Boron-Doped MXenes as Electrocatalysts for Nitrogen Reduction Reaction: A Theoretical Study

Electrocatalytic nitrogen reduction reaction (NRR) is a promising and sustainable approach for ammonia production. Since boron as an active center possesses electronic structure similar to that of transition metals with d-orbitals (J. Am. Chem. Soc., 2019, 141 (7), 2884), it is supposed to be able to effectively activate the triple bond in N2. MXenes can be applied as substrates due to the large specific surface area, high conductivity, and tunable surface composition. In this work, the catalytic performance of a series of MXenes-supported single boron atom systems (labeled as B@MXenes) has been systematically studied by using density functional theory (DFT). B@Nb4C3O2, B@Ti4N3O2, and B@Ti3N2O2 were screened out owing to outstanding catalytic activity with limiting potentials of −0.26, −0.15, and −0.10 V, respectively. Further analysis shows that the unique property of boron that can intensely accept lone pair and back-donate the anti-bond of nitrogen contributes to the activation of inert triple bond. This work provides a new idea for the rational design of NRR catalyst and is of great significance for the future development of nitrogen reduction catalysts.

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Screening Highly Efficient Hetero-Diatomic Doped PC6 Electrocatalysts For Selective Nitrogen Reduction to Ammonia

Journal of The Electrochemical Society ◽

10.1149/1945-7111/ac3aba ◽

2021 ◽

Author(s):

Qiuling Jiang ◽

Yanan Meng ◽

Kai Li ◽

Ying Wang ◽

Zhijian Wu

Keyword(s):

Density Functional ◽

Rational Design ◽

Synergistic Effects ◽

Reduction Reaction ◽

Functional Theory ◽

Faradaic Efficiency ◽

Nitrogen Reduction ◽

Highly Efficient ◽

Metal Atoms ◽

Transition Metal Atoms

Abstract Searching for highly efficient electrocatalysts toward nitrogen reduction reaction (NRR) is an important but challenging task for nitrogen utilization in industry. Here we have systematically designed a series of hetero-diatomic catalysts (DACs), in which transition metal atoms (Ti, V, Cr, Mn, Fe, Co, and Ni) are dispersed on PC6 monolayer to form AB@PC6 (A, B= Ti, V, Cr, Mn, Fe, Co, and Ni). Employing density functional theory (DFT) calculation, the V and Cr co-doped PC6 monolayer (VCr@PC6) among the 21 AB@PC6 catalysts is the most promising catalyst due to its low limiting potential of -0.41V, relatively low energy barrier, and high ammonia selectivity toward hydrogen evolution reaction (HER). Insights on the high NRR activity of VCr@PC6 are also explored. The synergistic effect in DACs facilitates the electron transfer from metal pairs to PC6 monolayer, as well as suppresses the HER, leading to high selectivity and Faradaic efficiency. This work not only aims to seek the efficient DACs towards N2 reduction but also provides insights towards synergistic effects between hetero-atoms for the rational design of DACs.

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Morphological Attributes Govern CO2 Reduction on Mesoporous Carbon Nanosphere with Embedded Axial Co-N5 Sites

10.21203/rs.3.rs-999257/v1 ◽

2021 ◽

Author(s):

Youzhi Li ◽

Bo Wei ◽

Zhongjian Li ◽

Lei Fan ◽

Qike Jiang ◽

...

Keyword(s):

Mesoporous Carbon ◽

High Performance ◽

Density Functional ◽

Rational Design ◽

Co2 Reduction ◽

Catalytic Performance ◽

Reduction Reaction ◽

Single Atom ◽

High Turnover ◽

Morphological Attributes

Abstract Although single-atom catalysts (SACs) have been widely employed in the CO2 reduction reaction (CO2RR), the understanding regarding the effect of morphological attributes on catalytic performance are still lacking, which prevents the rational design of high-performance catalysts for electrochemical CO2RR. Here, we developed a novel catalyst with axial Co-N5 sites embedded on controllable mesoporous carbon nanosphere with different graded pore structures. Benefiting from the precise control of porosity, the influence of morphological attributes on catalytic performance was well revealed. In situ characterization combined with density functional theory (DFT) calculations revealed that axial N-coordination induced local d-p orbitals coupling enhancement of Co with oxides and the optimal pore size of 27 nm promoted the interfacial bonding characteristics, which facilitate both the COOH* generation and CO desorption. Consequently, A superior selectivity of nearly 100% at -0.8 V vs. RHE and commercially relevant current densities of >150 mA cm−2 could be achieved, and a strikingly high turnover frequency of 1.136*104 h−1 at -1.0 V has been obtained, superior to the most of Co-based catalysts.

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High-Entropy Alloys as Catalysts for the CO2 and CO Reduction Reactions

10.26434/chemrxiv.9850997.v1 ◽

2019 ◽

Author(s):

Jack Pedersen ◽

Thomas Batchelor ◽

Alexander Bagger ◽

Jan Rossmeisl

Keyword(s):

Density Functional ◽

Rational Design ◽

Hydrogen Adsorption ◽

Co Adsorption ◽

Reduction Reaction ◽

Supervised Machine Learning ◽

High Entropy Alloys ◽

High Entropy ◽

Co Reduction ◽

Disordered Alloy

Using the high-entropy alloys (HEAs) CoCuGaNiZn and AgAuCuPdPt as starting points we provide a framework for tuning the composition of disordered multi-metallic alloys to control the selectivity and activity of the reduction of carbon dioxide (CO2) to highly reduced compounds. By combining density functional theory (DFT) with supervised machine learning we predicted the CO and hydrogen (H) adsorption energies of all surface sites on the (111) surface of the two HEAs. This allowed an optimization for the HEA compositions with increased likelihood for sites with weak hydrogen adsorption{to suppress the formation of molecular hydrogen (H2) and with strong CO adsorption to favor the reduction of CO. This led to the discovery of several disordered alloy catalyst candidates for which selectivity towards highly reduced carbon compounds is expected, as well as insights into the rational design of disordered alloy catalysts for the CO2 and CO reduction reaction.

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Rational Design of Single-Atom Catalysts for Enhanced Electrocatalytic Nitrogen Reduction Reaction

The Journal of Physical Chemistry C ◽

10.1021/acs.jpcc.1c00742 ◽

2021 ◽

Author(s):

Sakshi Agarwal ◽

Ritesh Kumar ◽

Rakesh Arya ◽

Abhishek K. Singh

Keyword(s):

Rational Design ◽

Reduction Reaction ◽

Single Atom ◽

Nitrogen Reduction

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Fe3 Cluster Anchored on the C2N Monolayer for Efficient Electrochemical Nitrogen Fixation

Catalysts ◽

10.3390/catal10090974 ◽

2020 ◽

Vol 10 (9) ◽

pp. 974

Author(s):

Bing Han ◽

Haihong Meng ◽

Fengyu Li ◽

Jingxiang Zhao

Keyword(s):

Nitrogen Fixation ◽

First Principles ◽

Catalytic Performance ◽

Reduction Reaction ◽

First Principles Calculations ◽

Ammonia Gas ◽

Nitrogen Reduction ◽

Single Cluster ◽

Excellent Catalytic Performance ◽

Production Of Ammonia

Under the current double challenge of energy and the environment, an effective nitrogen reduction reaction (NRR) has become a very urgent need. However, the largest production of ammonia gas today is carried out by the Haber–Bosch process, which has many disadvantages, among which energy consumption and air pollution are typical. As the best alternative procedure, electrochemistry has received extensive attention. In this paper, a catalyst loaded with Fe3 clusters on the two-dimensional material C2N (Fe3@C2N) is proposed to achieve effective electrochemical NRR, and our first-principles calculations reveal that the stable Fe3@C2N exhibits excellent catalytic performance for electrochemical nitrogen fixation with a limiting potential of 0.57 eV, while also suppressing the major competing hydrogen evolution reaction. Our findings will open a new door for the development of non-precious single-cluster catalysts for effective nitrogen reduction reactions.

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Highly active and selective oxygen reduction to H2O2 on boron-doped carbon for high production rates

Nature Communications ◽

10.1038/s41467-021-24329-9 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yang Xia ◽

Xunhua Zhao ◽

Chuan Xia ◽

Zhen-Yu Wu ◽

Peng Zhu ◽

...

Keyword(s):

Oxygen Reduction ◽

Density Functional ◽

High Selectivity ◽

Density Functional Theory Calculations ◽

Reduction Reaction ◽

Production Rates ◽

Practical Applications ◽

Highly Active ◽

Boron Doped ◽

Oxidized Carbon

AbstractOxygen reduction reaction towards hydrogen peroxide (H2O2) provides a green alternative route for H2O2 production, but it lacks efficient catalysts to achieve high selectivity and activity simultaneously under industrial-relevant production rates. Here we report a boron-doped carbon (B-C) catalyst which can overcome this activity-selectivity dilemma. Compared to the state-of-the-art oxidized carbon catalyst, B-C catalyst presents enhanced activity (saving more than 210 mV overpotential) under industrial-relevant currents (up to 300 mA cm−2) while maintaining high H2O2 selectivity (85–90%). Density-functional theory calculations reveal that the boron dopant site is responsible for high H2O2 activity and selectivity due to low thermodynamic and kinetic barriers. Employed in our porous solid electrolyte reactor, the B-C catalyst demonstrates a direct and continuous generation of pure H2O2 solutions with high selectivity (up to 95%) and high H2O2 partial currents (up to ~400 mA cm−2), illustrating the catalyst’s great potential for practical applications in the future.

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Atomically Dispersed Fe-N4 Modified with Precisely Located S for Highly Efficient Oxygen Reduction

Nano-Micro Letters ◽

10.1007/s40820-020-00456-8 ◽

2020 ◽

Vol 12 (1) ◽

Cited By ~ 3

Author(s):

Yin Jia ◽

Xuya Xiong ◽

Danni Wang ◽

Xinxuan Duan ◽

Kai Sun ◽

...

Keyword(s):

Oxygen Reduction ◽

Density Functional ◽

Catalytic Performance ◽

Reduction Reaction ◽

Edge Structure ◽

Onset Potential ◽

Local Environments ◽

Half Wave ◽

Reaction Performance ◽

Specific Configuration

AbstractImmobilizing metal atoms by multiple nitrogen atoms has triggered exceptional catalytic activity toward many critical electrochemical reactions due to their merits of highly unsaturated coordination and strong metal-substrate interaction. Herein, atomically dispersed Fe-NC material with precise sulfur modification to Fe periphery (termed as Fe-NSC) was synthesized, X-ray absorption near edge structure analysis confirmed the central Fe atom being stabilized in a specific configuration of Fe(N3)(N–C–S). By enabling precisely localized S doping, the electronic structure of Fe-N4 moiety could be mediated, leading to the beneficial adjustment of absorption/desorption properties of reactant/intermediate on Fe center. Density functional theory simulation suggested that more negative charge density would be localized over Fe-N4 moiety after S doping, allowing weakened binding capability to *OH intermediates and faster charge transfer from Fe center to O species. Electrochemical measurements revealed that the Fe-NSC sample exhibited significantly enhanced oxygen reduction reaction performance compared to the S-free Fe-NC material (termed as Fe-NC), showing an excellent onset potential of 1.09 V and half-wave potential of 0.92 V in 0.1 M KOH. Our work may enlighten relevant studies regarding to accessing improvement on the catalytic performance of atomically dispersed M-NC materials by managing precisely tuned local environments of M-Nx moiety.

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Rationally designed indium oxide catalysts for CO2 hydrogenation to methanol with high activity and selectivity

Science Advances ◽

10.1126/sciadv.aaz2060 ◽

2020 ◽

Vol 6 (25) ◽

pp. eaaz2060 ◽

Cited By ~ 15

Author(s):

Shanshan Dang ◽

Bin Qin ◽

Yong Yang ◽

Hui Wang ◽

Jun Cai ◽

...

Keyword(s):

Density Functional ◽

Rational Design ◽

Density Functional Theory Calculations ◽

Catalytic Performance ◽

Oxide Catalysts ◽

Great Promise ◽

Experimental Realization ◽

Successful Case ◽

Catalytic Stability ◽

Pure Phases

Renewable energy-driven methanol synthesis from CO2 and green hydrogen is a viable and key process in both the “methanol economy” and “liquid sunshine” visions. Recently, In2O3-based catalysts have shown great promise in overcoming the disadvantages of traditional Cu-based catalysts. Here, we report a successful case of theory-guided rational design of a much higher performance In2O3 nanocatalyst. Density functional theory calculations of CO2 hydrogenation pathways over stable facets of cubic and hexagonal In2O3 predict the hexagonal In2O3(104) surface to have far superior catalytic performance. This promotes the synthesis and evaluation of In2O3 in pure phases with different morphologies. Confirming our theoretical prediction, a novel hexagonal In2O3 nanomaterial with high proportion of the exposed {104} surface exhibits the highest activity and methanol selectivity with high catalytic stability. The synergy between theory and experiment proves highly effective in the rational design and experimental realization of oxide catalysts for industry-relevant reactions.

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Unsaturated and Benzannulated N-Heterocyclic Carbene Complexes of Titanium and Hafnium: Impact on Catalysts Structure and Performance in Copolymerization of Cyclohexene Oxide with CO2

Molecules ◽

10.3390/molecules25194364 ◽

2020 ◽

Vol 25 (19) ◽

pp. 4364

Author(s):

Lakshmi Suresh ◽

Ralte Lalrempuia ◽

Jonas B. Ekeli ◽

Francis Gillis-D’Hamers ◽

Karl W. Törnroos ◽

...

Keyword(s):

Density Functional ◽

Lone Pair ◽

Catalytic Performance ◽

Nbo Analysis ◽

Cyclohexene Oxide ◽

Group 4 ◽

Low Co2 ◽

And Performance ◽

High Yields ◽

Oxygen Lone Pair

Tridentate, bis-phenolate N-heterocyclic carbenes (NHCs) are among the ligands giving the most selective and active group 4-based catalysts for the copolymerization of cyclohexene oxide (CHO) with CO2. In particular, ligands based on imidazolidin-2-ylidene (saturated NHC) moieties have given catalysts which exclusively form polycarbonate in moderate-to-high yields even under low CO2 pressure and at low copolymerization temperatures. Here, to evaluate the influence of the NHC moiety on the molecular structure of the catalyst and its performance in copolymerization, we extend this chemistry by synthesizing and characterizing titanium complexes bearing tridentate bis-phenolate imidazol-2-ylidene (unsaturated NHC) and benzimidazol-2-ylidene (benzannulated NHC) ligands. The electronic properties of the ligands and the nature of their bonds to titanium are studied using density functional theory (DFT) and natural bond orbital (NBO) analysis. The metal–NHC bond distances and bond strengths are governed by ligand-to-metal σ- and π-donation, whereas back-donation directly from the metal to the NHC ligand seems to be less important. The NHC π-acceptor orbitals are still involved in bonding, as they interact with THF and isopropoxide oxygen lone-pair donor orbitals. The new complexes are, when combined with [PPN]Cl co-catalyst, selective in polycarbonate formation. The highest activity, albeit lower than that of the previously reported Ti catalysts based on saturated NHC, was obtained with the benzannulated NHC-Ti catalyst. Attempts to synthesize unsaturated and benzannulated NHC analogues based on Hf invariably led, as in earlier work with Zr, to a mixture of products that include zwitterionic and homoleptic complexes. However, the benzannulated NHC-Hf complexes were obtained as the major products, allowing for isolation. Although these complexes selectively form polycarbonate, their catalytic performance is inferior to that of analogues based on saturated NHC.

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