Pengcheng Xiang,Lili Wang,Qin Geng,Changyan Guo,Hongtao Xie,Yizhao Li,Yangyang Yu,Jide Wang
Structural design of semiconductor photocatalysts plays an important role in promoting light absorption, molecular activation, and charge separation in the CO 2 reduction reaction, which is beneficial for improving photocatalytic activity. In this paper, a simple photodeposition strategy was employed to load Cu onto Bi 2 O 2 SO 4 and form a Cu-Bi alloy. Under simulated sunlight conditions, the optimal catalyst demonstrates impressive photocatalytic activity and selectivity for CO 2 reduction, with a corresponding yield of 18.8 μmol g -1 h -1 , 15 times higher than that of pure Bi 2 O 2 SO 4 , and CO selectivity reaching 97.1%. The results indicate that metal deposition enhances light absorption utilization efficiency and promotes the separation and transfer of photogenerated carriers. Additionally, the combination of in-situ FT-IR spectra and theoretical calculations reveal the molecular mechanisms of photocatalytic CO 2 reduction. This work discusses the synergistic effect of metal deposition and oxygen vacancies on photocatalytic reduction of CO 2 , providing a feasible method for constructing metal deposition structures with defects.
Hongtao Xie,Limi Yan,Shijian Lu,Pengcheng Xiang,Dongliang Liu,Lili Wang
The electrocatalytic reduction of CO2into value-added chemicals offers a promising route to mitigate greenhouse gas emissions, yet the uncontrollable structural reconstruction and surface rearrangement of electrocatalysts during operation often lead to severe activity degradation. Herein, we reveal that Bi2O2SO4(BSO) undergoes an irreversible phase transformation into Bi2O2CO3(BCO) nanosheets accompanied by the partial reduction of Bi3+to metallic Bi0under cathodic potentials. A series of BCO/BSO heterojunction catalysts with tunable compositions are synthesized via a mild in situ ion-exchange method. To circumvent the detrimental effects of this dynamic reconstruction, we devise a pre-activation strategy that deliberately completes the structural evolution prior to electrocatalysis. The optimized 20%-BCO/BSO heterojunction achieves a remarkable Faradaic efficiency of 98.4% for formate production in a flow cell at elevated potentials, with >95% FE(HCOOH)over a wide potential window (−0.8 to −1.7 V vs. RHE). In situ infrared spectroscopy elucidates that the reconstructed interface can promote CO2adsorption, stabilize the *OCHO intermediate, and facilitate HCOOH desorption. This work provides experimental evidence of the reconstruction behaviour of bismuth-based catalysts and offers a rational design method for constructing structurally stable heterojunction electrocatalysts.
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