Achieving convenient CO2 electroreduction and photovoltage in tandem using potential-insensitive disordered Ag nanoparticles

AbstractSurface chemistry modification represents a promising strategy to tailor the adsorption and activation of reaction intermediates for enhancing activity. Herein, we designed a surface oxygen-injection strategy to tune the electronic structure of SnS2 nanosheets, which showed effectively enhanced electrocatalytic activity and selectivity of CO2 reduction to formate and syngas (CO and H2). The oxygen-injection SnS2 nanosheets exhibit a remarkable Faradaic efficiency of 91.6% for carbonaceous products with a current density of 24.1 mA cm−2 at −0.9 V vs RHE, including 83.2% for formate production and 16.5% for syngas with the CO/H2 ratio of 1:1. By operando X-ray absorption spectroscopy, we unravel the in situ surface oxygen doping into the matrix during reaction, thereby optimizing the Sn local electronic states. Operando synchrotron radiation infrared spectroscopy along with theoretical calculations further reveals that the surface oxygen doping facilitated the CO2 activation and enhanced the affinity for HCOO* species. This result demonstrates the potential strategy of surface oxygen injection for the rational design of advanced catalysts for CO2 electroreduction.

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Double sulfur vacancies by lithium tuning enhance CO2 electroreduction to n-propanol

Nature Communications ◽

10.1038/s41467-021-21901-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Chen Peng ◽

Gan Luo ◽

Junbo Zhang ◽

Menghuan Chen ◽

Zhiqiang Wang ◽

...

Keyword(s):

Anion Vacancy ◽

High Energy ◽

Hydrogen Electrode ◽

Cycle Number ◽

Faradaic Efficiency ◽

Flow Cells ◽

Forming Mechanism ◽

Co2 Electroreduction ◽

Tuning Strategy ◽

Partial Current

AbstractElectrochemical CO2 reduction can produce valuable products with high energy densities but the process is plagued by poor selectivities and low yields. Propanol represents a challenging product to obtain due to the complicated C3 forming mechanism that requires both stabilization of *C2 intermediates and subsequent C1–C2 coupling. Herein, density function theory calculations revealed that double sulfur vacancies formed on hexagonal copper sulfide can feature as efficient electrocatalytic centers for stabilizing both CO* and OCCO* dimer, and further CO–OCCO coupling to form C3 species, which cannot be realized on CuS with single or no sulfur vacancies. The double sulfur vacancies were then experimentally synthesized by an electrochemical lithium tuning strategy, during which the density of sulfur vacancies was well-tuned by the charge/discharge cycle number. The double sulfur vacancy-rich CuS catalyst exhibited a Faradaic efficiency toward n-propanol of 15.4 ± 1% at −1.05 V versus reversible hydrogen electrode in H-cells, and a high partial current density of 9.9 mA cm−2 at −0.85 V in flow-cells, comparable to the best reported electrochemical CO2 reduction toward n-propanol. Our work suggests an attractive approach to create anion vacancy pairs as catalytic centers for multi-carbon-products.

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CuZnAl-Oxide Nanopyramidal Mesoporous Materials for the Electrocatalytic CO2 Reduction to Syngas: Tuning of H2/CO Ratio

Nanomaterials ◽

10.3390/nano11113052 ◽

2021 ◽

Vol 11 (11) ◽

pp. 3052

Author(s):

Hilmar Guzmán ◽

Daniela Roldán ◽

Adriano Sacco ◽

Micaela Castellino ◽

Marco Fontana ◽

...

Keyword(s):

Noble Metals ◽

Co2 Reduction ◽

Reduction Process ◽

Mesoporous Structure ◽

Catalytic Performance ◽

H2 Production ◽

Ambient Conditions ◽

Transfer Resistance ◽

Faradaic Efficiency ◽

Co2 Electroreduction

Inspired by the knowledge of the thermocatalytic CO2 reduction process, novel nanocrystalline CuZnAl-oxide based catalysts with pyramidal mesoporous structures are here proposed for the CO2 electrochemical reduction under ambient conditions. The XPS analyses revealed that the co-presence of ZnO and Al2O3 into the Cu-based catalyst stabilize the CuO crystalline structure and introduce basic sites on the ternary as-synthesized catalyst. In contrast, the as-prepared CuZn- and Cu-based materials contain a higher amount of superficial Cu0 and Cu1+ species. The CuZnAl-catalyst exhibited enhanced catalytic performance for the CO and H2 production, reaching a Faradaic efficiency (FE) towards syngas of almost 95% at −0.89 V vs. RHE and a remarkable current density of up to 90 mA cm−2 for the CO2 reduction at −2.4 V vs. RHE. The physico-chemical characterizations confirmed that the pyramidal mesoporous structure of this material, which is constituted by a high pore volume and small CuO crystals, plays a fundamental role in its low diffusional mass-transfer resistance. The CO-productivity on the CuZnAl-catalyst increased at more negative applied potentials, leading to the production of syngas with a tunable H2/CO ratio (from 2 to 7), depending on the applied potential. These results pave the way to substitute state-of-the-art noble metals (e.g., Ag, Au) with this abundant and cost-effective catalyst to produce syngas. Moreover, the post-reaction analyses demonstrated the stabilization of Cu2O species, avoiding its complete reduction to Cu0 under the CO2 electroreduction conditions.

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Rational design of a polypyrrole-based competent bifunctional magnetic nanocatalyst

RSC Advances ◽

10.1039/c9ra02544h ◽

2019 ◽

Vol 9 (32) ◽

pp. 18245-18255 ◽

Cited By ~ 3

Author(s):

Wael A. Amer ◽

Basel Al-saida ◽

Mohamad M. Ayad

Keyword(s):

Efficient Method ◽

Ag Nanoparticles ◽

Rational Design ◽

Synergetic Effect ◽

Magnetic Nanocomposite ◽

Magnetic Nanocatalyst ◽

Catalytic Activities

An efficient method to synthesize a magnetic nanocomposite with dual catalytic activities with a synergetic effect between Ag nanoparticles, polypyrrole and TiO2 is described.

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Tracking structural evolution: operando regenerative CeOx/Bi interface structure for high-performance CO2 electroreduction

National Science Review ◽

10.1093/nsr/nwaa187 ◽

2020 ◽

Author(s):

Ruichao Pang ◽

Pengfei Tian ◽

Hongliang Jiang ◽

Minghui Zhu ◽

Xiaozhi Su ◽

...

Keyword(s):

High Performance ◽

Density Functional ◽

Structural Evolution ◽

Density Functional Theory Calculations ◽

Active Phase ◽

Interface Structure ◽

Operating Conditions ◽

Faradaic Efficiency ◽

Co2 Electroreduction ◽

Water Activation

Abstract Unveiling the structural evolution and working mechanism of catalysts under realistic operating conditions is crucial for the design of efficient electrocatalysts for CO2 electroreduction, yet remains highly challenging. Here, by virtue of operando structural measurements at multiscale levels, it is identified under CO2 electroreduction conditions that an as-prepared CeO2/BiOCl precatalyst gradually evolves into CeOx/Bi interface structure with enriched Ce3+ species, which serves as the real catalytically active phase. The derived CeOx/Bi interface structure compared to pure Bi counterpart delivers substantially enhanced performance with a formate Faradaic efficiency approaching 90% for 24 hours in a wide potential window. The formate Faradaic efficiency can be further increased by using isotope D2O instead of H2O. Density functional theory calculations suggest that the regenerative CeOx/Bi interfacial sites can not only promote water activation to increase local *H species for CO2 protonation appropriately, but also stabilize the key intermediate *OCHO in formate pathway.

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A Universal Principle to Accurately Synthesize Atomically Dispersed Metal–N4 Sites for CO2 Electroreduction

Nano-Micro Letters ◽

10.1007/s40820-020-00443-z ◽

2020 ◽

Vol 12 (1) ◽

Cited By ~ 7

Author(s):

Wanzhen Zheng ◽

Feng Chen ◽

Qi Zeng ◽

Zhongjian Li ◽

Bin Yang ◽

...

Keyword(s):

Metal Atom ◽

Peak Power ◽

Electric Energy ◽

Energy Output ◽

Central Metal ◽

Faradaic Efficiency ◽

Onset Potential ◽

Co Conversion ◽

Co2 Electroreduction ◽

Specific Selectivity

AbstractAtomically dispersed metal–nitrogen sites-anchored carbon materials have been developed as effective catalysts for CO2 electroreduction (CO2ER), but they still suffer from the imprecisely control of type and coordination number of N atoms bonded with central metal. Herein, we develop a family of single metal atom bonded by N atoms anchored on carbons (SAs–M–N–C, M = Fe, Co, Ni, Cu) for CO2ER, which composed of accurate pyrrole-type M–N4 structures with isolated metal atom coordinated by four pyrrolic N atoms. Benefitting from atomically coordinated environment and specific selectivity of M–N4 centers, SAs–Ni–N–C exhibits superior CO2ER performance with onset potential of − 0.3 V, CO Faradaic efficiency (F.E.) of 98.5% at − 0.7 V, along with low Tafel slope of 115 mV dec−1 and superior stability of 50 h, exceeding all the previously reported M–N–C electrocatalysts for CO2-to-CO conversion. Experimental results manifest that the different intrinsic activities of M–N4 structures in SAs–M–N–C result in the corresponding sequence of Ni > Fe > Cu > Co for CO2ER performance. An integrated Zn–CO2 battery with Zn foil and SAs–Ni–N–C is constructed to simultaneously achieve CO2-to-CO conversion and electric energy output, which delivers a peak power density of 1.4 mW cm−2 and maximum CO F.E. of 93.3%.

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Continuous Electrochemical Reduction of CO2 to Formate: Comparative Study of the Influence of the Electrode Configuration with Sn and Bi-Based Electrocatalysts

Molecules ◽

10.3390/molecules25194457 ◽

2020 ◽

Vol 25 (19) ◽

pp. 4457 ◽

Cited By ~ 1

Author(s):

Guillermo Díaz-Sainz ◽

Manuel Alvarez-Guerra ◽

Angel Irabien

Keyword(s):

Formic Acid ◽

Raw Materials ◽

Value Added ◽

Gas Diffusion ◽

Faradaic Efficiency ◽

Co2 Electroreduction ◽

Current Densities ◽

Reduction Of Co2 ◽

Value Added Products ◽

Electrocatalytic Reduction Of Co2

Climate change has become one of the most important challenges in the 21st century, and the electroreduction of CO2 to value-added products has gained increasing importance in recent years. In this context, formic acid or formate are interesting products because they could be used as raw materials in several industries as well as promising fuels in fuel cells. Despite the great number of studies published in the field of the electrocatalytic reduction of CO2 to formic acid/formate working with electrocatalysts of different nature and electrode configurations, few of them are focused on the comparison of different electrocatalyst materials and electrode configurations. Therefore, this work aims at presenting a rigorous and comprehensive comparative assessment of different experimental data previously published after many years of research in different working electrode configurations and electrocatalysts in a continuous mode with a single pass of the inputs through the reactor. Thus, the behavior of the CO2 electroreduction to formate is compared operating with Sn and Bi-based materials under Gas Diffusion Electrodes (GDEs) and Catalyst Coated Membrane Electrodes (CCMEs) configurations. Considering the same electrocatalyst, the use of CCMEs improves the performance in terms of formate concentration and energy consumption. Nevertheless, higher formate rates can be achieved with GDEs because they allow operation at higher current densities of up to 300 mA·cm−2. Bi-based-GDEs outperformed Sn-GDEs in all the figures of merit considered. The comparison also highlights that in CCME configuration, the employ of Bi-based-electrodes enhanced the behavior of the process, increasing the formate concentration by 35% and the Faradaic efficiency by 11%.

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Electrochemical Reduction of CO2 to Formate on Easily Prepared Carbon-Supported Bi Nanoparticles

Molecules ◽

10.3390/molecules24112032 ◽

2019 ◽

Vol 24 (11) ◽

pp. 2032 ◽

Cited By ~ 12

Author(s):

Beatriz Ávila-Bolívar ◽

Leticia García-Cruz ◽

Vicente Montiel ◽

José Solla-Gullón

Keyword(s):

Electron Microscopy ◽

Electrochemical Reduction ◽

Carbon Paper ◽

Faradaic Efficiency ◽

X Ray ◽

Bismuth Nanoparticles ◽

Electrode Potentials ◽

Co2 Electroreduction ◽

Reduction Of Co2 ◽

Bi Nanoparticles

Herein, the electrochemical reduction of CO2 to formate on carbon-supported bismuth nanoparticles is reported. Carbon-supported Bi nanoparticles (about 10 nm in size) were synthesized using a simple, fast and scalable approach performed under room conditions. The so-prepared Bi electrocatalyst was characterized by different physicochemical techniques, including transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction and subsequently air-brushed on a carbon paper to prepare electrodes. These electrodes were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy and also by cyclic voltammetry. Finally, CO2 electroreduction electrolyses were performed at different electrode potentials for 3 h. At the optimal electrode potential (−1.6 V vs AgCl/Ag), the concentration of formate was about 77 mM with a faradaic efficiency of 93 ± 2.5%. A 100% faradaic efficiency was found at a lower potential (−1.5 V vs AgCl/Ag) with a formate concentration of about 55 mM. In terms of stability, we observed that after about 70 h (in 3 h electrolysis experiments at different potentials), the electrode deactivates due to the gradual loss of metal as shown by SEM/EDX analyses of the deactivated electrodes.

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Impedimetric Characterization of Bioelectronic Nano-Antennae

10.26434/chemrxiv.12601883.v3 ◽

2020 ◽

Author(s):

Andie Robinson ◽

Akhil Jain ◽

Ruman Rahman ◽

Sidahmed Abayzeed ◽

Richard Hague ◽

...

Keyword(s):

Tissue Engineering ◽

Electric Fields ◽

Rational Design ◽

Au Nanoparticle ◽

Drive Current ◽

Cellular Behavior ◽

Bipolar Electrodes ◽

Electrochemical Systems ◽

Bioelectronic Medicine

<p>The merging of electronics with biology at the nanoscale holds considerable promise for sensing and modulating cellular behavior. Advancing our understanding of nano-bioelectronics will facilitate development and enable applications in biosensing, tissue engineering and bioelectronic medicine. However, studies investigating the electrical effects when merging wireless conductive nanoelectrodes with biology are lacking. Consequently, a new tool is required to develop a greater understanding of the bioelectrical effects of merging conductive nanoparticles with biology. Herein, this challenge is addressed by developing an impedimetric method to evaluate bipolar electrochemical systems (BESs) that could act as nano-antennas. A theoretical framework is provided, using impedance to determine if conductive nanoparticles can be polarized and used to drive current. It is then demonstrated that 125 nm Au nanoparticle bipolar electrodes (BPEs) could be sensed in the presence of biology when incorporated intracellularly at 500 mg/ml, using water and PBS as electrolytes. These results highlight how nanoscale BPEs act within biological systems and characterize their behavior in electric fields. This research will impact on the rational design of using BPE systems in biology for both sensing and actuating applications.</p>

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Impedimetric Characterization of Bioelectronic Nano-Antennae

10.26434/chemrxiv.12601883 ◽

2020 ◽

Author(s):

Andie Robinson ◽

Akhil Jain ◽

Ruman Rahman ◽

Sidahmed Abayzeed ◽

Richard Hague ◽

...

Keyword(s):

Tissue Engineering ◽

Electric Fields ◽

Rational Design ◽

Au Nanoparticle ◽

Drive Current ◽

Cellular Behavior ◽

Bipolar Electrodes ◽

Electrochemical Systems ◽

Bioelectronic Medicine

<p>The merging of electronics with biology at the nanoscale holds considerable promise for sensing and modulating cellular behavior. Advancing our understanding of nano-bioelectronics will facilitate development and enable applications in biosensing, tissue engineering and bioelectronic medicine. However, studies investigating the electrical effects when merging wireless conductive nanoelectrodes with biology are lacking. Consequently, a new tool is required to develop a greater understanding of the bioelectrical effects of merging conductive nanoparticles with biology. Herein, this challenge is addressed by developing an impedimetric method to evaluate bipolar electrochemical systems (BESs) that could act as nano-antennas. A theoretical framework is provided, using impedance to determine if conductive nanoparticles can be polarized and used to drive current. It is then demonstrated that 125 nm Au nanoparticle bipolar electrodes (BPEs) could be sensed in the presence of biology when incorporated intracellularly at 500 mg/ml, using water and PBS as electrolytes. These results highlight how nanoscale BPEs act within biological systems and characterize their behavior in electric fields. This research will impact on the rational design of using BPE systems in biology for both sensing and actuating applications.</p>

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