhancement of the catalytic activity is demonstrated by introduction of electrochemically inert Fe-MOF nanoparticles onto active 2D MOFs nanosheets. In the case of active Ni-MOF nanosheets (Ni-MOF@Fe-MOF), the overpotential is 265 mV to reach a current density of 10 mA cm in 1 M KOH, which is lowered by ca. 100 mV after hybridization due to the 2D nanosheet morphology and the synergistic effect between Ni active centers and Fe species. Similar performance improvement is also successfully demonstrated in active NiCo-MOF nanosheets. More importantly, the real catalytic active species in the hybrid Ni-MOF@FeMOF catalyst are unraveled. We find that, NiO nanograins (~5 nm) are formed in situ during OER process and act as OER active centers as well as building blocks of the porous nanosheet catalysts. These findings provide new insights into understanding MOF-based catalysts for

Platinum/Nickel Bicarbonate Heterostructures towards Accelerated Hydrogen Evolution under Alkaline Conditions

Abstract: Heterostructured nanomaterials, generally have physicochemical properties that differ from those of the individual components, and thus have potential in a wide range of applications. New platinum (Pt)/nickel bicarbonate (Ni(HCO3 )2 ) heterostructures are designed for an efficient alkaline hydrogen evolution reaction (HER). Notably, the specific and mass activity of Pt in Pt/Ni(HCO3 )2 are substantially improved compared to the bare Pt nanoparticles (NPs). The Ni(HCO3 )2 provides abundant water adsorption/dissociation sites and modulate the electronic structure of Pt, which determine the elementary reaction kinetics of alkaline HER. The Ni(HCO3 )2 nanoplates offer a platform for the uniform dispersion of Pt NPs, ensuring the maximum exposure of active sites. The results demonstrate that, Ni(HCO3 )2 is an effective catalyst promoter for alkaline HER.

Low-Coordinate Iridium Oxide Confined on Graphitic Carbon Nitride for Highly Efficient Oxygen Evolution.

Abstract: Highly active and durable electrocatalysts for the oxygen evolution reaction (OER) is greatly desired. Iridium oxide/graphitic carbon nitride (IrO2 /GCN) heterostructures are designed with low-coordinate IrO2 nanoparticles (NPs) confined on superhydrophilic highly stable GCN nanosheets for efficient acidic OER. The GCN nanosheets not only ensure the homogeneous distribution and confinement of IrO2 NPs but also endows the heterostructured catalyst system with a superhydrophilic surface, which can maximize the exposure of active sites and promotes mass diffusion. The coordination number of Ir atoms is decreased owing to the strong interaction between IrO2 and GCN, leading to lattice strain and increment of electron density around Ir sites and hence modulating the attachment between the catalyst and reaction intermediates. The optimized IrO2 /GCN heterostructure delivers not only by far the highest mass activity among the reported IrO2 -based catalysts but also decent durability.

Recent Progress on Nickel-Based Oxide/(Oxy)Hydroxide Electrocatalysts for the Oxygen Evolution Reaction.

Abstract: Developing clean and sustainable energies as alternatives to fossil fuels is in strong demand within modern society. The oxygen evolution reaction (OER) is the efficiency-limiting process in plenty of key renewable energy systems, such as electrochemical water splitting and rechargeable metal-air batteries. In this regard, ongoing efforts have been devoted to seeking high-performance electrocatalysts for enhanced energy conversion efficiency. Apart from traditional precious-metal-based catalysts, nickel-based compounds are the most promising earth-abundant OER catalysts, attracting ever-increasing interest due to high activity and stability. In this review, the recent progress on nickel-based oxide and (oxy)hydroxide composites for water oxidation catalysis in terms of materials design/synthesis and electrochemical performance is summarized. Some underlying mechanisms to profoundly understand the catalytic active sites are also highlighted. In addition, the future research trends and perspectives on the development of Ni-based OER electrocatalysts are discussed.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Mn3O4-Graphene Hybrid as a High Capacity Anode Material for Lithium Ion Batteries

Abstract: We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

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.

Recent progress made in the mechanism comprehension and design of electrocatalysts for alkaline water splitting

Abstract: Alkaline water splitting is an attractive method for sustainable hydrogen production. Owing to the sluggish kinetics of alkaline water reduction and oxidation, it is crucial to understand the mechanism of the hydrogen evolution reaction/oxygen evolution reaction (HER/OER) and construct efficient electrocatalysts based on the structure–activity relationship. This review describes the fundamentals of the alkaline HER and OER, the design of noble and nonnoble HER electrocatalysts with low energy barriers, OER electrocatalysts based on binding energy, electronic structure, lattice oxygen, and surface reconstruction as well as the recent developments of bifunctional HER/OER electrocatalysts. Future perspectives towards alkaline water splitting electrocatalysts are also proposed.