Au aerogel for selective CO2 electroreduction to CO: ultrafast preparation with high performance

2021 ◽  
Author(s):  
Shenglin Yan ◽  
Samah Awadh Mahyoub ◽  
Jing Lin ◽  
Chunxiao Zhang ◽  
Qing Hu ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Gelation Time ◽  
Active Surface ◽  
Active Surface Area ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
External Force Field ◽  
Co2 Electroreduction ◽  
Turbulence Mixing

Abstract Noble metal aerogels (NMAs) have been used in a variety of (photo-)electrocatalytic reactions, but pure Au aerogels (AG) have not been used in CO2 electroreduction to date. To explore the potential application in this direction, AG was prepared to be used as the cathode in CO2 electroreduction to CO. However, the gelation time of NMAs is usually very long, up to several weeks. Here, an excess NaBH4 and turbulence mixing-promoted gelation approach was developed by introducing magnetic stirring as an external force field, which therefore greatly shortened the formation time of Au gels to several seconds. The AG-3 (AG with Au loading of 0.003 g) exhibited a high CO Faradaic efficiency (FE) of 95.6% at an extremely low overpotential of 0.39 V, and over 91% of CO FE was reached in a wide window of -0.4 ~ -0.7 V vs. the reversible hydrogen electrode (RHE). Partial current density in CO was measured to be -19.35 mA cm-2 at -0.8 V vs. RHE under 1 atm of CO2. The excellent performance should be ascribed to its porous structure, abundant active sites, and large electrochemical active surface area. It provides a new method for preparation of AG with ultrafast gelation time and large production at room temperature, and the resulting pure AG was for the first time used in the field of CO2 electroreduction.

scholarly journals Zn- and Ti-Doped SnO2 for Enhanced Electroreduction of Carbon Dioxide

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2354
Author(s):  
Katarzyna Bejtka ◽  
Nicolò B. D. Monti ◽  
Adriano Sacco ◽  
Micaela Castellino ◽  
Samuele Porro ◽  
...  
Keyword(s):  
Formic Acid ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Active Surface ◽  
Active Surface Area ◽  
Co2 Conversion ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Wet Impregnation

The electrocatalytic reduction of CO2 into useful fuels, exploiting rationally designed, inexpensive, active, and selective catalysts, produced through easy, quick, and scalable routes, represents a promising approach to face today’s climate challenges and energy crisis. This work presents a facile strategy for the preparation of doped SnO2 as an efficient electrocatalyst for the CO2 reduction reaction to formic acid and carbon monoxide. Zn or Ti doping was introduced into a mesoporous SnO2 matrix via wet impregnation and atomic layer deposition. It was found that doping of SnO2 generates an increased amount of oxygen vacancies, which are believed to contribute to the CO2 conversion efficiency, and among others, Zn wet impregnation resulted the most efficient process, as confirmed by X-ray photoelectron spectroscopy analysis. Electrochemical characterization and active surface area evaluation show an increase of availability of surface active sites. In particular, the introduction of Zn elemental doping results in enhanced performance for formic acid formation, in comparison to un-doped SnO2 and other doped SnO2 catalysts. At −0.99 V versus reversible hydrogen electrode, the total faradaic efficiency for CO2 conversion reaches 80%, while the partial current density is 10.3 mA cm−2. These represent a 10% and a threefold increases for faradaic efficiency and current density, respectively, with respect to the reference un-doped sample. The enhancement of these characteristics relates to the improved charge transfer and conductivity with respect to bare SnO2.

Hollow structure engineering of FeCo alloy nanoparticles electrospun in nitrogen-doped carbon enables high performance flexible all-solid-state zinc–air batteries

2020 ◽  
Vol 4 (4) ◽  
pp. 1747-1753 ◽  
Author(s):  
Yuanyuan Ma ◽  
Wenjie Zang ◽  
Afriyanti Sumboja ◽  
Lu Mao ◽  
Ximeng Liu ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Hollow Structure ◽  
Active Surface ◽  
Oxygen Electrode ◽  
Active Surface Area ◽  
Active Components ◽  
Nitrogen Doped Carbon ◽  
Structure Engineering ◽  
Kinetics Of

Hollow structuring of active components is an effective strategy to improve the kinetics of oxygen electrode catalysts, arising from the increased the active surface area, the defects on the exposed surface, and the accessible active sites.

scholarly journals Atomically Dispersed Fe-Co Bimetallic Catalysts for the Promoted Electroreduction of Carbon Dioxide

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Zhangsen Chen ◽  
Gaixia Zhang ◽  
Yuren Wen ◽  
Ning Chen ◽  
Weifeng Chen ◽  
...  
Keyword(s):  
Bimetallic Catalysts ◽  
Active Sites ◽  
High Performance ◽  
High Selectivity ◽  
Bimetallic Catalyst ◽  
Hydrogen Electrode ◽  
Zeolitic Imidazolate Framework ◽  
Faradaic Efficiency ◽  
Dispersed Catalysts ◽  
Wide Potential

AbstractThe electroreduction reaction of CO2 (ECO2RR) requires high-performance catalysts to convert CO2 into useful chemicals. Transition metal-based atomically dispersed catalysts are promising for the high selectivity and activity in ECO2RR. This work presents a series of atomically dispersed Co, Fe bimetallic catalysts by carbonizing the Fe-introduced Co-zeolitic-imidazolate-framework (C–Fe–Co–ZIF) for the syngas generation from ECO2RR. The synergistic effect of the bimetallic catalyst promotes CO production. Compared to the pure C–Co–ZIF, C–Fe–Co–ZIF facilitates CO production with a CO Faradaic efficiency (FE) boost of 10%, with optimal FECO of 51.9%, FEH2 of 42.4% at − 0.55 V, and CO current density of 8.0 mA cm−2 at − 0.7 V versus reversible hydrogen electrode (RHE). The H2/CO ratio is tunable from 0.8 to 4.2 in a wide potential window of − 0.35 to − 0.8 V versus RHE. The total FECO+H2 maintains as high as 93% over 10 h. The proper adding amount of Fe could increase the number of active sites and create mild distortions for the nanoscopic environments of Co and Fe, which is essential for the enhancement of the CO production in ECO2RR. The positive impacts of Cu–Co and Ni–Co bimetallic catalysts demonstrate the versatility and potential application of the bimetallic strategy for ECO2RR.

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

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.

scholarly journals High-Performance Lead-Acid Batteries Enabled by Pb and PbO2 Nanostructured Electrodes: Effect of Operating Temperature

2021 ◽  
Vol 11 (14) ◽  
pp. 6357
Author(s):  
Roberto Luigi Oliveri ◽  
Maria Grazia Insinga ◽  
Simone Pisana ◽  
Bernardo Patella ◽  
Giuseppe Aiello ◽  
...  
Keyword(s):  
High Performance ◽  
Active Material ◽  
Active Surface ◽  
Effect Of Temperature ◽  
Active Surface Area ◽  
Polycarbonate Membrane ◽  
Nanostructured Electrodes ◽  
Lead Acid Batteries ◽  
Improved Stability ◽  
Lead Acid

Lead-acid batteries are now widely used for energy storage, as result of an established and reliable technology. In the last decade, several studies have been carried out to improve the performance of this type of batteries, with the main objective to replace the conventional plates with innovative electrodes with improved stability, increased capacity and a larger active surface. Such studies ultimately aim to improve the kinetics of electrochemical conversion reactions at the electrode-solution interface and to guarantee a good electrical continuity during the repeated charge/discharge cycles. To achieve these objectives, our contribution focuses on the employment of nanostructured electrodes. In particular, we have obtained nanostructured electrodes in Pb and PbO2 through electrosynthesis in a template consisting of a nanoporous polycarbonate membrane. These electrodes are characterized by a wider active surface area, which allows for a better use of the active material, and for a consequent increased specific energy compared to traditional batteries. In this research, the performance of lead-acid batteries with nanostructured electrodes was studied at 10 C at temperatures of 25, −20 and 40 °C in order to evaluate the efficiency and the effect of temperature on electrode morphology. The batteries were assembled using both nanostructured electrodes and an AGM-type separator used in commercial batteries.

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

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.

scholarly journals A Pd/MnO2 Electrocatalyst for Nitrogen Reduction to Ammonia under Ambient Conditions

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 802
Author(s):  
Chang Sun ◽  
Yingxin Mu ◽  
Yuxin Wang
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Pd Nanoparticles ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Transmission Electron ◽  
Alternative Approach ◽  
Supported Pd

Electrochemical ammonia synthesis, which is an alternative approach to the Haber–Bosch process, has attracted the attention of researchers because of its advantages including mild working conditions, environmental protection, and simple process. However, the biggest problem in this field is the lack of high-performance catalysts. Here, we report high-efficiency electroreduction of N2 to NH3 on γ-MnO2-supported Pd nanoparticles (Pd/γ-MnO2) under ambient conditions, which exhibits excellent catalytic activity with an NH3 yield rate of 19.72 μg·mg−1Pd h−1 and a Faradaic efficiency of 8.4% at −0.05 V vs. the reversible hydrogen electrode (RHE). X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterization shows that Pd nanoparticles are homogeneously dispersed on the γ-MnO2. Pd/γ-MnO2 outperforms other catalysts including Pd/C and γ-MnO2 because of its synergistic catalytic effect between Pd and Mn.

scholarly journals Exposed facet-controlled N2 electroreduction on distinct Pt3Fe nanostructures of nanocubes, nanorods and nanowires

2020 ◽  
Author(s):  
Wu Tong ◽  
Bolong Huang ◽  
Pengtang Wang ◽  
Qi Shao ◽  
Xiaoqing Huang
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Active Surface ◽  
Reduction Reaction ◽  
Active Surface Area ◽  
Hydrogen Electrode ◽  
Functional Theory ◽  
Effective Strategies ◽  
Exposed Facet ◽  
Coupling Correlation

Abstract Understanding the correlation between exposed surfaces and performances of controlled nanocatalysts can aid effective strategies to enhance electrocatalysis, but this is as yet unexplored for the nitrogen reduction reaction (NRR). Here, we first report controlled synthesis of well-defined Pt3Fe nanocrystals with tunable morphologies (nanocube, nanorod and nanowire) as ideal model electrocatalysts for investigating the NRR on different exposed facets. The detailed electrocatalytic studies reveal that the Pt3Fe nanocrystals exhibit shape-dependent NRR electrocatalysis. The optimized Pt3Fe nanowires bounded with high-index facets exhibit excellent selectivity (no N2H4 is detected), high activity with NH3 yield of 18.3 μg h−1 mg−1cat (0.52 μg h−1 cm−2ECSA; ECSA: electrochemical active surface area) and Faraday efficiency of 7.3% at −0.05 V versus reversible hydrogen electrode, outperforming the {200} facet-enclosed Pt3Fe nanocubes and {111} facet-enclosed Pt3Fe nanorods. They also show good stability with negligible activity change after five cycles. Density functional theory calculations reveal that, with high-indexed facet engineering, the Fe-3d band is an efficient d-d coupling correlation center for boosting the Pt 5d-electronic exchange and transfer activities towards the NRR.

High performance of Pt-free dye-sensitized solar cells based on two-step electropolymerized polyaniline counter electrodes

2014 ◽  
Vol 2 (10) ◽  
pp. 3452-3460 ◽  
Author(s):  
Yaoming Xiao ◽  
Gaoyi Han ◽  
Yanping Li ◽  
Miaoyu Li ◽  
Yunzhen Chang
Keyword(s):  
Cyclic Voltammetry ◽  
High Performance ◽  
Dye Sensitized Solar Cells ◽  
Active Surface ◽  
Active Surface Area ◽  
Counter Electrodes ◽  
Polyaniline Nanofibers ◽  
Dye Sensitized ◽  
Branched Structure ◽  
Sensitized Solar Cells

Two-step cyclic voltammetry approach is employed to prepare polyaniline nanofibers, which supplies a quick and controllable method to obtain polyanilines with short-branched structure to increase the active surface area.

scholarly journals A review on the application of nanomaterials in improving microbial fuel cells

2021 ◽  
Vol 8 (2) ◽  
pp. 1400-1416
Author(s):  
Mehrdad Mashkour ◽  
Mostafa Rahimnejad ◽  
Fereshteh Raouf ◽  
Nahid Navidjouy
Keyword(s):  
Microbial Fuel Cells ◽  
High Performance ◽  
Active Surface ◽  
Environmental Safety ◽  
Reduction Reaction ◽  
Cell Performance ◽  
Cathode Side ◽  
Future Research ◽  
Active Surface Area ◽  
Antibacterial Nanoparticles

Materials at the nanoscale show exciting and different properties. In this review, the applications of nanomaterials for modifying the main components of microbial fuel cell (MFC) systems (i.e., electrodes and membranes) and their effect on cell performance are reviewed and critically discussed. Carbon and metal-based nanoparticles and conductive polymers could contribute to the growth of thick anodic and cathodic microbial biofilms, leading to enhanced electron transfer between the electrodes and the biofilm. Extending active surface area, increasing conductivity, and biocompatibility are among the significant attributes of promising nanomaterials used in MFC modifications. The application of nanomaterials in fabricating cathode catalysts (catalyzing oxygen reduction reaction) is also reviewed herein. Among the various nanocatalysts used on the cathode side, metal-based nanocatalysts such as metal oxides and metal-organic frameworks (MOFs) are regarded as inexpensive and high-performance alternatives to the conventionally used high-cost Pt. In addition, polymeric membranes modified with hydrophilic and antibacterial nanoparticles could lead to higher proton conductivity and mitigated biofouling compared to the conventionally used and expensive Nafion. These improvements could lead to more promising cell performance in power generation, wastewater treatment, and nanobiosensing. Future research efforts should also take into account decreasing the production cost of the nanomaterials and the environmental safety aspects of these compounds.

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