Given the simultaneous presence of two metal active centres, some special interactions occur between active sites in diatomic catalysts (DACs). Such interactions play an important role in determining the rate and selectivity of the reaction, denoted as long-range interaction (LRI). The right combination must be screened and clarified to achieve the targeted efficiency. To date, various types of DACs have been synthesised and applied in electrochemistry. However, the LRI has not been systematically summarised. Herein, the regulation, mechanism and electrocatalytic applications of LRI are comprehensively summarised and discussed. In addition to the basic information above, the challenges, opportunities, and future development of LRI on DACs are proposed to present an overall view and reference for future research.

Long-Range Interaction on Diatomic Catalysts Boosting Electrocatalysis.

Atomic Lego Catalysts Synthesized by Atomic Layer Deposition

Single/dual-metal atoms supported on carbon matrix can be modulated by coordination structure and neighboring active sites. Precisely designing the geometric and electronic structure and uncovering the structure-property relationships of single/dual-metal atoms confront with grand challenges. Herein, this review summarizes the latest progress in microenvironment engineering of single/dual-atom active sites via a comprehensive comparison of single-atom catalyst (SACs) and dual-atom catalysts (DACs) in term of design principles, modulation strategy, and theoretical understanding of structure-performance correlations. Subsequently, recent advances in several typical electrocatalysis process are discussed to get general understanding of the reaction mechanisms on finely-tuned SACs and DACs. Finally, full-scaled summaries of the challenges and prospects are given for microenvironment engineering of SACs and DACs. This review will provide new inspiration on the development of atomically dispersed catalysts for electrocatalytic application. This article is protected by copyright. All rights reserved.

Microenvironment Engineering of Single/Dual-atom Catalysts for Electrocatalytic Application.

Regulation of the atom-atom interspaces of dual-atom catalysts is essential to optimize the dual-atom synergy to achieve high activity but remains challenging. Herein, we report an effective strategy to regulate the Pt 1 -Ni 1 interspace to achieve Pt 1 Ni 1 dimers and Pt 1 +Ni 1 heteronuclear dual-single-atom catalysts (HDSACs) by tailoring steric hindrance between metal precursors during synthesis. Spectroscopic characterization reveals obvious electron transfers in Pt 1 Ni 1 oxo dimers but not in Pt 1 +Ni 1 HDSAC. In the hydrolysis of ammonia borane (AB), the H 2 formation rates show an inverse proportion to the Pt 1 -Ni 1 interspace. The rate of Pt 1 Ni 1 dimers is ~13 and 2 times higher than those of Pt 1 and Pt 1 +Ni 1 HDSAC, manifesting the interspace-dependent synergy. Theoretical calculations reveal that the bridging OH group in Pt 1 Ni 1 dimers promotes water dissociation, while Pt 1 facilitates the cleavage of B-H bonds in AB, which boosts a bifunctional synergy to accelerate H 2 production cooperatively.

Dehydrogenation of Ammonia Borane by Platinum--Nickel Dimers: Regulation of the Heteroatom Interspace Boosts Bifunctional Synergetic Catalysis.

Developing efficient platinum (Pt)-based electrocatalysts with high tolerance to CO poisoning for the methanol oxidation reaction is critical for the development of direct methanol fuel cells. In this work, cobalt single atoms are introduced to enhance the electrocatalytic performance of N-doped carbon supported Pt (N-C/Pt) for the methanol oxidation reaction. The cobalt single atoms are believed to play a critical role in accelerating the prompt oxidation of CO to CO2 and minimizing the CO blocking of the adjacent Pt active sites. Benefitting from the synergistic effects among the Co single atoms, the Pt nanoparticles, and the N-doped carbon support, the Co-modified N-C/Pt (Co-N-C/Pt) electrocatalyst simultaneously delivers impressive electrocatalytic activity and durability with lower onset potential and superb CO poisoning resistance as compared to the N-C/Pt and the commercial Pt/C electrocatalysts.

Cobalt Single Atoms Enabling Efficient Methanol Oxidation Reaction on Platinum Anchored on Nitrogen-Doped Carbon.

Planar metal clusters possess high metal utilization, distinct electronic properties, and catalytic functions from their 3D counterparts. However, synthesis of these materials is challenging due to much elevated surface free energies. Here it is reported that silica supported planar bilayer Pt-CoOx subnano clusters, consisting of approximately one atomic layer of Pt and one CoOx layer on top, can be achieved by employing strong-electrostatic interactions during impregnation and precisely-controlled CoOx coating using atomic layer deposition. Such bilayer structure is unambiguously confirmed by electron microscopy and in situ X-ray absorption fine spectroscopy which is never reported before. This synthetic approach can be extended to another eight permutations of planar metal-oxide subnano clusters. The resulting bilayer catalysts, owing to unique electronic properties and the abundant metal-oxide interfaces created, exhibit excellent catalytic performances in the reactions of preferential oxidation of CO in H2 and selective hydrogenation of acetylene, by showing much higher selectivity and intrinsic activities at least 8 and 48 times greater than those conventional oxide coated 3D metal clusters/nanoparticles, highlighting the advances of bilayer interfacial structure. These findings open a new avenue to design abundant and highly active metal-oxide interfaces for advanced metal catalysis.

Synthesis of Quasi-Bilayer Subnano Metal-Oxide Interfacial Cluster Catalysts for Advanced Catalysis.

We present the rigorous theoretical framework of the generalized spin mapping representation for non-adiabatic dynamics. Our work is based upon a new mapping formalism recently introduced by Runeson and Richardson [J. Chem. Phys. 152, 084110 (2020)], which uses the generators of the su(N) Lie algebra to represent N discrete electronic states, thus preserving the size of the original Hilbert space. Following this interesting idea, the Stratonovich-Weyl transform is used to map an operator in the Hilbert space to a continuous function on the SU(N) Lie group, i.e., a smooth manifold which is a phase space of continuous variables. We further use the Wigner representation to describe the nuclear degrees of freedom and derive an exact expression of the time-correlation function as well as the exact quantum Liouvillian for the non-adiabatic system. Making the linearization approximation, this exact Liouvillian is reduced to the Liouvillian of several recently proposed methods, and the performance of this linearized method is tested using non-adiabatic models. We envision that the theoretical work presented here provides a rigorous and unified framework to formally derive non-adiabatic quantum dynamics approaches with continuous variables and connects the previous methods in a clear and concise manner.

Non-adiabatic mapping dynamics in the phase space of the SU(N) Lie group.

We present the quantum dynamics of a spin coupling to a bath of independent spins via the dissipaton equation of motion (DEOM) approach. The bath, characterized by a continuous spectral density function, is composed of spins that are independent level systems described by the su (2) Lie algebra. This represents an extreme class of anharmonic environment. Based on the conclusion drawn by Suarez and Silbey [J. Chem. Phys. 95, 9115 (1991)] and Makri [J. Chem. Phys. 111, 6164 (1999)] that the spin bath can be mapped to a Gaussian environment under its linear response limit, we derive the ﬂuctuation-dissipation theorem (FDT) of the spin bath from a microscopic perspective, and generalize the discussion to the case of arbitrary bath spin quantum number S . Next, the time-domain Prony ﬁtting decomposition scheme is applied to the bare-bath time correlation function (TCF) given by FDT to generate the exponential decay basis (or pseudo modes) for DEOM construction. The accuracy and eﬃciency of this strategy has been justiﬁed by a variety of numerical results. We envision this work provides new insights to extend the hierarchical equations of motion (HEOM) and DEOM approach to certain types of anharmonic enviroments with arbitrary TCF or spectral density.

Wenxiang Ying

Papers

Dehydrogenation of Ammonia Borane by Platinum--Nickel Dimers: Regulation of the Heteroatom Interspace Boosts Bifunctional Synergetic Catalysis.

Synthesis of Quasi-Bilayer Subnano Metal-Oxide Interfacial Cluster Catalysts for Advanced Catalysis.

Non-adiabatic mapping dynamics in the phase space of the SU(N) Lie group.

Spin relaxation dynamics with a continuous spin environment: the dissipaton equation of motion approach

Erratum: "Non-adiabatic mapping dynamics in the phase space of the SU(N) Lie group" [J. Chem. Phys. 157, 084105 (2022)].