A Strong Magnetic Field Alters the Activity and Selectivity of the CO2RR by Restraining C–C Coupling

Abstract

As an external field, a magnetic field can change the electrocatalytic activity of catalysts through various effects. Among them, electron spin polarization on the catalyst surface has attracted much attention. Herein, we investigate the sensitive response behavior of a Cu2O nanocubes to an in situ magnetic field. Under a 3 T strong magnetic field, the total transferred electron quantity in IT test (−1.1 VRHE) and the current density in the polarization curve increase by 28.7% and 54.7%, respectively, while the onset potential decreases significantly by 114 mV. Moreover, it was found that product selectivity was also altered by the magnetic field. The Faraday efficiency of C1 increases substantially, along with the inhibition of C2+ reaction paths and the HER. Our experimental results and DFT calculation demonstrate that a hybrid magnetic effect accelerates the CO2RR kinetic and generates spin polarization of the catalyst surface. The polarized surface changes the binding energy of *OCHO/*COOH and inhibits singlet C–C coupling, which restrains the C2+ reduction path and thus more CO2 is reduced to HCOOH.

Perspectives of Magnetically Enhanced Electroconversion of CO2 to Formic Acid and Formate

“…Hence, increasing the amount of singlet radical pairs leads to an enhancement in the efficiency for obtaining P. The spin evolution from triplet to singlet could be promoted by applying a magnetic field, thus enhancing the production of P. 31,62 It is worth noting that magnetic fields can improve the ERCO 2 not only by regulating the spin states of radical pairs involved in the electrocatalytic reactions but also by inducing spin polarization of the catalyst's surface. 75 According to this approach, the spin-polarized surface that results from the application of magnetic fields alters the interaction between catalyst's surface atoms and the intermediate compounds. Consequently, the selectivity of the ERCO 2 products is affected.…”

“…Consequently, the selectivity of the ERCO 2 products is affected. 75 This strategy represents a promising method to enhance CO 2 conversion toward the desired products; further details can be found in the work of Wang et al 75 Magnetically Enhanced CO 2 Conversion to Formic Acid/Formate. Due to the scarcity of studies on the use of magnetic fields in ERCO 2 , only four articles have investigated the magnetically enhanced conversion of CO 2 to formic acid/ formate so far to the best of our knowledge.…”

“…Moreover, they found that the formate yield could increase by 47% (Figure 3c). A different strategy based on enhancing ERCO 2 toward the desired products by affecting the catalyst-intermediates interaction via the magnetic field-induced spin polarization of the catalyst's surface was investigated by Wang et al 75 They determined that this strategy could modify the product selectivity toward C 1 products (such as formic acid, carbon monoxide, etc.) instead of toward C 2+ products (including ethylene, ethanol, etc.).…”

“…instead of toward C 2+ products (including ethylene, ethanol, etc.). Wang and co-workers 75 demonstrated that the application of a magnetic field led to the spin polarization of catalyst's surface electrons, which ultimately resulted in the inhibition of the singlet C−C coupling, thus restraining the formation of C 2+ products. In this way, the reduction of CO 2 to the target products, including formic acid, was enhanced (Figure 3d).…”

Directionality and additivity effects of molecular acidity and aromaticity for substituted benzoic acids under external electric fields

“…Essential in many chemical and physical phenomena and processes, the impact of external fields has attracted noticeable attention lately in the literature [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] because it can influence the molecular structure, [17][18][19][20][21][22] chemical reactivity, [23][24][25][26][27][28] and other electronic properties. [29][30][31][32][33][34] In a previous study, we investigated the impact of uniform external electric fields on molecular acidity and aromaticity propensities for the benzoic acid molecule.…”