组分可调PdxM1-x合金纳米材料的光辅助CO2加氢催化性能

Compared with the conventional CO2 hydrogenation process through thermal catalysis, light-assisted CO2 hydrogenation could proceed under mild conditions, so it has gained increasing research attention. Currently, there are two problems needed to be tackled for this technique. One is that the catalytic efficiency needs to be further enhanced and the reaction mechanism for the catalytic process is not well understood. In this research program, we propose the synthesis of PdxM1-x alloy nanoparticles with tunable compositions for the highly efficient CO2 hydrogenation reaction with improved product selectivity. According to the d-band theory, by gradually adjusting the composition ratios of the two metal elements in bimetallic nanoalloys, it is possible to manipulate the electronic structure of the alloy nanoparticles and this would change the catalytic behaviors. In this project, we will prepare the PdxM1-x nanoparticles through the co-reduction method and characterize the morphology, size, phase structure of the alloy nanoparticles and the interaction between the two elements in alloy nanoparticles using XRD, HAADF-STEM and XPS. We will also figure out how the electronic structures change in alloy nanoparticles by using UPS and DFT calculations. By hybridizing the alloy nanoparticles with various support materials, we will investigate the light-assisted CO2 hydrogenation properties of the composited catalysts. Finally, in-situ FTIR, in-situ XPS and DFT modelling will be employed to unravel the reaction mechanisms of the light-assisted CO2 hydrogenation process occurring on the alloy catalysts. We conduct this project with the aim to providing better understanding on this technique and more theoretical guidance for the future design of better catalysts.

相对于热催化CO2加氢过程，光辅助CO2加氢反应能够在温和条件下进行，因此受到了广泛关注。当前光辅助CO2加氢技术面临着(i)活性有待进一步提高，(ii)催化机理尚未明确的问题。本项目提出构筑组分可调的PdxM1-x合金纳米催化剂来进一步提高光辅助CO2加氢的催化活性和改善产物选择性。d带理论认为，通过连续调节合金内元素相对含量，可以逐渐调控合金颗粒电子结构，从而影响其催化活性和产物选择性。本项目拟通过共还原的方法制备PdxM1-x合金纳米颗粒，利用XRD、HAADF-STEM、XPS等表征纳米颗粒粒径、相结构以及颗粒内部元素间相互作用，结合UPS测试、DFT计算明确合金颗粒内部电子结构变化规律；将PdxM1-x合金纳米颗粒与不同载体复合，考察其光辅助CO2加氢反应催化性能，并通过原位FTIR、原位XPS技术和DFT计算阐明催化机理，为进一步设计高效光辅助CO2加氢催化剂提供理论指导。

光辅助催化CO2加氢反应是一种CO2资源化利用的有效手段，因为它可以在温和的条件下运行，并且可以整合到目前商业化的热催化CO2加氢系统中。然而其仍然面临着催化效率低和催化机理尚不完善等问题。本项目提出组建不同尺寸的Pd纳米颗粒库以及构筑组分可调的PdxM1-x合金纳米催化剂来调控纳米颗粒电子结构进一步提高CO2加氢的催化活性和产物选择性。在此基础上，通过共还原法制备了一系列组分连续变化的RuxM1-x、PtxCu1-x合金纳米颗粒，通过连续调节合金内元素相对含量来调控合金纳米颗粒的电子结构，探索了合金纳米颗粒电子结构变化与催化性能之间的内在规律，并揭示了纳米合金催化剂结构改变对催化性能的影响机制。.通过本项目的实施，验证了双金属合金纳米颗粒/半导体复合材料作为光辅助催化材料的设计思路，开发出了一系列具有优异催化性能的双金属合金纳米颗粒/半导体复合材料，探索出了科学调控合金纳米颗粒元素组分、提高催化活性以及产物选择性的新途径，在光辅助催化CO2加氢的基础研究和制备方法上，取得了原创性研究成果。.项目发表SCI论文26篇，申请相关专利6项，已获得授权1项，完成了项目的预定目标。培养博士生2人（在读2人），硕士生6人（在读3人）。