Efficient Photoreduction Research Articles

Inside Front Cover: Enhancing d/p‐2π* Orbitals Hybridization via Strain Engineering for Efficient Photoreduction CO2

Inside Front Cover: Enhancing d/p‐2π* Orbitals Hybridization via Strain Engineering for Efficient Photoreduction CO₂

Inside Front Cover: Enhancing d/p‐2π* Orbitals Hybridization via Strain Engineering for Efficient Photoreduction CO2

Inside Front Cover: Enhancing d/p‐2π* Orbitals Hybridization via Strain Engineering for Efficient Photoreduction CO₂

Regulating the interaction between Bi metal and Bi24O31Br10 nanosheets for efficient photoreduction of CO2

Artificial photosynthesis converting CO2 into valuable compounds has garnered significant interest. However, the insufficient surface activity sites, weak adsorption capacity of CO2 and poor electron-hole separation capability hinder CO2 photoreduction used for practical implementation. Herein, Bi nanoparticles/Bi24O31Br10 composite photocatalyst (Bi/BOB) was designed constructed through in-situ reduction of bismuth metal on the surface of ultra-thin Bi24O31Br10 nanosheets. Bi/BOB exhibits an excellent ability to reduce CO2 to CO. The CO2 reduction rate of the optimized Bi/BOB composite catalyst is 43.07 μmol·g−1·h−1, which is significantly superior to other reported bismuth-based photocatalysts. Experimental characterization and Theoretical simulation calculation reveal that the in-situ reduction of bismuth metal causes significant local lattice distortion and uneven charge distribution, thereby producing a strong interaction between Bi nanoparticles and BOB support. So, it enhances the adsorption and activation of carbon dioxide molecules and reduces the Gibbs free energy barrier during the catalytic reaction. Moreover, the strong interaction helps to enhance the separation of photogenerated charge carriers and stability of catalysts. This study offers research suggestions for the interaction between metal and support to enhance CO2 reduction.

Synergy of P doping and crystallinity modulation in carbon nitride for enhancing photocatalytic uranyl reduction

Doping modification is a useful way to promote the catalytic activity of carbon nitride (CN). However, most doped CNs have lower structural symmetry and several edge defects, which hinder the transfer of charge carriers. This work reports a P-doped crystalline carbon nitride (crystalline PCN) for the efficient photoreduction of uranyl. The thermal polymerization and salt post-treatment convert the amorphous PCN into crystalline PCN. Compared to the pristine CN, the crystalline PCN has over 1620 % higher activity for uranyl (U(VI)) reduction, reaching a 97.8 % reduction rate in 60 min. Furthermore, the 2-PCN shows excellent stability and a U(VI) removal efficiency >85.7 % in the pH range of 5–8. Characterization analysis reveal that both the P doping and crystalline modulation do not obviously change their morphology, light absorption property and energy band structure, but markedly promote the delocalization of electrons around the doped P atoms, thereby severely inhibit direct electron-hole recombination. Thus, the more efficient separation of charge carriers generates more reactive specials to participate in the photocatalytic uranyl reduction reaction. This study demonstrates a dual-modification strategy for the rational synthesis of highly active metal-free CN-based photocatalysts for uranyl reduction.

Covalent Organic Frameworks for Photocatalytic Reduction of Carbon Dioxide: A Review.

Covalent organic frameworks (COFs) are crystalline networks with extended backbones cross-linked by covalent bonds. Due to the semiconductive properties and variable metal coordinating sites, along with the rapid development in linkage chemistry, the utilization of COFs in photocatalytic CO2RR has attracted many scientists' interests. In this Review, we summarize the latest research progress on variable COFs for photocatalytic CO2 reduction. In the first part, we present the development of COF linkages that have been used in CO2RR, and we discuss four mechanisms including COFs as intrinsic photocatalysts, COFs with photosensitive motifs as photocatalysts, metalated COF photocatalysts, and COFs with semiconductors as heterojunction photocatalysts. Then, we summarize the principles of structural designs including functional building units and stacking mode exchange. Finally, the outlook and challenges have been provided. This Review is intended to give some guidance on the design and synthesis of diverse COFs with different linkages, various structures, and divergent stacking modes for the efficient photoreduction of CO2.

Efficient photoreduction of CO2 to tunable syngas by Zn-doped Co3O4: Tuning binding strength to versatile reaction intermediates simultaneously

Photochemical reduction of CO2 (CO2RR) to syngas is an attractive approach for carbon–neutral recycling. Manipulating binding strength to reactive species on catalyst surfaces is challenging but essential for achieving efficient syngas production with a desired CO/H2 ratio. Here, we demonstrate that the binding strength to key reaction intermediates (*CO2, *H and *CO) on the Co3O4 surface can be fine-tuned by incorporating varying amount of Zn atoms. Dedicated experiments and theoretical simulations unveil that Zn doping allows for simultaneous control of both CO2 adsorption/activation and the adsorption affinity of *CO on Zn-Co3O4 catalysts, resulting in a significant enhancement in CO2 to CO conversion. Moreover, Zn doping can alter the hydrophilicity of the catalyst surface, affecting the water adsorption behavior and adjusting the hydrogen evolution reaction (HER) activity. As a result, the CO/H2 ratio can be readily tuned via varying the Zn doping level. This study presents an effective and economical method approach to manipulate the electronic structure of catalyst surfaces for controlling the kinetics of CO2RR and HER reactions, providing valuable insight into the design of highly active transition metal oxides (TMOs) based photocatalysts for syngas production with a tailored CO/H2 ratio.

Synthesis of strongly interactive FeWO4/BiOCl heterostructures for efficient photoreduction of CO2 and piezo-photodegradation of bisphenol A

Development of multi-functional photocatalysts for CO2 reduction and pollutant elimination is practically significant for solving the environmental problems and energy shortages. In this study, we have immobilized FeWO4 (FWO) nanoparticles on the surface of (001)-facet-exposed BiOCl (BOC) nanosheets through their strong electrostatic interaction to form FWO/BOC heterojunctions. Experimental and theoretical studies corroborate that the FWO/BOC heterojunctions exhibit high-efficiency Z-scheme transfer and separation of photocarriers, and possess excellent photocatalysis for CO2 reduction and bisphenol A (BPA) degradation. Under simulated-sunlight irradiation, the 9 %FWO/BOC heterojunction exhibits a photoreduction performance with CH4/CO yield rates of 4.25/9.41 μmol g−1 h−1 (5 h reaction), which are 3.86/5.26 times higher than those for bare BOC; whereas its photodegradation performance (η(60 min) = 66.8 %, kapp = 0.01755 min−1) is enhanced by 4.3 and 2.7 times compared with that of bare FWO and BOC, respectively. Furthermore, when ultrasonic vibration is simultaneously employed during the simulated-sunlight illumination, the ultrasonic-induced piezoelectric polarization field in BOC nanosheets accelerates the bulk photocarrier separation, resulting in a further improvement in the BPA degradation, and the calculated SF = 1.79 quantifies the degree of enhancement achieved by piezo-photocatalysis collaboration. The introduction of a moderate amount of H2O2 or peroxymonosulfate (PMS) in the reaction solution plays a significant role in promoting the BPA degradation due to the generation of additional •OH and •SO4− reactive species. The mechanisms for photocatalytic CO2 reduction and piezo-photodegradation of BPA catalysis were deeply studied by combining experiments and theory.

Dual vacancies synergistically induced hybridization effect of Ti3C2Tx-based photocatalyst for enhanced U(VI) photoreduction

The exact understanding for each promotional role of anion and cation vacancies in efficient photocatalytic reduction U(VI) reaction system will contribute to the development of photocatalysts. Herein, a Ti3C2Tx/CNv/MnOx (CTM) photocatalyst with Ti3C2Tx and MnOx as cocatalysts was successfully synthesized by construction of N anionic and Ti cationic dual vacancies synergistically induced hybridization and was used for efficient U(VI) photoreduction in absence of sacrificial agents. The introduction of dual vacancies can change the charge distribution on the photocatalyst surface to effectively surmount the deficiency of poor U(VI) capture ability and reduce band gap. Especially, the strategy of di-vacancies synergistically induced cocatalysts hybridization effect promotes the accelerated accumulation of electrons and holes on corresponding cocatalysts to participate in redox reactions, greatly enhancing the charge spatial separation. Impressively, the U(VI) removal ratio of the CTM is as high as 96.1 % within 90 min, and CTM exhibits excellent selectivity (1.55×104 mL g-1) even in complex tailings wastewater. Even after five cycles, the U(VI) removal rate can still be as high as 93.2 %. This strategy may provide a new avenue for rational design of photocatalysts for efficient photoreduction U(VI).

Highly efficient photoreduction of CO2 to CO: Synergistic optimisation of progressive electron transfer via Fe2+ and oxygen vacancies

The electron transfer in photocatalytic reaction, including electron transfer between the components in the catalyst, electron transfer between reactant molecules and catalysts. Fe2+/Fe3+ and oxygen vacancies (VOs) were simultaneously introduced in Fe-In2O3, the 5 wt% Fe-In2O3 exhibited a 13.7-fold increase in activity (4.80 mmol·g−1·h−1) compared to the In2O3 and a CO selectivity of approximately 84.32 %. Multiple in-situ techniques indicated that the doping of FeOX serves to effectively modulate the concentration of VOs, FeOX and In2O3 form a p-n heterojunction interfacial structure and match energy bands, promoting carrier separation. More importantly, Fe2+, In2+, and VOs serve as electron-donating adsorption sites, increasing the number of electrons received by CO2 and H2O, which causing pre-reduction activation of the reactant molecules. Eventually the dual-reduction reaction of CO2 and H2O were realized, subsequently, CO2 was selectively converted into CO through intermediate species such as formate. This study employs Fe2+ and VOs to synergistic optimize the progressive transfer of photogenerated electrons, and presents a novel approach for elucidating the catalytic mechanism.

Mn/Fe co-doped TiO2 nanotube arrays for photoelectrochemical water splitting in neutral medium

Manganese and iron co-doped TiO2 nanotube arrays (TNTs) are grown on Ti foil by in situ electro-anodization method and employed for overall photoelectrochemical water splitting. The band gap of TiO2 is reduced from 3.3 eV to 3.1 eV with co-doping of Mn and Fe in Mn/Fe-TNT@Ti sample. Annealing Mn/Fe-TNT@Ti at 500 °C leads to the formation of trap states associated with the Fe3+ and Mn2+ ions present in the TiO2 lattice. The anatase structure of TNTs in Mn/Fe-TNT@Ti-500 sample is confirmed by XRD and Raman spectroscopy. An anodic shift in the onset potential from 0.2 VRHE to 0.08 VRHE is observed in Mn/Fe-TNT@Ti-500 sample compared to Mn/FeTNT@Ti sample. The overall photocurrent density at −0.4 VRHE is higher for Mn/Fe-TNT@Ti-500 sample (331μA/cm2) than Mn/Fe-TNT@Ti sample (251μA/cm2). The oxygen evolution activity shows similar trend with Mn/Fe-TNT@Ti-500 displaying a photocurrent density of 13.6 μA/cm2 at 1.23 VRHE. The anodic photocurrent density of Mn/Fe-TNT@Ti-500 sample is six times higher than that of the Mn/Fe-TNT@Ti at 0.8 VRHE. The incident photon to current efficiency (IPCE) measurements show that the photon absorption and conversion efficiency of the Mn/Fe-TNT@Ti-500 sample are significantly higher than that of the Mn/Fe-TNT@Ti sample. The results of this study complement the DFT calculations carried out with the generalized gradient approximation (GGA) technique. This work demonstrates possibility of designing composite materials for efficient photoreduction studies using n-type titanium nanotubes as precursors.

Mussel-inspired polydopamine and Zr-porphyrin MOF co-decoration of a cellulose paper-based composite membrane for efficient photoreduction of Cr(VI) and photothermal antibacterial in wastewater

Abundant hazardous pollutants, in particular heavy metal ions and microbes, in aqueous systems seriously threaten ecological safety and human health. Photocatalysis is deemed an appealing solution yet remains challenging to exploit more efficient, economical, and sustainable photocatalytic materials. In this study, we successfully fabricated a cellulose paper-based composite membrane, namely Zr-TCPP@PDA@FP, for photoreduction of Cr(VI) and photothermal antimicrobial. For the resultant composite membrane, the self-polymerization polydopamine (PDA)-coated cellulose fibers act as sustainable scaffolds to anchor the in-situ synthesized porphyrin-doped UiO-66-NH2 (Zr-TCPP) nano-photocatalysts. The hypotheses are that: 1) porphyrin doping in Zr-TCPP can both reinforce the visible-light absorption and the transport of photogenerated electrons; 2) mussel-inspired PDA coating on fiber surface not only services as binder to promote the Zr-TCPP loading and dispersion, but also functions as heterojunction interface to accelerate photogenerated electron separation and transfer from Zr-TCPP; As a result, Zr-TCPP@PDA@FP exhibited significant photocatalytic reduction towards Cr(VI), achieving a removal efficiency of 93.9 % within 20 mins and cycling stability. Besides, the hybrid membrane also featured excellent photothermal antibacterial performance (over 99 % for both E. coli and S. aureus). This work will inspire the development of economic and sustainable cellulose-based functional materials for efficient wastewater remediation.

Step-by-step transfer of photoexcited electron in donor-acceptor-catalyst configuration covalent triazine framework for efficient photoreduction CO2 to formic acid

Covalent triazine frameworks (CTFs) have great potential for photocatalysis. However, the electron-hole recombination and the lack of efficient catalytic sites constrain the activity and selectivity. Herein, a novel design strategy of donor–acceptor-catalyst (D-A-C) configuration is proposed. This configuration enables the photoexcited electron undergoes stepwise transfer from donor unit to acceptor unit and ultimately reaches catalytic center, effectively inhibiting electron-hole recombination. The proof-of-concept model CTF-TT-Ir, in which thieno[3,2-b]thiophene (TT) serves as the donor unit, triazine as the acceptor unit, and Cp*Ir(bpy) (Ir) as the built-in catalytic site, was prepared for the photocatalytic reduction of CO2 to HCOOH. The stepwise transfer of photoexcited electrons in the ternary structure has been demonstrated through the in-situ XPS measurements and the theoretical calculations. Photoluminescence and photocurrent tests have indicated CTF-TT-Ir exhibits superior charge separation efficiency. Without additional photosensitizer and co-catalyst, the photocatalytic HCOOH yield rate of CTF-TT-Ir reached 245 μmol g−1h−1 (selectivity of 97 %).

Versatile MOF-based nanofibrous heterostructures for engineering the CO2 photoreduction activity and selectivity: From CO to C2H5OH

Photocatalytic CO2 reduction is a potential promising strategy for eliminating the global energy crisis and environmental issue. However, the complex reduction pathway leads to multiple possible products with limited efficiency, representing a great barrier for the further development. Herein, we report a Metal-organic framework (MOF) based heterostructure model for the efficient photoreduction of CO2 with full controllable product selectivity between CO and C2H5OH. Novel core-sheath like MOF@TiO2 heterostructures could be efficiently prepared by the layer-by-layer (LBL) growth of HKUST-1 onto Cu-embedded TiO2 nanofibers (NFs), affording covalent heterointerfaces for efficient S-scheme charge separation and promising potential in photocatalytic activity regulation. By improving the CO2 capture and retention via in situ amino-functionalization of HKUST-1, the photocatalytic CO production rate could be greatly promoted from 8.76 ± 0.84 to 43.46 ± 0.86 μmol g−1h−1 accompanied by an enhancement of selectivity from 91.7 % to 98.3 %. Moreover, the product could be efficiently engineered into ethanol with a C2 product selectivity of 94.2 % by introducing Cu nanoparticles (NPs) as the additional CC coupling site. The in situ FT-IR and DFT calculations reveal the mechanistic process and decisive role of amino-functionalization and Cu NPs deposition in photocatalytic activity engineering. This work highlights the key factors and significance of fabricating MOFs based heterostructures with tunable photocatalytic activity for achieving CO2 neutralization.

Surface-Engineered Cesium Lead Bromide Perovskite Nanocrystals for Enabling Photoreduction Activity.

In recent years, colloidal lead halide perovskite (LHP) nanocrystals (NCs) have exhibited such intriguing light absorption properties to be contemplated as promising candidates for photocatalytic conversions. However, for effective photocatalysis, the light harvesting system needs to be stable under the reaction conditions propaedeutic to a specific transformation. Unlike photoinduced oxidative reaction pathways, photoreductions with LHP NCs are challenging due to their scarce compatibility with common hole scavengers like amines and alcohols. In this contribution, it is investigated the potential of CsPbBr3 NCs protected by a suitably engineered bidentate ligand for the photoreduction of quinone species. Using an in situ approach for the construction of the passivating agent and a halide excess environment, quantum-confined nanocubes (average edge length = 6.0 ± 0.8 nm) are obtained with a low ligand density (1.73 ligand/nm2) at the NC surface. The bifunctional adhesion of the engineered ligand boosts the colloidal stability of the corresponding NCs, preserving their optical properties also in the presence of an amine excess. Despite their relatively short exciton lifetime (τAV = 3.7 ± 0.2 ns), these NCs show an efficient fluorescence quenching in the presence of the selected electron accepting quinones (1,4-naphthoquinone, 9,10-phenanthrenequinone, and 9,10-anthraquinone). All of these aspects demonstrate the suitability of the NCs for an efficient photoreduction of 1,4-naphthoquinone to 1,4-dihydroxynaphthalene in the presence of triethylamine as a hole scavenger. This chemical transformation is impracticable with conventionally passivated LHP NCs, thereby highlighting the potential of the surface functionalization in this class of nanomaterials for exploring new photoinduced reactivities.

Enhanced conversion of CO2 into C2H4 on single atom Cu-anchored graphitic carbon nitride: Synergistic diatomic active sites interaction

Single atom metal–nitrogen–carbon materials have emerged as remarkably potent catalysts, demonstrating unprecedented potential for the photo-driven reduction of CO2. Herein, a unique Cu@g-C3N5 catalyst obtained by cooperation of single atom Cu and nitrogen-rich g-C3N5 is proposed. The particular CuN diatomic active sites (DAS) in Cu@g-C3N5 contribute to the formation of highly stable CuOCN adsorption, a key configuration for CO2 activation and CC coupling. The synergistic diatomic active sites interaction is found responsible for the efficient photoreduction of CO2 to C2H4 which has been demonstrated in our Gibbs free energy calculation and COHP analysis. The CO2 activation mechanism was studied, the charge density difference and DOS analysis show that the low oxidation state Cu atom significantly affects the electronic structure of g-C3N5 and then enhance the catalytic activity of CO2 hydrogenation.

Visible-light-driven 2D carbonaceous-based SnSe nanohybrid soft materials: A photocatalyst for efficient photo reduction of malachite green dye

Preserving a healthy environment of air, land, and water requires the treatment of dangerous organic effluents. Efficiently degrading hazardous pollutants requires low-cost, high-absorption visible-light-driven photocatalysts. Furthermore, the tin selenide exhibited a tiny band gap that promotes the faster recombination of electrons and holes, and rGO shows restacking morphology that reduces the surface area of the materials. Both issues have been resolved by adding the rGO into SnSe to make an rGO/SnSe resolving the restacking issue and narrowing the band gap. In this research work, we report a hydrothermally synthesize tin selenide (SnSe) sustained on reduced graphene oxide (rGO) nanosheets as photocatalysts. Our research focuses on the degradation of hazardous industrial malachite green dye. Our analysis suggests that the rGO/SnSe nanocomposite effectively degrades malachite green (MG) dyes by 95.52% compared to pure SnSe (83.52%). The rGO sheets facilitate electron (e-) excitation from the valence band (V.B) to the conduction band (C.B), which significantly enhances the photocatalytic performance. We also investigated the reusability of the photocatalyst and the mineralization activity of a malachite green (MG) pollutant to check the photocatalytic mechanism and stability. The reusability test indicates that rGO/SnSe exhibited excellent 86.45% stability. The scavenger’s analysis suggests that electrons (e-) and holes (h+) play a significant part in the photocatalytic mineralization of MG dye. Our research explores that the rGO/SnSe nanohybrid is a significant material for wastewater treatment, solar energy conversion as well as environmental restoration.

Efficient Photoreduction of CO2 to CO with 100% Selectivity by Slowing Down Electron Transport.

It remains challenging to obtain a single product in the gas-solid photocatalytic reduction of CO2 because CO and CH4 are usually produced simultaneously. This study presents the design of the I-type nested heterojunction TiO2/BiVO4 with controllable electron transport by modulating the TiO2 component. This study demonstrates that slowing electron transport could enable TiO2/BiVO4-4 to generate CO with 100% selectivity. In addition, modifying TiO2/BiVO4-4 by loading a Cu single atom further increased the CO product yield by 3.83 times (17.33 μmol·gcat-1·h-1), while maintaining 100% selectivity for CO. Characterization and density functional theory (DFT) calculations revealed that the selectivity was mainly determined by the electron transport of the support, whereas CO2 was efficiently adsorbed and activated by the Cu single atom. Such a two-step regulation strategy of combining heterojunction with single atom enhances the possibility of simultaneously obtaining high selectivity and high yield in the photocatalytic reduction of CO2.

Construction of Au-modified CN-based donor-acceptor system coupled with dual photothermal effects for efficient photoreduction of carbon dioxide

Conversion of CO2 into high value-added fuels through the photothermal effect is an effective approach for utilizing solar energy. In this study, we prepared the CN-based photocatalyst Py-CTN-Au with both donor-acceptor (D-A) system and dual photothermal effects using a simple two-step method involving calcination and photo-deposition. Real-time monitoring with a thermal imaging camera revealed that Py-CTN-Au0.5 achieved a maximum stable temperature of 180 °C, which was approximately 1.2 times higher than that of Py-CTN (155 °C) and 1.9 times higher than that of g-CN (95 °C) under the same reaction conditions. Under the optimized reaction conditions, Py-CTN-Au0.5 exhibited a CO release rate of 30.59 umol g−1 after 4 h of reaction, which was 7.3 times higher than that of pure g-CN (4.18 umol g−1). The D-A system not only facilitated the separation and transformation of charge carriers but also induced a photothermal effect to accelerate the photoreduction of CO2. Additionally, the cocatalyst Au nanoparticles (Au NPs) further enhanced the charge carrier dynamics and photothermal effect by increasing the built-in electric field intensity and localized surface plasmon resonance (LSPR) effect, respectively. The dual photothermal effects resulting from the non-radiative photon conversion of the D-A structure and the Au NPs LSPR effect, along with the enhanced charge carrier dynamics, catalyzed the efficient photoreduction of CO2. DFT simulations were used to confirm the effect of D-A system and Au NPs. In-situ FTIR results demonstrated that the synergistic photothermal effect promoted the formation of the key intermediate species COOH*, which is beneficial for the photocatalytic reduction of CO2. This study provides valuable insights into the multiple photothermal synergistic effects in photocatalytic reactions.

CQDs-interspersed floral CdS/NiAl-LDH heterojunction towards efficient photoreduction of CO2-to-CO

A series of hierarchical flower-like CdS/carbon quantum dots/NiAl-LDH (CCL) photocatalyst have been successfully prepared to achieve efficient conversion of CO2-to-CO via a simple yet effective hydrothermal method. In the CCL, interspersed-CQDs not only increase the number of reactive sites but also reduce inner electronic impedance with the assistance of light reflecting-scattering effect. This significantly improves electron migration efficiency and inhibits the recombination of photoinduced electron-holes pairs. Without any sacrificial agent or photosensitizer, the sample of CCL-1 exhibits the highest CO evolution rate of 7.04 μmol·g−1·h−1 in water under simulated sunlight illumination with a large specific surface area (129.15 m2 g−1) and an appropriate CQDs content of 15.2 wt%, which is 12.8- and 11.2-fold higher than those of pristine LDH, pure CdS, and many previously reported LDH-based counterparts. A type-Ⅱ interfacial charge transfer mechanism is proposed, where electrons migrate rapidly from CdS to LDH with highly-interspersed CQDs as unhindered electron conduction bridges. The present work outlines a simple and controllable LDH-based heterojunction, which give rise to superior photocatalytic activity for CO2 photoreduction.

Construction of P−N charge-transfer bridge in porous g-C3N4 for highly efficient visible-light-driven photocatalytic N2 fixation

Solar N2 fixation is a green and pollution-free technology to realize solar energy to chemical energy. Here, P doped g-C3N4 nanosheets (PCNx) with porous structure has been fabricated via a one-step calcination process for efficient ammonia generation. The optimal PCN0.6 catalyst provided an improved visible light photo-performance with an ammonia generation rate of 3110 µg L−1h−1g−1, 15 times higher than that for pristine g-C3N4 (CN). And the quantum efficiency at 400 nm monochromatic light reached 3.29%. Characterization results revealed that the implantation of P−N bonds in g-C3N4 resulted in expanded optical response, larger accessible active sites and efficient separation of electron-hole pairs than that of bulk counterpart. Wavefunction contour maps revealed a more localized charge density distribution upon P doping, leading to a favorable electron-rich structure. The calculated N2 adsorption energy and N2-TPD tests showed the strong capacity of nitrogen chem-adsorption by PCN0.6. Charge density differences and Bader charge demonstrated the electrons transfer from the P doping sites of g-C3N4 to adsorbed N2, thus activating N2 molecules for effective NH4+ generation. This work offered significant insights into the heteroatom doping engineering to construct active sites and steer the charge migration pathways in g-C3N4 for efficient photo-reduction of N2.