Dual-optimization strategy engineered Ti-based metal-organic framework with Fe active sites for highly-selective CO2 photoreduction to formic acid

Computational Design of Single‐atom Modified Ti‐MOFs for Photocatalytic CO2 Reduction to C1 Chemicals

“…From Figure 4(a) and 4 (b), it can be seen that the coord-Fe/Ti-BPDC has a very low limiting potential (U L = À 0.40 V) and is located at the top of the volcano-type curve, indicating that coord-Fe/Ti-BPDC is the best catalyst for CO 2 reduction to formic acid, which is in agreement with the results from our experimental study. [33] In addition, coord-Ag/Ti-BPDC, coord-Cr/Ti-BPDC, coord-Mn/ Ti-BPDC, coord-Rh/Ti-BPDC, coord-Zr/Ti-BPDC, coord-Nb/Ti-BPDC, coord-Ru/Ti-BPDC, and coord-Cu/Ti-BPDC have moderate limiting potentials (U L = À 0.50, À 0.51, À 0.56, À 0.65, À 0.69, À 0.76, À 0.79, and À 0.80 V, respectively) and are distributed near the top of the volcano-type curve, thus these candidates would also be active for CO 2 reduction to formic acid. For the remaining materials of coord-M/Ti-BPDC (M = Co, Ni, Zn, Pd, Hf, Ta, Os, Ir, Pt), CO 2 reduction to formic acid would hardly occur due to the large limiting potentials caused by substantial hydrogenation barriers or weak CO 2 adsorption strength.…”

“…Our previous studies have shown that photogenerated electrons are generated by the visible light excitation of H 2 BPDC ligands during the photocatalytic process. [33,37] Subsequently, these photogenerated electrons transfer from the ligand to the Ti-oxo cluster via the ligand-to-metal charge transfer (LMCT) process. However, in the coord-M/Ti-BPDC (M = Fe, Mn, Ag, Cr, and Pd), the emergence of new energy levels effectively suppresses the rapid complexation of electrons with holes, providing more stable platforms for photogenerated electrons, possessing superior photocatalytic performance.…”

“…The experimental results showed that the Fe/ Ti-BPDC catalyst exhibits excellent photocatalytic performance in the conversion of CO 2 to HCOOH product under visible light conditions. [33] Furthermore, single atom modified NH 2 -MIL-101(Fe)/g-C 3 N 4 and NH 2 -MIL-88B(Fe) with amino-functionalized MOFs catalysts showed excellent activity and selectivity in the reduction of CO 2 to HCOOH or C 2 H 4 . [34,35] In terms of theoretical calculations, the computational study of CO 2 photoreduction to HCOOH on a series of metallated porphyrinic MOF-525(M) was carried out by Jiang et al using density functional theory (DFT).…”

“…[32] Our research group has successfully synthesized a novel two-dimensional Ti-MOF-based photocatalyst named Fe/ Ti-BPDC where BPDC stands for 2,2'-bipyridine-5,5'-dicarboxylic acid. [33] The unsaturated N atoms of BPDC ligands in the designed catalyst provide rigid and stable coordination sites for the metal atoms. The experimental results showed that the Fe/ Ti-BPDC catalyst exhibits excellent photocatalytic performance in the conversion of CO 2 to HCOOH product under visible light conditions.…”

“…In this work, based on our previous experimental results on Ti-based MOF catalysts, [33,37] we chose Ti-BPDC as the support material because the unsaturated N atoms in the bipyridine functional group of Ti-BPDC provide suitable platform to anchor the metal single-atom. Experimental characterizations show that the Ti and O atoms in the Ti-BPDC framework form a periodic arrangement of TiÀ O layers, and each Ti atom is connected to six O atoms to form TiÀ O clusters, of which two O atoms are from the ligand H 2 BPDC and four O atoms are from the TiÀ O layer.…”