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Regulating intermediates through elaborate catalyst design to control the reaction direction is crucial for promoting the selectivity of electrocatalytic CO2‐to‐CH4. M−C (M=metal) bonds are particularly important for tuning the multi‐electron reaction; however, its construction in nanomaterials is challenging. Here, via rational design of in situ anchoring of Cu SAs (single atoms) on the unique platform graphdiyne, we firstly realize the construction of a chemical bond Cu−C (GDY). In situ Raman spectroelectrochemistry and DFT calculations confirm that due to the fabrication of the Cu−C bond, during CO2 reduction, the formation of *OCHO intermediates is dominant rather than *COOH on Cu atoms, facilitating the formation of CH4. Therefore, we find that constructing the Cu−C bond in Cu SAs/GDY can supply an efficient charge transfer channel, but most importantly control the reaction intermediates and guide a more facile reaction pathway to CH4, thereby significantly boosting its catalytic performance. This work provides new insights on enhancing the selectivity for CO2RR at the atomic level.

As the first experimentally confirmed ferroelectric metal, LiOsO3 has received extensive research attention recently. Using density-functional calculations, we perform a systematic study on the origin of the metallic ferroelectricity in LiOsO3. We confirm that the ferroelectric transition in this compound is order-disorder like. In addition, we find that the distribution of the conduction electron is extremely anisotropic, which suggests that the electric screening ability is also highly anisotropic. Then, by doing electron screening analysis, we unambiguously demonstrate that the long range ferroelectric order in LiOsO3 results from the incomplete screening of the dipole-dipole interaction along the nearest neighboring Li-Li chain direction. We therefore conclude highly anisotropic screening and local dipole-dipole interactions are two most important keys to form LiOsO3-type metallic ferroelectricity. 72.80.Ga, 61.50.Ah The ferroelectric (FE) instability can be explained by a delicate balance between short-range elastic restoring forces supporting the undistorted paraelectric (PE) structure and long-range Coulomb interactions favoring the FE phase [1]. Itinerant electrons can screen the electric fields and inhibit the electrostatic forces, metallic systems are thus not expected to exhibit ferroelectric like structural distortion. Despite the incompatibility, using a phenomenological theory, Anderson and Blount proposed in 1965 that metals can break inversion symmetry [2]. They found that the FE metal is possible through a continuous structural transition accompanied by the appearance of a polar axis, and the disappearance of an inversion center [2]. In 2004, Cd 2 Re 2 O 7 had been proposed as a rare example of ferroelectric metals [3], however, it was found that although this compound exhibits a second order phase transition to a structure that lacks inversion symmetry, a unique polar axis could not be identified [4], which does not fit the criteria about the FE metal.Very recently, the first convincing success was achieved experimentally in LiOsO 3 [1]. LiOsO 3 remains metallic behavior while it undergoes a second-order phase transition from the high temperature centrosymmetric R3c to a FE-like R3c structure at T s = 140K [1]. Neutron and xray diffraction studies showed that the structural phase transition involves the displacements of Li ions accompanying also a slight shift of O ions [1]. The electronic structure and lattice instability were studied by several groups [6][7][8]. It was found that the local polar distortion in LiOsO 3 is solely due to the instability of the A-site Li ion [6][7][8]. The importance of the Coulomb interaction among 5d electrons and the hybridization between oxygen p orbitals and Os empty e g orbitals has also been emphasized by Giovannetti and Capone[8]. Despite these efforts devoted to understanding the origin of the FE like structural transition in this metallic system, there are still two fundamental issues have not been clearly clarified. The first is the origin of the fer...

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Integrated 3D porous TiO2@MoS2 architectures containing Ti–S bonds were fabricated for efficient electroreduction of CO2 to CO.

Tungstates AWO4 with the wolframite structure characterized by the AO6 octahedral zigzag chains along the c-axis, can be magnetic if A=Mn, Fe, Co, Cu, Ni. Among them, MnWO4 is a unique member with a cycloid Mn 2+ spin order developed at low temperature, leading to an interesting type-II multiferroic behavior. However, so far no other multiferroic material in the tungstate family has been found. In this work, we present the synthesis and the systematic study of the double tungstate LiFe(WO4)2. Experimental characterizations including structural, thermodynamic, magnetic, neutron powder diffraction, and pyroelectric measurements, unambiguously confirm that LiFe(WO4)2 is the secondly found multiferroic system in the tungstate family. The cycloidal magnetism driven ferroelectricity is also verified by density functional theory calculations. Although here the magnetic couplings between Fe ions are indirect, namely via the so-called super-superexchanges, the temperatures of magnetic and ferroelectric transitions are surprisingly much higher than those of MnWO4.