Modulating structural oxygen/crystallinity enables ambient cascade photo-upgrading of biomass saccharides to lactic acid

Abstract

Photocatalytic transformation of biomass into biofuels and value-added chemicals is of great significance for carbon neutrality. Metal-free carbon nitride has extensive applications but with almost no absorption and utilization of near-infrared light, accounting for 50% of sunlight. Here, a molten salt-assisted in-plane “stitching” and interlayer “cutting” protocol is developed for constructing a highly crystalline carbon nitride catalyst containing structural oxygen (HC-CN). HC-CN is highly efficient for the photothermal cascade transformation of biomass-derived glucose into lactic acid (LA) with an unprecedented yield (94.3%) at 25°C under full-spectrum light irradiation within 50 min, which is also applicable to quantitatively photo-upgrading various saccharides. Theoretical calculations expound that the light-induced glucose-to-catalyst charge transfer can activate the C_β–H bond to promote the rate-determining step of intramolecular hydrogen shift in glucose-to-fructose isomerization. Meanwhile, the introduced structural oxygen in HC-CN can not only facilitate the local electric field formation to achieve rapid charge transport/separation and regulate selective •O₂⁻ generation for oriented C3–C4 bond cleavage of fructose but also narrow the energy band gap to broaden the light absorption range of HC-CN, contributing to enhanced LA production without exogenous heating. Moreover, HC-CN is highly recyclable and exhibits negligible environmental burden and low energy consumption, as disclosed by the life cycle assessment. Tailored construction of full-spectrum light adsorption and versatile reaction sites provides a reference for implementing multi-step biomass and organic conversion processes under mild conditions.

Keywords

biomass valorization / lactic acid / life cycle assessment / photocatalysis / pyroelectric effect

References

[1] Li H, Yang S, Riisager A, et al. Zeolite and zeotype-catalysed transformations of biofuranic compounds. Green Chem. 2016; 18(21): 5701-5735.

[2] Dai L, Qiu Y, Xu YY, Ye S. Biomass transformation of cellulose via N-heterocyclic carbene-catalyzed umpolung of 5-(chloromethyl) furfural. Cell Rep Phys Sci. 2020; 1(6): 100071.

[3] Huang J, Jian Y, Li H. A new lamellar biocarbon catalyst with enhanced acidity and contact sites for efficient biodiesel production. Waste Biomass Valori. 2022; 13(10): 4223-4238.

[4] Paul S, Dutta A. Challenges and opportunities of lignocellulosic biomass for anaerobic digestion. Resour Conserv Recy. 2018; 130: 164-174.

[5] Wu X, Luo N, Xie S, et al. Photocatalytic transformations of lignocellulosic biomass into chemicals. Chem Soc Rev. 2020; 49(17): 6198-6223.

[6] Li Y, Ma J, Jin D, et al. Copper oxide functionalized chitosan hybrid hydrogels for highly efficient photocatalytic-reforming of biomass-based monosaccharides to lactic acid. Appl Catal B. 2021; 291: 120123.

[7] Wang E, Mahmood A, Chen SG, et al. Solar-driven photocatalytic reforming of lignocellulose into H₂ and value-added biochemicals. ACS Catal. 2022; 12(18): 11206-11215.

[8] Liu Z, Ma J, Guo Y, Hong M, Sun R. Photocatalytic CO₂ reduction integrated with biomass selective oxidation via single-atom Ru and P dual sites on carbon nitride. Appl Catal B. 2024; 342: 123429.

[9] Fan Y, Zhou C, Zhu X. Selective catalysis of lactic acid to produce commodity chemicals. Catal Rev. 2009; 51(3): 293-324.

[10] Song S, Qu J, Han P, et al. Visible-light-driven amino acids production from biomass-based feedstocks over ultrathin CdS nanosheets. Nat Commun. 2020; 11(1): 4899-4909.

[11] Zhang X, Huang W, Yu L, et al. Enabling heterogeneous catalysis to achieve carbon neutrality: directional catalytic conversion of CO₂ into carboxylic acids. Carbon Energy. 2024; 6(3): e362.

[12] Ding Y, Cao Y, Chen D, et al. Relay photo/thermal catalysis enables efficient cascade upgrading of sugars to lactic acid: mechanism study and life cycle assessment. Chem Eng J. 2023; 452(4): 139687.

[13] Yang X, Ma J, Sun S, Liu Z, Sun R. K/O co-doping and introduction of cyano groups in polymeric carbon nitride towards efficient simultaneous solar photocatalytic water splitting and biorefineries. Green Chem. 2022; 24(5): 2104-2113.

[14] Tan XQ, Ng SF, Mohamed AR, Ong WJ. Point-to-face contact heterojunctions: interfacial design of 0D nanomaterials on 2D g-C₃N₄ towards photocatalytic energy applications. Carbon Energy. 2022; 4(5): 665-730.

[15] Wang X, Song Y, Huang C, Liang F, Chen B. Lactic acid production from glucose over polymer catalysts in aqueous alkaline solution under mild conditions. Green Chem. 2014; 16(9): 4234-4240.

[16] Nagarajan D, Oktarina N, Chen PT, Chen CY, Lee DJ, Chang JS. Fermentative lactic acid production from seaweed hydrolysate using Lactobacillus sp. and Weissella sp. Bioresour Technol. 2022; 344: 126166.

[17] Wang Y, Zhang Y, Sun A, Hu Y. Characterization of a novel marine microbial esterase and its use to make D-methyl lactate. Chin J Catal. 2016; 37(8): 1396-1402.

[18] Yan X, Jin F, Tohji K, Moriya T, Enomoto H. Production of lactic acid from glucose by alkaline hydrothermal reaction. J Mater Sci. 2007; 42(24): 9995-9999.

[19] Li L, Shen F, Smith RL, Qi X. Quantitative chemocatalytic production of lactic acid from glucose under anaerobic conditions at room temperature. Green Chem. 2017; 19(1): 76-81.

[20] Duo J, Zhang Z, Yao G, Huo Z, Jin F. Hydrothermal conversion of glucose into lactic acid with sodium silicate as a base catalyst. Catal Today. 2016; 263: 112-116.

[21] Wang Y, Deng W, Wang B, et al. Chemical synthesis of lactic acid from cellulose catalysed by lead(II) ions in water. Nat Commun. 2013; 4(1): 2141-2148.

[22] Kiatphuengporn S, Junkaew A, Luadthong C, et al. Roles of acidic sites in alumina catalysts for efficient D-xylose conversion to lactic acid. Green Chem. 2020; 22(24): 8572-8583.

[23] Cao D, Cai W, Tao W, Zhang S, Wang D, Huang D. Lactic acid production from glucose over a novel Nb₂O₅ nanorod catalyst. Catal Lett. 2017; 147(4): 926-933.

[24] Li H, Fang Z, Smith RL, Yang S. Efficient valorization of biomass to biofuels with bifunctional solid catalytic materials. Prog Energy Combust Sci. 2016; 55: 98-194.

[25] Zhang Y, Luo H, Kong L, et al. Highly efficient production of lactic acid from xylose using Sn-beta catalysts. Green Chem. 2020; 22(21): 7333-7336.

[26] Holm MS, Saravanamurugan S, Taarning E. Conversion of sugars to lactic acid derivatives using heterogeneous zeotype catalysts. Science. 2010; 328(5978): 602-605.

[27] Wang FF, Liu J, Li H, Liu CL, Yang RZ, Dong WS. Conversion of cellulose to lactic acid catalyzed by erbium-exchanged montmorillonite K10. Green Chem. 2015; 17(4): 2455-2463.

[28] Sun X, Huang H, Zhao Q, Ma T, Wang L. Thin-layered photocatalysts. Adv Funct Mater. 2020; 30(22): 1910005.

[29] Schultz DM, Yoon TP. Solar synthesis: prospects in visible light photocatalysis. Science. 2014; 343(6174): 1239176.

[30] Shen YS, Bai FY, Wei K, et al. Zn_0.1Cd_0.9S/NiS heterojunction photocatalysts for enhanced H₂ production and glucose conversion. Appl Surf Sci. 2023; 626: 157237.

[31] Wang TW, Yin ZW, Guo YH, et al. Highly selective photocatalytic conversion of glucose on holo-symmetrically spherical three-dimensionally ordered macroporous heterojunction photonic crystal. CCS Chem. 2023; 5(8): 1773-1788.

[32] Cao Y, Chen D, Meng Y, Saravanamurugan S, Li H. Visible-light-driven prompt and quantitative production of lactic acid from biomass sugars over a N-TiO₂ photothermal catalyst. Green Chem. 2021; 23(24): 10039-10049.

[33] Ye X, Shi X, Zhong H, et al. Photothermal strategy for the highly efficient conversion of glucose into lactic acid at low temperatures over a hybrid multifunctional multi-walled carbon nanotube/layered double hydroxide catalyst. Green Chem. 2022; 24(2): 813-822.

[34] Ma J, Li Y, Jin D, et al. Functional B@mCN assisted photocatalytic oxidation of biomass-derived pentoses and hexoses to lactic acid. Green Chem. 2020; 22(19): 6384-6392.

[35] Jin D, Jiao G, Ren W, Zhou J, Ma J, Sun R. Boosting photocatalytic performance for selective oxidation of biomass-derived pentoses and hexoses to lactic acid using hierarchically porous Cu/Cu₂O/CuO@CA. J Mater Chem C. 2021; 9(46): 16450-16458.

[36] Wu X, Ma H, Zhong W, Fan J, Yu H. Porous crystalline g-C₃N₄: bifunctional NaHCO₃ template-mediated synthesis and improved photocatalytic H₂-evolution rate. Appl Catal B. 2020; 271: 118899.

[37] Zhang G, Liu M, Heil T, et al. Electron deficient monomers that optimize nucleation and enhance the photocatalytic redox activity of carbon nitrides. Angew Chem Int Ed. 2019; 131(42): 15092-15096.

[38] Chen Z, Vorobyeva E, Mitchell S, et al. Single-atom heterogeneous catalysts based on distinct carbon nitride scaffolds. Natl Sci Rev. 2018; 5(5): 642-652.

[39] Lin L, Yu Z, Wang X. Crystalline carbon nitride semiconductors for photocatalytic water splitting. Angew Chem Int Ed. 2019; 58(19): 6164-6175.

[40] Wang Y, Yang W, Chen X, Wang J, Zhu Y. Photocatalytic activity enhancement of core-shell structure g-C₃N₄@TiO₂ via controlled ultrathin g-C₃N₄ layer. Appl Catal B. 2018; 220: 337-347.

[41] Xu Y, He X, Zhong H, Singh DJ, Zhang L, Wang R. Solid salt confinement effect: an effective strategy to fabricate high crystalline polymer carbon nitride for enhanced photocatalytic hydrogen evolution. Appl Catal B. 2019; 246: 349-355.

[42] Song C, Wang Z, Yin Z, Xiao D, Ma D. Principles and applications of photothermal catalysis. Chem Catal. 2022; 2(1): 52-83.

[43] Lin L, Ren W, Wang C, Asiri AM, Zhang J, Wang X. Crystalline carbon nitride semiconductors prepared at different temperatures for photocatalytic hydrogen production. Appl Catal B. 2018; 231: 234-241.

[44] Zhang G, Li G, Lan ZA, et al. Optimizing optical absorption, exciton dissociation, and charge transfer of a polymeric carbon nitride with ultrahigh solar hydrogen production activity. Angew Chem Int Ed. 2017; 56(43): 13445-13449.

[45] Wang Q, Zhang G, Xing W, et al. Bottom-up synthesis of single-crystalline poly (triazine imide) nanosheets for photocatalytic overall water splitting. Angew Chem Int Ed. 2023; 62(37): e202307930.

[46] Ren W, Cheng J, Ou H, Huang C, Anpo M, Wang X. Optimizing the crystallization process of conjugated polymer photocatalysts to promote electron transfer and molecular oxygen activation. J Catal. 2020; 389: 636-645.

[47] Ming H, Zhang P, Yang Y, et al. Tailored poly-heptazine units in carbon nitride for activating peroxymonosulfate to degrade organic contaminants with visible light. Appl Catal B. 2022; 311: 121341.

[48] Aruja E. Displacement of X-ray reflexions. Nature. 1994; 154(3897): 53.

[49] Yang Q, Zhao LR. Characterization of nano-layered multilayer coatings using modified Bragg law. Mater Charact. 2008; 59(9): 1285-1291.

[50] Zhang J, Ye G, Zhang C, et al. Heptazine-based ordered-distorted copolymers with enhanced visible-light absorption for photocatalytic hydrogen production. ChemSusChem. 2022; 15(24): e202201616.

[51] Yuan J, Liu X, Tang Y, et al. Positioning cyanamide defects in g-C₃N₄: engineering energy levels and active sites for superior photocatalytic hydrogen evolution. Appl Catal B. 2018; 237: 24-31.

[52] Schwinghammer K, Tuffy B, Mesch MB, et al. Triazine-based carbon nitrides for visible-light-driven hydrogen evolution. Angew Chem Int Ed. 2013; 52(9): 2435-2439.

[53] Lv X, Xiao Z, Wang H, et al. In situ construction of Co/N/C-based heterojunction on biomass-derived hierarchical porous carbon with stable active sites using a Co-N protective strategy for high-efficiency ORR, OER and HER trifunctional electrocatalysts. J Energy Chem. 2021; 54: 626-638.

[54] Chen J, Mao Z, Zhang L, et al. Nitrogen-deficient graphitic carbon nitride with enhanced performance for lithium ion battery anodes. ACS Nano. 2017; 11(12): 12650-12657.

[55] Li B, Peng W, Zhang J, et al. High-throughput one-photon excitation pathway in 0D/3D heterojunctions for visible-light driven hydrogen evolution. Adv Funct Mater. 2021; 31(18): 2100816.

[56] Zhang G, Zhang J, Zhang M, Wang X. Polycondensation of thiourea into carbon nitride semiconductors as visible light photocatalysts. J Mater Chem. 2012; 22(16): 8083-8091.

[57] Yu W, Yu Z, Cui Y, Bao Z. Degradation and speciation of Li salts during XPS analysis for battery research. ACS Energy Lett. 2022; 7(10): 3270-3275.

[58] Yang J, Gao Z, Ferber T, et al. Guided-formation of a favorable interface for stabilizing Na metal solid-state batteries. J Mater Chem A. 2020; 8(16): 7828-7835.

[59] Peng SS, Shao XB, Gu MX, et al. Catalytically stable potassium single-atom solid superbases. Angew Chem Int Ed. 2022; 61(52): e202215157.

[60] Zhang G, Savateev A, Zhao Y, Li L, Antonietti M. Advancing the n→π* electron transition of carbon nitride nanotubes for H₂ photosynthesis. J Mater Chem A. 2017; 5(25): 12723-12728.

[61] Han Q, Hu C, Zhao F, Zhang Z, Chen N, Qu L. One-step preparation of iodine-doped graphitic carbon nitride nanosheets as efficient photocatalysts for visible light water splitting. J Mater Chem A. 2015; 3(8): 4612-4619.

[62] Huang ZF, Song J, Pan L, et al. Carbon nitride with simultaneous porous network and O-doping for efficient solar-energy-driven hydrogen evolution. Nano Energy. 2015; 12: 646-656.

[63] Jiang Y, Sun Z, Tang C, Zhou Y, Zeng L, Huang L. Enhancement of photocatalytic hydrogen evolution activity of porous oxygen doped g-C₃N₄ with nitrogen defects induced by changing electron transition. Appl Catal B. 2019; 240: 30-38.

[64] An S, Zhang G, Li K, et al. Self-supporting 3D carbon nitride with tunable n→π* electronic transition for enhanced solar hydrogen production. Adv Mater. 2021; 33(49): 2104361.

[65] Zhang G, Li G, Lan ZA, et al. Optimizing optical absorption, exciton dissociation, and charge transfer of a polymeric carbon nitride with ultrahigh solar hydrogen production activity. Angew Chem Int Ed. 2017; 56(43): 13445-13449.

[66] Liu M, Wei C, Zhuzhang H, et al. Fully condensed poly (triazine imide) crystals: extended π-conjugation and structural defects for overall water splitting. Angew Chem Int Ed. 2022; 61(2): e202113389.

[67] Wu D, Hu S, Xue H, et al. Protonation and microwave-assisted heating induced excitation of lone-pair electrons in graphitic carbon nitride for increased photocatalytic hydrogen generation. J Mater Chem A. 2019; 7(35): 20223-20228.

[68] Yang W, Godin R, Kasap H, et al. Electron accumulation induces efficiency bottleneck for hydrogen production in carbon nitride photocatalysts. J Am Chem Soc. 2019; 141(28): 11219-11229.

[69] Li B, Wang H, Kawakita Y, et al. Liquid-like thermal conduction in intercalated layered crystalline solids. Nat Mater. 2018; 17(3): 226-230.

[70] Li M, Sun J, Chen G, Wang S, Yao S. Inducing photocarrier separation via 3D porous faveolate cross-linked carbon to enhance photothermal/pyroelectric property. Adv Powder Mater. 2022; 1(3): 100032.

[71] Li X, Qiu Y, Zhu Z, Chen T, Zhang H, Yin D Construction of magnetically separable dual Z-scheme g-C₃N₄/α-Fe₂O₃/Bi₃TaO₇ photocatalyst for effective degradation of ciprofloxacin under visible light. Chem Eng J 2022; 440: 135840.

RIGHTS & PERMISSIONS

2025 The Author(s). Carbon Energy published by Wenzhou University and John Wiley & Sons Australia, Ltd.