Direct reduction of diluted CO₂ gas to C₂ products by copper hydroxyphosphate microrods

Abstract

Electrochemical reduction of CO2 is widely researched in recent years. However, direct electro‐reduction of diluted CO2 to C2 products is seldomly studied. In this work, electrocatalytic reduction of CO2 with different concentrations were conducted on Cu2(PO4)(OH) catalysts. The catalytic performance in diluted CO2 is comparable with that in pure CO2 by using Cu2(PO4)(OH) as catalyst. Besides, the selectivity of C2 product is still as high as 64.6% in 50%CO2 concentration. The normalized C2 current density of Cu2(PO4)(OH) was over 6.8 times higher than that of commonly used Cu2O–Cu catalyst with similar size. In situ Raman spectroscopy proved that Cu+ is the main active site at higher potentials. More importantly, a higher local pH is realized under diluted CO2 test conditions which is favorable for promoting C–C coupling. Finally, in situ ATR‐FTIR spectroscopy was performed to further monitor and identify the adsorbed intermediates and help reveal the mechanism for the catalysts.

Copper Electrocatalyst Produced by Cu2(OH)2CO3-Mediated In Situ Deposition for Diluted CO2 Reduction to Multicarbon Products

“…In order to further reveal the mechanism of M-Cu during the electrocatalytic CO 2 reduction process, in situ Raman spectroscopy was performed to test the reaction intermediate as well as reveal the reactive site under different applied voltages (Figure ). The characteristic peaks at 276 and 384 cm –1 belong to Cu(0)-CO . It exhibits an increase in intensity with the rise of overpotential, indicating the generation of the *CO intermediate under larger overpotentials.…”

Molecular Enhancement of Direct Electrolysis of Dilute CO2

“…Despite these difficulties, researchers have developed a group of strategies to increase local CO 2 concentrations in reaction microenvironments around catalytically active sites by enriching CO 2 from dilute streams, namely, the integration of carbon capture and conversion into a single system. , In nature, such an enrichment effect performed by enzymes enables efficient photosynthesis of complex carbohydrates directly from atmospheric CO 2 . This bioinspired strategy has recently been applied to the rational design of molecular catalysts and heterogeneous catalysts with specific structures and functional groups for direct electrolysis of dilute CO 2 . − The production of CO, a two-electron reduction product, has gained great attention due to its excellent techno-economic feasibility , and good suitability as a reactant for improved C–C coupling in tandem electrolysis routes. , However, previous studies on the direct electrolysis of dilute CO 2 to CO are mostly performed at low current densities and use catalysts prepared by complicated synthesis protocols (Table S1). −, − There is an urgent need to develop efficient catalyst systems for high-rate direct electrolysis of dilute CO 2 streams toward practical application.…”