Fast operando spectroscopy tracking in situ generation of rich defects in silver nanocrystals for highly selective electrochemical CO2 reduction

Abstract

Electrochemical CO2 reduction (ECR) is highly attractive to curb global warming. The knowledge on the evolution of catalysts and identification of active sites during the reaction is important, but still limited. Here, we report an efficient catalyst (Ag-D) with suitable defect concentration operando formed during ECR within several minutes. Utilizing the powerful fast operando X-ray absorption spectroscopy, the evolving electronic and crystal structures are unraveled under ECR condition. The catalyst exhibits a ~100% faradaic efficiency and negligible performance degradation over a 120-hour test at a moderate overpotential of 0.7 V in an H-cell reactor and a current density of ~180 mA cm−2 at −1.0 V vs. reversible hydrogen electrode in a flow-cell reactor. Density functional theory calculations indicate that the adsorption of intermediate COOH could be enhanced and the free energy of the reaction pathways could be optimized by an appropriate defect concentration, rationalizing the experimental observation.

Homoleptic Alkynyl‐Protected Ag15 Nanocluster with Atomic Precision: Structural Analysis and Electrocatalytic Performance toward CO2 Reduction

“…This is probably caused by that the surface ligands of Ag 15 NCs partially fall off during the CO 2 RR process,l eading to some Ag 15 NCs aggregating into nanoparticles.N ext, we performed XPS measurements on sole Ag 15 ,XC-72 adsorbed Ag 15 (abbreviated as XC-72-Ag 15 ), and the XC-72-Ag 15 after the CO 2 RR reaction (Figure S2). Theb inding energy of Ag 3d 5/2 in sole Ag 15 is 367.8 eV (Figure S2 d), which is between the value of Ag foil (368.6 eV) [43] and Ag I (367.3 eV). [44,45] When adsorbed on XC-72, the Ag 3d 5/2 binding energy shows almost no change (367.9 eV) (Figure S2 d).…”

Enhanced Electrochemical Reduction of CO2to CO on Ag/SnO2by a Synergistic Effect of Morphology and Structural Defects

“…where * refers to a catalytic site at which a species can adsorb. Generally, the first step to form *COOH becomes the rate‐limiting step of the whole chemical reaction process due to the weak binding of catalytic sites with COOH [33–35] . The theoretical studies and experimental results have indicated that Ag appears in the weak binding section with intermediate *COOH in volcanic map [36] .…”

Anode Catalysts in CO2 Electrolysis: Challenges and Untapped Opportunities

“…In almost half of the cases (47%), Ir was employed as the anode catalyst, 10 , 12 , 13 , 16 , 18 , 29 , 32 , 34 , 36 − 87 Another 30% and 14% account for Ni 7 − 10 , 17 , 36 , 39 , 41 − 44 , 88 − 117 and Pt, 32 , 114 , 118 − 133 respectively, while only 9% is related to other metals, metal alloys, or carbon 11 , 45 , 60 , 117 , 134 − 140 ( Figure 3 A). The dominance of Ir and Ni is rooted in the fact that these are the generally used catalysts in acidic and alkaline water electrolyzers, respectively.…”