Peroxymonosulfate activation by boron doped C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} metal-free materials with n rarrpi^(**)n \rightarrow \pi^{*} electronic transitions for tetracycline degradation under visible light: Insights into the generation of reactive species 在可见光下通过 n rarrpi^(**)n \rightarrow \pi^{*} 具有电子跃迁的无硼 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 材料对四环素降解的无硼材料进行过氧一硫酸盐活化：深入了解反应性物质的生成
Yao Tong ^(a,b){ }^{\mathrm{a}, \mathrm{b}}, Shaojiang Huang ^(a,b){ }^{\mathrm{a}, \mathrm{b}}, Xuecong Zhao ^(a,b){ }^{\mathrm{a}, \mathrm{b}}, Yang Yang ^(a,b){ }^{\mathrm{a}, \mathrm{b}}, Li Feng ^(a,b,^(**)){ }^{\mathrm{a}, \mathrm{b},{ }^{*}}, Qi Han ^(a,b){ }^{\mathrm{a}, \mathrm{b}}, Liqiu Zhang ^("a,b, ")^("* "){ }^{\text {a,b, }}{ }^{\text {* }} 彤姚 ^(a,b){ }^{\mathrm{a}, \mathrm{b}} ， 黄 ^(a,b){ }^{\mathrm{a}, \mathrm{b}} 绍江 ， 赵雪聪 ^(a,b){ }^{\mathrm{a}, \mathrm{b}} ， 杨 ^(a,b){ }^{\mathrm{a}, \mathrm{b}} 洋 ， 李峰 ^(a,b,^(**)){ }^{\mathrm{a}, \mathrm{b},{ }^{*}} ， 韩琦 ^(a,b){ }^{\mathrm{a}, \mathrm{b}} ， 张丽秋 ^("a,b, ")^("* "){ }^{\text {a,b, }}{ }^{\text {* }}^("a "){ }^{\text {a }} Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China ^("a "){ }^{\text {a }} 北京林业大学 环境科学与工程学院， 水污染源头控制技术北京市重点实验室， 北京 100083^(b){ }^{\mathrm{b}} Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China ^(b){ }^{\mathrm{b}} 中国北京林业大学环境科学与工程学院水污染源控制与生态修复工程研究中心，中国北京 100083
Heterogeneous photocatalysis coupled with peroxymonosulfate (PMS) activation is regarded as an advanced water treatment technology for emerging contaminates degradation. We introduce a novel coupling system that integrates PMS with metal-free visible light-driven photocatalysis, utilizing boron doped C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} (BCNs), with the objective of swiftly eliminating tetracycline (TC) from wastewater. With commendable traits including a robust response to visible light, n rarrpi^(**)n \rightarrow \pi^{*} electronic transitions and a narrow bandgap, 3BCN optimized from BCNs, exhibited superior catalytic activity in photocatalysis and PMS activation. In 3BCN/PMS/vis system, the degradation efficiency of TC reached 88.6%88.6 \% in 120 min , with an observed rate constant ( k_("obs ")k_{\text {obs }} ) of 0.0222min^(-1)0.0222 \mathrm{~min}^{-1} for TC removal. Moreover, in real water matrices including tap water, landscape water and secondary effluent, the 3BCN/PMS/vis system consistently maintained high and stable pollutant removal efficiency. To elucidate the underlying mechanisms, the origins of reactive species ( h^(+),SO_(4)^(-),∙OH\mathrm{h}^{+}, \mathrm{SO}_{4}^{-}, \bullet \mathrm{OH} and ^(1)O_(2){ }^{1} \mathrm{O}_{2} ) were identified and the enhanced pathways in the PMS-based photocatalytic system were systematically investigated. Based on theoretical calculations, generation pathway of reactive oxygen species involving PMS oxidation and reduction over the region of boron atom neighboring N in BCN was unraveled. The BCN catalyst was employed in a flowthrough device to explore its potential in practical application. The results showed that continuous and impressive efficient removal of TC was achieved with over 93%93 \% removal rate during 32 h operation. Our findings underscore the substantial promise of chemical-photocatalysis synergy for environment remediation, offering a feasible approach to optimize the performance of metal-free materials in photo-catalytic oxidation of antibiotics. 非均相光催化结合过氧一硫酸盐 （PMS） 活化被认为是一种针对新出现的污染物降解的先进水处理技术。我们介绍了一种新颖的耦合系统，该系统将 PMS 与无金属可见光驱动的光催化相结合，利用掺硼 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} （BCN），目的是快速消除废水中的四环素 （TC）。由 BCN 优化的 3BCN 具有值得称道的特性，包括对可见光的强烈响应、 n rarrpi^(**)n \rightarrow \pi^{*} 电子跃迁和窄带隙，在光催化和 PMS 活化中表现出优异的催化活性。在 3BCN/PMS/vis 系统中，TC 的降解效率在 120 分钟内达到 88.6%88.6 \% ，观察到的 TC 去除速率常数 （ k_("obs ")k_{\text {obs }} ） 为 0.0222min^(-1)0.0222 \mathrm{~min}^{-1} 。此外，在包括自来水、景观水和二次污水在内的实际水基质中，3BCN/PMS/vis 系统始终保持高而稳定的污染物去除效率。为了阐明潜在机制，确定了反应性物质 （ h^(+),SO_(4)^(-),∙OH\mathrm{h}^{+}, \mathrm{SO}_{4}^{-}, \bullet \mathrm{OH} 和 ^(1)O_(2){ }^{1} \mathrm{O}_{2} ） 的来源，并系统研究了基于 PMS 的光催化系统中的增强途径。基于理论计算，揭示了 BCN 中硼原子与 N 相邻区域涉及 PMS 氧化和还原的活性氧的生成途径。BCN 催化剂用于流通装置，以探索其实际应用的潜力。结果表明，在 32 h 作期间，在去除率过高 93%93 \% 的情况下实现了连续和令人印象深刻的 TC 高效去除。 我们的研究结果强调了化学-光催化协同作用在环境修复方面的巨大前景，提供了一种可行的方法来优化无金属材料在抗生素光催化氧化中的性能。
1. Introduction 1. 引言
Given an essential role for prevention and treatment of diseases, the utilization of antibiotics has witnessed a significant surge in recent decades [1,2][1,2]. Nevertheless, antibiotics exhibit physical and chemical stability that renders them impervious to natural degradation or microbial biodegradation, as the presence of antibiotics in the environment can result in genetic mutations and emergence of bacterial resistance, which engenders an alarming hazard to human and animal well-being [3,4]. Thus, there is an imminent need to explore the effective and sustainable methodologies for the decomposition of residual antibiotics 鉴于抗生素在预防和治疗疾病方面发挥着重要作用，近几十年 [1,2][1,2] 来抗生素的使用出现了显着激增。然而，抗生素表现出物理和化学稳定性，使其不受自然降解或微生物生物降解的影响，因为环境中抗生素的存在会导致基因突变和细菌耐药性的出现，从而对人类和动物的健康造成令人担忧的危害[3,4]。因此，迫切需要探索有效和可持续的方法来分解残留抗生素
in natural environment. 在自然环境中。
So far, many technologies including adsorption, biodegradation, and photocatalysis have been applied for antibiotics removal [5-8]. Due to the potential of remarkable solar energy conversion and the unique effect on pollutant decomposition, visible-light-driven photocatalysis is widely acknowledged as a highly promising technology for the elimination of organic contaminants from water [9,10]. As a compelling conjugated polymer, C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5}, boasting a high N ratio, has emerged as a prominent photocatalyst in the field of photocatalysis [11,12]. However, the recombination of electron-hole pairs in C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} still poses a considerable constraint on the photocarrier utilization efficiency 到目前为止，包括吸附、生物降解和光催化在内的许多技术已被用于去除抗生素 [5-8]。由于可见光驱动的光催化具有显著的太阳能转换潜力和对污染物分解的独特作用，因此被广泛认为是一种非常有前途的去除水中有机污染物的技术[9,10]。作为一种引人注目的共轭聚合物， C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 具有高 N 比，已成为光催化领域的重要光催化剂 [11,12]。然而，电子 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} -空穴对的复合仍然对光载流子利用效率构成相当大的限制
The integration of visible-light-driven photocatalysts with peroxymonosulfate (PMS) in advanced heterogeneous oxidation processes (AOPs) holds considerable potential, thereby facilitating the attainment of synergistic effect [14,15][14,15]. Specifically in the processes involved in photocatalysis, PMS substantially enhances the photocatalytic activity of photocatalysts, through two primary mechanisms: by producing oxidizing radicals through reductive conversion using conduction band (CB) electrons as well as impeding charge recombination by quenching CB electrons [16-18]. In this way, the consumption of electrons would therefore decrease the recombination rate of photogenerative carriers. In addition, investigations into the PMS-based AOPs have revealed additional nonradical pathways, such as ^(1)O_(2){ }^{1} \mathrm{O}_{2} and electron transfer, which can directly induce oxidation processes and exhibit high efficacy and selectivity for the elimination of organic pollutants in complex water environments [16,17]. 可见光驱动的光催化剂与过氧一硫酸盐 （PMS） 在高级非均相氧化过程 （AOP） 中的整合具有相当大的潜力，从而促进了协同效应 [14,15][14,15] 的实现。特别是在光催化过程中，PMS 通过两个主要机制显著增强光催化剂的光催化活性：通过使用导带（CB）电子的还原转化产生氧化自由基，以及通过猝灭 CB 电子来阻碍电荷复合[16-18]。通过这种方式，电子的消耗因此会降低光生载流子的复合速率。此外，对基于 PMS 的 AOP 的研究揭示了其他非自由基途径，例如 ^(1)O_(2){ }^{1} \mathrm{O}_{2} 电子转移，这些途径可以直接诱导氧化过程，并在复杂水环境中表现出消除有机污染物的高效率和选择性 [16\u201217]。
However, in PMS-based AOPs by visible-light-driven, there remains ambiguity regarding the synergistic effects of radical and nonradical pathways, as well as the sources of reactive oxygen species (ROS). For instance, Liang et al. discovered that PMS could engage as electron donor to produce SO_(5)^(-)\mathrm{SO}_{5}^{-}, which reacted with water molecules to yield ^(1)O_(2){ }^{1} \mathrm{O}_{2} [19]. And Dong et al. revealed that SO_(4)^(-∙),∙OH\mathrm{SO}_{4}^{-\bullet}, \bullet \mathrm{OH}, and SO_(5)^(-)\mathrm{SO}_{5}^{-}all indeed participated in the transformation and generation of ^(1)O_(2){ }^{1} \mathrm{O}_{2} [18]. Moreover, Gao et al. provided additional verification that electron-poor Catoms which are are involved in the generation of ^(1)O_(2){ }^{1} \mathrm{O}_{2} during the process of PMS activating [20]. In this respect, the generation of ROS during PMS activation is closely related to the electronic structure of the photocatalysts. 然而，在可见光驱动的基于 PMS 的 AOP 中，关于自由基和非自由基途径的协同作用以及活性氧 （ROS） 的来源仍然存在歧义。例如，Liang 等人发现 PMS 可以作为电子供体参与产生 SO_(5)^(-)\mathrm{SO}_{5}^{-} ，它与水分子反应产生 ^(1)O_(2){ }^{1} \mathrm{O}_{2} [19]。Dong 等人揭示了 SO_(4)^(-∙),∙OH\mathrm{SO}_{4}^{-\bullet}, \bullet \mathrm{OH} ， SO_(5)^(-)\mathrm{SO}_{5}^{-} 并且所有确实参与了 ^(1)O_(2){ }^{1} \mathrm{O}_{2} [18] 的转化和生成。此外，Gao 等人提供了额外的验证，证明在 PMS 激活 ^(1)O_(2){ }^{1} \mathrm{O}_{2} 过程中参与产生的贫电子 Catom [20]。在这方面，PMS 激活过程中 ROS 的产生与光催化剂的电子结构密切相关。
Generally, desirable catalysts for photocatalytic PMS activation should be endowed with appropriate band structure to obtain satisfactory redox capacity [10,21]. Nowadays, elemental boron has received increasing more attention due to its unique properties, as a dopant to improve the activity of photocatalysts by optimizing their photoelectric properties [22,23]. In addition, the combination of boron and carbon nitride as an inorganic catalyst can well reduce environmental effects such as metal dissolution. 一般来说，用于光催化 PMS 活化的理想催化剂应具有适当的能带结构，以获得令人满意的氧化还原容量[10,21]。如今，元素硼因其独特的性质而受到越来越多的关注，作为一种掺杂剂，通过优化光催化剂的光电性能来提高光催化剂的活性[22,23]。此外，硼和氮化碳的组合作为无机催化剂可以很好地减少金属溶解等环境影响。
Herein, we fabricated boron-doped C_(3)N_(5)(BCN)\mathrm{C}_{3} \mathrm{~N}_{5}(\mathrm{BCN}) metal-free materials through thermopolymerization. The objectives of our research are: (1) to disclose the relationship between the structure and catalytic activity by 在此，我们通过热聚合制备了掺硼无 C_(3)N_(5)(BCN)\mathrm{C}_{3} \mathrm{~N}_{5}(\mathrm{BCN}) 金属材料。我们的研究目标是：（1） 通过以下方式揭示结构和催化活性之间的关系
crystal, electrochemical characterization and the band gaps; (2) to explore the TC degradation performance by BCN under visible light irradiation coupled with PMS activation and evaluate the effects of water background compounds along with the reusability of the catalyst; (3) to identify the active species through well-designed quenching experiments, electron spin resonance (ESR) and probes; (4) to reveal the mechanisms underlying the PMS activation by BCN under visible light by density functional theory (DFT) calculations and identified the degradation products; (5) to investigate device integration via continuous operation test for water purification. This work demonstrates the promising role of metal-free materials in heterogeneous photocatalysis coupled with PMS activation, offering a novel route for eco-friendly and efficient wastewater treatment. 晶体、电化学表征和带隙;（2） 探究 BCN 在可见光照射与 PMS 活化耦合下对 TC 的降解性能，并评价水背景化合物的影响以及催化剂的可重用性;（3） 通过精心设计的淬灭实验、电子自旋共振 （ESR） 和探针鉴定活性物质;（4） 通过密度泛函理论 （DFT） 计算揭示可见光下 BCN 激活 PMS 的潜在机制并鉴定降解产物;（5） 通过水净化的连续运行测试来研究设备集成。这项工作证明了无金属材料在多相光催化与 PMS 活化相结合中的巨大作用，为环保和高效的废水处理提供了一条新的途径。
2. Materials and methods 2. 材料和方法
2.1. Synthesis of catalysts 2.1. 催化剂的合成
The process for synthesizing BCN was illustrated in Fig. 1a. In a standard procedure, 3 -amino-1,2,4-triazole (3-AT) was heated to 550^(@)C550^{\circ} \mathrm{C} for 3 h in a muffle furnace, with a temperature increase rate of 5^(@)C5^{\circ} \mathrm{C}min^(-1)\mathrm{min}^{-1}. After cooling to room temperature, the collected samples were cautiously pulverized to obtain C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5}. Subsequently, an appropriate amount of boric acid was thoroughly ground with C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} in a quartz mortar. The resulting mixture was transferred to a muffle furnace and subjected to a temperature of 550^(@)C550^{\circ} \mathrm{C} for an additional 3 h . Upon cooling to room temperature, the gathered samples were subjected to a series of washes, alternating between ultra-pure water and pure ethyl alcohol for a total of three cycles. Ultimately, the resulting yellow powders were dried for a period of 12 h at 60^(@)C60^{\circ} \mathrm{C}. The prepared catalysts were denoted as 1BCN, 2BCN, 3BCN and 4BCN, corresponding to different mass ratios of boric acid and C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} as 4%,8%,12%4 \%, 8 \%, 12 \% and 16%16 \%, respectively. 合成 BCN 的过程如图 1a 所示。在标准程序中，将 3-氨基-1,2,4-三唑 （3-AT） 在马弗炉中加热至 550^(@)C550^{\circ} \mathrm{C} 3 小时，升温速率为 5^(@)C5^{\circ} \mathrm{C}min^(-1)\mathrm{min}^{-1} 。冷却至室温后，将收集的样品小心粉碎，得到 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 。随后，在石英砂浆 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 中用适量的硼酸彻底研磨。将所得混合物转移到马弗炉中，再加热 550^(@)C550^{\circ} \mathrm{C} 3 小时。冷却至室温后，对收集的样品进行一系列洗涤，在超纯水和纯乙醇之间交替进行，总共三个循环。最终，所得黄色粉末在 60^(@)C60^{\circ} \mathrm{C} 中干燥 12 h。制备的催化剂分别表示为 1BCN、2BCN、3BCN 和 4BCN，分别对应硼酸的不同质量比和 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} as 4%,8%,12%4 \%, 8 \%, 12 \% 和 16%16 \% 。
2.2. Catalytic performance evaluation 2.2. 催化性能评价
In this study, TC served as the designated target contaminant to assess catalytic activity. Experimental procedures were conducted within a photochemical reactor equipped with a Xenon lamp ( 500 W ) to provide the visible light irradiation. Firstly, 20 mg of the prepared catalyst was added into 100 mL TC solution ( 5mg//L5 \mathrm{mg} / \mathrm{L} ) and the mixture was stirred in darkness for 60 min to achieve adsorption-desorption 在本研究中，TC 作为评估催化活性的指定目标污染物。实验程序在配备有氙灯 （ 500 W ） 的光化学反应器内进行，以提供可见光照射。首先，将 20 mg 制备的催化剂加入 100 mL TC 溶液 （ 5mg//L5 \mathrm{mg} / \mathrm{L} ） 中，并在黑暗中搅拌 60 min，实现吸附-脱附
The study also explored the impact of various factors on the removal of TC in BCN/PMS/vis system. Specifically, the effects of initial pH (3.2-11.0), TC concentration ( 5-30mg//L5-30 \mathrm{mg} / \mathrm{L} ) and common matrix species (Cl^(-),SO_(4)^(2-),NO_(3)^(-),HCO_(3)^(-),H_(2)PO_(3)^(-):}\left(\mathrm{Cl}^{-}, \mathrm{SO}_{4}^{2-}, \mathrm{NO}_{3}^{-}, \mathrm{HCO}_{3}^{-}, \mathrm{H}_{2} \mathrm{PO}_{3}^{-}\right.and HA) were investigated. Furthermore, the degradation performances of TC in different real waters including tap water, landscape water and secondary effluent were carried out. The corresponding water quality parameters were given in Table S1. Besides, continuous operation test of TC degradation by 3BCN/PMS/vis system through device integration was evaluated to explore the potential of the system in practical applications and the detailed information was presented in the Supporting Information. 该研究还探讨了各种因素对 BCN/PMS/vis 系统中去除 TC 的影响。具体来说，研究了初始 pH 值 （3.2-11.0） 、TC 浓度 （ 5-30mg//L5-30 \mathrm{mg} / \mathrm{L} ） 和常见基质种类 (Cl^(-),SO_(4)^(2-),NO_(3)^(-),HCO_(3)^(-),H_(2)PO_(3)^(-):}\left(\mathrm{Cl}^{-}, \mathrm{SO}_{4}^{2-}, \mathrm{NO}_{3}^{-}, \mathrm{HCO}_{3}^{-}, \mathrm{H}_{2} \mathrm{PO}_{3}^{-}\right. 和 HA） 的影响。此外，还研究了 TC 在不同实际水域（包括自来水、景观水和二次污水）中的降解性能。表 S1 中给出了相应的水质参数。此外，还评估了 3BCN/PMS/vis 系统通过设备集成对 TC 降解的连续运行测试，以探索该系统在实际应用中的潜力，详细信息在支持信息中介绍。
2.3. Identification of reactive species 2.3. 反应性物质的鉴定
Radical quenching experiments were conducted by adding corresponding radical quenchers during catalytic process. Sodium oxalate (SA, 10 mM ), L-histamine (L-his, 10 mM ), tert-butanol (TBA, 10 mM ), Lascorbic acid (L-AA, 10 mM ) were applied to capture photogenerated holes ( h^(+)\mathrm{h}^{+}), singlet oxygen ( ^(1)O_(2){ }^{1} \mathrm{O}_{2} ), hydroxyl radical ( *OH\cdot \mathrm{OH} ), superoxide radical (*O_(2)^(-))\left(\cdot \mathrm{O}_{2}^{-}\right)and respectively. Ethanol ( EtOH,50mM\mathrm{EtOH}, 50 \mathrm{mM} ) was used for capturing both sulfate radicals (SO_(4)^(-∙))\left(\mathrm{SO}_{4}^{-\bullet}\right) and ∙OH[24,25]\bullet \mathrm{OH}[24,25]. 通过在催化过程中添加相应的自由基淬灭剂进行自由基淬灭实验。草酸钠 （SA， 10 mM） 、L-组胺 （L-his， 10 mM） 、叔丁醇 （TBA， 10 mM） 、抗坏血酸 （L-AA， 10 mM） 分别用于捕获光生空穴 （ h^(+)\mathrm{h}^{+} ）、单线态氧 （ ^(1)O_(2){ }^{1} \mathrm{O}_{2} ）、羟基自由基 （ *OH\cdot \mathrm{OH} ）、超氧自由基 (*O_(2)^(-))\left(\cdot \mathrm{O}_{2}^{-}\right) 和。乙醇 （ EtOH,50mM\mathrm{EtOH}, 50 \mathrm{mM} ） 用于捕获硫酸根自由基 (SO_(4)^(-∙))\left(\mathrm{SO}_{4}^{-\bullet}\right) 和 ∙OH[24,25]\bullet \mathrm{OH}[24,25] 。
ESR was conducted in the light spectrum range of lambda > 400nm\lambda>400 \mathrm{~nm} with 5,5 '-dimethyl-1-pirroline-N-oxide (DMPO), 2,2,6,6-teramethylpiperidine (TEMP) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as the spin-trap reagents [14]. ESR 是在 5,5'-二甲基-1-吡罗啉-N-氧化物（DMPO）、2,2,6,6-teramethylpiperidine（TEMP）和 2,2,6,6-四甲基哌啶-1-氧基（TEMPO）作为自旋捕获试剂的光谱范围内 lambda > 400nm\lambda>400 \mathrm{~nm} 进行的[14]。
To assess the presence of reactive species in the system, the steady- 为了评估系统中是否存在活性物质，稳态
state concentrations of reactive species ( [RS]_(SS)[\mathrm{RS}]_{\mathrm{SS}} ) were quantified based on known reaction rate constants ( k ) of varous probes. Specifically, nitrobenzene (NB, with k_((∙OH,NB))=3.9 xx10^(9)M^(-1)s^(-1)k_{(\bullet \mathrm{OH}, \mathrm{NB})}=3.9 \times 10^{9} \mathrm{M}^{-1} \mathrm{~s}^{-1} and k_((SO4∙-,NB)) <k_{(\mathrm{SO} 4 \bullet-, \mathrm{NB})}<10^(6)M^(-1)s^(-1)10^{6} \mathrm{M}^{-1} \mathrm{~s}^{-1} ), p-chlorobenzoic acid (pCBA, with k_((∙OH,pCBA))=5.0 xx10^(9)k_{(\bullet O H, p C B A)}=5.0 \times 10^{9}M^(-1)s^(-1)\mathrm{M}^{-1} \mathrm{~s}^{-1} and k_((SO4∙-,pCBA))=3.6 xx10^(8)M^(-1)s^(-1)k_{(S O 4 \bullet-, p C B A)}=3.6 \times 10^{8} \mathrm{M}^{-1} \mathrm{~s}^{-1} ) and furfuryl alcohol (FFA, with k_((∙OH,FFA))=1.5 xx10^(10)M^(-1)s^(-1),k_((SO4∙-,FFA))=4.1 xx10^(9)M^(-1)s^(-1)k_{(\bullet O H, F F A)}=1.5 \times 10^{10} \mathrm{M}^{-1} \mathrm{~s}^{-1}, k_{(S O 4 \bullet-, F F A)}=4.1 \times 10^{9} \mathrm{M}^{-1} \mathrm{~s}^{-1} and k_((1O2,FFA))=1.2 xx10^(8)M^(-1)s^(-1)k_{(1 O 2, F F A)}=1.2 \times 10^{8} \mathrm{M}^{-1} \mathrm{~s}^{-1} ) were used to quantify [∙OH]_(SS)[\bullet \mathrm{OH}]_{\mathrm{SS}}, [SO_(4)^(-)]_(SS)\left[\mathrm{SO}_{4}^{-}\right]_{\mathrm{SS}} and [^(1)O_(2)]_(SS)\left[{ }^{1} \mathrm{O}_{2}\right]_{\mathrm{SS}} as radical probes [26]. 根据各种探针的已知反应速率常数 （ K ） 对反应性物质的状态浓度 （ [RS]_(SS)[\mathrm{RS}]_{\mathrm{SS}} ） 进行定量。具体来说，硝基苯（NB，带 k_((∙OH,NB))=3.9 xx10^(9)M^(-1)s^(-1)k_{(\bullet \mathrm{OH}, \mathrm{NB})}=3.9 \times 10^{9} \mathrm{M}^{-1} \mathrm{~s}^{-1} 和 ）、 k_((SO4∙-,NB)) <k_{(\mathrm{SO} 4 \bullet-, \mathrm{NB})}<10^(6)M^(-1)s^(-1)10^{6} \mathrm{M}^{-1} \mathrm{~s}^{-1} 对氯苯甲酸（pCBA，带 k_((∙OH,pCBA))=5.0 xx10^(9)k_{(\bullet O H, p C B A)}=5.0 \times 10^{9}M^(-1)s^(-1)\mathrm{M}^{-1} \mathrm{~s}^{-1} 和 k_((SO4∙-,pCBA))=3.6 xx10^(8)M^(-1)s^(-1)k_{(S O 4 \bullet-, p C B A)}=3.6 \times 10^{8} \mathrm{M}^{-1} \mathrm{~s}^{-1} ）和糠醇（FFA，带 k_((∙OH,FFA))=1.5 xx10^(10)M^(-1)s^(-1),k_((SO4∙-,FFA))=4.1 xx10^(9)M^(-1)s^(-1)k_{(\bullet O H, F F A)}=1.5 \times 10^{10} \mathrm{M}^{-1} \mathrm{~s}^{-1}, k_{(S O 4 \bullet-, F F A)}=4.1 \times 10^{9} \mathrm{M}^{-1} \mathrm{~s}^{-1} 和 k_((1O2,FFA))=1.2 xx10^(8)M^(-1)s^(-1)k_{(1 O 2, F F A)}=1.2 \times 10^{8} \mathrm{M}^{-1} \mathrm{~s}^{-1} ）用于定量 [∙OH]_(SS)[\bullet \mathrm{OH}]_{\mathrm{SS}} ， [SO_(4)^(-)]_(SS)\left[\mathrm{SO}_{4}^{-}\right]_{\mathrm{SS}} 并 [^(1)O_(2)]_(SS)\left[{ }^{1} \mathrm{O}_{2}\right]_{\mathrm{SS}} 用作自由基探针 [26]。
The detailed information of chemical reagents, characterization of catalysts, DFT calculation and identification of TC degradation products could be found in the Supporting Information. 化学试剂、催化剂表征、DFT 计算和 TC 降解产物鉴定的详细信息可在支持信息中找到。
3. Results and discussion 3. 结果和讨论
3.1. Characterization of catalysts 3.1. 催化剂的表征
3.1.1. Morphology and chemical composition 3.1.1. 形态和化学成分
The structure and morphology of the catalysts were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). As shown in Fig. 1b and Fig. 1c, C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} exhibited an agglomerated solid structure, whereas 3BCN showed a layered structure resembling folds. This observed difference could mainly be attributed to the progressive oxidation decomposition of the polymeric chains located between the layers during the second pyrolysis [27]. These distinct structural properties led to a reduction in the diffraction distance of photoexcited electrons, thereby expediting the dissociation of charge carries [28]. Moreover, the surface area of the catalyst was calculated by the BET mode and summarized in Table S2. With modification of B doping, the specific surface area was enlarged by 30%30 \%. The structural disparities likely contribute to variations in electron transport between C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} and 3BCN. Furthermore, TEM-EDS mapping (Fig. 1d,e) confirmed the presence of C,N,B\mathrm{C}, \mathrm{N}, \mathrm{B}, and O in 3BCN, providing compelling evidence of successful boron incorporation. High resolution TEM (HRTEM) images of 3BCN3 B C N and C_(3)N_(5)C_{3} N_{5} were presented in Fig. S1. As a result of the undistinguishable contrast of 3 BCN and C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5}, the B doping on C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} was not vividly observed. The results suggested that B was not deposited on the surface of C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} in any form of oxide crystals, but may enter the C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} skeleton structure in the way of element substitution. 通过扫描电子显微镜 （SEM） 和透射电子显微镜 （TEM） 对催化剂的结构和形貌进行了表征。如图 1b 和图 1c 所示， C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 呈现出团聚的固体结构，而 3BCN 呈现出类似于褶皱的层状结构。观察到的这种差异主要归因于第二次热解过程中位于各层之间的聚合物链的逐渐氧化分解[27]。这些独特的结构特性导致光激发电子的衍射距离减小，从而加速了电荷携带的解离[28]。此外，通过 BET 模式计算催化剂的表面积，并在表 S2 中总结。随着 B 掺杂的修饰，比表面积扩大 30%30 \% 。结构差异可能导致 3BCN 和 3BCN 之间的 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 电子传输变化。此外，TEM-EDS 映射（图 1d、e）证实了 C,N,B\mathrm{C}, \mathrm{N}, \mathrm{B} 3BCN 中存在 和 O，为硼成功掺入提供了令人信服的证据。的高分辨率 TEM （HRTEM） 图像 3BCN3 B C NC_(3)N_(5)C_{3} N_{5} 如图 S1 所示。由于 3 BCN 和 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 的对比无法区分，没有生动地观察到 B 掺杂 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 。结果表明，B 没有 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 以任何形式的氧化物晶体沉积在表面，而是可能以元素取代的方式进入 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 骨架结构。
The crystal phases of both C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} and BCNs were investigated by X-ray diffraction (XRD). As illustrated in Fig. 2a, a distinct peak at 27.7^(@)27.7^{\circ} was 通过 X 射线衍射 （XRD） 研究了两者 C_(3)N_(5)\mathrm{C}_{3} \mathrm{~N}_{5} 和 BCN 的晶相。如图 2a 所示，在 27.7^(@)27.7^{\circ}
Corresponding authors at: College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China. 通讯作者：北京林业大学环境科学与工程学院，中国北京市海淀区清华东路 35 号，中国100083。
