In-situ construction of Ohmic-contact Ov-Ag/ZnO composites for enhanced highly selective photocatalytic CO2 reduction: Novel insights of kinetic charge transfer characteristics and two staged reactions from in-situ XPS and FTIR analyses and DFT calculations

被引：0

作者：

Feng, Zixiang ^{[1
]}

Chen, Hao ^{[1
]}

Zhang, Shujuan ^{[1
]}

Liu, Zhao ^{[2
]}

Liu, Tingzhi ^{[1
]}

机构：

[1] Jiangxi Sci & Technol Normal Univ, Sch Mat & Energy, Nanchang 330013, Jiangxi, Peoples R China

[2] Jiangxi Sci & Technol Normal Univ, Sch Informat Engn, Nanchang 330013, Jiangxi, Peoples R China

来源：

CHEMICAL ENGINEERING JOURNAL | 2025年 / 506卷

关键词：

O v -Ag/ZnO composite; In-situ XPS; In-situ FTIR; DFT calculations; Photocatalytic CO 2 reduction; RAMAN-SPECTRA; AG-ZNO; HETEROJUNCTION; FABRICATION; OXIDATION; ARRAYS;

D O I：

10.1016/j.cej.2025.159981

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

In-situ Ohmic-contact oxygen vacancies (Ov)-Ag/ZnO composites were constructed by hydrothermal method using N2H4 as a strong reducing agent. The best yields of photocatalytic CO2 reduction reaction (CO2RR) are 17.054 mu mol & sdot;g-1 (CO), and 0.737 mu mol & sdot;g- 1 (CH4) for 5 h under simulated sunlight irradiation, respectively. The CO yield over Ag/ZnO composites is 9.533 time higher than that of pure ZnO, suggesting enhanced photo- catalytic CO2RR performance. Meanwhile, high CO selectivity (Larger than 85.26 %) can be obtained. Density functional theory (DFT) calculations confirmed that C1-chemical pathways from in-situ FTIR are reasonable. The optimal active adsorption and reaction sites (ARS) are Ov sites. Ov can capture electrons, provide surface active sites, promote adsorption and activate CO2RR. The electrons continuously migrate from ZnO to Ag during photocatalytic process, indicating strong electron sink effect of Ag for excellent charge separation because of Ohmic junction between Ag and ZnO interface. Only when initial CO2RR occurs, part of the electrons of Ag from surface plasma resonance (SPR) effect return to ZnO to participate in CO2RR. Interestingly, two staged CO2RR can occur on Ov-Ag/ZnO composite: initial reduction from CO2 to CO and further reduction from CO to CH4 at active Ov ARS at different times. Low active Ag or Zn ARS, relatively difficult CO desorption and electron sink effect of Ag lead to staged CO2RR and high CO selectivity. The DFT results agree very well with the experiment ones in many aspects: charge carriers separation direction and efficiency, reduction pathways, active ARS, activated CO2RR, staged reduction reactions, high CO selectivity, Ohmic contact, Ov and Ag roles. The work provides novel insights into kinetic charge transfer and staged photocatalytic mechanisms.

引用

页数：18