Highly Selective Reduction of CO₂ to C₂₊ Hydrocarbons at Copper/Polyaniline Interfaces

Abstract

Electrochemical reduction of carbon dioxide (CO2RR) to liquid fuels and valued chemicals is a meaningful approach to decreasing CO2 emissions and alleviating the energy crisis. In particular, the conversion of CO2 into multicarbon products is of technological significance. Cu is the only transition metal that is able to catalyze the CO2RR to produce C2+ hydrocarbons, but the catalytic selectivity of pristine Cu is low. Herein we report a facile method to largely enhance the C2+ selectivity of polycrystalline Cu toward the CO2RR. By coating the Cu surface with a 50 nm thick film of polyaniline (PANI), the faradaic efficiency (FE) of C2+ hydrocarbons was increased from ca. 15% to 60% at −1.1 VRHE in KHCO3 solutions. When applying the PANI coating onto Cu nanoparticles, the FE of C2+ hydrocarbons can even reach 80%, with the FE of ethylene over 40%. Such performance remained stable in a test period of 20 h. The superiority of the Cu/PANI interface is not due to the change in the morphology or the electronic properties of the Cu substrate but instead is due to an improvement in the coverage and interaction of the CO intermediate, which facilitates the CO–CO coupling, as revealed by in situ infrared spectroscopy. This study opens an avenue to tuning the catalytic activity and selectivity of Cu toward the CO2RR, not through the structure of the catalyst but through the environment above the surface.

Unveiling the Synergistic Effect between Graphitic Carbon Nitride and Cu2O toward CO2Electroreduction to C2H4

“…Similarly, Wei et al. used operando attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS) to confirm that the increased performance for Cu‐based catalyst comes from the increased coverage of CO intermediate, which was generated by polyaniline [36] . Besides above discussions, we propose a sequential electrocatalytic mechanism for the CO 2 RR to C 2 H 4 for our Cu 2 O/CN (Scheme 1), which involves multiple electron transfer steps.…”

Transition metal-based catalysts for the electrochemical CO2reduction: from atoms and molecules to nanostructured materials

“…Several representative examples of functional organometallic surfaces, based on bulk metal electrodes chemically interacting with nitrogen-based organic additives (e.g. ionic liquids, [432][433][434][435] aminoacids, 437 N-arylpyridinium [438][439][440] or N,N 0 -phenanthrolinium, 441 benzimidazole, 442 polyamines, 443 polyaniline, 444 triazole, 445 etc.) or supramolecular organic assemblies, 446 have been also recently reported for CO 2 RR.…”

Single‐Atom Electrocatalysts from Multivariate Metal–Organic Frameworks for Highly Selective Reduction of CO2 at Low Pressures

“…[27][28][29] In addition to the active site identification, another critical issue in CO 2 RR is the energy-consuming capture and purification process of CO 2 .Specifically speaking,toachieve high selectivity,t he currently reported CO 2 RR are generally performed in pure CO 2 . [30][31][32][33][34][35][36][37][38][39][40][41][42] However,t he actual concentration of CO 2 feedstock available from industrial processes such as coal power plant (5-15 %CO 2 )and steel/petrochemical industry (14-33 %C O 2 )i sr elatively low. [43][44][45] Given the thermodynamic stability of the C = Obond ( % 806 kJ mol À1 )of CO 2 and its limited solubility in aqueous solution, low CO 2 concentration will significantly affect the activity,setting great barriers for the direct CO 2 utilization.…”