Rojas-Luna Raúl, Romero-Salguero Francisco J, Esquivel Dolores, Roy Souvik
Departamento de Química Orgánica, Instituto Químico para la Energía y el Medioambiente (IQUEMA), Facultad de Ciencias, Universidad de Córdoba, Campus de Rabanales, Edificio Marie Curie, Córdoba E-14071, Spain.
School of Chemistry, University of Lincoln, Green Lane, Lincoln LN6 7DL, U.K.
ACS Appl Energy Mater. 2024 Jun 29;7(14):5924-5936. doi: 10.1021/acsaem.4c01161. eCollection 2024 Jul 22.
Photocatalytic CO reduction, including reaction rate, product selectivity, and longevity, is highly sensitive to the coordination structure of the catalytic active sites, and the precise design of the active site remains a challenge in heterogeneous catalysts. Herein, we report on the modulation of the coordination structure of MN -type active sites (M = Co or Ni; = 4 or 5) anchored on a periodic mesoporous organosilica (PMO) support to improve photocatalytic CO reduction. The PMO was functionalized with pendant 3,6-di(2'-pyridyl)pyridazine (dppz) groups to allow immobilization of molecular Co and Ni complexes with polypyridine ligands. A comparative analysis of CO photoreduction in the presence of an organic photosensitizer (4CzIPN, 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene) and a conventional [Ru(bpy)]Cl sensitizer revealed strong influence of the coordination environment on the catalytic performance. CoN-PMO demonstrated a superior CO photoreduction activity than the other materials and displayed a cobalt-based turnover number (TON) of 92 for CO evolution at ∼75% selectivity after 3 h irradiation in the presence of 4CzIPN. The hybrid CoN-PMO catalyst exhibited better activity than its homogeneous [CoN] counterpart, indicating that the heterogenization promotes the formation of isolated active sites with improved longevity and faster catalytic rate.
光催化CO还原，包括反应速率、产物选择性和寿命，对催化活性位点的配位结构高度敏感，而活性位点的精确设计在多相催化剂中仍然是一个挑战。在此，我们报道了锚定在周期性介孔有机硅（PMO）载体上的MN型活性位点（M = Co或Ni； = 4或5）的配位结构的调控，以改善光催化CO还原。PMO用侧基3,6-二（2'-吡啶基）哒嗪（dppz）基团进行功能化，以固定带有多吡啶配体的分子Co和Ni配合物。在有机光敏剂（4CzIPN，1,2,3,5-四（咔唑-9-基）-4,6-二氰基苯）和传统的[Ru（bpy）]Cl光敏剂存在下对CO光还原的比较分析表明，配位环境对催化性能有很大影响。CoN-PMO表现出比其他材料更好的CO光还原活性，在4CzIPN存在下照射3小时后，对于CO生成显示出基于钴的周转数（TON）为92，选择性约为75%。杂化CoN-PMO催化剂表现出比其均相[CoN]对应物更好的活性，表明异质化促进了具有改善的寿命和更快催化速率的孤立活性位点的形成。
