<br>利用缺陷富集二氧化钛基异质结光催化剂定制可见光到近红外活性二维 MXene，用于产生绿色氢气,ACS Applied Materials & Interfaces

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利用缺陷富集二氧化钛基异质结光催化剂定制可见光到近红外活性二维 MXene，用于产生绿色氢气
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2024-01-03 , DOI: 10.1021/acsami.3c13075
Sudeshna Das Chakraborty ₁ , Uttam Kumar ₁ , Pallab Bhattacharya _{1,

2} , Trilochan Mishra _{1,

2}

Affiliation

宽的太阳光吸收窗口及其利用、长期稳定性和改进的界面电荷转移是可扩展和卓越的太阳能光催化性能的关键。基于此目标，开发了一种不含贵金属的复合光催化剂，采用导电MXene（Ti ₃ C ₂ ）和半导体花椰菜形CdS和多孔Cu ₂ O。对TiO _y @Ti ₃ C ₂进行XPS、HRTEM和ESR分析确认在水热处理过程中，Ti ₃ C ₂表面形成了足够的缺陷富集的 TiO _y （其中y < 2），从而产生了具有足够氧空位的第三个半导体位点。最终材料TiO _y @Ti ₃ C ₂ /CdS/Cu ₂ O显示出300至2000 nm的宽吸收窗口，覆盖太阳光谱的可见光到近红外(NIR)范围。二元复合材料（TiO _y @Ti ₃ C ₂ /CdS）和三元复合材料（TiO _y @Ti ₃ C ₂ /CdS/Cu ₂ O）光_催化产氢活性分别为12.23和16.26 mmol g ^–1 h ^–1 ），使用乳酸作为空穴清除剂，在可见光-近红外光下分别具有良好的重复性。由于近红外光吸收，三元复合材料的效率明显提高了1.53 mmol g ^–1 h ^–1，支持了电子的固有上转换，这将为太阳光利用开辟新的前景。 EIS 图上电荷转移电阻的降低和 PL 强度的降低使得三元复合材料中的界面电荷分离得到改善。与纯CdS相比，不含贵金属的三元复合材料的H ₂生成效率提高了29.6倍，表观量子效率为12.34%。缺陷富集的 TiO _y形成、在 Ti ₃ C ₂片上形成适当的双 p-n 结（由莫特-肖特基图支持）、显着的近红外光吸收、增加的电子迁移率以及导电 Ti 上的电荷转移的协同效应即使在多次重复循环之后， ₃ C ₂层仍有助于显着提高氢析出速率。预计，具有所需界面工程的缺陷富集双 p-n 结的基于 2D MXene 的异质结构将有助于在广泛的太阳光谱范围内实现可扩展的光催化水分解。

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Tailoring of Visible to Near-Infrared Active 2D MXene with Defect-Enriched Titania-Based Heterojunction Photocatalyst for Green H2 Generation

A wide solar light absorption window and its utilization, long-term stability, and improved interfacial charge transfer are the keys to scalable and superior solar photocatalytic performance. Based on this objective, a noble metal-free composite photocatalyst is developed with conducting MXene (Ti₃C₂) and semiconducting cauliflower-shaped CdS and porous Cu₂O. XPS, HRTEM, and ESR analyses of TiO_y@Ti₃C₂ confirm the formation of enough defect-enriched TiO_y (where y is < 2) on the surface of Ti₃C₂ during hydrothermal treatment, thus creating a third semiconducting site with enough oxygen vacancy. The final material, TiO_y@Ti₃C₂/CdS/Cu₂O, shows a broad absorption window from 300 to 2000 nm, covering the visible to near-infrared (NIR) range of the solar spectrum. Photocatalytic H₂ generation activity is found to be 12.23 and 16.26 mmol g^–1 h^–1 in the binary (TiO_y@Ti₃C₂/CdS) and tertiary composite (TiO_y@Ti₃C₂/CdS/Cu₂O), respectively, with good repeatability under visible–NIR light using lactic acid as the hole scavenger. A clear increase of efficiency by 1.53 mmol g^–1 h^–1 in the tertiary composite due to NIR light absorption supports the intrinsic upconversion of electrons, which will open a new prospective of solar light utilization. Decreased charge-transfer resistance from the EIS plot and a decrease in PL intensity established the improved interfacial charge separation in the tertiary composite. Compared to pure CdS, H₂ generation efficiency is 29.6 times higher on the noble metal-free tertiary composite with an apparent quantum efficiency of 12.34%. Synergistic effect of defect-enriched TiO_y formation, creation of proper dual p–n junction on a Ti₃C₂ sheet as supported by the Mott–Schottky plot, significant NIR light absorption, increased electron mobility, and charge transfer on the conductive Ti₃C₂ layer facilitate the drastically increased hydrogen evolution rate even after several cycles of repetition. Expectantly, the 2D MXene-based heterostructure with defect-enriched dual p–n junctions of desired interface engineering will facilitate scalable photocatalytic water splitting over a broad range of the solar spectrum.

更新日期：2024-01-03

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