다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

DFT combined with machine learning methods are explored for the rational design of nitrogen reduction reaction (NRR) single-atom catalysts of supported by molybdenum disulfide MoS 2 . 

Mutual modulation<i>via</i>charge transfer and unpaired electrons of catalytic sites for the superior intrinsic activity of N<sub>2</sub>reduction: from high-throughput computation assisted with a machine learning perspective

Large-scale ammonia synthesis via the electrochemical nitrogen reduction reaction (eNRR) under mild reaction conditions represents a green prospect for agriculture, industry, and energy. This bioinspired and carbon-free reaction has been proposed as an ideal alternative to the Haber–Bosch process. However, the yield and selectivity of the current eNRR have not met the requirements for industrialization. Mechanistic understanding and catalysts’ design are still long-term pursuits in this field, where theoretical simulations will have significant contributions. In this Review, we will start with the natural N2 fixation enzymes, the nitrogenases, followed by a summary of the key experimental eNRR performances on hundreds of recently reported catalysts, and we analyze the general trend and challenges before eNRR can significantly impact the ammonia industry. Then, we will systematically review the recent progress and contributions of computational studies in understanding the reaction mechanism and rational catalyst design for eNRR. The fundamental principles, reaction mechanisms, crucial theoretical criteria, modeling methods, and computationally predicted catalysts for eNRR are systematically summarized and discussed. Finally, we outline the current challenges and future opportunities for experimental and computational studies of electrochemical N2 reduction. 

Progress of Experimental and Computational Catalyst Design for Electrochemical Nitrogen Fixation

Computational prediction of Mo2@g-C6N6 monolayer as an efficient electrocatalyst for N2 reduction

A nitrogen reduction reaction (NRR) which converts nitrogen (N2) to ammonia (NH3) normally requires harsh conditions to break the bound nitrogen bond. Herein, via first-principles calculation it is revealed that a superior NRR catalytic activity could be obtained by anchoring an atomic catalyst above the phosphorene-like puckered surface of germanium selenide (GeSe). By examining the single- and double-atoms (B, Fe, Mo Ru and W) decorated on GeSe, it is found that its rippled structure allows an intimate contact between the deposited species and the GeSe which significantly promotes the states hybridization. Out of all the various atomic catalysts, it is found that the Ru dimer decorated GeSe monolayer (Ru2@GeSe) has superior catalytic activity for the N2 fixation and reduction. By examining the three NRR pathways (distal, alternating and enzymatic), it was found that the distal and enzymatic pathways are both thermodynamically favorable with the maximum Gibbs free energy change (ΔGMAX) of 0.25 and 0.26 eV, respectively. Such a superior activity could be attributed to the Ru dimer filtering the states of GeSe which leads to the effective activation of the adsorbed N2 bond. As an efficient near-infrared absorber of GeSe, the Ru mediated hybridization of the GeSe–Ru–N2 complex enables an in-gap state which further broadens the absorption window, rendering for a broadband solar absorption and possible photocatalysis.

Activation of phosphorene-like two-dimensional GeSe for efficient electrocatalytic nitrogen reduction via states filtering of Ru

Layered chalcogenide materials are a wealth of nanoelectronics applications, like resistive switching and energy-harvesting (such as photocatalysis), owing to its electronics, orbitals, and lattice excitations. In this work, we explore monochalcogenide germanium selenide GeSe with respect to substitutional doping with 13 metallic cations by first-principles calculations. Typical dopants, including s-shell (alkali elements Li and Na), p-shell (Al, Pb and Bi), 3d (Fe, Cu, Co and Ni), 4d (Pd and Ag) and 5d (Au and Pt) elements, are systematically examined. Amongst all cationic dopants, Al with highest oxidation states, implying a high mobility driven by the electric field, and Al-doped GeSe may be promising candidates for novel resistive switching devices. We show that many localized induced states exist in the band gap of GeSe on doping with Fe, Co, or Ni. In contrast, for the Cu, Ag, and Au, there is no such state in the gap. Ag and Cu have +0.27 and +0.35 charges respectively, and the positive charges are beneficial for the field-driven motion in GeSe. In contrast, Au is slightly negatively charged, which renders the Au-doped GeSe as a promising photocatalyst and enhanced surface plasmon. Moreover, we explore the coexistence of the dopant and strain in GeSe, and find dynamical adjustments of localized states in GeSe with levels successively shifting upward/downward with strain. This induces dynamic oxidative states of the dopants under strain, which should be quite popular in composites where the motion of metal adatoms causes significant deformation.

Zheng Shu

Papers

Activation of phosphorene-like two-dimensional GeSe for efficient electrocatalytic nitrogen reduction via states filtering of Ru

Substitutional doped GeSe: tunable oxidative states with strain engineering