原卟啉碳点的合成及其在光催化还原CO_(2)/H_(2)O制甲醇中的应用

Synthesis and application of protoporphyrin carbon dots in photocatalytic reduction of CO_(2)/H_(2)O to methanol

CO_(2)资源化利用是当前能源与环境领域的研究热点,光催化还原CO_(2)作为一种绿色、温和的转化技术备受关注,其中提高光催化转化过程中光利用效率和降低载流子复合速率是促进CO_(2)光催化还原过程的关键。利用柠檬酸、乙二胺和原卟啉为原料,通过一步水热法制备原卟啉碳点,并考察了其光催化还原CO_(2)性能。研究表明,碳点为3.3 nm左右的球形颗粒,原卟啉以共价键的形式成功引入碳点中,并且碳点中保留了原卟啉结构中的共轭大π键的骨架,增强了碳点催化剂对400~500 nm的光的吸收,降低了光催化还原CO_(2)过程中的载流子复合速率。光催化还原CO_(2)性能测试表明,以含有质量分数为1%原卟啉的碳点作为光催化剂转化CO_(2)为CH_(3)OH的产率达到285.5μmol·g~(-1)·h~(-1),是未添加原卟啉催化剂产率的2.16倍。

The resource utilization of CO_(2)is a research hotspot in the field of energy and environment at present.Photocatalytic reduc-tion of CO_(2)as a green and mild conversion technology has attracted much attention.Among them,improving the light absorption effi-ciency and reducing the carrier recombination rate are the keys to promote the process of CO_(2)photocatalytic reduction.Using citric acid,ethylenediamine and protoporphyrin as raw materials,protoporphyrin carbon dots(PP-CDs)were prepared by one-step hydro-thermal method,and their photocatalytic reduction of CO_(2)was investigated.The results show that carbon dots are spherical particles with about 3.3 nm.Protoporphyrin was successfully introduced into CDs in the form of covalent bond and retained the conjugated large T bond skeleton of the protoporphyrin structure in the CDs,which enhanced the absorption of the sunlight at 400~500 nm of the CDs photocatalyst and reduced the carrier recombination rate in the photocatalytic reduction of CO_(2).The performance test of photocatalytic reduction of CO_(2)shows that the conversion rate of CO_(2)to CH_(3) OH is 285.5μmol·g^(-1)·h^(-1) using carbon dots containing 1%protoporphy-rin as photocatalyst,with 2.16 times the yield of the catalyst without protoporphyrin.