Tremendous efforts have been devoted to preparing the ultrathin two‐dimensional (2D) transition‐metal dichalcogenides (TMDCs) and TMDCs‐based heterojunctions owing to their unique properties and great potential applications in next generation electronics and optoelectronics over the past decade. However, to fulfill the demands for practical applications, the batch production of 2D TMDCs with high quality and large area at the mild conditions is still a challenge. This feature article reviews the state‐of‐the‐art research progresses that focus on the preparation and the applications in electronics and optoelectronics of 2D TMDCs and their van der Waals heterojunctions. First, the preparation methods including chemical and physical vapor deposition growth are comprehensively outlined. Then, recent progress on the application of fabricated 2D TMDCs‐based materials is revealed with particular attention to electronic (eg, field effect transistors and logic circuits) and optoelectronic (eg, photodetectors, photovoltaics, and light emitting diodes) devices. Finally, the challenges and future prospects are considered based on the current advance of 2D TMDCs and related heterojunctions.

No abstract

No abstract

No abstract

Electrochemical water splitting is an environmentally friendly technology to store renewable but intermittent energy into hydrogen fuels. Nowadays, exploiting low‐costing, high‐performance, and robust catalysts for the electrochemical oxygen evolution reaction (OER) is essential to improve the overall efficiency of water splitting. Herein, the synthesis, structural characterization, and electrocatalytic OER performance of NiO‐NiFe2O4 nanoparticles anchored on reduced graphite oxide frameworks (NiO‐NiFe2O4/rGO) were investigated. Facile thermal annealing of the NiFe layered double hydroxide (NiFe‐LDH) precursor led to the formation of highly dispersible NiO‐NiFe2O4 nanoparticles (20–30 nm in size) across the rGO substrate with a NiO/NiFe2O4 molar ratio up to 4.42. In contrast to the nanostructured NiFe‐LDH/rGO catalyst, the NiO‐NiFe2O4/rGO nanohybrid exhibits a lower OER onset potential (Eonset=1.436 V vs. RHE), affords a smaller overpotential of 296 mV, and achieves a current density of 10 mA cm−2 with a Tafel slope of about 43 mV dec−1; these values are comparable to those of the benchmark IrO2 catalyst. The synergy between the abundant catalytically active sites through good dispersion of NiO‐NiFe2O4 across the rGO substrate and fluent electron transport arising from the rGO and NiFe2O4 components results in the outstanding electrocatalytic activity. The extremely high catalytic activity, facile synthesis, and low‐cost of the NiO‐NiFe2O4/rGO nanohybrid make it a very promising catalyst for the OER.

No abstract

No abstract

Chemical looping combustion (CLC) is a promising technology to capture CO 2 . However, the low conversion efficiency of fuel is the key challenge for the in situ gasification CLC with natural iron ore as an oxygen carrier. The reactivity of the selected 6% K 2 CO 3 -modified iron ore (6KMIO) was first determined by H 2 and CO in TGA, and an enhanced reduction reactivity of 6KMIO was confirmed. Afterward, the feasibility of 6MKIO for coal CLC was tested in a 1 kW continuous reactor. The continuous reactor could be stably operated without any tendency of agglomeration or sintering among 6KMIO particles. Compared with use of the raw iron ore, the use of 6KMIO enhanced the coal conversion and the gasification-products conversion, promoting the CO 2 capture efficiency. Furthermore, the mechanism of the catalyzed coal CLC process and the release of sulfur was explored.