Quasi-one-dimensional (quasi-1D) fibrous red phosphorus (RP) has triggered growing interest recently for its unique properties and promising applications in energy storage, sensing, and heterogeneous catalysis. However, attempts to explore its anisotropy and transport properties have progressed slowly. In this work, we report the fabrication of large-size and pure bulk fibrous RP crystals using a chemical vapor transport reaction by modifying growth kinetics. For the first time, the weak layer number-dependent anisotropic electronic structure of fibrous RP is revealed based on theoretical calculations. The b-axis-aligned fibrous RP nanoribbons with a high aspect ratio exceeding 1000 are easily prepared by facile liquid exfoliation. Impressively, the field-effect transistor device built with fibrous RP nanoribbons exhibits p-type transport behavior and a high mobility reaching 236.7 cm 2 V −1 s −1 with an On/Off ratio approaching 1.6 × 10 3 , which are superior to those of other reported RP-based materials in general. The results demonstrate the great potential of fibrous RP as a promising channel material and lay a solid foundation to further study the intrinsic properties of quasi-1D van der Waals materials.

Doping has been a reliable way to improve the properties of black phosphorus (BP). However, a uniform and large amount of doping in BP remains a challenge. Herein, the synthesis of tellurium-doped black phosphorus (Te-doped BP) single crystals with high crystalline quality is achieved by the chemical vapor transport reaction method. The synthetic route enables a uniform and relatively large amount (up to 0.5% atomic ratio) of Te-doping in BP single crystals. The electrocatalytic oxygen evolution reaction (OER) properties of few-layer Te-doped BP nanosheets prepared by liquid exfoliation were also investigated for the first time. Electrochemical tests demonstrated that the OER onset-potential of undoped and Te-doped BP nanosheets was 1.63 and 1.49 V, respectively. The result implies that doping provides an effective route to enhance the electrochemical OER performance of BP.

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Ammonia (NH3) is a promising clean energy carrier, provided that its production is driven by renewable energy rather than fossil fuel-based Haber–Bosch (H–B) process. Chemical looping ammonia synthesis (denoted as CLAS) can intervene in the ubiquitous scaling relations in catalytic ammonia synthesis by separately feeding reactants to a nitrogen carrier to achieve atmospheric operation, which provides an alternative synthetic route to the H-B process. The key of CLAS is to develop efficient N carrier materials with suitable thermodynamic and kinetic properties. Metal nitrides and metal imides are two kinds of N carrier materials for the CLAS process, and H2 and H2O are commonly used as the hydrogen sources of NH3. Here, we first analyze the thermodynamic properties of the reactions of various metal nitrides and imides with water or hydrogen to produce NH3, N2 fixation on metals or metal hydrides, and the regeneration of metals from metal oxides, respectively. The thermodynamic calculation results display the reduction of main group metal hydroxide, early transition metal oxides, and rare earth metal oxides to the corresponding metallic state or hydrides, the nitridation of late transition metals to the corresponding nitrides, are the thermodynamic limiting steps for the metal nitride carriers. The metal imides, such as lithium imide and barium imide, have the relatively proper thermodynamics for two-step chemical looping reactions, however, their performance is limited by the thermodynamics of hydrogenation reaction. Moreover, for the thermodynamically unfavorable steps in the CLAS, we propose potential electrochemical processes to run the loop, such as molten salt electrolytic cell and solid electrolyte electrolytic cell. Finally, we put forward some strategies, such as controllable synthesis of N carriers and adding efficient catalysts, to improve the kinetics of chemical looping reactions.