基于原位光谱结合量化计算方法的钙钛矿催化剂定向设计及高效脱除VOCs反应机理研究

Volatile organic compounds (VOCs) have becoming the major air pollutants after the removal of SO2 and NOx emission in our country. This project planned to use the catalytic oxidation technology for the stationary VOCs emission to develop the high efficiency with low cost catalysts without noble metals as active sites. Based on the selective dissolution (SD) method on perovskite catalysts, we try to tune the ratio of alkali metals sites to transitional metals sites, improving the quantity of surface oxygen vacancy and oxidation ability of catalysts. Except for preserving the crystallization structure and thermal stability of the treated catalysts by SD method, the BET surface area and pore volume of the catalysts also increase. Combined the in situ IR spectra with Raman spectra, the reaction key intermediate species, active sites and reaction pathways are elucidated. Further, we also employed the DFT calculations to investigate the adsorption/desorption behaviors and activation abilities VOCs and O2 molecules on catalyst surfaces. The calculation results show good accordance with the experiments, and indicate the catalysis mechanism, surface structures, oxidation ability and structure-activity relationship. The research conclusion could provide the theoretical support in the rational and redirect design of perovskite catalysts.

挥发性有机物（VOCs）已经成为我国继SO2和NOx后主要的大气污染物。本项目针对固定源排放VOCs污染物的催化氧化技术，以开发高效低成本非贵金属催化剂为研究目标，利用选择性溶解方法，通过对钙钛矿的碱（土）金属位与过渡金属位的比例进行调变，改善催化剂表面氧缺陷位的数量及氧化能力。在保证催化剂晶体结构和热稳定性的前提下，提高催化剂的比表面积与孔容。通过原位红外耦合原位拉曼光谱技术，揭示催化剂高效催化氧化VOCs的关键反应中间物种，确认反应的活性中心与反应路径。利用量子化学计算手段，模拟VOCs及O2分子在催化剂活性表面的吸附/脱附以及活化能力，补充验证和辅助诠释实验结果，揭示催化剂催化能力，表面结构和氧化能力之间的构效关系，最终为催化剂的定向、理性设计提供理论支持。