Dual Localized Surface Plasmon Resonance effect enhances Nb2AlC/Nb2C MXene thermally coupled photocatalytic reduction of CO2 hydrogenation activity

• Published in: Journal of colloid and interface science 2023-12, Vol.652, p.599-611
• Main Authors: Liu, Tian, Tan, Guoqiang, Feng, Shuaijun, Zhang, Bixin, Liu, Ying, Wang, Zeqiong, Bi, Yu, Yang, Qian, Xia, Ao, Liu, Wenlong, Ren, Huijun, Lv, Long
• Format: Article
• Language: English
• Subjects: carbon dioxide; CO2 reduction; hydrogenation; LSPR effect; Nb2AlC/Nb2C MXene; photocatalysis; photocatalysts; photoreduction; Selective etching; solar radiation; surface plasmon resonance; Thermally coupled photocatalysis
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.08.097

[Display omitted] •Selective etching of Al layer obtained Nb2AlC/Nb2C MXene heterojunction photocatalyst with double LSPR effect.•146.25 μmol·g−1 electrons and 15.28 μmol·g−1 holes were stored in Nb2AlC/Nb2C MXene heterogeneous crystals.•The CO selectivity of heterojunction thermo-coupled photocatalytic reduction was more than 92%. Nb2AlC/Nb2C MXene (NAC/NC) heterojunction photocatalysts with Schottky junctions were obtained by selective etching of the Al layer, resulting in 146.25 μmol·g−1 electrons and 15.28 μmol·g−1 holes stored in the heterojunction. The average conversion of NAC/NC thermally coupled photocatalytic reduction of CO2 under the simulated solar irradiation reached 110.15 μmol⋅g−1⋅h−1, and the CO selectivity reached over 92%, which was 1.49 and 1.74 times higher than that of pure Nb2AlC and Nb2C MXene, respectively. After light excitation, the localized surface plasmon resonance (LSPR) effect of holes distributed on the surface of Nb2C MXene crystals in the heterojunction will form high-energy thermal holes to dissociate H2 to H+ and reduce CO2 to form H2O at the same time. The high-energy electrons formed by the LSPR effect of Nb2C MXene and the conduction band electrons generated by the photoexcitation of Nb2C MXene can be migrated to Nb2AlC under the action of the interfacial Schottky junction to supplement the electrons needed for the LSPR effect of Nb2AlC, which continuously forms high-energy hot electrons to convert the adsorbed CO2 into *CO2−, b-HCO3, and HCOO. Subsequently, HCOO releases ⋅OH in a cyclic reaction to continuously reduce to form CO. The dual LSPR effect of Nb2AlC and Nb2C MXene is used to enhance the hydrogenation activity of thermally coupled photocatalytic reduction of CO2, which provides a new research idea for the application of MXene in thermally coupled photoreduction of CO2.