In Situ Surface-Enhanced Raman Spectroscopy of the Electrochemical Reduction of Carbon Dioxide on Silver with 3,5-Diamino-1,2,4-Triazole

Abstract

The influence of 3,5-diamino-1,2,4-triazole (DAT) on the electrochemical reduction of carbon dioxide to carbon monoxide on a silver electrode was studied via in situ surface-enhanced Raman spectroscopy (SERS). SERS bands obtained in the absence of DAT indicate potentialdependent adsorption of the CO product to bridge and 3-fold hollow sites. With the addition of DAT, CO adsorption to less-coordinated surface sites was found, including a physisorbed or non-coordinating site that exhibited no significant Stark vibrational shift. Raman peaks associated with adsorbed DAT observed at the same potentials as this species suggest that the ligand promotes weaker CO adsorption, which may be responsible for the high efficiency of the AgDAT catalyst. The observation of potential-dependent methylene stretching vibrations indicates the presence of surface hydrocarbon species while the presence of C-D stretches in deuterated electrolyte confirm that these hydrocarbons are generated as a CO 2 reduction byproduct.1.90 V 9 , indicating a large activation barrier to product formation. This large activation barrier has led to suggestions that other species might be involved in CO 2 reduction in aqueous solution, particularly HCO 3 -, since CO 2 dissolved in water exists in equilibrium with HCO 3 -, which is far For Ar control trials, the pH was reduced through the addition of HClO 4 (Optima, Fischer Scientific) to match. A 1 M KOD deuterated electrolyte was prepared by diluting 40 wt % KOD (98 atom % D, Aldrich) in D 2 O (99.9% D, Cambridge Isotope Laboratories).

Rational Design of Ag‐Based Catalysts for the Electrochemical CO2 Reduction to CO: A Review

“…Surface modification with functional groups has recently been demonstrated to be an effective way to improve catalytic performances for the ECR to CO over Ag catalysts as well . For example, Schmitt et al.…”

“…found that a Ag catalyst with its surface modified with 3,5‐diamino‐1,2,4‐triazole (DAT) showed improved CO selectivity, which was assigned to the weakening of the bonding strength of . CO intermediate on the DAT‐modified Ag‐based catalyst surface, as revealed by in situ surface‐enhanced Raman scattering combined with electrochemical analysis . In another study, Tornow et al.…”

A Disquisition on the Active Sites of Heterogeneous Catalysts for Electrochemical Reduction of CO2 to Value‐Added Chemicals and Fuel

“…These peaks were further decreased with an increase of negative potential in the range of 0 to −0.24 V (vs Ag/AgCl) which indicate that the CO and HCOO − were an important intermediate during CO 2 RR. In addition, solution additive, such as 3,5‐diamino‐1,2,4‐triazole (DAT) has been found to enhance CO production on Ag electrodes, with much lower mass loading of Ag . In situ SERS revealed that the addition of DAT is associated with observed CO adsorption to sites with less surface coordination as observed on SERS spectra at wavenumber of 1880, 1945, 2049, and 2095 cm −1 (Figure b,c).…”

“…b) In situ SERS during cathodic polarization without DAT and c) with DAT. Reproduced with permission . Copyright 2017, American Chemical Society.…”

Study of Chemical Intermediates by Means of ATR-IR Spectroscopy and Hybrid Hard- and Soft-Modelling Multivariate Curve Resolution-Alternating Least Squares

“…3,5-Diamino-1,2,4-triazole (DAT) as one of the triazole derivatives has been a significant energetic intermediate towards energetic compounds including 5-amino-3-nitro-1,2,4-triazole (ANTA) and 4,6-bis(5-amino-3-nitro-1,2,4-triazol-1-yl)-5-nitropyrimidine (BANTNP) [1, 2]. Moreover, its derivatives have been applied widely in many fields [3–5], such as in dyes [6], cathode catalysts [7, 8] and ligands to transition metals [9–11]. Therefore, there has been growing interest in the synthesis of DAT in recent years [12–14].…”