Unravelling the Reaction Mechanisms of N2 Fixation on Molybdenum Nitride: A Full DFT study from the Pristine Surface to Heteroatom Anchoring

Transition metal nitrides (TMNs)-based materials have attracted increasing attention in electrochemical nitrogen reduction reaction (eNRR) because of their unique structures and inherent electronic properties. However, the eNRR mechanism on such nitrogen contained catalysts is still unclear, for example, which part of the catalyst act as the active sites, and how to achieve the optimal efficiency is also challenging. In this work, a comprehensive study was conducted to unravel the reaction mechanisms of N2 fixation on molybdenum nitride by using density functional theory (DFT) calculations. The activity and selectivity of eNRR on pristine (001) and (110) Mo5N6 surfaces as well as few specific numbers of heteroatom-anchored N-terminated surfaces were all evaluated and compared. It was found that the Mo and N atoms on the pristine Mo5N6 surface were both active for eNRR while following different pathways in mechanism. Moreover, the eNRR catalytic performance of Mo5N6 could be further boosted by specific metal atoms anchoring, such as single atom, metal dimer, and heterodiatom pair. Finally, a full map of eNRR mechanism on pristine and metal atom-decorated Mo5N6 surfaces was illustrated. This work not only provides a fundamental understanding of eNRR mechanism on TMNs based materials but also offers powerful strategies towards the rational design of efficient NRR electrocatalysts.</p

Unravelling the Reaction Mechanisms of N2 Fixation on Molybdenum Nitride : A Full DFT Study from the Pristine Surface to Heteroatom Anchoring

Transition metal nitrides (TMNs)-based materials have attracted increasing attention in electrochemical nitrogen reduction reaction (eNRR) because of their unique structures and inherent electronic properties. However, the eNRR mechanism on such nitrogen contained catalysts is still unclear, for example, which part of the catalyst act as the active sites, and how to achieve the optimal efficiency is also challenging. In this work, a comprehensive study was conducted to unravel the reaction mechanisms of N2 fixation on molybdenum nitride by using density functional theory (DFT) calculations. The activity and selectivity of eNRR on pristine (001) and (110) Mo5N6 surfaces as well as few specific numbers of heteroatom-anchored N-terminated surfaces were all evaluated and compared. It was found that the Mo and N atoms on the pristine Mo5N6 surface were both active for eNRR while following different pathways in mechanism. Moreover, the eNRR catalytic performance of Mo5N6 could be further boosted by specific metal atoms anchoring, such as single atom, metal dimer, and heterodiatom pair. Finally, a full map of eNRR mechanism on pristine and metal atom-decorated Mo5N6 surfaces was illustrated. This work not only provides a fundamental understanding of eNRR mechanism on TMNs based materials but also offers powerful strategies towards the rational design of efficient NRR electrocatalysts.</p

Graphynes as emerging 2D-platforms for electronic and energy applications: A computational perspective

Among all the 2D-carbon materials, graphyne is currently one of the most interesting carbon allotropes besides graphene. It has potential applications in a wide variety of scientific fields owing to its unique sp-sp2 hybrid network, which endows desirable electronic properties towards energy-related applications. In this review, we summarize the recent progress in graphynes for electronic and energy applications from a theoretical point of view. The intrinsic electronic structure of graphyne and its chemical and mechanical properties are comprehensively described. It is hoped that this review could provide a strong theoretical understanding of graphynes, thus accelerating the design of robust and efficient graphyne-based advanced energy and electronic devices in the future.</p

Rational Modulation of Single Atom Coordination Microenvironments in a BCN Monolayer for Multifunctional Electrocatalysis

Single-atom (SA) catalysts (SACs) have demonstrated outstanding catalytic performances toward plenty of relevant electrochemical reactions. Nevertheless, controlling the coordination microenvironment of catalytically active SAs to further enhance their catalytic oerformences has remained elusive up to now. Herein, a systematic investigation of 20 transition metal atoms that are coordinated with 20 different microenvironments in a boroncarbon-nitride monolayer (BCN) is conducted using high-throughput density functional theory calculations. The experimentally synthesized ternary BCN monolayer contains carbon, nitrogen, and boron atoms in its 2D network, thus providing a lot of new coordination environments than those of the current CxNy nanoplatforms. By exploring the structural/electrochemical stability, catalytic activity, selectivity, and electronic properties of 400 (20 × 20) TM-BCN moieties, it is discovered that specific SA coordination environments can achieve superior stability and selectivity for different electrocatalytic reactions. Moreover, a universal descriptor to accelerate the experimental process toward the synthesis of BCN-SACs is reported. These findings not only provide useful guidance for the synthesis of efficient multifunctional BCN-SACs but also will immediately benefit researchers by levering up their understanding of the mechanistic effects of SA coordination microenvironments on electrocatalytic reactions.</p

Atomically Dispersed Heteronuclear Dual-Atom Catalysts: A New Rising Star in Atomic Catalysis

Atomic catalysts (AC) are gaining extensive research interest as the most active new frontier in heterogeneous catalysis due to their unique electronic structures and maximum atom-utilization efficiencies. Among all the atom catalysts, atomically dispersed heteronuclear dual-atom catalysts (HDACs), which are featured with asymmetric active sites, have recently opened new pathways in the field of advancing atomic catalysis. In this review, the up-to-date investigations on heteronuclear dual-atom catalysts together with the last advances on their theoretical predictions and experimental constructions are summarized. Furthermore, the current experimental synthetic strategies and accessible characterization techniques for these kinds of atomic catalysts, are also discussed. Finally, the crucial challenges in both theoretical and experimental aspects, as well as the future prospects of HDACs for energy-related applications are provided. It is believed that this review will inspire the rational design and synthesis of the new generation of highly effective HDACs.</p