Controllable States and Porosity of Cu‐Carbon for CO₂ Electroreduction to Hydrocarbons

Abstract

The electrocatalytic carbon dioxide reduction reaction (CO2RR) to value‐added chemical products is an effective strategy for both greenhouse effect mitigation and high‐density energy storage. However, controllable manipulation of the oxidation state and porous structure of Cu‐carbon based catalysts to achieve high selectivity and current density for a particular product remains very challenging. Herein, a strategy derived from Cu‐based metal‐organic frameworks (MOFs) for the synthesis of controllable oxidation states and porous structure of Cu‐carbon (Cu‐pC, Cu2O‐pC, and Cu2O/Cu‐pC) is demonstrated. By regulating oxygen partial pressure during the annealing process, the valence state of the Cu and mesoporous structures of surrounding carbon are changed, leads to the different selectivity of products. Cu2O/CuO‐pC with the higher oxidation state exhibits FEC2H4 of 65.12% and a partial current density of −578 mA cm−2, while the Cu2O‐pC shows the FECH4 over 55% and a partial current density exceeding −438 mA cm−2. Experimental and theoretical studies indicate that porous carbon‐coated Cu2O structures favor the CH4 pathway and inhibit the hydrogen evolution reaction. This work provides an effective strategy for exploring the influence of the various valence states of Cu and mesoporous carbon structures on the selectivity of CH4 and C2H4 products in CO2RR.

Mesoporous Carbon-Based Materials: A Review of Synthesis, Modification, and Applications

“…Among them, mesoporous carbon structures with a broad or narrow distribution of pores have recently attracted enormous attention in different fields because of high specific surface area, good chemical and mechanical properties, high thermal stability, large pore volume, and uniform and controllable porous structure. These outstanding properties enable mesoporous structures to be excellent candidates for various practical applications, including as a catalyst and its support, adsorption and separation, energy conversion and storage, environmental remediation, drug delivery, and biomedical applications [12][13][14][15][16][17][18][19]. At first, mesopores in carbon structures were produced by enlarging micropores via oxidation during activation process, such as activated carbons, or at the interstices between carbon particles, such as carbon aerogels.…”

Engineering COBridge Adsorption in Cu2O-TiO2 Heterojunction Catalyst for Selective Electrochemical CO2 Reduction to Ethanol

“…The morphology of the Cu 2 O-TiO 2 catalyst was further examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), as displayed in Figure d and e. High-resolution TEM (HRTEM) images of Cu 2 O-TiO 2 (Figure f) depict Cu 2 O nanoparticles decorated with TiO 2 nanoparticles. Corresponding local (Fast Fourier transform) FFT patterns present the diffraction points of the Cu 2 O (111) planes and TiO 2 (101) planes that are assigned to the about 0.250 and 0.352 nm lattice spacings, respectively (Figure g). These values are in good agreement with those of pure Cu 2 O (0.249 nm, Figure S2) and TiO 2 (0.350 nm, Figure S3).…”

Advances and challenges in the electrochemical reduction of carbon dioxide

“…Fang and co-workers used Cu-BTC as a sacrificial template to synthesize a series of Cu-carbon-based catalysts (Cu-pC, Cu 2 O-pC, and Cu 2 O/Cu-pC) with various valence states and mesoporous structures and found that Cu 2 O/CuO-pC with higher oxidation state can effectively enhance the CO 2 RR activity. 254 In addition, multi-site tandem electrocatalytic CO 2 reduction can be realized by tuning the geometry of Cu-BTC. Cao et al prepared a series of Cu-based nanoreactors by adjusting the geometrical morphology of MOF precursors.…”