Grain-Boundary-Engineered La₂CuO₄ Perovskite Nanobamboos for Efficient CO₂ Reduction Reaction

Abstract

Electroreduction of carbon dioxide (CO 2 RR) has been regarded as a promising approach to realize the production of useful fuels and to decrease greenhouse gas levels simultaneously, where highefficiency catalysts are required. Herein, we report La 2 CuO 4 nanobamboo (La 2 CuO 4 NBs) perovskite with rich twin boundaries showing a high Faraday efficiency (FE) of 60% toward ethylene (C 2 H 4 ), whereas bulk La 2 CuO 4 exhibits a FE CO of 91%. X-ray absorption spectroscopy (XAS) reveals that the Cu in La 2 CuO 4 NBs is in the Cu 2+ state, and no obvious change can be observed during the catalytic process, as monitored by in situ XAS. Density functional theory calculations reveal that the superior FE C 2 H 4 of La 2 CuO 4 NBs originates from the active (113) surfaces with intrinsic strain. The formation of gap states annihilates the electron transfer barrier of C−C coupling, resulting in the high FE C 2 H 4 . This work provides a new perspective for developing efficient perovskite catalysts via grain boundary engineering.

Cation‐Deficiency‐Dependent CO2 Electroreduction over Copper‐Based Ruddlesden–Popper Perovskite Oxides

“…Thetemperatures for desorption of chemisorbed CO 2 of these samples were about 307.4 8 8C( L 2 C), 325.7 8 8C( L 1.9 C), 307.9 8 8C (L 1.8 C), and 292.7 8 8C( L 1.7 C), indicating that the CO 2 chemisorption strength was enhanced in the following order:L 1.7 C < L 1.8 C % L 2 C < L 1.9 C. It was previous suggested that, the chemisorption of CO 2 on the catalyst surface was ak ey prerequisite for the CER, and its strength was positively correlated with the CER property. [15] As shown in Figure 6d, we calculated the FE ratios of CER/H 2 of these catalysts,with the values of 2.78 (L 2 C), 3.78 (L 1.9 C), 2.83 (L 1.8 C), and 1.3 (L 1.7 C). As expected, these values resembled the trend of CO 2 chemisorption strength (Figure 6d), further reinforcing the strong correlation between CO 2 chemisorption and CER property of the catalysts.B esides,b yu sing CO-TPD,w e evaluated the CO adsorption behaviors on these catalysts (Figure 6e).…”

“…Given the above,D FT calculations were performed to predict the CER properties of the L 2Àx Ccatalysts.T oconform the actual structure and composition of the L 2Àx Cseries as far as possible,t he DFT calculations were implemented on the L 2 C(111), oxygen-vacancy-contained L 2 C(111) (labelled as O v -L 2 C(111)) and CuO/L 2 C(111) surfaces. [15,25] Noting that the A-site cation deficiency was not considered in our models, because the A-site cations typically did not play as the active sites toward catalysis. [31] Since the HER competed with the CER during electrolysis,w ef irst evaluated the Gibbs free energy profiles for HER in alkaline solution on the three surfaces (Figure 4a)toclarify whether the oxygen vacancy or CuO could suppress the HER.…”

“…[11,12] On this basis,i fo ne could substitute the Cu element into the B-site cations of the RP perovskite oxides,t hey are anticipated to provide attractive CER catalytic properties.Asdemonstrated by af ew previous studies,t ypical examples including A 1.8 Sr 0.2 CuO 4Àd (A = La, Pr, and Gd) as well as La 2 CuO 4Àd were active toward the CER for the formation of high-order products. [14][15][16][17][18] Nonetheless,w ith the insufficient studies,t he Cu-based RP perovskite oxides for CER are in their infancy, but their catalytic performance is supposed to have plenty of space to promote.T ot his end, there is an urgent need for further rational design and development of highly efficient Cu-based RP perovskite oxides for CER.…”

Perovskite Oxides for Cathodic Electrocatalysis of Energy‐Related Gases: From O2 to CO2 and N2

“…[ 110 ] The density functional theory calculations revealed that the intrinsic strain between the (113) surfaces in La 2 CuO 4 can increase the bond length of Cu‐O and Cu‐La, resulting in the enhanced selectivity toward C 2 H 4 . [ 110 ]…”

“…[ 109 ] More recently, Huang and co‐workers reported that the valence state of Cu in La 2 CuO 4 nanobamboo remained unchanged during electrocatalysis. [ 110 ] On the basis of these reports, we can reason that the phase changes of La 2 CuO 4 , including surface amorphization, should relate to the conditions of bulk electrolysis and the catalyst‐electrolyte interface, while further detailed studies are needed to tune the selectivity and maintain the stability. In short, further in‐depth researches of Cu‐containing perovskite oxides would allow precise structural manipulation of the Cu‐containing perovskite oxide and facilitate the rational design of this important type of CO 2 RR catalysts.…”