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Efficient, Selective CO2 Photoreduction Enabled by Facet-Resolved Redox-Active Sites on Colloidal CdS Nanosheets
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2022-08-25 , DOI: 10.1021/jacs.2c06164
Nianfang Wang 1 , Seokhyeon Cheong 2 , Da-Eun Yoon 1 , Pan Lu 1 , Hyunjoo Lee 2, 3 , Young Kuk Lee 4 , Young-Shin Park 1 , Doh C Lee 1
Affiliation  

Advances in nanotechnology have enabled precise design of catalytic sites for CO2 photoreduction, pushing product selectivity to near unity. However, activity of most nanostructured photocatalysts remains underwhelming due to fast recombination of photogenerated electron–hole pairs and sluggish hole transfer. To address these issues, we construct colloidal CdS nanosheets (NSs) with the large basal planes terminated by S2– atomic layers as intrinsic photocatalysts (CdS–S2– NSs). Experimental investigation reveals that the S2– termination endows ultrathin CdS–S2– NSs with facet-resolved redox-catalytic sites: oxidation occurs on S2–-terminated large basal facets and reduction happens on side facets. Such an allocation of redox sites not only promotes spatial separation of photoinduced electrons and holes but also facilitates balanced extraction of holes and electrons by shortening the hole diffusion distance along the (001) direction of the ultrathin NSs. Consequently, the CdS–S2– NSs exhibit superb performance for photocatalytic CO2-to-CO conversion, which was verified by the isotope-labeled experiments to be a record-breaking performance: a CO selectivity of 99%, a CO formation rate of 2.13 mol g–1 h–1, and an effective apparent quantum efficiency of 42.1% under the irradiation (340 to 450 nm) of a solar simulator (AM 1.5G). The breakthrough performance achieved in this work provides novel insights into the precise design of nanostructures for selective and efficient CO2 photoreduction.

中文翻译:

胶体 CdS 纳米片上刻面分辨的氧化还原活性位点实现高效、选择性的 CO2 光还原

纳米技术的进步使得能够精确设计用于 CO 2光还原的催化位点,将产物选择性推向接近统一。然而,由于光生电子-空穴对的快速复合和缓慢的空穴转移,大多数纳米结构光催化剂的活性仍然不足。为了解决这些问题,我们构建了胶体 CdS 纳米片 (NSs),其大基面由 S 2-原子层终止作为本征光催化剂 (CdS-S 2- NSs)。实验研究表明,S 2–末端赋予超薄 CdS–S 2– NSs 小平面分辨的氧化还原催化位点:氧化发生在 S 2–-终止的大基面和减少发生在侧面。这种氧化还原位点的分配不仅促进了光生电子和空穴的空间分离,而且通过缩短沿超薄 NS 的(001)方向的空穴扩散距离,促进了空穴和电子的平衡提取。因此,CdS-S 2- NSs 表现出极好的光催化 CO 2到 CO 转化的性能,同位素标记的实验证实了这一点是破纪录的性能:99% 的 CO 选择性,CO 形成率2.13 mol g –1 h –1, 在太阳模拟器 (AM 1.5G) 的照射 (340 至 450 nm) 下的有效表观量子效率为 42.1%。在这项工作中取得的突破性性能为精确设计用于选择性和高效 CO 2光还原的纳米结构提供了新的见解。
更新日期:2022-08-25
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