Increasing exposure of atomically dispersed Ni sites via constructing hierarchically porous supports for enhanced electrochemical CO2 reduction

Liu, Youzhen; Li, Chenhui; Loubidi, Mohammed; Wang, Dongdong; Zhou, Ling; Niu, Songyang; Liu, Qingquan

doi:10.1016/j.cej.2021.131414

Cited by 10 publications

(13 citation statements)

References 51 publications

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“…On the contrary, the Fe-SAC shows a large gap of current density to catalyze NO 3 RR than the reaction without nitrate ions but negligible response to the CO 2 RR. The distinguishing activities originated from that the Ni sites in Ni-SAC are favorable for the absorption and activation of CO 2 but the Fe sites in Fe-SAC tend to be occupied by the nitrate reactant [27][28][29][30] . The subsequent product analysis of relevant reactions demonstrates that the Faradaic efficiency (FE) of CO 2 RR to CO on Ni-SAC is up to 86.9% but a much lower FE of 19.9% was obtained for NH 3 generation at −1.5 V versus RHE.…”

Section: Realizing Coordinated Activation and Promoting C-n Coupling ...mentioning

confidence: 99%

Identifying and tailoring C–N coupling site for efficient urea synthesis over diatomic Fe–Ni catalyst

et al. 2022

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Electrocatalytic urea synthesis emerged as the promising alternative of Haber–Bosch process and industrial urea synthetic protocol. Here, we report that a diatomic catalyst with bonded Fe–Ni pairs can significantly improve the efficiency of electrochemical urea synthesis. Compared with isolated diatomic and single-atom catalysts, the bonded Fe–Ni pairs act as the efficient sites for coordinated adsorption and activation of multiple reactants, enhancing the crucial C–N coupling thermodynamically and kinetically. The performance for urea synthesis up to an order of magnitude higher than those of single-atom and isolated diatomic electrocatalysts, a high urea yield rate of 20.2 mmol h−1 g−1 with corresponding Faradaic efficiency of 17.8% has been successfully achieved. A total Faradaic efficiency of about 100% for the formation of value-added urea, CO, and NH3 was realized. This work presents an insight into synergistic catalysis towards sustainable urea synthesis via identifying and tailoring the atomic site configurations.

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Section: Realizing Coordinated Activation and Promoting C-n Coupling ...mentioning

confidence: 99%

Identifying and tailoring C–N coupling site for efficient urea synthesis over diatomic Fe–Ni catalyst

et al. 2022

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“…valent state between 0 and +2, which is consistent with the XPS data and those in the previously reported single-atom Ni electrocatalysts. 9,35 The coordination environment of hp-BioNC-Ni was disclosed from extended x-ray absorption fine structure (EXAFS) analysis. As shown in Figure 3F, a dominant peak at 1.44 Å is observed in the Fourier transformed (FT) EXAFS spectrum of hp-BioNC-Ni, which can be attributed to Ni-N coordination 9,35 and is very close to that in NiPc (1.50 Å).…”

Section: Physical Characterizationmentioning

confidence: 99%

Porosity engineering of biochar‐based single‐atom Ni catalysts to promote CO₂ electroreduction over a broad potential window

et al. 2023

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Developing electrocatalysts for CO2 electroreduction with high activity and superior selectivity is extremely important and desirable from both academic and industrial perspectives. However, owing to competition with hydrogen evolution, highly efficient CO2 reduction is mostly achieved with high CO selectivity in a narrow potential range, which is incompatible with a large cell voltage required for industrial‐level CO2 reduction. Herein, we report an effective strategy to regulate CO2 reduction performances of single‐atom Ni electrocatalysts over a broad potential window by engineering their pore structures (micropores, mesopores, or hierarchical pores with both micropores and mesopores). It is revealed that hierarchically pores can significantly promote CO2 reduction efficiency of single‐atom Ni electrocatalysts. The hierarchically porous electrocatalyst achieves a maximum CO Faradaic efficiency (FECO) of 97.4% at −1.2 V (vs. RHE) and shows high FECO of >85% over a broad potential window from −0.7 to −1.7 V, much superior to electrocatalysts with other pore structures. More impressively, turnover frequency of the hierarchically porous electrocatalyst increases rapidly with increasing the applied potential and reaches 50,067 h−1 at −1.7 V. Such CO2 electroreduction promotion could be attributed to a synergistic effect of micropores for enhancing CO2 adsorption and mesopores for facilitating rapid release of product bubbles, which significantly improves CO2 reduction and suppresses hydrogen evolution.

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“…[36][37][38] In this work, N-doped carbon electrocatalysts were fabricated by the pyrolysis of the Zncoordination polymer, as shown in Figures 1A and S1, which derived from the mixing and grinding of zinc salts and 2-methylimidazole ligands. 39 The obtained N-doped carbon networks were denoted N-C-900, N-C-950, N-C-1000, and N-C-1050 according to the annealing temperature (see the Methods section for more details).…”

Section: Physical Characterization Of Electrocatalystsmentioning

confidence: 99%

Balancing sub‐reaction activity to boost electrocatalytic urea synthesis using a metal‐free electrocatalyst

Chen

Zhu

et al. 2023

Carbon Energy

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Electrocatalytic urea synthesis via coupling of nitrate with CO2 is considered as a promising alternative to the industrial urea synthetic process. However, the requirement of sub‐reaction (NO3RR and CO2RR) activities for efficient urea synthesis is not clear and the related reaction mechanisms remain obscure. Here, the construction, breaking, and rebuilding of the sub‐reaction activity balance would be accompanied by the corresponding regulation in urea synthesis, and the balance of sub‐reaction activities was proven to play a vital role in efficient urea synthesis. With rational design, a urea yield rate of 610.6 mg h−1 gcat.−1 was realized on the N‐doped carbon electrocatalyst, superior to that of noble‐metal electrocatalysts. Based on the operando SR‐FTIR measurements, we proposed that urea synthesis arises from the coupling of *NO and *CO to generate the key intermediate of *OCNO. This work provides new insights and guidelines into urea synthesis from the aspect of activity balance.

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Increasing exposure of atomically dispersed Ni sites via constructing hierarchically porous supports for enhanced electrochemical CO2 reduction

Cited by 10 publications

References 51 publications

Identifying and tailoring C–N coupling site for efficient urea synthesis over diatomic Fe–Ni catalyst

Identifying and tailoring C–N coupling site for efficient urea synthesis over diatomic Fe–Ni catalyst

Porosity engineering of biochar‐based single‐atom Ni catalysts to promote CO₂ electroreduction over a broad potential window

Balancing sub‐reaction activity to boost electrocatalytic urea synthesis using a metal‐free electrocatalyst

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Increasing exposure of atomically dispersed Ni sites via constructing hierarchically porous supports for enhanced electrochemical CO2 reduction

Cited by 10 publications

References 51 publications

Identifying and tailoring C–N coupling site for efficient urea synthesis over diatomic Fe–Ni catalyst

Identifying and tailoring C–N coupling site for efficient urea synthesis over diatomic Fe–Ni catalyst

Porosity engineering of biochar‐based single‐atom Ni catalysts to promote CO2 electroreduction over a broad potential window

Balancing sub‐reaction activity to boost electrocatalytic urea synthesis using a metal‐free electrocatalyst

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Porosity engineering of biochar‐based single‐atom Ni catalysts to promote CO₂ electroreduction over a broad potential window