TY - JOUR
T1 - Coupling of a new porphyrin photosensitizer and cobaloxime cocatalyst for highly efficient photocatalytic H2evolution
AU - Bodedla, Govardhana Babu
AU - Wong, Wai Yeung
AU - Zhu, Xunjin
N1 - Funding Information:
The research was supported by the General Research Fund (HKBU 12304320) from the Hong Kong Research Grants Council, and Initiation Grant for Faculty Niche Research Areas (IG-FNRA) (2020/21)-RC-FNRA-IG/20-21/SCI/06 from Research Committee of Hong Kong Baptist University. W.-Y. W. acknowledges the nancial support from the Science, Technology and Innovation Committee of Shenzhen Municipality (JCYJ20180507183413211), the RGC Senior Research Fellowship Scheme (SRFS2021-5S01), the Hong Kong Polytechnic University (1-ZE1C), Research Institute for Smart Energy (RISE) and Ms Clarea Au for the Endowed Professorship in Energy (847S).
Publisher Copyright:
© The Royal Society of Chemistry 2021.
PY - 2021/9/28
Y1 - 2021/9/28
N2 - Photocatalytic hydrogen evolution (PHE) is a promising strategy to produce environmentally friendly clean energy with the use of solar power and water. For this, developing an efficient and noble metal free photocatalytic system (PS) comprising high light-harvesting and photostable photosensitizers is an important and challenging task. Herein, a new porphyrin photosensitizer ZnDC(p-NI)PP, containing two naphthalimide (NI) donor chromophores and 4-carboxyphenyl substituents is developed for PHE. Using chloropyridinecobaloxime (CoPyCl) as a cocatalyst in phosphate buffer/THF solution at pH 7.4, the homogeneous PS of ZnDC(p-NI)PP exhibits a very high hydrogen evolution rate (ηH2) of 35.70 mmol g−1h−1, turnover number (TON) of 5958 and apparent quantum efficiency (AQE) of 10.01%. This performance recorded under the same conditions is significantly higher than that of the PS of ZnDCPP which lacks the NI moieties (ηH2of 4.64 mmol g−1h−1, TON of 1397 and AQE of 1.30%), the typical PS of ZnTCPP with four 4-carboxyphenyl substituent groups (ηH2of 2.43 mmol g−1h−1, TON of 562 and AQE of 1.00%), and previously reported ZnD(p-NI)PP containing only two NI chromophores (ηH2of 3.8 mmol g−1h−1, TON of 590 and AQE of 1.5%). The noticeable performance of ZnDC(p-NI)PP in PHE is attributed to the intramolecular energy transfer from the NI donor chromophore to the porphyrin acceptor that would promote the long-lived photoexcitation states. At the same time, the anionic form (-COO−) of 4-carboxyphenyl substituents at pH 7.4 enables a faster electron transfer from the porphyrin group to the cationic Co(iii) due to electrostatic force. To the best of our knowledge, the PHE results of ZnDC(p-NI)PP represent the best one for porphyrin photosensitizers and cobaloxime PSs reported so far. This work paves a new direction for developing new porphyrin-based materials for efficient PHE through facile molecular structure engineering.
AB - Photocatalytic hydrogen evolution (PHE) is a promising strategy to produce environmentally friendly clean energy with the use of solar power and water. For this, developing an efficient and noble metal free photocatalytic system (PS) comprising high light-harvesting and photostable photosensitizers is an important and challenging task. Herein, a new porphyrin photosensitizer ZnDC(p-NI)PP, containing two naphthalimide (NI) donor chromophores and 4-carboxyphenyl substituents is developed for PHE. Using chloropyridinecobaloxime (CoPyCl) as a cocatalyst in phosphate buffer/THF solution at pH 7.4, the homogeneous PS of ZnDC(p-NI)PP exhibits a very high hydrogen evolution rate (ηH2) of 35.70 mmol g−1h−1, turnover number (TON) of 5958 and apparent quantum efficiency (AQE) of 10.01%. This performance recorded under the same conditions is significantly higher than that of the PS of ZnDCPP which lacks the NI moieties (ηH2of 4.64 mmol g−1h−1, TON of 1397 and AQE of 1.30%), the typical PS of ZnTCPP with four 4-carboxyphenyl substituent groups (ηH2of 2.43 mmol g−1h−1, TON of 562 and AQE of 1.00%), and previously reported ZnD(p-NI)PP containing only two NI chromophores (ηH2of 3.8 mmol g−1h−1, TON of 590 and AQE of 1.5%). The noticeable performance of ZnDC(p-NI)PP in PHE is attributed to the intramolecular energy transfer from the NI donor chromophore to the porphyrin acceptor that would promote the long-lived photoexcitation states. At the same time, the anionic form (-COO−) of 4-carboxyphenyl substituents at pH 7.4 enables a faster electron transfer from the porphyrin group to the cationic Co(iii) due to electrostatic force. To the best of our knowledge, the PHE results of ZnDC(p-NI)PP represent the best one for porphyrin photosensitizers and cobaloxime PSs reported so far. This work paves a new direction for developing new porphyrin-based materials for efficient PHE through facile molecular structure engineering.
UR - http://www.scopus.com/inward/record.url?scp=85115731451&partnerID=8YFLogxK
U2 - 10.1039/d1ta04517b
DO - 10.1039/d1ta04517b
M3 - Journal article
AN - SCOPUS:85115731451
SN - 2050-7488
VL - 9
SP - 20645
EP - 20652
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 36
ER -