Photoelectrocatalytic CO2 reduction based on metalloporphyrin-modified TiO2 photocathode  

卟啉修饰的光阴极用于光电催化二氧化碳还原（英文）

作　　者：Yapeng Dong Rong Nie Jixian Wang Xiaogang Yu Pengcheng Tu Jiazang Chen Huanwang Jing 董亚鹏;聂融;王继贤;于晓刚;涂鹏程;陈加藏;景欢旺(兰州大学化学化工学院,功能有机分子化学国家重点实验室,甘肃兰州730000;中国科学院山西煤炭化学研究所,煤转化国家重点实验室,山西太原030001)

机构地区：[1]State Key Laboratory of Applied Organic Chemistry,College of Chemistry and Chemical Engineering,Lanzhou University,Lanzhou 730000,Gansu,China [2]State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,Shanxi,China

出　　处：《Chinese Journal of Catalysis》2019年第8期1222-1230,共9页催化学报（英文）

基　　金：funded by the Natural Science Foundation of Gansu Province(17JR5RA212);the State Key Laboratory of Coal Conversion(J19-20-913-1)~~

摘　　要：The conversion of CO2 and water to value-added chemicals under sunlight irradiation, especially by photoelectrocatalytic reduction process, is always a dream for human beings. A new artificial photosynthesis system composed of a metalloporphyrin-functionalized TiO2 photocathode and BiVO4 photoanode can efficiently transform CO2 and water to methanol, which is accompanied by oxygen release. This photoelectrocatalytic system smoothly produces methanol at a rate of 55.5 μM h^–1 cm^– 2, with 0.6 V being the membrane voltage in plants. The production of hydrogen can also be observed when the voltage is more than 0.75 V, due to photocatalysis. Our results evidently indicate that the molecules of metalloporphyrin attached onto the surface of anatase (TiO2) behave as chlorophyll, NADP, and Calvin cycle in plant cells.将二氧化碳有效地转化为高附加值化学品是人类的梦想,尤其是通过光电催化实现该过程更加令人期待.本文报道了一种新的人工光合成体系,它是由金属卟啉配合物修饰的二氧化钛光电阴极以及羟基氧化铁和羟基氧化镍修饰的钒酸铋光电阳极构成,电解液是0.1 M碳酸氢钠水溶液.该体系在有硅太阳电池供电和一个标准太阳下工作.在外加电压为-0.6V时,甲醇是光电池的唯一产物,同时放出氧气;生成甲醇的速率是55.5 μM h^–1 cm^–2.当外加电压大于-0.75 V时,光电催化电池有氢气生成.卟啉和金属卟啉按照文献合成并命名为Dx,即D1 (meso-tetra-p-carboxyphenylporphyrin), D2 (CoTCPP), D3 (NiTCPP),D4 (CuTCPP),和D5 (PdTCPP).制备电极时,首先将P25粉涂覆在FTO玻璃上,然后经胺丙基三乙基硅烷(APTES)修饰,再与Dx反应生成酰胺键,从而实现卟啉染料与TiO2半导体材料的共价键键合,制备的系列电极记为Dx@TiO2.对卟啉和金属卟啉进行了紫外吸收、发射光谱(PL)、核磁共振和电化学循环伏安测试等检测,以及简单的DFT计算.对制备的光电阴极进行了红外光谱、固体紫外和电化学交流阻抗测试,计算了电极的Mott-Schottky曲线,得到了电极材料的平带电位,对于n型半导体,一般认为是近似的导带电位(CB).所有电极的CB电位均高于-0.56 V,高于甲醇生成需要的电位-0.38 V.经过卟啉修饰的电极材料,其能带结构发生了根本变化,由TiO2锐钛矿的3.2 eV降低到了2.37-2.73 eV. SEM及其元素分布彩色图表明所需元素都均匀分布在电极表面.电化学线性伏安扫描图表明,在光照条件下电流的提升是能带修饰和降低的结果.最好的光电阴极在光电还原电池D3@TiO2|NaHCO3|BiVO4中,-0.6 V条件下,一个标准太阳光照射2 h,生成甲醇的光量子效率用500 nm光子估算为0.92%,达到了自然界植物光合作用效率的2倍.循环实验表明,光电阴极经过4次2 h照射后仍有约50%

关 键 词：Artificial photosynthesis Carbon dioxide reduction PHOTOELECTROCATALYSIS METALLOPORPHYRIN Titanium dioxide 

分 类 号：O643.32[理学—物理化学]