Tackling the Activity and Selectivity Challenges of Electrocatalysts toward the Nitrogen Reduction Reaction via Atomically Dispersed Biatom Catalysts

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(12), P. 5709 - 5721

Published: Feb. 18, 2020

Developing efficient catalysts for nitrogen fixation is becoming increasingly important but still challenging due to the lack of robust design criteria tackling activity and selectivity problems, especially electrochemical reduction reaction (NRR). Herein, by means large-scale density functional theory (DFT) computations, we reported a descriptor-based principle explore large composition space two-dimensional (2D) biatom (BACs), namely, metal dimers supported on 2D expanded phthalocyanine (M2-Pc or MM'-Pc), toward NRR at acid conditions. We sampled both homonuclear (M2-Pc) heteronuclear (MM'-Pc) BACs constructed map using N2H* adsorption energy as descriptor, which reduces number promising catalyst candidates from over 900 less than 100. This strategy allowed us readily identify 3 28 BACs, could break metal-based benchmark NRR. Particularly, free difference H* screened out five systems, including Ti2-Pc, V2-Pc, TiV-Pc, VCr-Pc, VTa-Pc, exhibit strong capability suppressing competitive hydrogen evolution (HER) with favorable limiting potential -0.75, -0.39, -0.74, -0.85, -0.47 V, respectively. work not only broadens possibility discovering more N2 also provides feasible rational electrocatalysts helps pave way fast screening other reactions.

Language: Английский

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Efficient Ammonia Electrosynthesis from Nitrate on Strained Ruthenium Nanoclusters

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(15), P. 7036 - 7046

Published: March 30, 2020

The limitations of the Haber-Bosch reaction, particularly high-temperature operation, have ignited new interests in low-temperature ammonia-synthesis scenarios. Ambient N2 electroreduction is a compelling alternative but impeded by low ammonia production rate (mostly <10 mmol gcat-1 h-1), small partial current density (<1 mA cm-2), and high-selectivity hydrogen-evolving side reaction. Herein, we report that room-temperature nitrate catalyzed strained ruthenium nanoclusters generates at higher (5.56 mol h-1) than process. primary contributor to such performance hydrogen radicals, which are generated suppressing hydrogen-hydrogen dimerization during water splitting enabled tensile lattice strains. radicals expedite nitrate-to-ammonia conversion hydrogenating intermediates rate-limiting steps lower kinetic barriers. nanostructures can maintain nearly 100% ammonia-evolving selectivity >120 cm-2 densities for 100 h due robust subsurface Ru-O coordination. These findings highlight potential real-world, synthesis.

Language: Английский

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Modulating the local coordination environment of single-atom catalysts for enhanced catalytic performance

Nano Research, Journal Year: 2020, Volume and Issue: 13(7), P. 1842 - 1855

Published: March 30, 2020

Language: Английский

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Atomically dispersed metal–nitrogen–carbon catalysts for fuel cells: advances in catalyst design, electrode performance, and durability improvement

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(11), P. 3484 - 3524

Published: Jan. 1, 2020

The urgent need to address the high-cost issue of proton-exchange membrane fuel cell (PEMFC) technologies, particularly for transportation applications, drives development simultaneously highly active and durable platinum group metal-free (PGM-free) catalysts electrodes. past decade has witnessed remarkable progress in exploring PGM-free cathode oxygen reduction reaction (ORR) overcome sluggish kinetics catalyst instability acids. Among others, scientists have identified newly emerging atomically dispersed transition metal (M: Fe, Co, or/and Mn) nitrogen co-doped carbon (M-N-C) as most promising alternative PGM catalysts. Here, we provide a comprehensive review significant breakthroughs, remaining challenges, perspectives regarding M-N-C terms activity, stability, electrode assembly (MEA) performance. A variety novel synthetic strategies demonstrated effectiveness improving intrinsic increasing site density, attaining optimal porous structures Rationally designing engineering coordination environment single MNx sites their local are crucial enhancing activity. Increasing density relies on innovative restricting migration agglomeration into metallic clusters. Relevant understandings correlations among nature sites, nanostructures, catalytic activity at atomic scale through combination experimentation theory. Current knowledge transferring properties MEA performance is limited. morphologic features play vital role boosting exposing more accessible realizing uniform ionomer distribution, facilitating mass/proton transports. We outline future research directions concerning evaluation MEAs. considerable challenge current unsatisfied stability rapid degradation Therefore, further discuss practical methods mitigate degradation, which fundamentally essential make viable PEMFC technologies.

Language: Английский

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Electrocatalytic Refinery for Sustainable Production of Fuels and Chemicals

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(36), P. 19572 - 19590

Published: Feb. 19, 2021

Abstract Compared to modern fossil‐fuel‐based refineries, the emerging electrocatalytic refinery (e‐refinery) is a more sustainable and environmentally benign strategy convert renewable feedstocks energy sources into transportable fuels value‐added chemicals. A crucial step in conducting e‐refinery processes development of appropriate reactions optimal electrocatalysts for efficient cleavage formation chemical bonds. However, compared well‐studied primary (e.g., O 2 reduction, water splitting), mechanistic aspects materials design complex are yet be settled. To address this challenge, herein, we first present fundamentals heterogeneous electrocatalysis some reactions, then implement these establish framework by coupling situ generated intermediates (integrated reactions) or products (tandem reactions). We also set principles strategies efficiently manipulate reaction pathways.

Language: Английский

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Regulating the Coordination Environment of MOF‐Templated Single‐Atom Nickel Electrocatalysts for Boosting CO₂ Reduction

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(7), P. 2705 - 2709

Published: Dec. 10, 2019

The general synthesis and control of the coordination environment single-atom catalysts (SACs) remains a great challenge. Herein, host-guest cooperative protection strategy has been developed to construct SACs by introducing polypyrrole (PPy) into bimetallic metal-organic framework. As an example, introduction Mg2+ in MgNi-MOF-74 extends distance between adjacent Ni atoms; PPy guests serve as N source stabilize isolated atoms during pyrolysis. result, series (named NiSA -Nx -C) with different numbers have fabricated controlling pyrolysis temperature. Significantly, -N2 -C catalyst, lowest number, achieves high CO Faradaic efficiency (98 %) turnover frequency (1622 h-1 ), far superior those -N3 -N4 -C, electrocatalytic CO2 reduction. Theoretical calculations reveal that low number sites is favorable formation COOH* intermediate thus accounts for its activity.

Language: Английский

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Coordination Tunes Selectivity: Two‐Electron Oxygen Reduction on High‐Loading Molybdenum Single‐Atom Catalysts

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(23), P. 9171 - 9176

Published: March 20, 2020

Single-atom catalysts (SACs) have great potential in electrocatalysis. Their performance can be rationally optimized by tailoring the metal atoms, adjacent coordinative dopants, and loading. However, doing so is still a challenge because of limited synthesis approach insufficient understanding structure-property relationships. Herein, we report new kind Mo SAC with unique O,S coordination high loading over 10 wt %. The isolation local environment was identified high-angle annular dark-field scanning transmission electron microscopy extended X-ray absorption fine structure. SACs catalyze oxygen reduction reaction (ORR) via 2 e- pathway H2 O2 selectivity 95 % 0.10 m KOH. critical role single atoms structure revealed both electrochemical tests theoretical calculations.

Language: Английский

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Understanding the structure-performance relationship of active sites at atomic scale

Nano Research, Journal Year: 2022, Volume and Issue: 15(8), P. 6888 - 6923

Published: June 14, 2022

Language: Английский

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Activating lattice oxygen in NiFe-based (oxy)hydroxide for water electrolysis

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: April 21, 2022

Abstract Transition metal oxides or (oxy)hydroxides have been intensively investigated as promising electrocatalysts for energy and environmental applications. Oxygen in the lattice was reported recently to actively participate surface reactions. Herein, we report a sacrificial template-directed approach synthesize Mo-doped NiFe (oxy)hydroxide with modulated oxygen activity an enhanced electrocatalyst towards evolution reaction (OER). The obtained MoNiFe displays high mass of 1910 A/g at overpotential 300 mV. combination density functional theory calculations advanced spectroscopy techniques suggests that Mo dopant upshifts O 2 p band weakens metal-oxygen bond (oxy)hydroxide, facilitating vacancy formation shifting pathway OER. Our results provide critical insights into role determining demonstrate tuning constructing highly active electrocatalysts.

Language: Английский

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Theoretical Insights into the Mechanism of Selective Nitrate‐to‐Ammonia Electroreduction on Single‐Atom Catalysts

Advanced Functional Materials, Journal Year: 2020, Volume and Issue: 31(11)

Published: Dec. 21, 2020

Abstract Selective nitrate‐to‐ammonia electrochemical conversion is an efficient pathway to solve the pollution of nitrate and attractive strategy for low‐temperature ammonia synthesis. However, current studies electroreduction (NO 3 RR) mainly focus on metal‐based catalysts, which remains challenging because poor understanding catalytic mechanism. Herein, taking single transition metal atom supported graphitic carbon nitrides (g‐CN) as example, NO RR feasibility single‐atom catalysts (SACs) first demonstrated by using density functional theory calculations. The results reveal that highly toward NH can be achieved Ti/g‐CN Zr/g‐CN with low limiting potentials −0.39 −0.41 V, respectively. Furthermore, considerable energy barriers are observed during formation byproducts 2 , NO, N O, Zr/g‐CN, guaranteeing their high selectivity. This work provides a new route application SACs paves way development RR.

Language: Английский

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