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Despite the various strategies for achieving metal–nitrogen–carbon (M–N–C) single-atom catalysts (SACs) with different microenvironments for electrochemical carbon dioxide reduction reaction (CO 2 RR), the synthesis–structure–performance correlation remains elusive due to the lack of well-controlled synthetic approaches. Here, we employed Ni nanoparticles as starting materials for the direct synthesis of nickel (Ni) SACs in one spot through harvesting the interaction between metallic Ni and N atoms in the precursor during the chemical vapor deposition growth of hierarchical N-doped graphene fibers. By combining with first-principle calculations, we found that the Ni-N configuration is closely correlated to the N contents in the precursor, in which the acetonitrile with a high N/C ratio favors the formation of Ni-N 3 , while the pyridine with a low N/C ratio is more likely to promote the evolution of Ni-N 2 . Moreover, we revealed that the presence of N favors the formation of H-terminated edge of sp 2 carbon and consequently leads to the formation of graphene fibers consisting of vertically stacked graphene flakes, instead of the traditional growth of carbon nanotubes on Ni nanoparticles. With a high capability in balancing the *COOH formation and *CO desorption, the as-prepared hierarchical N-doped graphene nanofibers with Ni-N 3 sites exhibit a superior CO 2 RR performance compared to that with Ni-N 2 and Ni-N 4 ones.

Amorphous materials with unique atomic arrangements have attracted great attention owing to their unique optical and electronic properties. In this work, amorphization of pristine WO2.72 was successfully achieved with the assistance of supercritical carbon dioxide (SC CO2). Experimental results indicate that the obtained amorphous sample has strong optical absorbance in the near-infrared (NIR) region. Furthermore, an excellent photothermal conversion efficiency (PCE) of 52.5% indicates that it enables the capture of solar energy and converts it into thermal energy efficiently.

Synergistic photocatalysis is an important concept for designing the high-efficiency catalysis for fundamental research and technical applications. In this study a well-defined synergistic photocatalysis system is realized by the 2D amorphous heterostructures (2DAHs) Ag/a-WO3-x, which are constructed by Ag nanoparticles on 2D amorphous tungsten oxide (a-WO3-x) fabricated via supercritical CO2 method. We demonstrate theoretically that the oxygen evolution reactions (OER), characterized by photocurrent response, have been dramatically improved in Ag/a-WO3-x than those of both single a-WO3-x and Ag/WO3 systems. Such an enhanced photoelectrochemical performance attributes to the superposition effect of amorphous effect catalysis and local surface plasmon resonances (LSPR) catalysis. More interestingly, the ab inito density-functional theory calculations reveal that the amorphous effect catalysis ascribes to the unique d-d tail states coupling of both Ag and W atoms in the 2DAHs. Overall, our findings not only propose the prototype of synergistic photocatalysis, but also provide a new methodology to the design of novel catalyst.

Metallic bismuth (Bi) holds great promise in efficient conversion of carbon dioxide (CO

Amorphous materials with unique atomic arrangements have attracted great attention owing to their unique optical and electronic properties. In this work, amorphization of pristine WO2.72 was successfully achieved with the assistance of supercritical carbon dioxide (SC CO2). Experimental results indicate that the obtained amorphous sample has strong optical absorbance in the near-infrared (NIR) region. Furthermore, an excellent photothermal conversion efficiency (PCE) of 52.5% indicates that it enables the capture of solar energy and converts it into thermal energy efficiently.

In this work, Au nanoparticles (NPs) grown on defective WO3-x (Au/WO3-x) show superior electrocatalytic N2 reduction activity under ambient conditions in 0.1 M KOH. At -0.2 V versus the reversible hydrogen electrode (vs. RHE), the Au/WO3-x catalyst achieves a large NH3 yield of 23.15 μg h-1 mg-1 and a high faradaic efficiency (FE) of 14.72%. Further density functional theory (DFT) calculations indicate that electron transfer between the Au nanoparticles and defective WO3-x promotes the activation of N2 molecules effectively.

Advanced two-dimensional (2D) materials with unique structural features and fascinating physicochemical properties are reviewed for diverse applications. Based on the unique properties of supercritical carbon dioxide (SC CO2), we focus on the recent progress on fabrication of advanced 2D materials and their heterostructure with the assistance of SC CO2 and further exploration of fabrication for functional nanomaterials such amorphous materials and quantum dots. Furthermore, promising features, challenges and opportunities in SC CO2-assisted fabrication techniques are discussed.