Amorphous N_xC Coating Promotes Electrochemical CO₂ Deep Reduction to Hydrocarbons over Ag Nanocatalysts

Abstract

The electrochemical conversion of CO 2 into high value-added hydrocarbon products provides a promising path to reduce the dependence on fossil energy and close carbon cycle. Cubased catalyst is so far the only material that can effectively realize this process, limiting the optional catalysts for industrial application. Therefore, it is urgent to design other strategies to boost hydrocarbon products beyond Cu-based materials. Here, the N x C shell is constructed on the surface of Ag nanoparticle core (core−shell structure Ag@N x C) to boost the formation of CH 4 and CH 2 CH 2 . The N x C shell does not modify the electronic property of Ag but prolongs the residence time of the CO intermediate to enhance the C−C coupling and deep reduction, which are proved by in situ ATR-SEIRAS. In addition, the activated H 2 O molecules could provide sufficient adsorbed H to enhance the further reduction of the carbonaceous intermediate during the CO 2 reduction reaction. As a result, the Faradaic efficiency (FE) of the hydrogen evolution reaction is enhanced over the Ag@N x C-2 catalyst (∼12% at −1.4 V vs RHE), and the FEs of CH 4 and CH 2 CH 2 are significantly enhanced (above 43.8 and 8.4%, respectively). Our findings provide a strategy to achieve the conversion of CO 2 into hydrocarbon products over non-Cu-based catalysts.

NxC-Induced Switching of Methane and Ethylene Products’ Selectivity from CO2 Electroreduction over Cu Catalyst

“…The XPS spectra of N 1s and C 1s were further analyzed to find out the essential reason for the different product selectivities over Cu@N x C-350 °C (10:4) and Cu@N x C-400 °C (10:4) catalysts. Figure S25 presented the C 1s spectra, which could be split into four peaks centered at 284.3, 284.8, 285.3, and 286.6 eV, attributing to graphitic carbon, CC, C–C, and C–N, respectively. , Figure c depicted the N 1s spectra, which is composed of three peaks centered at 398.4, 399.2, and 400.4 eV, sequentially corresponding to pyridinic N, pyrrolic N and graphitic N. , The N species are believed to be favorable for the electrocatalytic CO 2 RR, due to the interaction with CO 2 molecules. ,, Even though no obvious binding energy shifts of N 1s and C 1s spectra were observed between Cu@N x C-350 °C (10:4) and Cu@N x C-400 °C (10:4) catalysts, the relative content of series N species had a significantly distinction. The contents of pyridinic N and pyrrolic N were about 28.1% and 23.8% over Cu@N x C-350 °C (10:4) catalyst, respectively, while it was about 15.6% and 37.5% over Cu@N x C-400 °C (10:4) catalyst, respectively.…”

“…The electrocatalytic conversion of carbon dioxide (CO 2 ) into value-added fuels and chemical feedstocks driven by renewable energy is a promising strategy to not only reduce atmospheric CO 2 concentration and store intermittent renewable energy but also to solve the environmental and energy problems. − Electrocatalytic CO 2 reduction reaction (CO 2 RR) in aqueous solution is attractive, since water is a green and sustainable proton and electron donor. , However, hydrogen evolution reaction (HER) competition and product selectivity toward the CO 2 RR in aqueous solution are still the major challenges because of the diversity of products and the complexity of the reaction networks involved. Thus, developing and discovering catalysts with high energy efficiency and selectivity toward desired products have become the most important topics.…”

High-Performance Electrocatalytic CO2 Reduction for CO Generation Using Hydrophobic Porous Carbon Supported Au

“…Combined with the structure, morphology, and electronic properties analysis as detailed above, it is reasonable to speculate that the better performance was associated to the porous architecture of FPC-800. Figure c presented the intensity ratio of *CO intermediate and adsorbed H 2 O (about 2623 cm –1 ), , the curve showed the same tendency with the applied potential increase on both electrodes. Nevertheless, intensity ratio of the 20%Au/FPC-800 electrocatalyst was much larger than that of the 20%Au/FXC-72 electrocatalyst, implying the better CO 2 RR performance and lower HER activity over the 20%Au/FPC-800 electrocatalyst, which was consistent with the observed preference of CO over H 2 generation.…”

Gaining Deep Understanding of Electrochemical CO2RR with In Situ/Operando Techniques

“…[52] Surface-enhanced IR absorption (SEIRA) is now widely applied since it provides significant IR signal enhancement, making it a powerful tool to monitor surface-adsorbed reactants and intermediates with high sensitivity (Figure 3b). [44,[58][59][60] With a thin nanostructured metal film deposited on the ATR optical window, the absorption of molecules adsorbed on it is significantly enhanced. SEIRAS in ATR mode (ATR-SEIRAS) is not substrate-specific and can thus be performed on many metals like Au, Ag, Cu, Fe, Pt, Pd, Rh, and Ru.…”