scholarly journals Ensemble effects in Cu/Au ultrasmall nanoparticles control the branching point for C1 selectivity during CO2 electroreduction

2021 ◽  
Author(s):  
Hongyu Shang ◽  
Dongjoon Kim ◽  
Spencer K. Wallentine ◽  
Minkyu Kim ◽  
Daniel M. Hofmann ◽  
...  
Keyword(s):  
Bimetallic Catalysts ◽  
Scaling Laws ◽  
Co2 Electroreduction ◽  
Branching Point ◽  
Ensemble Effects ◽  
Ultrasmall Nanoparticles

Bimetallic catalysts provide opportunities to overcome scaling laws governing C1 selectivity of CO2 reduction (CO2R).

A Versatile Synthetic Method for Screening Bimetallic Catalysts for CO2 Electroreduction

2021 ◽  
Author(s):  
Laura C. Pardo Perez ◽  
Zora Chalkley ◽  
Alvaro Diaz Duque ◽  
Matthew T. Mayer
Keyword(s):  
Bimetallic Catalysts ◽  
Synthetic Method ◽  
Co2 Electroreduction

scholarly journals Copper Sulfide as the Cation Exchange Template for Synthesis of Bimetallic Catalysts for CO2 Electroreduction

2021 ◽  
Author(s):  
Jinghan Li ◽  
Junrui Li ◽  
Chaochao Dun ◽  
Di Zhang ◽  
Jiajun Gu ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Bimetallic Catalysts ◽  
Co2 Reduction ◽  
Initial Increase ◽  
Gradual Change ◽  
Shape Distortion ◽  
Exchange Method ◽  
Faradaic Efficiency ◽  
Co2 Electroreduction ◽  
Cu Foil

Among metals used for CO2 electroreduction in water, Cu appears to be unique in its ability to produce C2+ products like ethylene. Bimetallic combinations of Cu with other metals have been investigated with the goal of steering selectivity via creating a tandem pathway through the CO intermediate or by changing the surface electronic structure. Here, we demonstrate a facile cation exchange method to synthesize Ag/Cu electrocatalysts for CO2 reduction using Cu sulfides as a growth template. Beginning with Cu2−xS nanosheets (C?nano-0, 100 nm lateral dimension, 10 nm thick), varying the Ag+ concentration in the exchange solution produces a gradual change in crystal structure from Cu7S4 to Ag2S, as the Ag/Cu mass ratio varies from 0.1 to 10 (CA-nano-x, x indicating increasing Ag fraction). After cation exchange, the nanosheet morphology remains but with increased shape distortion as the Ag fraction is increased. Interestingly, the control (C-nano-0) and cation exchanged nanosheets have very high Faradaic efficiency for producing formate at low overpotential (−0.2 V vs. RHE). The primary effect of Ag incorporation is increased production of C2+ products at −1.0 V vs. RHE compared with C-nano-0, which primarily produces formate. Cation exchange can also be used to modify the surface of Cu foils. A two-step electro-oxidation/sulfurization process was used to form Cu sulfides on Cu foil (C-foil-x) to a depth of a few 10s of microns. With lower Ag+ concentrations, cation exchange produces uniformly dispersed Ag; however, at higher concentrations, Ag particles nucleate on the surface. During CO2 electroreduction testing, the product distribution for Ag/Cu sulfides on Cu foil (CA-foil-x-y) changes in time with an initial increase in ethylene and methane production followed by a decrease as more H2 is produced. The catalysts undergo a morphology evolution towards a nest-like structure which could be responsible for the change in selectivity. For cation-exchanged nanosheets (CA-nano-x), pre-reduction at negative potentials increases the CO2 reduction selectivity compared to tests of as-synthesized material, although this led to the aggregation of nanosheets into filaments. Both types of bimetallic catalysts are capable of selective reduction of CO2 to multi-carbon products, although the optimal configurations appear to be metastable. <br>

Highly Selective CO2 Electroreduction to CO on Cu–Co Bimetallic Catalysts

2020 ◽  
Vol 8 (33) ◽  
pp. 12561-12567
Author(s):  
Weiwei Guo ◽  
Jiahui Bi ◽  
Qinggong Zhu ◽  
Jun Ma ◽  
Guanying Yang ◽  
...  
Keyword(s):  
Bimetallic Catalysts ◽  
Co2 Electroreduction

Metal-organic frameworks derived carbon supported Cu-In bimetallic nanoparticles for highly selective CO2 electroreduction to CO

2021 ◽  
Author(s):  
Xia Ma ◽  
Jianjian Tian ◽  
Min Wang ◽  
Xixiong Jin ◽  
Meng Shen ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Bimetallic Catalysts ◽  
Bimetallic Nanoparticles ◽  
Metal Organic Frameworks ◽  
Co2 Reduction ◽  
Reduction Reaction ◽  
Co2 Electroreduction ◽  
Metal Organic ◽  
Co2 Reduction Reaction

Cu-based materials are promising electrocatalysts for CO2 reduction reaction (CO2RR). However, they still suffer intense hydrogen evolution, low selectivity and efficiency for CO2RR. In this work, Cu-In bimetallic catalysts for...

Hierarchically porous Cu/Zn bimetallic catalysts for highly selective CO2 electroreduction to liquid C2 products

2020 ◽  
Vol 269 ◽  
pp. 118800 ◽  
Author(s):  
Xingsong Su ◽  
Yuanmiao Sun ◽  
Lei Jin ◽  
Lei Zhang ◽  
Yue Yang ◽  
...  
Keyword(s):  
Bimetallic Catalysts ◽  
Hierarchically Porous ◽  
Co2 Electroreduction

scholarly journals Copper sulfide as the cation exchange template for synthesis of bimetallic catalysts for CO2 electroreduction

RSC Advances ◽  
2021 ◽  
Vol 11 (39) ◽  
pp. 23948-23959
Author(s):  
Jinghan Li ◽  
Junrui Li ◽  
Chaochao Dun ◽  
Wenshu Chen ◽  
Di Zhang ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Bimetallic Catalysts ◽  
Copper Sulfide ◽  
Morphology Evolution ◽  
Sulfide Catalysts ◽  
Co2 Electroreduction ◽  
Product Generation

Cu sulfides as a template for Ag/Cu sulfide catalysts for electrochemical CO2. With the introduction of Ag, nanosheet show increased C2+ product generation. The catalysts undergo a morphology evolution as CO2 reduction proceeds.

scholarly journals Copper Sulfide as the Cation Exchange Template for Synthesis of Bimetallic Catalysts for CO2 Electroreduction

2021 ◽  
Author(s):  
Jinghan Li ◽  
Junrui Li ◽  
Chaochao Dun ◽  
Di Zhang ◽  
Jiajun Gu ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Bimetallic Catalysts ◽  
Co2 Reduction ◽  
Initial Increase ◽  
Gradual Change ◽  
Shape Distortion ◽  
Exchange Method ◽  
Faradaic Efficiency ◽  
Co2 Electroreduction ◽  
Cu Foil

Among metals used for CO2 electroreduction in water, Cu appears to be unique in its ability to produce C2+ products like ethylene. Bimetallic combinations of Cu with other metals have been investigated with the goal of steering selectivity via creating a tandem pathway through the CO intermediate or by changing the surface electronic structure. Here, we demonstrate a facile cation exchange method to synthesize Ag/Cu electrocatalysts for CO2 reduction using Cu sulfides as a growth template. Beginning with Cu2−xS nanosheets (C?nano-0, 100 nm lateral dimension, 10 nm thick), varying the Ag+ concentration in the exchange solution produces a gradual change in crystal structure from Cu7S4 to Ag2S, as the Ag/Cu mass ratio varies from 0.1 to 10 (CA-nano-x, x indicating increasing Ag fraction). After cation exchange, the nanosheet morphology remains but with increased shape distortion as the Ag fraction is increased. Interestingly, the control (C-nano-0) and cation exchanged nanosheets have very high Faradaic efficiency for producing formate at low overpotential (−0.2 V vs. RHE). The primary effect of Ag incorporation is increased production of C2+ products at −1.0 V vs. RHE compared with C-nano-0, which primarily produces formate. Cation exchange can also be used to modify the surface of Cu foils. A two-step electro-oxidation/sulfurization process was used to form Cu sulfides on Cu foil (C-foil-x) to a depth of a few 10s of microns. With lower Ag+ concentrations, cation exchange produces uniformly dispersed Ag; however, at higher concentrations, Ag particles nucleate on the surface. During CO2 electroreduction testing, the product distribution for Ag/Cu sulfides on Cu foil (CA-foil-x-y) changes in time with an initial increase in ethylene and methane production followed by a decrease as more H2 is produced. The catalysts undergo a morphology evolution towards a nest-like structure which could be responsible for the change in selectivity. For cation-exchanged nanosheets (CA-nano-x), pre-reduction at negative potentials increases the CO2 reduction selectivity compared to tests of as-synthesized material, although this led to the aggregation of nanosheets into filaments. Both types of bimetallic catalysts are capable of selective reduction of CO2 to multi-carbon products, although the optimal configurations appear to be metastable. <br>

Siphon Flows in Stratified Coronal Loops

1994 ◽  
Vol 144 ◽  
pp. 185-187
Author(s):  
S. Orlando ◽  
G. Peres ◽  
S. Serio
Keyword(s):  
Heat Flux ◽  
Scaling Laws ◽  
Flow Model ◽  
Supersonic Flows ◽  
Coronal Loops ◽  
Characteristic Parameters

AbstractWe have developed a detailed siphon flow model for coronal loops. We find scaling laws relating the characteristic parameters of the loop, explore systematically the space of solutions and show that supersonic flows are impossible for realistic values of heat flux at the base of the upflowing leg.

Structure and composition of metal particles in Pt-Sn/Al2O3 bimetallic catalysts

1990 ◽  
Vol 48 (4) ◽  
pp. 278-279
Author(s):  
A. Sachdev ◽  
J. Schwank
Keyword(s):  
Bimetallic Catalysts ◽  
Bimetallic Catalyst ◽  
Size Structure ◽  
High Surface ◽  
High Surface Area ◽  
Metal Particles ◽  
Alloy Formation ◽  
Particle Size Range ◽  
Oxide Supports ◽  
Petroleum Fractions

Platinum - tin bimetallic catalysts have been primarily utilized in the chemical industry in the catalytic reforming of petroleum fractions. In this process the naphtha feedstock is converted to hydrocarbons with higher octane numbers and high anti-knock qualities. Most of these catalysts contain small metal particles or crystallites supported on high surface area insulating oxide supports. The determination of the structure and composition of these particles is crucial to the understanding of the catalytic behavior. In a bimetallic catalyst it is important to know how the two metals are distributed within the particle size range and in what way the addition of a second metal affects the size, structure and composition of the metal particles. An added complication in the Pt-Sn system is the possibility of alloy formation between the two elements for all atomic ratios.

Equilibrium scaling laws for layered spin glasses

1993 ◽  
Vol 3 (10) ◽  
pp. 2041-2062 ◽  
Author(s):  
M. J. Thill ◽  
H. J. Hilhorst
Keyword(s):  
Spin Glasses ◽  
Scaling Laws ◽  
Layered Spin
Sign in / Sign up

Export Citation Format

Share Document