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Urea synthesis through the simultaneous electrocatalytic reduction of N₂and CO₂molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production, in which the development of stable, highly efficient, and highly selective catalysts to boost the chemisorption, activation, and coupling of inert N₂and CO₂molecules remains rather challenging. Herein, by means of density functional theory computations, we proposed a new class of two‐dimensional nanomaterials, namely, transition‐metal phosphide monolayers (TM₂P, TM = Ti, Fe, Zr, Mo, and W), as the potential electrocatalysts for urea production. Our results showed that these TM₂P materials exhibit outstanding stability and excellent metallic properties. Interestingly, the Mo₂P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier (0.35 eV) for C–N coupling, low limiting potential (−0.39 V), and significant suppressing effects on the competing side reactions. The outstanding catalytic activity of the Mo₂P monolayer can be ascribed to its optimal adsorption strength with the key *NCON species due to its moderate positive charges on the Mo active sites. Our findings not only propose a novel catalyst with high‐efficiency and high‐selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.

 

Abstract Metal-free electrocatalysts represent a main branch of active materials for oxygen evolution reaction (OER), but they excessively rely on functionalized conjugated carbon materials, which substantially restricts the screening of potential efficient carbonaceous electrocatalysts. Herein, we demonstrate that a mesostructured polyacrylate hydrogel can afford an unexpected and exceptional OER activity – on par with that of benchmark IrO 2 catalyst in alkaline electrolyte, together with a high durability and good adaptability in various pH environments. Combined theoretical and electrokinetic studies reveal that the positively charged carbon atoms within the carboxylate units are intrinsically active toward OER, and spectroscopic operando characterizations also identify the fingerprint superoxide intermediate generated on the polymeric hydrogel backbone. This work expands the scope of metal-free materials for OER by providing a new class of polymeric hydrogel electrocatalysts with huge extension potentials. 

Two differently substituted pyrazole ligands have been investigated with regard to the topology of their Pt complexes: upon deprotonation, two mononuclear 1:2 PtII-pyrazole complexes—one of the sterically unhindered 4-Me-pzH and one of the bulky 3,5-tBu-pzH (pzH = pyrazole)—yield the corresponding 1:2 PtII-pyrazolato species; the former a triangular, trinuclear metallacycle (1), and the latter a dinuclear, half-lantern species (2) formed via the unprecedented cyclometallation of a butyl group. Stoichiometric oxidation of the colorless PtII2 complex produces the deep-blue, metal–metal bonded PtIII2 analog (3) with a rarely encountered unsymmetrical coordination across the Pt-Pt bond. All three complexes have been characterized by single crystal X-ray structure determination, 1H-NMR, IR, and UV-vis-NIR spectroscopic methods. The XPS spectra of the PtII2 and PtIII2 species are also reported. Density functional theory calculations were carried out to investigate the electronic structure, spectroscopic properties, and chemical bonding of the new complexes. The calculated natural population analysis charges and Wiberg bonding indices indicate a weak σ-interaction in the case of 2 and a formal Pt-Pt single bond in 3. 

Carbocations play crucial roles during catalytic reactions by dictating the reaction pathways and genuine mechanisms, but the instability of carbocations prevents thorough observations. The stabilization of carbocations would greatly help us gain a deep understanding of the reaction mechanisms. By means of ab initio molecular dynamics (AIMD) simulations and an in situ experimental approach, a complete scrambling of 13C-labeled C4 = products was observed during the isomerization reaction in the H-ZSM5 zeolite at room temperature, and the corner-protonated methyl cyclopropanes (as a non-classical carbocation) featuring the three center two-electron (3c–2e) bonds were confirmed to be the highly active metastable intermediates of C4 isomerization. Our results not only uncover the nature of facile C shift in carbocations during zeolite-catalyzed reactions but also bring some fundamental understandings to carbocation chemistry in a zeolite confined environment 

Using a starlike Be 6 Au 7 − cluster as a building block and following the bottom-up strategy, an intriguing two-dimensional (2D) binary s-block metal Be 2 Au monolayer with a P 6/ mmm space group was theoretically designed. Both the Be 6 Au 7 − cluster and the 2D monolayer are global minima featuring rule-breaking planar hexacoordinate motifs (anti-van't Hoff/Le Bel arrangement), and their high stabilities are attributed to good electron delocalization and electronic-stabilization-induced steric force. Strikingly, the Be 2 Au monolayer is a rare Dirac material with two perfect Dirac node-loops in the band structure and is a phonon-mediated superconductor with a critical temperature of 4.0 K. The critical temperature can be enhanced up to 11.0 K by applying compressive strain at only 1.6%. This study not only identifies a new binary s-block metal 2D material, namely Be 2 Au, which features planar hexacoordination, and a candidate superconducting material for further explorations, but also provides a new strategy to construct 2D materials with novel chemical bonding. 

Inspired by the advantages of bi-atom catalysts and recent exciting progresses of nanozymes, by means of density functional theory (DFT) computations, we explored the potential of metal dimers embedded in phthalocyanine monolayers (M2-Pc), which mimics the binuclear centers of methane monooxygenase, as catalysts for methane conversion using H2O2 as an oxidant. In total, 26 transition metal (from group IB to VIIIB) and four main group metal (M = Al, Ga, Sn and Bi) dimers were considered, and two methane conversion routes, namely *O-assisted and *OH-assisted mechanisms were systematically studied. The results show that methane conversion proceeds via an *OH-assisted mechanism on the Ti2-Pc, Zr2-Pc and Ta2-Pc, a combination of *O- and *OH-assisted mechanism on the surface of Sc2-Pc, respectively. Our theoretical work may provide impetus to developing new catalysts for methane conversion and help stimulate further studies on metal dimer catalysts for other catalytic reactions. 

To achieve specific applications, it is always desirable to design new materials with peculiar topological properties. Herein, based on a D2h B2Cu6H6 molecule with the unique chemical bonding of planar pentacoordinate boron (ppB) as a building block, we constructed an infinite CuB monolayer by linking B2Cu6 subunits in an orthorhombic lattice. The planarity of the CuB sheet is attributed to the multicenter bonds and electron donation-back donation, as revealed by chemical bonding analysis. As a global minimum confirmed by the particle swarm optimization method, the CuB monolayer is expected to be highly stable, as indicated by its rather high cohesive energy, absence of soft phonon modes, and good resistance to high temperature, and thus is highly feasible for experimental realization. Remarkably, this CuB monolayer is metallic and predicted to be superconducting with an estimated critical temperature (Tc) of 4.6 K, and the critical temperature could be further enhanced by tensile strains (to 21 K at atmospheric pressure).