Introduction:
[1] M. Arumugam, M. Tahir, P. Praserthdam, Effect of nonmetals (B, O, P, and S) doped with porous g-C3N4 for improved electron transfer towards photocatalytic CO2 reduction with water into CH4, Chemosphere 286 (2022) 131765-131776.
[2] W.H. Gu, S.Y. Zhai, Z. Liu, Effect of coordination interaction between water and zinc on photochemistry property of Zn3(PO4)2•2H2O, Chem. Phys. 536 (2020) 110811-110821.
[3] N. Han, Y. Wang, J. Deng, Self-templated synthesis of hierarchical mesoporous SnO2 nanosheets for selective CO2 reduction, J. Mater. Chem. A 7 (2019) 1267-1273.
[4] F. Li, D. Wang, Q.J. Xing, Design and syntheses of MOF/COF hybrid materials via postsynthetic covalent modification: An efficient strategy to boost the visible-light-driven photocatalytic performance, Appl. Catal. B-Environ. 243 (2019) 621-628.
[5] S.Y. Chen, G.T. Hai, H.Y. Gao, Modulation of the charge transfer behavior of Ni(II)-doped NH2-MIL-125(Ti): Regulation of Ni ions contents and enhanced photocatalytic CO2 reduction performance, Chem. Eng. J. 406 (2021) 126886-126895.
[6] F. Guo, M. Yang, R.X. Xia, Nanosheet-engineered NH2-MIL-125 with highly active facets for enhanced solar CO2 reduction, ACS Catal. 12 (2022) 9486-9493.
[7] R.N. Wang, Z. Wang, X.F. Shang, A novel S-scheme heterojunction constructed by Ti-based hydrotalcite decorating MOFs for boosting CO2-to-CO photoreduction and mechanism insights, J. Mater. Chem. A 11 (2023) 630-642.
[8] W.F. Zhang, Q.L. Zhou, N. Li, Enhanced photocatalytic reduction of CO2 into CH4 over N, Eu co-doped TiO2: Insight into the synergistic effect of N and Eu, Appl. Catal. A-Gen. 650 (2023) 118977-118989.

XRD:
[1] D. Ao, J. Zhang, H. Liu, Visible-light-driven photocatalytic degradation of pollutants over Cu-doped NH2-MIL-125(Ti), J. Photoch. Photobio. A 364 (2018) 524-533.
[2] Y.B. Yan, Y.L. Yu, S.L. Huang, Adjustment and matching of energy band of TiO2-based photocatalysts by metal ions (Pd, Cu, Mn) for photoreduction of CO2 into CH4, J. Phys. Chem. C 121 (2017) 1089-1098.
[3] H.F. Zhou, J. Yang, W. Cao, Hollow meso-crystalline Mn-doped Fe3O4 fenton-like catalysis for ciprofloxacin degradation: Applications in water purification on wide pH range, Appl. Surf. Sci. 590 (2022) 153120-153132.
[4] G. Ali, A. Badshah, K.Y. Chung, Superior shuttling of lithium and sodium ions in manganese-doped titania@functionalized multiwall carbon nanotube anodes, Nanoscale 9 (2017) 9859-9871. 
[5] P.K. Sharma, O.P. Pandey, Enhanced photocatalytic activity with metal ion doping and co-doping in CeO2 nanoparticles, Solid State Sci. 126 (2022) 106846-106859.

FT-IR:
[1] R.M. Abdelhameed, M.M.Q. Simtes, A.M.S. Silva, Enhanced photo-catalytic activity of MIL-125 by post-synthetic modification with CrIII and Ag nanoparticles, Chem. Eur. J. 21 (2021) 11072-11081.
[2] Z.W. Yang, X.Q.Xu, X.X. Liang, Construction of heterostructured MIL-125/Ag/g-C3N4 nanocomposite as an efficient bifunctional visible light photocatalyst for the orignic oxidation and reduction reactions, Appl. Catal. B: Environ. 205 (2017) 42-54.
[3] L.Z. Huang, B.S. Liu, Synthesis of a novel and stable reduced graphene oxide/MOF hybrid nanocomposite and photocatalytic performance for the degradation of dyes, RSC Adv. 6 (2016) 17873-17879.
[4] S. Mao, J.W. Shi, G. Sun, Cu(II) decorated thiol-functionalized MOF as an efficient transfer medium of charge carriers promoting photocatalytic hydrogen evolution, Chem. Eng. J. 404 (2021) 126533-126543.

BET:
[1] Z. Gao, J.X. Wang, Y. Muhammad, Enhanced moisture-resistance and excellent photocatalytic performance of synchronous N/Zn-decorated MIL-125(Ti) for vaporous acetaldehyde degradation, Chem. Eng. J. 388 (2020) 124389-124402.
[2] P. Sun, Z. Mo, H. Chen, Highly efficient photosynthesis of H2O2 via two-channel pathway photocatalytic water splitting, Inorg. Chem. Front. 9 (2022) 1701-1707.

XPS；
[1] X. Xin, Z.F. Zhao, Y. Chen, Dual-ligand Ti-MOFs with push-pull effect for photocatalytic H2 production, ACS Appl. Mater. Interfaces 15 (2023) 1053-1062
[2] Y.Z. He, H.F. Li, J. Wu, In-situ formation of Au nanoparticles with surface plasmon resonance confined in the framework of Cu ions doped NH2-MIL-125(Ti) to enhance photocatalytic hydrogen production and NO removal, Appl. Surf. Sci. 604 (2022) 154641-154651.
[3] Q. Wang, W. Ruan, Y. Teng, Boosting hydrogen production of uniform CuCo-ZIF nanododecahedrons by bimetal node and glycerol, Mater. Today Chem. 28 (2023) 101359-101073.
[4] S. Latif, K. Tahir, A.U. Khan, F. Abdulaziz, Green synthesis of Mn-doped TiO2 nanoparticles and investigating the influence of dopant concentration on the photocatalytic activity, Inorg. Chem. Commun. 146 (2022) 110091-110099.
[5] B. Gobaut, P. Orgiani, A. Sambri, Role of oxygen deposition pressure in the formation of Ti defect states in TiO2(001) anatase thin films, ACS Appl. Mater. Interfaces 9 (2017) 23099-23106.
[6] Z.H. Lin, M.Y. He, Y.L. Liu, Effect of calcination temperature on the structural and formaldehyde removal acyivity of Mn/Fe2O3 catalysts, Res. Chem. Intermediat. 47 (2021) 3245-3261. 
[7] Z. Tong, D. Yang, T. Xiao, Biomimetic fabrication of g-C3N4/TiO2 nanosheets with enhanced photocatalytic activity toward organic pollutant degradation. Chem. Eng. J. 260 (2015) 117-125.
[8] S. Paul, P. Chetri, A. Choudhury, Effect of ,amganese doping on the optical property and photocatalytic activity of nanocrystalline titania: Experimental and theoretical investigation, J. Alloy. Compd. 583 (2014) 578-586.
[9] S. V. Stefanovskya, O. I. Stefanovskya, I. L. Prusakova, Speciation of sulphate ions in sodium alumino (iron) phosphate glasses, J. Non-Cryst. Solids 512 (2019) 81-89.

UV-vis spectra:
[1] D. Ao, J. Zhang, H. Liu, Visible-light-driven photocatalytic degradation of pollutants over Cu-doped NH2-MIL-125(Ti), J. Photoch. Photobio. A 364 (2018) 524-533.
[2] Q.R. Deng, X.H. Xia, M.L. Guo, Mn-doped TiO2 nanopowders with remarkable visible light photocatalytic activity, Mater. Lett. 65 (2011) 2051-2054.
[3] S. Latif, K. Tahir, A.U. Khan, Green synthesis of Mn-doped TiO2 nanoparticles and investigating the influence of dopant concentration on the photocatalytic activity, Inorg. Chem. Commun. 146 (2022) 110091-110099.

DOS:
[1] Y.Z. He, H.F. Li, J. Wu, In-situ formation of Au nanoparticles with surface plasmon resonance confined in the framework of Cu ions doped NH2-MIL-125(Ti) to enhance photocatalytic hydrogen production and NO removal, Appl. Surf. Sci. 604 (2022) 154641-154651.
[2] X. Zhang, Y.T. Huang, M.J. Bao, A post-synthetic modified NH2-MIL-125(Ti) catalyst for boosting photochemical Cr (VI) reduction, Process Saf. Environ. 172 (2023) 778-786.
[3] J.Z. Liao, L.C. Chen, M.L. Sun, Improving visible-light-driven photocatalytic NO oxidation over BiOBr nanoplates through tunable oxygen vacancies, Chinese J. Catal. 39 (2018) 779-789. 

Photocatalytic performace:
[1] R.R. Ikreedeegh, M. Tahir, Indirected Z-scheme heterojunction of NH2-MIL-125(Ti) MOF/g-C3N4 nanocomposite with RGO solid electron mediator for efficient photocatalytic CO2 redution to CO and CH4, J. Environ. Chem. Eng. 9 (2021) 105600-105617.
[2] S.C. Sun, B. Peng, Y. Song, Engineering Z-Sscheme FeOOH/PCN with fast photoelectron transfer and surface redox kinetics for efficient solar-driven CO2 reduction, ACS Appl. Mater. Interfaces 15 (2023) 12957-12966.

Photocatalytic stability:
[1] Y. Zhang, Y. Wei, B. Wang, Highly advanced degradation of thiamethoxam by synergistic chemisorption-catalysis strategy using MIL(Fe)/Fe-SPC composites with ultrasonic irradiation, ACS Appl. Mater. Interfaces 10 (2018) 35260-35272.
[2] H. Wang, X. Yuan, Y. Wu, Facile synthesis of amino-functionalized titanium metal-organic frameworks and their superior visible-light photocatalytic activity for Cr(VI) reduction, J. Hazard. Mater. 286 (2015) 187-194.
[3] Z. Gao, J.X. Wang, Y. Muhammad, Enhanced moisture-resistance and excellent photocatalytic performance of synchronous N/Zn-decorated MIL-125(Ti) for vaporous acetaldehyde degradation, Chem. Eng. J. 388 (2020) 124389-124402.

Mott-Schottky:
[1] Y.H. Fu, H. Yang, R.F. Du, Enhanced photocatalytic CO2 reduction over Co-doped NH2-MIL-125(Ti) under visible light, RSC Adv. 7 (2017) 42819-42827.
[2] J.C. Meng, Q. Chen, J.Q. Lu, Z-scheme photocatalytic CO2 reduction on a heterostructure of oxygen-defective ZnO/reduced graphene oxide/UiO-66-NH2 under visible light, ACS Appl. Mater. Interfaces 11 (2019) 550-562.
[3] M. Liu, X. Qiu, M. Miyauchi, Cu(II) oxide amorphous nanoclusters grafted Ti3+ self-doped TiO2: An efficient visible light photocatalyst, Chem. Mater. 23 (2011) 5282-5286.
[4] C.A. Celaya, M.M. Galvan, O.C. Ocampo, Exploring the CO2 conversion into hydrocarbons via a photocatalytic process onto M-doped titanate nanotubes (M = Ni and Cu), Fuel 324 (2022) 124440-124451.

Steady-state PL:
[1] Y. Zhang, L.L. Zang, S.T. Zhao, Brominated metal phthalocyanine-based covalent organic framework for enahnced selective photocatalytic reduction of CO2, J. Colloid Interf. Sci. 655 (2024) 1-11.
[2] X.W. Zhu, H.M. Xu, C.Z. Bi, Piezo-photocatalysis for efficient charge separation to promote CO2 photoreduction in nanoclusters, Ultrason. Sonochem. 101 (2023) 1066553-1066564.
[3] J.G. Santaclara, M.A. Nasalevich, S. Castellanos, Origanic linker defines the excited-state decay of photocatalytic MIL-125(Ti)-type materials, ChemSuschem 9 (2016) 388-395. 

time-resolved PL:
[1] L. Sun, Y. Yuan, F. Wang, Selective wet-chemical etching to create TiO2@MOF frame heterostructure for efficient photocatalytic hydrogen evolution, Nano Energy 74 (2020) 104909-104917.
[2] X.M. Cheng, X.Y. Zhang, X.Y. Dao, High-index facets exposed on metal-organic framework for boosting photocatalytic carbon dioxide reduction, Chem. Eng. J. 431 (2022) 134125-134132.

PC:
[1] H. Wang, Q. Zhang, J.J. Li, The covalent coordination-driven Bi2S3@NH2-MIL-125(Ti)-SH heterojunction with boosting photocatalytic CO2 reduction and dye degradation performance, J. Colloid Interf. Sci. 606 (2022) 1745-1757. 

EPR:
[1] S. Zhang, Y.X. Zhao, R. Sui, Efficient photocatalytic nitrogen fixation over Cuδ+-modified defective ZnAl-layered double hydroxide nanosheets, Adv. Energy Mater. 10 (2020) 1901973-1901983.
[2] K.H. Ye, K.S. Li, Y.R. Lu, An overview of advanced methods for the characterization of oxygen vacancies in materials, Trend. Anal. Chem. 116 (2019) 102-108.
[3] X.X. Zou, G.D. Li, K.X. Wang, Light-induced formation of porous TiO2 with superior electron-storing capacity, Chem. Commun. 46 (2010) 2112-2114.
[4] J. Wang, L. Xiong, Y. Bai, Mn-doped perovskite nanocrystals for photocatalytic CO2 reduction: Insight into the role of the charge carriers with prolonged lifetime, Sol. Rrl. 6 (2022) 2200294-2200302.
[5] W. M. Swain, H.J. Lin, Z.J. Li, Facilitated electron transfer by Mn dopants in 1-dimensional CdS nanorods for enhanced photocatalytic hydrogen generation, J. Mater. Chem. A 11 (2023) 7066-7076.
[6] Z. Wang, A. Meijerink, Concentration quenching in upconversion nanocaystals, J. Phys. Chem. C Nanomater. Interfaces 112 (2018) 26298-26306.
[7] J. Cao, J. Yang, Y. Zhang, Optimized doping concentration of manganese in zinc sulfide nanoparticles for yellow-orange light emission, J. Alloys. Compd. 486 (2009) 890-894.

Mechanism:
[1] Y. Bo, C. Gao, Y. Xiong, Recent advances in engineering active sites for photocatalytic CO2 reduction, Nanoscale 12 (2020) 12196-12209.
[2] W.H. Gu, F. Teng, SPR-promoted visible-light photocatalytic activity of Bi/ZIF hybrids, J. Photoch. Photobio. A 400 (2020) 112679-112687.
[3] S. V. Stefanovskya, O. I. Stefanovskya, I. L. Prusakova, Speciation of sulphate ions in sodium alumino (iron) phosphate glasses, J. Non-Cryst. Solids 512 (2019) 81-89.
[4] Y. Xia, J.W. Man, X.D. Wu, Oxygen-vacancy-assisted construction of Ce-TiO2 aerogel for efficiently boosting photocatalytic CO2 reduction without any sacrifice agent, Ceram. Int. 49 (2023) 6100-6112.
[5] W. M. Swain, H.J. Lin, Z.J. Li, Facilitated electron transfer by Mn dopants in 1-dimensional CdS nanorods for enhanced photocatalytic hydrogen generation, J. Mater. Chem. A 11 (2023) 7066-7076.
有重复出现的吗