OH Sites Research Articles

Action pattern of Sulfolobus O-α-glycoligase for synthesis of highly water soluble resveratrol 3,4′-α-diglucoside

This study presents the enzymatic synthesis of resveratrol-3,4′-O-α-diglucoside (RDG) using a hyperactive O-α-glycoligase (MalA-D416R/Q450S) and α-glucopyranosyl fluoride as the donor substrate. The transglycosylation rate for resveratrol by MalA-D416R/Q450S was maximized in 100 mM Tris-HCl (pH 9.5) containing 20 % DMSO at 45°C. Because the pKa of the 4′-OH group of resveratrol is lower than that of the 3-OH group, the 4′-OH group is more nucleophilic at the alkaline pH, leading to a preference for glycosylation at the 4′-OH site rather than the 3-OH site. This preference makes resveratrol 3-O-α-glucoside (R3G) as the more efficient acceptor than resveratrol 4′-O-α-glucoside (R4′G), resulting in negligible production of resveratrol 3-O-α-glucoside (R3G) due to its complete consumption in the second transglycosylation reaction when using a 2:1 ratio of donor to acceptor substrates. From a preparative scale reaction, R4′G and RDG were isolated with yields of 41.2 % and 43.3 %, respectively. The water solubility of RDG exceeded 1.67 M, which represents more than a 9,800-fold improvement compared to resveratrol. In a hydrolysis experiment using intestinal α-glycosidase from rat, the α-glucosides of resveratrol (R4′G and RDG) were completely deglycosylated to the aglycone.

Computational Insights into the Radical Scavenging Activity and Xanthine Oxidase Inhibition of the Five Anthocyanins Derived from Grape Skin.

Anthocyanins, typical polyphenol compounds in grape skin, have attracted increasing interest due to their health-promoting properties. In this body of work, five representative anthocyanins (Cy-3-O-glc, Dp-3-O-glc, Pn-3-O-glc, Mv-3-O-glc, and Pt-3-O-glc) were studied using the density functional theory (DFT) to elucidate structure-radical scavenging activity in the relationship and the reaction path underlying the radical-trapping process. Based on thermodynamic parameters involved in HAT, SET-PT, and SPLET mechanisms, along with the structural attributes, it was found that the C4' hydroxyl group mainly contributes to the radical scavenging activities of the investigated compounds. Pt-3-O-glc exhibits a good antioxidant capacity among the five compounds. The preferred radical scavenging mechanisms vary in different phases. For the Pt-3-O-glc compound, the calculations indicate the thermodynamically favoured product is benzodioxole, rather than o-quinone, displaying considerably reduced energy in double HAT mechanisms. Additionally, the thermodynamic and kinetic calculations indicate that the reaction of •OH into the 4'-OH site of Pt-3-O-glc has a lower energy barrier (7.6 kcal/mol), a higher rate constant (5.72 × 109 M-1 s-1), and exhibits potent •OH radical scavenging properties. Molecular docking results have shown the strong affinity of the studied anthocyanins with the pro-oxidant enzyme xanthine oxidase, displaying their significant role in inhibiting ROS formation.

Unveiling the mechanistic synergy in Mn-doped NiO catalysts with atomic-burry structure: Enhanced CO oxidation via Ni-OH and Mn bifunctionality

The development of non-noble metal catalysts for low-temperature CO oxidation is a pivotal subject in various disciplines. In this study, an optimized Mn-doped NiO catalyst (Mn-NiO-0.5), prepared via aerosol pyrolysis with an equal molar ratio of Ni to Mn, demonstrates remarkable performance. It achieves an 82 % CO conversion at -20 °C and a 100 % conversion between 10 °C and 800 °C. The catalyst’s turnover frequency (TOF) for CO oxidation significantly surpasses that of previously reported noble-metal-based catalysts, underscoring its superior efficiency. Dynamic analyses suggest that the enhanced catalytic activity is a result of the unique atom burr structure, which presents an extensive surface area replete with abundant active sites. This structural feature is instrumental in maximizing the catalyst’s interaction with CO molecules. Experimental findings, corroborated by density functional theory (DFT) calculations, elucidate the mechanism of CO oxidation on the Mn-NiO-0.5 catalyst. The process is facilitated by the synergistic action of bimetallic sites, where the Ni–OH site acts as the primary adsorption point for CO. Subsequently, the CO is oxidized to bicarbonate through the interaction with the oxygen (O or O2) at adjacent Mn sites. This pioneering study introduces a paradigm-shifting insight: the effectiveness of non-noble metal oxide catalysts can now compete with, and in some cases, outperform their noble metal counterparts. This breakthrough is set to transform the industry, presenting a compelling alternative to conventional noble metal catalysts and propelling the evolution of state-of-the-art environmental conservation technologies.

Advancing understanding of polymer-based superplasticizers for diverse concrete applications: Insights from quantum chemistry and nanoscale adsorption behavior

Polycarboxylate superplasticizers (PCEs) are the most commonly used admixture in the concrete industry. Their premise for work is often considered to be the adsorption of the cement particles through the anchoring groups. Here we suggest a nanoscale perspective to understand the effects of anchoring groups on the adsorption of PCEs by employing the density functional theory (DFT) method. The electronic structural analyses consider various typically anchoring groups of (COO−, PO42−, PO32−, Silanol, and SO3−). The findings indicate that anchoring adsorption predominantly occurs at apex calcium and silicon hydroxyl (Si–OH) sites on the C–S–H surface. Specifically, PCEs containing the PO32− groups exhibit the highest degree of chemical adsorption at the apex cacium site, whereas those with COO− groups show the most pronounced chemical adsorption affinity at the Si–OH site. This observation suggests that varying calcium content in cementitious materials may necessitate the use of different anchoring groups for optimal PCE performance. Further analyses of the Reduced Density Gradient (RDG) indicate that PCE with the COO− and PO32− groups demonstrate the most robust adsorption with the corresponding site. Furthermore, quantitative examination of the peak value at the intersection of the electron localization function (ELF) curve derived an inference that aligns with the findings from the RDG analysis. This study provides a robust framework for understanding the adsorption mechanisms of PCEs with various anchoring groups and offers valuable insights for evaluating the performance of PCEs in more complex cementitious systems.

Reactions of Hydroperoxyl Radicals (HO2) with Oxygenated Aromatic Bio-oil Model Compounds

During thermal utilization of biomass, a complex array of reactions ensues in the oxidative environment between fragments of the biomass and reactive species. In the low-temperature window, hydroperoxyl (HO[Formula: see text] radicals assume a central role prior to the establishment of the O/H radical pool. Anisole, cresol, guaiacol and vanillin are often utilized as representative model compounds to comprehend the combustion chemistry of the phenolic entities in biomass and oxygen-containing derived bio-oil. This paper reports thermo-kinetic parameters for the reactions of HO2 radicals with anisole, cresol, guaiacol and vanillin. Computed activation enthalpies entail facile values for H abstraction from the side-chain functional groups in the investigated compounds. H abstraction from the hydroxyl groups incurs lower activation energies in reference to methyl sites in cresol and guaiacol. Hence, H abstraction from the OH sites in these two molecules proceeds at a faster reaction rate constant when compared to abstraction from the methyl site. In the vanillin molecule, abstraction from the aldehydic and hydroxyl sites portrays comparable importance. The effect of scaling vibrational frequencies and the type of applied quantum tunneling on the computed reaction rate constants were thoroughly explored. Analysis of entropies of activation indicates that the transition states exhibit a product-like character. While ignition delay times of fuels often exhibit a profound sensitivity towards initial H abstraction reactions by HO2, we found that ignition delay times of the four title molecules remain almost unchanged when updating literature kinetics models with new reaction rate constants calculated herein. It is anticipated that reported outcomes from this study aid in formulating a better understanding of the complex chemical reactions that dictate oxidative decomposition of oxygenated bio-oil model compounds.

Mechanism study of trimetallic single-cluster catalysts loaded on graphdiyne for highly efficient oxygen-reduction reactions

Single-cluster catalysts (SCCs) have become a research hotspot due to their abundant active sites and tunable interatomic electronic structure, demonstrating excellent catalytic properties. However, the diversity of metal species in SCCs leads to unclear intrinsic activity toward metals and interaction between different metal species. In this manuscript, the impact of a series of precious metal-based (Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au) trimetallic SCCs loaded on graphdiyne (UxVyWz@GDY) on the performance of the oxygen reduction reaction (ORR) is investigated using first-principles. The results show that the 18 holes of graphdiyne (GDY) efficiently achieve uniform doping of trimetallic clusters. In the UxVyWz@GDY structure, Pt3@GDY, Pt2Pd@GDY, and AuPdPt@GDY displayed high thermodynamic limit potentials near the top of the volcano plot at 0.79 eV, 0.80 eV, and 0.82 eV, respectively. These catalysts also show low overpotentials of 0.44 V, 0.43 V and 0.50 V, respectively. Deeper scrutiny of the interaction mechanism between *OH and the catalytic sites on Pt3@GDY, Pt2Pd@GDY, and AuPdPt@GDY unveils the pivotal role of electron transfer and intermetallic interactions in modulating the d-band center. Notably, the observed left shift of the d-band center in these catalysts, leading to the generation of more electron-deficient centers, effectively mitigates the issue of over-absorption between *OH and metal active sites, thereby significantly enhancing *OH desorption. This work provides inspiration for the efficient design of trimetallic SCCs.

Determination of concentration of basic sites on oxides by IR spectroscopy

As it is commonly known, CO2 reacts simultaneously with basic O2− and basic OH sites on oxides forming carbonates and bicarbonates, which can be followed by infrared spectroscopy (IR). However, here, we succeeded to elaborate experimental conditions under which CO2 reacted solely with O2− forming CO32− for ZrO2 and CeO2, and calculated the extinction coefficients of diagnostic bands of carbonate and bicarbonate species. For the first time, the developed IR method enabled the concentrations of O2− and basic OH for ZrO2, CeO2, Al2O3 and CuO to be measured separately. Moreover, in the case of all IR studied oxides, the sum of concentrations of O−2 and basic OH basic sites was comparable with the concentration determined by pulse adsorption of CO2. Thus, the presented extinction coefficients can be applied for IR basicity studies of various basic catalysts. We also followed the effect of thermal treatment on basicity of oxides.

Exploration of a novel depressant pullulan gum for the flotation separation of specularite from aegirite

The successful separation of specularite and aegirite in the flotation process heavily relies on efficient depressants due to their closely similar physical and chemical properties. This study focuses on investigating the specific depressive impact and mechanism of pullulan gum (PG) on specularite and aegirite. The findings from single mineral flotation tests revealed the maximum floatability difference was 49.7 percentage point when pH was 8 and the dosage of PG and DDA were 90 mg/L and 30 mg/L respectively, which indicated that PG selectively depressed specularite while displaying a notably weaker depression effect on aegirite. The selective depressive impact of PG was further affirmed through artificial mineral mixed mineral flotation tests. Additionally, results derived from contact angle measurement, adsorption capacity measurement, Zeta potential measurement, and FT-IR analysis collectively highlighted the significantly higher affinity of PG to the surface of specularite compared to aegirite. This stronger interaction between PG and specularite obstructed the adsorption of DDA onto the latter mineral. Moreover, XPS analysis provided insights indicating that PG chemically adsorbs onto the specularite surface, forming a Fe-O complex via a potential reaction between OH and Fe site. As a result of these comprehensive findings, PG emerges as a promising novel depressant for effectively separating specularite from aegirite.

High Capacity Arsenate Removal from Real Samples Using Dihydrotetrazine Decorated Zirconium-Based Metal-Organic Frameworks.

Zirconium metal-organic frameworks (Zr-MOFs) are potential candidates for decontamination of water resources from harmful pollutants due to their modulable porosity and chemical stability in aqueous solutions. Linker functionalization is an approach for tuning the host-guest chemistry of Zr-MOFs and extends their applications in environmental monitoring. In this work, the structure of UiO-66(Zr) (formulated Zr6(OH)4O4(BDC)6, BDC2- = benzene-1,4-dicarboxylate) was functionalized with dihydrotetrazine group via postsynthesis linker exchange (PSLE) method. The functionalized framework, UiO-66(Zr)-DHTZ, was applied for the removal of arsenate ions from aqueous solutions. The results show that UiO-66(Zr)-DHTZ can adsorb 583 mg g-1 of As(V) at pH = 7 after 2 h, which is significantly higher than that of the UiO-66(Zr). According to X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR), the removal mechanism is based on possible hydrogen bindings between free -C-NH and -C═N- sites of dihydrotetrazine function with -O- and -OH sites of As(V) species. Removal tests in real samples show that UiO-66(Zr)-DHTZ still has a high capacity (220 mg g-1) to As(V) ions in complex matrixes and also can decrease the concentration of As(V) below the detection limit (0.05 ppm) of the inductively coupled plasma optical emission spectroscopy (ICP-OES) method. Since the dihydrotetrazine-decorated UiO-66(Zr)-DHTZ reaches one the highest adsorption capacities to As(V) species, it can be considered a potential candidate for water treatment in real-life applications.

Operando study of HfO2 atomic layer deposition on partially hydroxylated Si(111)

The introduction of atomic layer deposition (ALD), to the microelectronics industry has introduced a large number of new possible materials able to be deposited in layers with atomic thickness control. One such material is the high-κ oxide HfO2; thermally stable and ultrathin HfO2 films deposited by ALD are a significant contender to replace SiO2 as the gate oxide in capacitor applications. We present a mechanistic study of the first deposition cycle of HfO2 on the Si(111) surface using tetrakis(dimethylamido) hafnium (TDMAHf) and water as precursors using operando ambient pressure x-ray photoelectron spectroscopy. Here, we show that the hydroxylation of the clean Si(111) surface by residual water vapor, resulting in a 0.3 monolayer coverage of hydroxyls, leads to instantaneous full surface coverage of TDMAHf. The change in the atomic ratio of Hf to C/N found during the first deposition half-cycle, however, does not match the assumed immediate ligand loss through reaction with surface hydroxyls. One would expect an immediate loss of ligands, indicated by a Hf:N ratio of approximately 1:3 as TDMAHf deposits onto the surface; however, a Hf:N ratio of 1:3.6 is observed. The partial hydroxylation on the Si(111) surface leads to binding through the TDMAHf ligand N atoms resulting in both N and CH3 being found remaining on the surface post water half-cycle. Although there is evidence of ligand exchange reactions occurring at Si–OH sites, it also seems that N binding can occur on bare Si, highlighting the complexity of the substrate/precursor reaction even when hydroxyls are present. Moreover, the initial low coverage of Si–OH/Si–H appears to severely limit the amount of Hf deposited, which we hypothesize is due to the specific geometry of the initial arrangement of Si–OH/Si–H on the rest- and adatoms.

Adsorption behavior of lead, cadmium, and arsenic on manganese-modified biochar: competition and promotion.

Biochar adsorption of heavy metals has been a research hotspot, yet there has been limited reports on the effect of heavy metal interactions on adsorption efficiency in complex systems. In this study, the adsorbent was prepared by pyrolysis of rice straw loaded with manganese (BC-Mn). The interactions of Pb, Cd and As adsorption on BC-Mn were systematically studied. The results of the adsorption isotherms for the binary metal system revealed a competitive adsorption between Pb and Cd, resulting in decreased Pb (from 214.38mg/g to 148.20mg/g) and Cd (from 165.73mg/g to 92.11mg/g). A notable promotion occurred between As and Cd, showing an increase from 234.93mg/g to 305.00mg/g for As and 165.73mg/g to 313.94mg/g for Cd. In the ternary metal system, Pb inhibition did not counteract the promotion of Cd and As. Furthermore, the Langmuir isotherm effectively described BC-Mn's adsorption process in monometallic, binary, and ternary metal systems (R2 > 0.9294). Zeta and FTIR analyses revealed simultaneous competition between Pb and Cd for adsorption on BC-Mn's -OH sites. XPS analysis revealed that As adsorption by BC-Mn facilitated the conversion of MnO2 and MnO to MnOOH, resulting in increased hydroxyl radical production on BC-Mn's surface. Simultaneously, Cd combined with the adsorbed As to form ternary Cd-As-Mn complexes, which expedited the removal of Cd. These results help to provide theoretical support as well as technical support for the treatment of Pb-Cd-As contaminated wastewater.

The Effects of ≡Ti–OH Site Distortion and Product Adsorption on the Mechanism and Kinetics of Cyclohexene Epoxidation over Ti/SiO2

The Effects of ≡Ti–OH Site Distortion and Product Adsorption on the Mechanism and Kinetics of Cyclohexene Epoxidation over Ti/SiO₂

Mechanism and Kinetics of Propane and n-Butane Dehydrogenation over Isolated and Nested ≡SiOZn–OH Sites Grafted onto Silanol Nests of Dealuminated Beta Zeolite

Mechanism and Kinetics of Propane and <i>n</i>-Butane Dehydrogenation over Isolated and Nested ≡SiOZn–OH Sites Grafted onto Silanol Nests of Dealuminated Beta Zeolite

Cadmium phosphates Cd2(PO4)OH and Cd5(PO4)2(OH)4 crystallizing in mineral structures

Single crystals of two basic cadmium phosphates, dicadmium orthophosphate hydroxide, Cd2(PO4)OH, and pentacadmium bis(orthophosphate) tetrakis(hydroxide), Cd5(PO4)2(OH)4, were obtained under hydrothermal conditions. Cd2(PO4)OH adopts the triplite [(Mn,Fe)2(PO4)F] structure type. Its asymmetric unit comprises two Cd, one P and five O sites, all situated at the general Wyckoff position 8 f of space group I2/a; two of the O atoms are positionally disordered over two sites, and the H atom could not be localized. Disregarding the disorder, distorted [CdO6] polyhedra form a tri-periodic network by edge-sharing with neighbouring [CdO6] units and by vertex-sharing with [PO4] units. The site associated with the OH group is coordinated by four Cd atoms in a distorted tetrahedral manner forming 1 ∞[(OH)Cd4/2] chains parallel to [001]. The oxygen environment around the OH site suggests multiple acceptor atoms for possible O—H...O hydrogen-bonding interactions and is the putative reason for the disorder. Cd5(PO4)2(OH)4 adopts the arsenoclasite [Mn5(AsO4)2(OH)4] structure type. Its asymmetric unit comprises five Cd, two P, and twelve O sites all located at the general Wyckoff position 4 a of space group P212121; the H atoms could not be localized. The crystal structure of Cd5(PO4)2(OH)4 can be subdivided into two main sub-units. One consists of three edge-sharing [CdO6] octahedra, and the other of two edge- and vertex-sharing [CdO6] octahedra. Each sub-unit forms corrugated ribbons extending parallel to [100]. The two types of ribbons are linked into the tri-periodic arrangement through vertex-sharing and through common [PO4] tetrahedra. Quantitative structure comparisons are made with isotypic M 5(XO4)2(OH)4 crystal structures (M = Cd, Mn, Co; X = P, As, V).

Binding of carbon dioxide and acetylene to free carboxylic acid sites in a metal-organic framework.

The functionalisation of organic linkers in metal-organic frameworks (MOFs) to improve gas uptake is well-documented. Although the positive role of free carboxylic acid sites in MOFs for binding gas molecules has been proposed in computational studies, relatively little experimental evidence has been reported in support of this. Primarily this is because of the inherent synthetic difficulty to prepare MOF materials bearing free, accessible -COOH moieties which would normally bind to metal ions within the framework structure. Here, we describe the direct binding of CO2 and C2H2 molecules to the free -COOH sites within the pores of MFM-303(Al). MFM-303(Al) exhibits highly selective adsorption of CO2 and C2H2 with a high selectivity for C2H2 over C2H4. In situ synchrotron X-ray diffraction and inelastic neutron scattering, coupled with modelling, highlight the cooperative interactions of adsorbed CO2 and C2H2 molecules with free -COOH and -OH sites within MFM-303(Al), thus rationalising the observed high selectivity for gas separation.

Unraveling the atomic structure and dissociation of interfacial water on anatase TiO2 (101) under ambient conditions with solid-state NMR spectroscopy.

Anatase TiO2 is a widely used component in photo- and electro-catalysts for water splitting, and the (101) facet of anatase TiO2 is the most commonly exposed surface. A detailed understanding of the behavior of H2O on this surface could provide fundamental insights into the catalytic mechanism. This, however, is challenging due to the complexity of the interfacial environments, the high mobility of interfacial H2O, and the interference from outer-layer H2O. Herein, we investigate the H2O/TiO2 interface using advanced solid-state NMR techniques. The atomic-level structures of surface O sites, OH groups, and adsorbed H2O have been revealed and the detailed interactions among them are identified on the (101) facet of anatase TiO2. By following the quantitative evolution of surface O and OH sites along with H2O loading, it is found that more than 40% of the adsorbed water spontaneously dissociated under ambient conditions on the TiO2 surface at a loading of 0.3 mmol H2O/g, due to the delicate interplay between water-surface and water-water interactions. Our study highlights the importance of understanding the atomic-level structures of H2O on the surface of TiO2 in catalytic reactions. Such knowledge can promote the design of more efficient catalytic systems for renewable energy production involving activation of water molecules.

Isoreticularity in a gallate-based metal–organic framework: Impact of the extension of the ligand on the porosity, stability and adsorption of CO2

Isoreticularity is one of the key aspects in the design of new Metal-Organic Frameworks (MOFs), but has been up to now scarcely applied to gallate (1,2-3-trioxobenzene) ligands. With the aim of building new materials isoreticular to the M(Hngal) (H4gal = gallic acid) small pore MOF series, we here designed the new elongated mixed gallate-carboxylate ligand 4-(3,4,5-trihydroxyphenyl)benzoic acid (H4bpgal). A thorough investigation of its reactivity with MgCl2 has led to the successful isolation of the targeted material Mg(H2bpgal)·n(solv) (solv = water, methanol, ethanol). A combination of experimental tools, including single-crystal X-ray diffraction (XRD), powder XRD, and 1H and 13C solid-state NMR studies confirmed the close structural relationship with the smaller analogue, including the presence of acidic OH sites arising from phenol groups bound to Mg cations. Contrary to the small pore analogue, Mg(H2bpgal) is of limited interest for gas capture, because of its moderate stability upon exposure to dioxygen and low affinity for CO2, both resulting from the intrinsic characteristics of the ligand (redox activity and flexibility, respectively). Nevertheless, it presents among the highest surface area and pore volume reported to date for a gallate MOF (1475 m2 g−1 and 0.59 cm3 g−1, respectively); these characteristics might be of interest in other fields of applications, including electrochemical energy storage or combined controlled drug release.

Experimental and Theoretical Evidence for Distorted Tetrahedral ≡Ti–OH Sites Supported on Amorphous Silica and Their Effect on the Adsorption of Polar Molecules

Experimental and Theoretical Evidence for Distorted Tetrahedral ≡Ti–OH Sites Supported on Amorphous Silica and Their Effect on the Adsorption of Polar Molecules

Dual Excited State Proton Transfer Pathways in the Bifunctional Photoacid 6-Amino-2-naphtol.

This study investigates the photoacidity and excited state proton transfer (ESPT) pathways of a bifunctional molecule, 6-amino-2-naphthol (6N2OH), using absorption, steady-state fluorescence, time-resolved fluorescence, and theoretical calculations. 6N2OH attains four different prototropic forms in the excited state (cation, neutral, anion, or zwitterion) depending on pH of the solution. Interestingly, ESPT at the OH site of the molecule can be controlled by the protonation state of the amino substituent. Conversion of the electron donating NH2 group to the electron withdrawing NH3+ group brings about a reduction of more than 7 pKa units for the deprotonation of OH in the excited state. Further, the position of the NH2 substituent on the naphthalene framework is found to play an important role in dictating the ESPT pathways of aminonaphthols. Unlike most aminonaphthol derivatives that undergo ESPT only at the OH site, akin to substituted naphthols, 6N2OH undergoes ESPT at both OH and NH3+ sites, indicating its similarity to substituted naphthols and substituted naphthylamines. ESPT at the NH3+ site resulting in cation ↔ neutral equilibrium of 6N2OH in the excited state is well-corroborated by comparative studies with another reference photoacid, 6-amino-2-methoxynaphthalene (6N2M). Correlation of the acidity constants of 6N2OH with the σp parameters according to the Hammett model reveals that while 6N2OH can be treated either as naphthol or as naphthylamine in the ground state, the structure-function correlation cannot be extrapolated directly in the excited state, thus highlighting the rich and complex photophysics of bifunctional photoacids.

Roles of alcohol group in functionalized carbon nitride for photocatalytic oxidation

Rational design of new active sites for g-C3N4-based photocatalysts to accelerate its charge transfer represents an advanced direction for pollutant photodegradation. Herein, alcohol group-modified g-C3N4 via integrated C-N site and –OH site using in situ C-N coupling is developed. The alcohol-modified g-C3N4 exhibits elevated phenol removal efficiency than g-C3N4. Experimental results and theoretic calculations disclosed that the C-N site adjacent to the introduced alcohol group not only constructs a built-in electric field for driving charge transfer but also acts as a new site for the activation of O2 molecules; the –OH site of alcohol group works as the adsorption site of phenol. Additionally, the discrepancy in activity between ethyl alcohol and methyl alcohol modification is due to the different oxidation ability, which is triggered by transfer rate of separated electrons. Importantly, this work achieved unique role of each active sites, providing a theoretical basis to the design of super-active photocatalysts, and reveals a clear pathway for evolution of ROS and phenol mineralization.