Construction of Multifunctional Photothermal/Photocatalytic Materials Based on the Principle of Three Primary Colors: A Case Study of g-C₃N₄/Ag₂CrO₄

Abstract

The strategic design and synthesis of photothermal/photocatalytic materials are pivotal to realizing photothermal conversion water evaporation coupled with photocatalytic sewage purification functions. In this work, based on the principle of three primary colors, brick-red g-C₃N₄/Ag₂CrO₄ composite was loaded onto a green polyurethane (PU) sponge using polyvinyl alcohol (PVA) as the linking agent. The resultant PU/PVA/g-C₃N₄/Ag₂CrO₄ composite exhibits outstanding performance in simultaneous photothermal/photocatalytic water evaporation, pollutant degradation, sterilization, and thermoelectric generation. Under 1.0 kW m⁻² irradiation, the water evaporation rate reaches 3.19 kg m⁻² h⁻¹, while a single thermoelectric module generates a maximum thermoelectric output power of 0.25 W m⁻². Concurrently, rhodamine B (RhB) at a concentration of 4.0 × 10⁻⁴ mol L⁻¹ undergoes complete photocatalytic degradation within 40 min. When the light intensity is 2.0 kW m⁻², the evaporation rate soars to 8.52 kg m⁻² h⁻¹, and the thermoelectric power output increases to 1.1 W m⁻². Furthermore, this photothermal/photocatalytic material based on the principle of three primary colors has excellent photothermal/photocatalytic antibacterial activity against Escherichia coli. By abandoning black light-absorbing materials, more active sites of the photocatalyst can be exposed. The g-C₃N₄/Ag₂CrO₄ heterojunction accelerates the separation of photogenerated carriers, while the hydrophilic groups in the photothermal/photocatalytic materials reduce the water evaporation enthalpy. This research provides a novel approach for fabricating multi-function photothermal/photocatalytic materials, which could quicken the development of solution to freshwater and electricity energy shortages as well as environmental pollution issues.

Keywords

g-C₃N₄/Ag₂CrO₄ / photocatalytic / photothermal / sterilization / thermoelectric generation / three primary colors

References

[1] N. Xu, J. Li, C. Finnerty, et al., “Going Beyond Efficiency for Solar Evaporation,” Nature Water 1, no. 6 (2023): 494-501.

[2] C. Pornrungroj, A. B. Mohamad Annuar, Q. Wang, et al., “Hybrid Photothermal-Photocatalyst Sheets for Solar-Driven Overall Water Splitting Coupled to Water Purification,” Nature Water 1, no. 11 (2023): 952-960.

[3] Q. Xu, Z. Xia, J. Zhang, et al., “Recent Advances in Solar-Driven CO₂ Reduction Over g-C₃N₄-Based Photocatalysts,” Carbon Energy 5, no. 2 (2023): e205.

[4] X. Huang, M. Sun, M. Humayun, et al., “In-Situ Synthesis of Efficient N-Graphyne/Bi/BiOBr Photocatalysts for Contaminants Removal and Nitrogen Fixation,” Journal of Alloys and Compounds 976 (2024): 173025.

[5] Y. Zheng, M. Sun, W. Sun, X. Meng, X. Huang, and Z. Li, “Nitrogen-Doped Graphyne/Biobr Nanocomposites: In-Situ Sonochemical Synthesis and Boosted Photocatalytic Performance,” Separation and Purification Technology 301 (2022): 122062.

[6] W. Liu, M. Sun, Z. Ding, et al., “Ball Milling Synthesis of Porous g-C₃N₄ Ultrathin Nanosheets Functionalized With Alkynyl Groups for Strengthened Photocatalytic Activity,” Separation and Purification Technology 282 (2022): 120097.

[7] S. Li, M. Sun, X. Huang, H. Chen, J. Zhao, and Z. Li, “In Situ Sonochemical Synthesis of Flower-Like N-Graphyne/BiOCl_0.5Br_0.5 Microspheres for Efficient Removal of Levofloxacin,” Dalton Transactions 53, no. 3 (2024): 917-931.

[8] B. Zhu, J. Sun, Y. Zhao, L. Zhang, and J. Yu, “Construction of 2D S-Scheme Heterojunction Photocatalyst,” Advanced Materials 36, no. 8 (2024): 2310600.

[9] M. Ding, D. Zhao, P. Feng, et al., “Highly Efficient Three-Dimensional Solar Evaporator for Zero Liquid Discharge Desalination of High-Salinity Brine,” Carbon Energy 6, no. 9 (2024): e548.

[10] F. Z. Jiao, J. Wu, T. Zhang, et al., “Simultaneous Solar-Thermal Desalination and Catalytic Degradation of Wastewater Containing Both Salt Ions and Organic Contaminants,” ACS Applied Materials & Interfaces 15, no. 34 (2023): 41007-41018.

[11] J. Wang, M. Sun, C. Liu, et al., “Customized Microenvironments Spontaneously Facilitate Coupled Engineering of Real-Life Large-Scale Clean Water Capture and Pollution Remediation,” Advanced Materials 35, no. 41 (2023): 2306103.

[12] L. Chen, J. Ren, J. Gong, J. Qu, and R. Niu, “Cost-Effective, Scalable Fabrication of Self-Floating Xerogel Foam for Simultaneous Photothermal Water Evaporation and Thermoelectric Power Generation,” Chemical Engineering Journal 454 (2023): 140383.

[13] J. Ren, L. Chen, J. Gong, J. Qu, and R. Niu, “Hofmeister Effect Mediated Hydrogel Evaporator for Simultaneous Solar Evaporation and Thermoelectric Power Generation,” Chemical Engineering Journal 458 (2023): 141511.

[14] Z. Fan, J. Ren, H. Bai, et al., “Shape-Controlled Fabrication of MnO/C Hybrid Nanoparticle From Waste Polyester for Solar Evaporation and Thermoelectricity Generation,” Chemical Engineering Journal 451 (2023): 138534.

[15] H. Wang, Z. Wang, T. Wang, et al., “Shooting Three Birds With One Stone: Device Construction and Thermal Management for Simultaneous Photothermal Conversion Water Evaporation, Thermoelectric Generation and Photocatalytic Degradation,” Advanced Functional Materials 34, no. 23 (2024): 2315211.

[16] X. Hao, H. Yao, P. Zhang, et al., “Multifunctional Solar Water Harvester With High Transport Selectivity and Fouling Rejection Capacity,” Nature Water 1, no. 11 (2023): 982-991.

[17] J. Wang, Z. Chen, L. Feng, et al., “Plants Transpiration-Inspired Antibacterial Evaporator With Multiscale Structure and Low Vaporization Enthalpy for Solar Steam Generation,” Nano Energy 114 (2023): 108631.

[18] Q. Bai, M. Liang, W. Wu, et al., “Plasmonic Nanozyme of Graphdiyne Nanowalls Wrapped Hollow Copper Sulfide Nanocubes for Rapid Bacteria-Killing,” Advanced Functional Materials 32, no. 20 (2022): 2112683.

[19] R. Wang, M. Shi, F. Xu, et al., “Graphdiyne-Modified TiO₂ Nanofibers With Osteoinductive and Enhanced Photocatalytic Antibacterial Activities to Prevent Implant Infection,” Nature Communications 11, no. 1 (2020): 4465.

[20] X. Lu, C. Mu, Y. Liu, L. Wu, Z. Tong, and K. Huang, “Recent Advances in Solar-Driven Interfacial Evaporation Coupling Systems: Energy Conversion, Water Purification, and Seawater Resource Extraction,” Nano Energy 120 (2024): 109180.

[21] X. Huang, M. Sun, W. Sun, Z. Li, H. Chen, and J. Zhao, “One-Step Hydrothermal Formation of Porous N-Graphyne Decorated TiO₂/Ti₃C₂ Composites With Enhanced Photocatalytic Activity,” International Journal of Hydrogen Energy 55 (2024): 581-591.

[22] L. Zhu, L. Tian, S. Jiang, et al., “Advances in Photothermal Regulation Strategies: From Efficient Solar Heating to Daytime Passive Cooling,” Chemical Society Reviews 52, no. 21 (2023): 7389-7460.

[23] X. Cui, Q. Ruan, X. Zhuo, et al., “Photothermal Nanomaterials: A Powerful Light-to-Heat Converter,” Chemical Reviews 123, no. 11 (2023): 6891-6952.

[24] M. Yang, L. Zhang, D. Ye, Y. Dong, Y. Zhan, and X. Jiang, “Facile Preparation of Sodium Alginate/Poly(Vinyl Alcohol)/Graphite Hybrid Porous Hydrogel for Efficient Solar Desalination,” Chemical Engineering Journal 480 (2024): 148226.

[25] Y. Li, Y. Shi, H. Wang, et al., “Recent Advances in Carbon-Based Materials for Solar-Driven Interfacial Photothermal Conversion Water Evaporation: Assemblies, Structures, Applications, and Prospective,” Carbon Energy 5, no. 11 (2023): e331.

[26] J. Wang, X. Cao, X. Cui, et al., “Recent Advances of Green Electricity Generation: Potential in Solar Interfacial Evaporation System,” Advanced Materials 36, no. 16 (2024): 2311151.

[27] S. Dong, Y. Zhao, J. Yang, et al., “Visible-Light Responsive PDI/rGO Composite Film for the Photothermal Catalytic Degradation of Antibiotic Wastewater and Interfacial Water Evaporation,” Applied Catalysis B: Environmental 291 (2021): 120127.

[28] Y. Zhang, S. Tan, T. Xu, Z. Zhou, and G. Ji, “Directionally Tailoring Micro-Nano Hierarchical Tower Structured Mn_0.6Ni_1.4Co₂O Toward Solar Interfacial Evaporation,” Journal of Materials Science & Technology 158 (2023): 21-30.

[29] L. Shi, L. Liang, F. Wang, M. Liu, and J. Sun, “Ag₂CrO₄ Nanoparticles Loaded on Two-Dimensional Large Surface Area Graphite-Like Carbon Nitride Sheets: Simple Synthesis and Excellent Photocatalytic Performance,” Dalton Transactions 45, no. 13 (2016): 5815-5824.

[30] N. Rajalakshmi, D. Barathi, S. Meyvel, and P. Sathya, “S-Scheme Ag₂CrO₄/g-C₃N₄ Photocatalyst for Effective Degradation of Organic Pollutants Under Visible Light,” Inorganic Chemistry Communications 132 (2021): 108849.

[31] J. Luo, X. Zhou, L. Ma, et al., “Fabrication of WO₃/Ag₂CrO₄ Composites With Enhanced Visible-Light Photodegradation Towards Methyl Orange,” Advanced Powder Technology 28, no. 3 (2017): 1018-1027.

[32] H. Yuan, H. Sun, Y. Shi, et al., “Cooperation of Carbon Doping and Carbon Loading Boosts Photocatalytic Activity by the Optimum Photo-Induced Electron Trapping and Interfacial Charge Transfer,” Chemical Engineering Journal 472 (2023): 144654.

[33] J. Luo, X. Zhou, L. Ma, and X. Xu, “Rational Construction of Z-Scheme Ag₂CrO₄/g-C₃N₄ Composites With Enhanced Visible-Light Photocatalytic Activity,” Applied Surface Science 390 (2016): 357-367.

[34] Y. Shang, X. Chen, W. Liu, et al., “Photocorrosion Inhibition and High-Efficiency Photoactivity of Porous g-C₃N₄/Ag₂CrO₄ Composites by Simple Microemulsion-Assisted Co-Precipitation Method,” Applied Catalysis B: Environmental 204 (2017): 78-88.

[35] A. Kumar, G. Sharma, M. Naushad, T. Ahamad, R. C. Veses, and F. J. Stadler, “Highly Visible Active Ag₂CrO₄/Ag/BiFeO₃@RGO Nano-Junction for Photoreduction of CO₂ and Photocatalytic Removal of Ciprofloxacin and Bromate Ions: The Triggering Effect of Ag and RGO,” Chemical Engineering Journal 370 (2019): 148-165.

[36] S. M. Abu-Sari, W. M. A. W. Daud, M. F. A. Patah, and B. C. Ang, “A Review on Synthesis, Modification Method, and Challenges of Light-Driven H₂ Evolution Using g-C₃N₄-Based Photocatalyst,” Advances in Colloid and Interface Science 307 (2022): 102722.

[37] L. Wang, W. Si, Y. Tong, et al., “Graphitic Carbon Nitride (g-C₃N₄)-Based Nanosized Heteroarrays: Promising Materials for Photoelectrochemical Water Splitting,” Carbon Energy 2, no. 2 (2020): 223-250.

[38] F. Yu, J. Cui, Y. Zhou, et al., “Structural and Optical Properties of Ultra-Thin g-C₃N₄ Nanotubes Based g-C₃N₄/Ag/Ag₂CrO₄ Ternary Composite Photocatalyst With Z-Scheme Carrier Transfer Mechanism,” Optical Materials 121 (2021): 111608.

[39] X. Ren, X. Zhang, R. Guo, et al., “Hollow Mesoporous g-C₃N₄/Ag₂CrO₄ Photocatalysis With Direct Z-Scheme: Excellent Degradation Performance for Antibiotics and Dyes,” Separation and Purification Technology 270 (2021): 118797.

[40] B. Peng, Y. Lu, J. Luo, et al., “Visible Light-Activated Self-Powered Photoelectrochemical Aptasensor for Ultrasensitive Chloramphenicol Detection Based on DFT-Proved Z-Scheme Ag₂CrO₄/g-C₃N₄/Graphene Oxide,” Journal of Hazardous Materials 401 (2021): 123395.

[41] Y. Gong, X. Quan, H. Yu, and S. Chen, “Synthesis of Z-Scheme Ag₂CrO₄/Ag/g-C₃N₄ Composite With Enhanced Visible-Light Photocatalytic Activity for 2,4-dichlorophenol Degradation,” Applied Catalysis B: Environmental 219 (2017): 439-449.

[42] F. Yousefi, M. Haghighi, and M. Shabani, “Potato-On-Rod Like of Z-Scheme Plasmon Ag₂CrO₄-Ag₂Mo₂O₇ Heterojunction Nanophotocatalyst With High Stability and Accelerated Photo-Degradation Evolution of Organic Contaminants,” Environmental Research 236 (2023): 116853.

[43] X. Jia, J. Cao, H. Sun, X. Li, H. Lin, and S. Chen, “Interfacial Engineering of Bi₁₂O₁₇Br₂/g-C₃N₄- S-Scheme Junction Boosting Charge Transfer for Cooperative Tetracycline Decomposition and CO₂ Reduction,” Applied Catalysis B: Environmental 343 (2024): 123522.

[44] Y. Deng, L. Tang, G. Zeng, et al., “Facile Fabrication of a Direct Z-Scheme Ag₂CrO₄/g-C₃N₄ Photocatalyst With Enhanced Visible Light Photocatalytic Activity,” Journal of Molecular Catalysis A: Chemical 421 (2016): 209-221.

[45] Y. Che, B. Lu, Q. Qi, et al., “Bio-Inspired Z-Scheme g-C₃N₄/Ag₂CrO₄ for Efficient Visible-Light Photocatalytic Hydrogen Generation,” Scientific Reports 8, no. 1 (2018): 16504.

[46] D. Xu, B. Cheng, W. Wang, C. Jiang, and J. Yu, “Ag₂CrO₄/g-C₃N₄/Graphene Oxide Ternary Nanocomposite Z-Scheme Photocatalyst With Enhanced CO₂ Reduction Activity,” Applied Catalysis B: Environmental 231 (2018): 368-380.

[47] B. Yang, Z. Zhang, P. Liu, et al., “Flatband λ-Ti₃O₅ Towards Extraordinary Solar Steam Generation,” Nature 622, no. 7983 (2023): 499-506.

[48] Y. D. Tu, J. W. Zhou, S. T. Lin, M. Alshrah, X. H. Zhao, and G. Chen, “Photomolecular Effect Leading to Water Evaporation Exceeding Thermal Limit,” Proceedings of the National Academy of Sciences of the United States of America 120, no. 45 (2023): e2312751120.

[49] A. Chu, M. Yang, J. Chen, et al., “Biomass-Enhanced Janus Sponge-Like Hydrogel With Salt Resistance and High Strength for Efficient Solar Desalination,” Green Energy & Environment 9, no. 11 (2024): 1698-1710.

[50] H. Jia, Y. Teng, N. Li, et al., “Dual Stimuli-Responsive Inks Based on Orthogonal Upconversion Three-Primary-Color Luminescence for Advanced Anticounterfeiting Applications,” ACS Materials Letters 4, no. 7 (2022): 1306-1313.

[51] Y. Ohtsuka, M. Sakai, T. Seki, R. Ohnuki, S. Yoshioka, and Y. Takeoka, “Stimuli-Responsive Structural Colored Gel That Exhibits the Three Primary Colors of Light by Using Multiple Photonic Band Gaps Acquired From Photonic Balls,” ACS Applied Materials & Interfaces 12, no. 48 (2020): 54127-54137.

[52] A. Roy, M. Z. Tariq, M. La, D. Choi, and S. J. Park, “Synergistic Effect of Electrochemically Fabricated Polyaniline Nanofibers and Silver for Efficient Solar Steam Generation,” Desalination 563 (2023): 116732.

[53] K. Zhu, Q. Liao, X. Hao, et al., “Low-Grade Waste Heat Enables Over 80 L m⁻² h⁻¹ Interfacial Steam Generation Based on 3D Superhydrophilic Foam,” Advanced Materials 35, no. 29 (2023): 2211932.

[54] R. Niu, J. Ren, J. J. Koh, et al., “Bio-Inspired Sandwich-Structured All-Day-Round Solar Evaporator for Synergistic Clean Water and Electricity Generation,” Advanced Energy Materials 13, no. 45 (2023): 2302451.

[55] L. Zhu, T. Ding, M. Gao, C. K. N. Peh, and G. W. Ho, “Shape Conformal and Thermal Insulative Organic Solar Absorber Sponge for Photothermal Water Evaporation and Thermoelectric Power Generation,” Advanced Energy Materials 9, no. 22 (2019): 1900250.

[56] H. Wang, Y. Shi, T. Liu, X. Zheng, S. Gao, and J. Lu, ““One Stone Two Birds” or “You Can't Have Your Cake and Eat It Too”? Effects of Device Dimensions and Position of the Thermoelectric Module on Simultaneous Solar-Driven Water Evaporation and Thermoelectric Generation,” Journal of Materials Chemistry A 11, no. 1 (2023): 419-433.

[57] X. K. Li, R. Yang, L. Zou, et al, “Reassessing the Role of Thermal Convection in Simultaneous Water Production and Pollutant Degradation in Interfacial Photothermal-Photocatalytic Systems,” Advanced Materials 37, no. 4 (2025): 2416283.

[58] X. Li, J. Li, J. Lu, et al., “Enhancement of Interfacial Solar Vapor Generation By Environmental Energy,” Joule 2, no. 7 (2018): 1331-1338.

[59] H. Yu, D. Wang, H. Jin, et al., “2D MoN_1.2-rGO Stacked Heterostructures Enabled Water State Modification for Highly Efficient Interfacial Solar Evaporation,” Advanced Functional Materials 33, no. 24 (2023): 2214828.

[60] Z. Chen, J. Wang, H. Zhou, et al., “Janus Nano-Micro Structure-Enabled Coupling of Photothermal Conversion, Heat Localization and Water Supply for High-Efficiency Solar-Driven Interfacial Evaporation,” Advanced Functional Materials 33, no. 41 (2023): 2303656.

[61] X. Wu, Z. Wu, Y. Wang, T. Gao, Q. Li, and H. Xu, “All-Cold Evaporation Under One Sun With Zero Energy Loss by Using a Heatsink Inspired Solar Evaporator,” Advanced Science 8, no. 7 (2021): 2002501.

[62] Z. Y. Wang, Y. J. Zhu, Y. Q. Chen, H. P. Yu, and Z. C. Xiong, “Bioinspired Aerogel With Vertically Ordered Channels and Low Water Evaporation Enthalpy for High-Efficiency Salt-Rejecting Solar Seawater Desalination and Wastewater Purification,” Small 19, no. 19 (2023): 2206917.

[63] D. Wei, C. Wang, J. Zhang, et al., “Water Activation in Solar-Powered Vapor Generation,” Advanced Materials 35, no. 47 (2023): 2212100.

[64] C. Gao, Y. M. Li, L. Z. Lan, et al., “Bioinspired Asymmetric Polypyrrole Membranes With Enhanced Photothermal Conversion for Highly Efficient Solar Evaporation,” Advancement of Science 11, no. 6 (2023): 2306833.

[65] Y. Gu, D. Wang, Y. Gao, et al., “Solar-Powered High-Performance Lignin-Wood Evaporator for Solar Steam Generation,” Advanced Functional Materials 33, no. 43 (2023): 2306947.

[66] F. Zhao, X. Zhou, Y. Shi, et al., “Highly Efficient Solar Vapour Generation Via Hierarchically Nanostructured Gels,” Nature Nanotechnology 13, no. 6 (2018): 489-495.

[67] Y. Li, K. Lv, W. Ho, F. Dong, X. Wu, and Y. Xia, “Hybridization of Rutile TiO₂ (rTiO₂) With g-C₃N₄ Quantum Dots (CN QDs): An Efficient Visible-Light-Driven Z-Scheme Hybridized Photocatalyst,” Applied Catalysis, B: Environmental 202 (2017): 611-619.

[68] M. Zhang, H. Xu, L. Wu, Y. Tan, D. Kong, and M. Yimiti, “Photocatalytic Degradation of Lignin by Low Content g-C₃N₄ Modified TiO₂ Under Visible Light,” New Journal of Chemistry 46, no. 18 (2022): 8644-8652.

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