Junxiang Chen

Oxygen‐Containing Amorphous Cobalt Sulfide Porous Nanocubes as High‐Activity Electrocatalysts for the Oxygen Evolution Reaction in an Alkaline/Neutral Medium

A novel OER electrocatalyst, namely oxygen-incorporated amorphous cobalt sulfide porous nanocubes (A-CoS4.6 O0.6 PNCs), show advantages over the benchmark RuO2 catalyst in alkaline/neutral medium. Experiments combining with calculation demonstrate that the desirable O* adsorption energy, associated with the distorted CoS4.6 O0.6 octahedron structure and the oxygen doping, contribute synergistically to the outstanding electrocatalytic activity.

3D graphene network encapsulating SnO2 hollow spheres as a high-performance anode material for lithium-ion batteries

Herein, we report a reliable method for the synthesis of nanohybrids with interconnected networks of reduced graphene oxide (rGO) enwrapping hollow SnO2 nanospheres (H-SnO2@rGO), which is implemented by an electrostatic assembly process between positively charged hollow SnO2 nanospheres and negatively charged rGO. Systematic characterizations demonstrate that the as-developed H-SnO2@rGO has a unique three-dimensional (3D) nanostructure with favorable features for lithium ions storage, which not only provides robust protection against the aggregation and volume changes of the SnO2 nanospheres, but also ensures high transport kinetics for both electrons and lithium ions. The as-developed H-SnO2@rGO exhibits an outstanding electrochemical performance as an anode material for lithium-ion batteries, showing a high reversible capacity of 1107 mA h g−1 after 100 cycles at a current density of 0.1 A g−1 and maintaining 552 mA h g−1 over 500 cycles at a current density up to 1 A g−1.

A self-supported Ni–Co perselenide nanorod array as a high-activity bifunctional electrode for a hydrogen-producing hydrazine fuel cell

Although the fundamental processes of electrolytic hydrogen generation are relatively well understood, fundamental studies and explorations of the new concepts and materials for electrolysis are highly desirable to make renewable hydrogen sufficiently cost-competitive. Herein, we report a proof-of-concept for an alkaline–acid-based hydrogen generating hydrazine fuel cell by coupling the hydrazine oxidation reaction (HzOR) at the alkaline anode with the hydrogen evolution reaction (HER) at the acidic cathode. Furthermore, we verified that such a hybrid cell could simultaneously fulfill hydrogen production and electricity generation owing to harvesting of two types of electrochemical energies, i.e., electrochemical energy of the HzOR and the electrochemical neutralization energy. To this end, a bifunctional electrode comprising a three-dimensional nanoporous Ni–Co perselenide nanorod array (NixCo1−xSe) was designed and prepared by a facile two-step synthesis process, involving the initial in situ electroplating on a carbon cloth followed by subsequent selenization. The optimized electrode, i.e., Ni0.5Co0.5Se2, showed high electrocatalytic activity toward HzOR in alkaline electrolyte and HER in acidic medium. The optimized alkaline–acid hydrazine fuel cell, with the Ni0.5Co0.5Se2 electrode as both the cathode and anode, could potentially deliver a power density of 13.3 mW cm−2 at a current density of 54.7 mA cm−2 with good long-term stability and a faradaic efficiency of nearly 100% for hydrogen production.

Perfluorinated Covalent Triazine Framework Derived Hybrids for the Highly Selective Electroconversion of Carbon Dioxide into Methane

Developing cost-effective electrocatalysts for high-selectivity CO2 electroreduction remains challenging. We herein report a perfluorinated covalent triazine framework (CTF) electrocatalyst that displays very high selectivity in the electroreduction of CO2 to CH4 with a faradaic efficiency of 99.3 % in aqueous electrolyte. Systematic characterization and electrochemical studies, in combination with density functional theory calculations, demonstrate that the presence of both nitrogen and fluorine in the CTF provides a unique pathway that is inaccessible with the individual components for CO2 electroreduction.