In Situ Dissociated Chalcogenide Anions Regulate the Bi-Catalyst/Electrolyte Interface with Accelerated Surface Reconstruction toward Efficient CO<sub>2</sub> Reduction
Shuxia Liu, Tanyuan Wang, Xuan Liu, Jianyun Liu, Hao Shi, Jiaoyang Lai, Jiashun Liang, Shenzhou Li, Zhao Cai, Yunhui Huang, Qing Li
Abstract
Understanding the structure change of the electrocatalysts during the electrochemical CO 2 reduction reaction (CO 2 RR) is of crucial importance to illustrate the structure–performance relationship. Here, the reconstruction of Bi–O–M (M = S, Se, or Cl) nanosheets induced by the in situ dissociated chalcogenide anions toward efficient CO 2 RR to formate is reported. The surface work function and potential of zero charge (PZC) of metallic Bi are reduced upon anions’ adsorption, facilitating the regeneration of active Bi–O structures during reduction. Moreover, a correlation between the p K b values of the anions and the local pH of the catalyst/electrolyte interface can be established. The anion with a smaller p K b (S 2– < Se 2– < Cl – ) would induce a more alkaline environment and further promote the formation of Bi–O structures. Among them, Bi 2 O 2 S with in situ released S 2– during reconstruction exhibits the best CO 2 RR-to-formate performance with a large current density of 32.7 mA cm –2 at −0.9 V RHE in H-cells, which is 3 times higher than metallic Bi and Bi 2 O 3 without trace S 2– and outperforming most of the reported Bi-based catalysts. In the flow cell, the current density can reach more than 280 mA cm –2 at −0.56 V RHE and a 96% average FE formate is achieved at a current density of 150 mA cm –2 in the long-term test. This work provides an approach to regulate the catalyst/electrolyte interface and electrocatalytic performance of metal electrocatalysts through the in situ released anions.