Peng Ting, Wang Yiqing, Dong Chung-Li, Nga Ta Thi Thuy, Wu Binglan, Wang Yiduo, Guan Qingqing, Zhang Wenjie, Shen Shaohua
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China.
Department of Physics, Tamkang University, New Taipei City, 25137, Taiwan, People's Republic of China.
Nanomicro Lett. 2025 Apr 18;17(1):223. doi: 10.1007/s40820-025-01723-2.
Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocatalysts, photocatalytic CO splitting into value-added chemicals has suffered from the poor activity and remained in great challenge for real application. Herein, hydrothermally synthesized BiOCl with layered structure (BOCNSs) was exfoliated into thickness reduced nanosheets (BOCNSs-w) and even atomic layers (BOCNSs-i) via ultrasonication in water and isopropanol, respectively. In comparison with the pristine BOCNSs, the exfoliated BiOCl, especially BOCNSs-i with atomically layered structure, exhibits much improved photocatalytic activity for CO overall splitting to produce CO and O at a stoichiometric ratio of 2:1, with CO evolution rate reaching 134.8 µmol g h under simulated solar light (1.7 suns). By surpassing the photocatalytic performances of the state-of-the-art BiOX (X: Cl, Br, I) based photocatalysts, the CO evolution rate is further increased by 99 times, reaching 13.3 mmol g h under concentrated solar irradiation (34 suns). This excellent photocatalytic performance achieved over BOCNSs-i should be benefited from the shortened transfer distance and the increased built-in electric field intensity, which accelerates the migration of photogenerated charge carriers to surface. Moreover, with oxygen vacancies (V) introduced into the atomic layers, BOCNSs-i is exposed with the electrons enriched Bi active sites that could transfer electrons to activate CO molecules for highly efficient and selective CO production, by lowering the energy barrier of rate-determining step (RDS), *OH + *CO → HCO. It is also realized that the HO vapor supplied during photocatalytic reaction would exchange oxygen atoms with CO, which could alter the reaction pathways and further reduce the energy barrier of RDS, contributing to the dramatically improved photocatalytic performance for CO overall splitting to CO and O.
鉴于已开发的光催化剂中活性位点的暴露有限以及光生电荷载流子的分离受阻，光催化将CO分解为增值化学品的活性较差，在实际应用中仍面临巨大挑战。在此，通过分别在水和异丙醇中超声处理，将水热合成的具有层状结构的BiOCl（BOCNSs）剥离成厚度减小的纳米片（BOCNSs-w）甚至原子层（BOCNSs-i）。与原始的BOCNSs相比，剥离后的BiOCl，尤其是具有原子层状结构的BOCNSs-i，在模拟太阳光（1.7个太阳）下对CO进行全分解以化学计量比2:1生成CO和O的光催化活性有了显著提高，CO析出速率达到134.8 μmol g⁻¹ h⁻¹。通过超越基于最先进的BiOX（X：Cl、Br、I）的光催化剂的光催化性能，在聚光太阳能照射（34个太阳）下，CO析出速率进一步提高了99倍，达到13.3 mmol g⁻¹ h⁻¹。在BOCNSs-i上实现的这种优异光催化性能应得益于转移距离的缩短和内建电场强度的增加，这加速了光生电荷载流子向表面的迁移。此外，通过将氧空位（V）引入原子层，BOCNSs-i暴露了富含电子的Bi活性位点，这些位点可以转移电子以激活CO分子，从而通过降低速率决定步骤（RDS）*OH + *CO → HCO的能垒来高效且选择性地生成CO。还认识到，光催化反应过程中供应的H₂O蒸汽会与CO交换氧原子，这可以改变反应途径并进一步降低RDS的能垒，有助于显著提高CO全分解为CO和O的光催化性能。
