Publications by authors named "Fanjie Xia"

The iridium oxide (IrO) catalyst for the oxygen evolution reaction used industrially (in proton exchange membrane water electrolyzers) is scarce and costly. Although ruthenium oxide (RuO) is a promising alternative, its poor stability has hindered practical application. We used well-defined extended surface models to identify that RuO undergoes structure-dependent corrosion that causes Ru dissolution.

View Article and Find Full Text PDF

The heterostructure of transition metal dichalcogenides (TMDs), such as one-dimensional (1D) nanowires embedded in two-dimensional (2D) nanosheets, has drawn much research attention due to its unique electronic, spintronic, magnetic, and catalytic properties. The general approach for preparing such a heterostructure is through electron beam lithography or annealing on the 2D template, triggering direct formation of the 1D component within the 2D matrix. However, the thermodynamic mechanism behind the transition from 2D to 1D is still not well clarified.

View Article and Find Full Text PDF

Topological defects are inevitable existence in carbon-based frameworks, but their intrinsic electrocatalytic activity and mechanism remain under-explored. Herein, the hydrogen evolution reaction (HER) of pentagonal carbon-rings is probed by constructing pentagonal ring-rich carbon (PRC), with optimized electronic structures and higher HER activity relative to common hexagonal carbon (HC). Furthermore, to improve the reactivity, we couple Ru clusters with PRC (Ru@PRC) through p-d orbital hybridization between C and Ru atoms, which drives a shortcut transfer of electrons from Ru clusters to pentagonal rings.

View Article and Find Full Text PDF

Fast-charging, non-aqueous lithium-based batteries are desired for practical applications. In this regard, LiMnO is considered an appealing positive electrode active material because of its favourable ionic diffusivity due to the presence of three-dimensional Li-ion diffusion channels. However, LiMnO exhibits inadequate rate capabilities and rapid structural degradation at high currents.

View Article and Find Full Text PDF

Developing a highly active, durable, and low-platinum-based electrocatalyst for the cathodic oxygen reduction reaction (ORR) is for breaking the bottleneck of large-scale applications of proton exchange membrane fuel cells (PEMFCs). Herein, ultrafine PtZn intermetallic nanoparticles with low Pt-loading and trace germanium (Ge) involvement confined in the nitrogen-doped porous carbon (Ge-L-PtZn@N-C) are reported. The Ge-L-PtZn@N-C exhibit superior ORR activity with a mass activity of 3.

View Article and Find Full Text PDF

Li-rich layered oxides (LLOs) are among the most promising cathode materials with high theoretical specific capacity (>250 mAh g ). However, capacity decay and voltage hysteresis due tostructural degradation during cycling impede the commercial application of LLOs. Surface engineering and element doping are two methods widely applied tomitigate the structural degradation.

View Article and Find Full Text PDF

Phase engineering of Pt-based intermetallic catalysts has been demonstrated as a promising strategy to optimize catalytic properties for a direct formic acid fuel cell. Pt-Bi intermetallic catalysts are attracting increasing interest due to their high catalytic activity, especially for inhibiting CO poisoning. However, the phase transformation and synthesis of intermetallic compounds usually occurring at high temperatures leads to a lack of control of the size and composition.

View Article and Find Full Text PDF

Overall photocatalytic conversion of CO and pure H O driven by solar irradiation into methanol provides a sustainable approach for extraterrestrial synthesis. However, few photocatalysts exhibit efficient production of CH OH. Here, BiOBr nanosheets supporting atomic Cu catalysts for CO reduction are reported.

View Article and Find Full Text PDF

Uneven distribution of electric fields at the electrolyte-anode interface and associated Zn dendrite growth is one of the most critical barriers that limit the life span of aqueous zinc-ion batteries. Herein, new-type Zn-A-O (A = Si, Ti) interface layers with thin and uniform thickness, porosity, and hydrophilicity properties are developed to realize homogeneous and smooth Zn plating. For ZnSiO nanosheet arrays on Zn foil (Zn@ZSO), their formation follows an "etching-nucleation-growth" mechanism that is confirmed by a well-designed Zn-island-based identical-location microscopy method, the geometric area of which is up to 1000 cm in one-pot synthesis based on a low-temperature wet-chemical method.

View Article and Find Full Text PDF

The design of highly active and durable catalysts for the sluggish anodic oxygen evolution reaction (OER) in acid remains an urgent yet challenging goal in water electrolysis. Herein, a core-shell nanostructured Ru@Ir-O catalyst with tensile strains and incorporated oxygens is introduced in the Ir shell that holds an extremely low OER overpotential of 238 mV at 10 mA cm in acid. The material also shows a remarkable 78-fold higher mass activity than the conventional IrO at 1.

View Article and Find Full Text PDF

BiTe-based materials are dominating thermoelectrics for almost all of the room-temperature applications. To meet the future demands, both their thermoelectric (TE) and mechanical properties need to be further improved, which are the requisite for efficient TE modules applied in areas such as reliable micro-cooling. The conventional zone melting (ZM) and powder metallurgy (PM) methods fall short in preparing BiTe-based alloys, which have both a highly textured structure for high TE properties and a fine-grained microstructure for high mechanical properties.

View Article and Find Full Text PDF

Manganese oxides are attracting great interest owing to their rich polymorphism and multiple valent states, which give rise to a wide range of applications in catalysis, capacitors, ion batteries, and so forth. Most of their functionalities are connected to transitions among the various polymorphisms and Mn valences. However, their atomic-scale dynamics is still a great challenge.

View Article and Find Full Text PDF

Collagen fibrils present periodic structures, which provide space for intrafibrillar growth of oriented hydroxyapatite nanocrystals in bone and contribute to the good mechanical properties of bone. However, there are not many reports focused on bioprocess-inspired synthesis of non-native inorganic materials inside collagen fibrils and detailed forming processes of crystals inside collagen fibrils remain poorly understood. Herein, the rapid intrafibrillar mineralization of calcium fluoride nanocrystals with a periodically patterned nanostructure is demonstrated.

View Article and Find Full Text PDF

The electronic metal-support interaction (EMSI) plays a crucial role in catalysis as it can induce electron transfer between metal and support, modulate the electronic state of the supported metal, and optimize the reduction of intermediate species. In this work, the tailoring of electronic structure of Pt single atoms supported on N-doped mesoporous hollow carbon spheres (Pt /NMHCS) via strong EMSI engineering is reported. The Pt /NMHCS composite is much more active and stable than the nanoparticle (Pt ) counterpart and commercial 20 wt% Pt/C for catalyzing the electrocatalytic hydrogen evolution reaction (HER), exhibiting a low overpotential of 40 mV at a current density of 10 mA cm , a high mass activity of 2.

View Article and Find Full Text PDF

Evaluating the alkaline water electrolysis (AWE) at 50-80 °C required in industry can veritably promote practical applications. Here, the thermally induced complete reconstruction (TICR) of molybdate oxygen evolution reaction (OER) pre-catalysts at 51.9 °C and its fundamental mechanism are uncovered.

View Article and Find Full Text PDF

Li-Se battery is a promising energy storage candidate owing to its high theoretical volumetric capacity and safe operating condition. In this work, for the first time, we report using the whole organic Melamine-based porous polymer networks (MPNs) as a precursor to synthesize a N, O, S co-doped hierarchically porous carbon nanobelts (HPCNBs) for both Li-ion and Li-Se battery. The N, O, S co-doping resulting in the defect-rich HPCNBs provides fast transport channels for electrolyte, electrons and ions, but also effectively relieve volume change.

View Article and Find Full Text PDF

The release of the lattice oxygen due to the thermal degradation of layered lithium transition metal oxides is one of the major safety concerns in Li-ion batteries. The oxygen release is generally attributed to the phase transitions from the layered structure to spinel and rocksalt structures that contain less lattice oxygen. Here, a different degradation pathway in LiCoO is found, through oxygen vacancy facilitated cation migration and reduction.

View Article and Find Full Text PDF

MXenes are a group of two-dimensional transition metal carbides/nitrides that have been widely used for many useful applications such as energy storage, catalysis and sensors. For large scale applications of MXenes, the ambient stability is a critical issue. However, the detailed degradation mechanism of MXenes remains largely unclear.

View Article and Find Full Text PDF