Despite significant advances in the fabrication and applications of graphene-like materials, it remains a challenge to prepare single-layered metallic materials, which have great potential applications in physics, chemistry and material science. Here we report the fabrication of poly(vinylpyrrolidone)-supported single-layered rhodium nanosheets using a facile solvothermal method. Atomic force microscope shows that the thickness of a rhodium nanosheet is o4 Å. Electron diffraction and X-ray absorption spectroscopy measurements suggest that the rhodium nanosheets are composed of planar single-atom-layered sheets of rhodium. Density functional theory studies reveal that the single-layered Rh nanosheet involves a d-bonding framework, which stabilizes the single-layered structure together with the poly(vinylpyrrolidone) ligands. The poly(vinylpyrrolidone)-supported single-layered rhodium nanosheet represents a class of metallic two-dimensional structures that might inspire further fundamental advances in physics, chemistry and material science.

Photocatalytic reduction of CO 2 to value-added fuels is a promising route to reduce global warming and enhance energy supply. However, poor selectivity and low efficiency of catalysts are usually the limiting factor of their applicability. Herein, a photoinduction method was developed to achieve the formation of Cu single atoms on a UiO-66-NH 2 support (Cu SAs/UiO-66-NH 2 ) that could significantly boost the photoreduction of CO 2 to liquid fuels. Notably, the developed Cu SAs/UiO-66-NH 2 achieved the solar-driven conversion of CO 2 to methanol and ethanol with an evolution rate of 5.33 and 4.22 μmol h −1 g −1 , respectively. These yields were much higher than those of pristine UiO-66-NH 2 and Cu nanoparticles/UiO-66-NH 2 composites. Theoretical calculations revealed that the introduction of the Cu SAs on the UiO-66-NH 2 greatly facilitates the conversion of CO 2 to CHO* and CO* intermediates, leading to excellent selectivity toward methanol and ethanol. This study provides new insights for designing high-performance catalyst for photocatalytic reduction of CO 2 at the atomic scale.

Tungsten-based catalysts are promising candidates to generate hydrogen effectively. In this work, a single-W-atom catalyst supported on metal-organic framework (MOF)-derived N-doped carbon (W-SAC) for efficient electrochemical hydrogen evolution reaction (HER), with high activity and excellent stability is reported. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption fine structure (XAFS) spectroscopy analysis indicate the atomic dispersion of the W species, and reveal that the W N C moiety may be the favored local structure for the W species. The W-SAC exhibits a low overpotential of 85 mV at a current density of 10 mA cm and a small Tafel slope of 53 mV dec , in 0.1 m KOH solution. The HER activity of the W-SAC is almost equal to that of commercial Pt/C. Density functional theory (DFT) calculation suggests that the unique structure of the W N C moiety plays an important role in enhancing the HER performance. This work gives new insights into the investigation of efficient and practical W-based HER catalysts.

Single-atom catalysts can serve as single-atom-based enzymes (SAzymes) with multi-antioxidative activities for reactive oxygen species scavenging.

Designing highly active and robust platinum-free catalysts for hydrogen evolution reaction is of vital importance for clean energy applications yet challenging. Here we report highly active and stable cobalt-substituted ruthenium nanosheets for hydrogen evolution, in which cobalt atoms are isolated in ruthenium lattice as revealed by aberration-corrected high-resolution transmission electron microscopy and X-ray absorption fine structure measurement. Impressively, the cobalt-substituted ruthenium nanosheets only need an extremely low overpotential of 13 mV to achieve a current density of 10 mA cm−2 in 1 M KOH media and an ultralow Tafel slope of 29 mV dec−1, which exhibit top-level catalytic activity among all reported platinum-free electrocatalysts. The theoretical calculations reveal that the energy barrier of water dissociation can greatly reduce after single cobalt atom substitution, leading to its superior hydrogen evolution performance. This study provides a new insight into the development of highly efficient platinum-free hydrogen evolution catalysts.