Song Guo

The mechanism of photoreduction of CO ₂ to CO using heavy-atom-free electron donor–acceptor dyad photosensitizers was studied using transient absorption spectroscopy.

The efficiency of photocatalytic CO ₂ reduction is governed by multiple critical factors, including visible‐light absorption, charge separation, hole utilization, and CO ₂ adsorption/activation. However, simultaneous regulation of these factors in a single photocatalyst to facilitate CO ₂ photoreduction remains underexplored. Herein, we proposed a dual‐regulation strategy to concurrently modulate the reduction center via heteroatom substitution and the oxidation center via 2,2,6,6‐tetramethylpiperidoxyl (TEMPO) coordination in cobalt porphyrin‐based metal–organic frameworks (Co‐MOFs), resulting in series of strong redox photocatalysts (TEMPO@Co‐XN ₃ ‐MOF, X═N, O, and S) for efficient CO ₂ photoreduction. Remarkably, CO yield with the dual‐regulated TEMPO@Co‐SN ₃ ‐PCN can reach 2000 µmol g ⁻¹ , over 10 and 50 times higher than that with single‐regulated Co‐SN ₃ ‐PCN and the typical Co‐N ₄ ‐PCN, respectively. Moreover, the photogenegrated hole can efficiently drive the photooxidation of lactic acid to pyruvic acid with a 85% yield, while the in situ‐generated CO is directly utilized in a tandem carbonylation reaction to afford benzophenone with a 90% yield. Investigations reveal that the dual regulation of redox centers endows TEMPO@Co‐SN ₃ ‐PCN with efficient hole utilzation, efficient charge separation, strong CO ₂ adsorption and activation, thereby facilitating green‐synthesis of pyruvic acid and carbonyl compounds via a negative carbon emission process.

The efficiency of photocatalytic CO ₂ reduction is governed by multiple critical factors, including visible‐light absorption, charge separation, hole utilization, and CO ₂ adsorption/activation. However, simultaneous regulation of these factors in a single photocatalyst to facilitate CO ₂ photoreduction remains underexplored. Herein, we proposed a dual‐regulation strategy to concurrently modulate the reduction center via heteroatom substitution and the oxidation center via 2,2,6,6‐tetramethylpiperidoxyl (TEMPO) coordination in cobalt porphyrin‐based metal–organic frameworks (Co‐MOFs), resulting in series of strong redox photocatalysts (TEMPO@Co‐XN ₃ ‐MOF, X═N, O, and S) for efficient CO ₂ photoreduction. Remarkably, CO yield with the dual‐regulated TEMPO@Co‐SN ₃ ‐PCN can reach 2000 µmol g ⁻¹ , over 10 and 50 times higher than that with single‐regulated Co‐SN ₃ ‐PCN and the typical Co‐N ₄ ‐PCN, respectively. Moreover, the photogenegrated hole can efficiently drive the photooxidation of lactic acid to pyruvic acid with a 85% yield, while the in situ‐generated CO is directly utilized in a tandem carbonylation reaction to afford benzophenone with a 90% yield. Investigations reveal that the dual regulation of redox centers endows TEMPO@Co‐SN ₃ ‐PCN with efficient hole utilzation, efficient charge separation, strong CO ₂ adsorption and activation, thereby facilitating green‐synthesis of pyruvic acid and carbonyl compounds via a negative carbon emission process.

For the first time, we reported a single-atom palladium photocatalyst, Pd-Ace-COF, for continuous C–C coupling reaction.

The reaction pathway, product selectivity and catalytic efficiency of photo‐oxidation are highly dependent on the specific reactive oxygen species (ROS), such as singlet oxygen ( ¹ O ₂ ) and superoxide (O ₂ ⋅ ⁻ ), generated via the sensitization of O ₂ by photosensitizers. Studies on uncovering the role of photosensitizing factors on the selective control of ¹ O ₂ and O ₂ ⋅ ⁻ generation are significant but remain underexplored. Here, we constructed a photosensitizing metal–organic framework molecular platform (UiO‐1–UiO‐4) by elaborately engineering Ir(III) complex ligands with pyrenyl group for modulating photosensitizing factors and elucidating their impact on ROS generation. Impressively, the ratios of ¹ O ₂ and O ₂ ⋅ ⁻ generation varied from 0 : 100 for UiO‐1 to 94 : 6 for UiO‐4 by modulating photosensitizing factors. UiO‐2 and UiO‐4 were respectively immobilized in a continuous‐flow reactor, achieving gram‐scale photosynthesis of phenol and juglone with high purity (>94 %) via O ₂ ⋅ ⁻ and ¹ O ₂ pathway, respectively. Investigations reveal that UiO‐4 with ligand localized excited state and long excited state lifetime contributed to triggering energy transfer to afford ¹ O ₂ , whereas UiO‐1 with charge‐transfer state and negative reduction potential facilitates charge transfer to produce O ₂ ⋅ ⁻ . This work offers a novel insight into regulating ROS generation by modulating the photosensitizing factors at the molecular level.

The reaction pathway, product selectivity and catalytic efficiency of photo‐oxidation are highly dependent on the specific reactive oxygen species (ROS), such as singlet oxygen ( ¹ O ₂ ) and superoxide (O ₂ ⋅ ⁻ ), generated via the sensitization of O ₂ by photosensitizers. Studies on uncovering the role of photosensitizing factors on the selective control of ¹ O ₂ and O ₂ ⋅ ⁻ generation are significant but remain underexplored. Here, we constructed a photosensitizing metal–organic framework molecular platform (UiO‐1–UiO‐4) by elaborately engineering Ir(III) complex ligands with pyrenyl group for modulating photosensitizing factors and elucidating their impact on ROS generation. Impressively, the ratios of ¹ O ₂ and O ₂ ⋅ ⁻ generation varied from 0 : 100 for UiO‐1 to 94 : 6 for UiO‐4 by modulating photosensitizing factors. UiO‐2 and UiO‐4 were respectively immobilized in a continuous‐flow reactor, achieving gram‐scale photosynthesis of phenol and juglone with high purity (>94 %) via O ₂ ⋅ ⁻ and ¹ O ₂ pathway, respectively. Investigations reveal that UiO‐4 with ligand localized excited state and long excited state lifetime contributed to triggering energy transfer to afford ¹ O ₂ , whereas UiO‐1 with charge‐transfer state and negative reduction potential facilitates charge transfer to produce O ₂ ⋅ ⁻ . This work offers a novel insight into regulating ROS generation by modulating the photosensitizing factors at the molecular level.

Photocatalytic efficiency is closely correlated to visible‐light absorption ability, electron transfer efficiency and catalytic center activity of photocatalysts, nevertheless, the concurrent management of these factors to improve photocatalytic efficiency remains underexplored. Herein, we proposed a sensitizer/catalyst dual regulation strategy on the polyoxometalate@Metal−Organic Framework (POM@MOF) molecular platform to construct highly efficient photocatalysts. Impressively, Ni−Sb₉@UiO−Ir−C6, obtained by coupling strong sensitizing [Ir(coumarin 6)₂(bpy)]⁺ with Ni−Sb₉ POM with extremely exposed nickel site [NiO₃(H₂O)₃], can drive H₂ evolution with a turnover number of 326923, representing a record value among all the POM@MOF composite photocatalysts. This performance is over 34 times higher than that of the typical Ni₄P₂@UiO−Ir constructed from [Ir(ppy)₂(bpy)]⁺ and Ni₄P₂ POM. Systematical investigations revealed that dual regulation of sensitizing and catalytic centers endowed Ni−Sb₉@UiO−Ir−C6 with strong visible‐light absorption, efficient inter‐component electron transfer and high catalytic activity to concurrently promote H₂ evolution. This work opens up a new avenue to develop highly active POM@MOF photocatalysts by dual regulation of sensitizing/catalytic centers at the molecular level.

Photocatalytic efficiency is closely correlated to visible‐light absorption ability, electron transfer efficiency and catalytic center activity of photocatalysts, nevertheless, the concurrent management of these factors to improve photocatalytic efficiency remains underexplored. Herein, we proposed a sensitizer/catalyst dual regulation strategy on the polyoxometalate@Metal−Organic Framework (POM@MOF) molecular platform to construct highly efficient photocatalysts. Impressively, Ni−Sb₉@UiO−Ir−C6, obtained by coupling strong sensitizing [Ir(coumarin 6)₂(bpy)]⁺ with Ni−Sb₉ POM with extremely exposed nickel site [NiO₃(H₂O)₃], can drive H₂ evolution with a turnover number of 326923, representing a record value among all the POM@MOF composite photocatalysts. This performance is over 34 times higher than that of the typical Ni₄P₂@UiO−Ir constructed from [Ir(ppy)₂(bpy)]⁺ and Ni₄P₂ POM. Systematical investigations revealed that dual regulation of sensitizing and catalytic centers endowed Ni−Sb₉@UiO−Ir−C6 with strong visible‐light absorption, efficient inter‐component electron transfer and high catalytic activity to concurrently promote H₂ evolution. This work opens up a new avenue to develop highly active POM@MOF photocatalysts by dual regulation of sensitizing/catalytic centers at the molecular level.

Quinolones and isoquinolones are of particular importance to pharmaceutical industry due to their diverse biological activities. However, their synthetic protocols were limited by high toxicity, high energy consumption, poor functional group tolerance and noble metal catalyst. This study concerns the development of a series of TEMPO@PCN‐222 (TEMPO: 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy; PCN: porous coordination network) composite photocatalysts by coordinating different amount of 4‐carboxy‐TEMPO with the secondary building units of PCN‐222. Upon visible‐light irradiation, photogenerated holes in the highest occupied molecular orbital of PCN‐222 can smoothly transfer to TEMPO, which can significantly boost the photosynthesis of bioactive (iso)quinolones from readily available N‐alkyl(iso)quinolinium salts. TEMPO@PCN‐222 exhibits an outstanding catalytic stability and substrate tolerance with a 1‐methyl‐2‐quinolinone yield of 86.7 %, over four times that with PCN‐222 (21.4 %). This work provides a new route to construct composite photocatalysts from abundant starting materials for efficient photosynthesis of high value‐added chemicals.

Rational construction of broadband and strong visible-light-absorbing (BSVLA) earth-abundant complexes is of great importance for efficient and sustainable solar energy utilization. Herein, we explore a universal Cu(I) center to couple with multiple strong visible-light-absorbing antennas to break the energy level limitations of the current noble-metal complexes, resulting in the BSVLA nonprecious complex ( Cu-3 ). Systematic investigations demonstrate that double “ping-pong” energy-transfer processes in Cu-3 involving resonance energy transfer and Dexter mechanism enable a BSVLA between 430 and 620 nm and an antenna-localized long-lived triplet state for efficient intermolecular electron/energy transfer. Impressively, Cu-3 exhibited an outstanding performance for both energy- and electron-transfer reactions. Pseudo-first-order rate constant of photooxidation of 1,5-dihydroxynaphthalene with Cu-3 can achieve a record value of 190.8 × 10 ^{− 3} min ^{− 1} among the molecular catalytic systems, over 30 times higher than that with a noble-metal photosensitizer (PS) [Ru(bpy) ₃ ] ²⁺ . These findings pave the way to develop BSVLA earth-abundant PSs for boosting photosynthesis.