The Activation and Reduction of N 2 by Single/Double‐Atom Electrocatalysts: A First‐Principle Study

ZrN6 -Doped Graphene for Ammonia Synthesis: A Density Functional Theory Study

Considering the pivotal role of ammonia in the modern chemical industry, designing effective catalysts for the N₂ -to-NH₃ conversion stimulates great research enthusiasms. In this work, by means of density functional theory calculations, we systematically investigated the electrocatalysis of six-coordinated transition metal atom anchored graphene for nitrogen fixation. The free energy analysis shows that the ZrN₆ configuration has a good activity toward ammonia synthesis under overpotential of 0.51 V. According to the electron transfer analysis, ZrN₆ site plays a bridging role in charge transfer between the functional graphene and the reactant. Furthermore, the presence of N₆ coordination increases the electron accumulation on the NNH_x intermediates, which weakens the intermolecular N-N bond, reducing the thermodynamic barrier of protonation process. This work provides a basic understanding of the interaction between transition metal and the adjacent coordination in tuning the reactivity.

Electrocatalytic Oxygen Reduction to Produce Hydrogen Peroxide: Rational Design from Single-Atom Catalysts to Devices

Electrocatalytic production of hydrogen peroxide (H2O2) via the 2e- transfer route of the oxygen reduction reaction (ORR) offers a promising alternative to the energy-intensive anthraquinone process, which dominates current industrial-scale production of H2O2. The availability of cost-effective electrocatalysts exhibiting high activity, selectivity, and stability is imperative for the practical deployment of this process. Single-atom catalysts (SACs) featuring the characteristics of both homogeneous and heterogeneous catalysts are particularly well suited for H2O2 synthesis and thus, have been intensively investigated in the last few years. Herein, we present an in-depth review of the current trends for designing SACs for H2O2 production via the 2e- ORR route. We start from the electronic and geometric structures of SACs. Then, strategies for regulating these isolated metal sites and their coordination environments are presented in detail, since these fundamentally determine electrocatalytic performance. Subsequently, correlations between electronic structures and electrocatalytic performance of the materials are discussed. Furthermore, the factors that potentially impact the performance of SACs in H2O2 production are summarized. Finally, the challenges and opportunities for rational design of more targeted H2O2-producing SACs are highlighted. We hope this review will present the latest developments in this area and shed light on the design of advanced materials for electrochemical energy conversion.

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