Fan-Lu Meng

Nitrogen‐Doped Porous Carbon Nanosheets as Low‐Cost, High‐Performance Anode Material for Sodium‐Ion Batteries

Between the sheets: Sodium-ion batteries are an attractive, low-cost alternative to lithium-ion batteries. Nitrogen-doped porous carbon sheets are prepared by chemical activation of polypyrrole-functionalized graphene sheets. When using the sheets as anode material in sodium-ion batteries, their unique compositional and structural features result in high reversible capacity, good cycling stability, and high rate capability.

Reactive Multifunctional Template‐Induced Preparation of Fe‐N‐Doped Mesoporous Carbon Microspheres Towards Highly Efficient Electrocatalysts for Oxygen Reduction

A novel in situ replication and polymerization strategy is developed for the synthesis of Fe-N-doped mesoporous carbon microspheres (Fe-NMCSs). This material benefits from the synergy between the high catalytic activity of Fe-N-C and the fast mass transport of the mesoporous microsphere structure. Compared to commercial Pt/C catalysts, the Fe-NMCSs show a much better electrocatalytic performance in terms of higher catalytic activity, selectivity, and durability for the oxygen reduction reaction.

Electrochemical Reduction of N2 under Ambient Conditions for Artificial N2 Fixation and Renewable Energy Storage Using N2 /NH3 Cycle.

Using tetrahexahedral gold nanorods as a heterogeneous electrocatalyst, an electrocatalytic N2 reduction reaction is shown to be possible at room temperature and atmospheric pressure, with a high Faradic efficiency up to 4.02% at -0.2 V vs reversible hydrogen electrode (1.648 µg h-1 cm-2 and 0.102 µg h-1 cm-2 for NH3 and N2 H4 ·H2 O, respectively).

A Biodegradable Polydopamine‐Derived Electrode Material for High‐Capacity and Long‐Life Lithium‐Ion and Sodium‐Ion Batteries

Polydopamine (PDA), which is biodegradable and is derived from naturally occurring products, can be employed as an electrode material, wherein controllable partial oxidization plays a key role in balancing the proportion of redox-active carbonyl groups and the structural stability and conductivity. Unexpectedly, the optimized PDA derivative endows lithium-ion batteries (LIBs) or sodium-ion batteries (SIBs) with superior electrochemical performances, including high capacities (1818 mAh g(-1) for LIBs and 500 mAh g(-1) for SIBs) and good stable cyclabilities (93 % capacity retention after 580 cycles for LIBs; 100 % capacity retention after 1024 cycles for SIBs), which are much better than those of their counterparts with conventional binders.

In Situ Activating Ubiquitous Rust towards Low-Cost, Efficient, Free-Standing, and Recoverable Oxygen Evolution Electrodes

Developing effective ways to recycle rusted stainless steel and to promote the sluggish oxygen evolution reaction (OER), associated with water splitting and metal-air batteries, is important for a resource-sustainable and environment-friendly society. Herein, we propose a strategy to enable rusted stainless steel plate to be used as an abundant and low-cost OER catalyst, wherein a hydrothermal combined in situ electrochemical oxidation-reduction cycle (EORC) method is developed to mimic and expedite the corrosion process, and thus activate stainless steel into free-standing OER electrodes. Benefiting from the plentiful electrolyte-accessible Fe/(Ni) oxyhydroxides, high conductivity and mechanical stability, this electrode exhibits remarkable OER performances including low overpotential, fast kinetics, and long-term durability. The slight degradation in current after long-term use can be repaired immediately in situ by an EORC.

Recent advances in metal–nitrogen–carbon catalysts for electrochemical water splitting

The urgent need for clean and renewable energy and environmental awareness have promoted extensive research into creating a future sustainable energy supply system. Water electrolysis, considered the most promising technology for hydrogen production, has attracted much attention. A series of metal–nitrogen–carbon based heterogeneous electrocatalysts have been developed for HER and OER. Recent advances in this field are summarized here, including their structures, synthetic methods and especially highlighting the applications of several major kinds of catalysts in water splitting. Finally, the existing key challenges and research directions for enhancing performance are pointed out.

Iron-chelated hydrogel-derived bifunctional oxygen electrocatalyst for high-performance rechargeable Zn–air batteries

Efficient oxygen electrocatalysts are the key elements of numerous energy storage and conversion devices, including fuel cells and metal–air batteries. In order to realize their practical applications, highly efficient and inexpensive non-noble metal-based oxygen electrocatalysts are urgently required. Herein, we report a novel iron-chelated urea-formaldehyde resin hydrogel for the synthesis of Fe-N-C electrocatalysts. This novel hydrogel is prepared using a new instantaneous (20 s) one-step scalable strategy, which theoretically ensures the atomic-level dispersion of Fe ions in the urea-formaldehyde resin, guaranteeing the microstructural homogeneity of the electrocatalyst. Consequently, the prepared electrocatalyst exhibits higher catalytic activity and durability in the oxygen reduction (ORR) and evolution (OER) reactions than the commercial Pt/C catalyst. Furthermore, the above catalyst also shows a much better performance in rechargeable Zn–air batteries, including higher power density and better cycling stability. The developed synthetic approach opens up new avenues toward the development of sustainable active electrocatalysts for electrochemical energy devices.

Three-dimensional interconnected Ni(Fe)O x H y nanosheets on stainless steel mesh as a robust integrated oxygen evolution electrode

The development of an electrocatalyst based on abundant elements for the oxygen evolution reaction (OER) is important for water splitting associated with renewable energy sources. In this study, we develop an interconnected Ni(Fe)OxHy nanosheet array on a stainless steel mesh (SSNNi) as an integrated OER electrode, without using any polymer binder. Benefiting from the well-defined three-dimensional (3D) architecture with highly exposed surface area, intimate contact between the active species and conductive substrate improved electron and mass transport capacity, facilitated electrolyte penetration, and improved mechanical stability. The SSNNi electrode also has excellent OER performance, including low overpotential, a small Tafel slope, and long-term durability in the alkaline electrolyte, making it one of the most promising OER electrodes developed.

Integrated Cu3N porous nanowire array electrode for high-performance supercapacitors

An integrated Cu3N porous nanowire array directly grown on a Cu foam substrate is developed for the first time by simple nitridation reaction. When used in supercapacitors, benefiting from good conductivity to favor fast charge transport, one-dimensional (1D) porous structure for large specific surface area, and 3D framework for strong stability, this electrode has excellent capacitive performances, such as a high capacitance of 966.7 F g−1 and good stability during prolonged cycle measurements. When constructing an asymmetric supercapacitor opposite to active carbons, excellent performance is also achieved.

Composition-tunable synthesis of “clean” syngas via a one-step synthesis of metal-free pyridinic-N-enriched self-supported CNTs: the synergy of electrocatalyst pyrolysis temperature and potential

Exploring efficient and environmentally friendly ways for producing clean syngas is of great significance for realizing an artificial carbon cycle associated with clean and renewable energy. Herein, as a proof-of-concept experiment, we controllably synthesized syngas via electroreduction of CO2 using an integrated 3D electrode as the catalyst. An efficient electrode was synthesized in only one step and immediately used for electroreduction of CO2 to CO with a low overpotential. Moreover, pyridinic-N predominated in the synthesized N-CNTs, followed by graphitic-N, both of which were demonstrated to supply the active nitrogen defects for the CO2 conversion. Impressively, by tuning the pyrolysis temperature or applied potential, we were able to easily tailor the H2/CO ratio in the clean syngas products in a large range between 1 : 3 and 3 : 1. This ability to tailor the H2/CO ratio has important applications in industrial production.