Photocatalytic Reduction Of N2 Research Articles

The construction of Cs3MoxSbyBr9/BiVO4 S-scheme heterojunction photocatalyst for efficient photocatalytic N2 fixation

Synergistic nitrogen (N2) reduction with water (H2O) oxidation is meaningful but challenging owing to the inertness of the N2 molecule and the sluggish kinetics of H2O oxidation. Herein, a simutaneous-promotion strategy of redox capacities is presented for constructing a lead-free Cs3Sb2Br9-based S-scheme heterojunction, by decorating Mo-functionalized Cs3Sb2Br9 nanocrystals (Cs3MoxSbyBr9) on BiVO4 nanosheet through an in-situ plane-to-point growth manner. The Mo-functionalization for Cs3Sb2Br9 enables the regulation of the d-band center position, greatly improving surface reaction kinetics for N2 reduction. Furthermore, the construction of the S-scheme heterojunction enhances the driving force for H2O oxidation and spatial charge separation of photocatalysts. As anticipated, the resultant Cs3MoxSbyBr9/BiVO4 exhibits an excellent photocatalytic N2 reduction activity under ambient atmosphere, achieving ammonia (NH3) production at a rate of 300 ± 5 μmol g−1 h−1 under simulated sunlight illumination (100 mW cm−2), which is nearly 20-fold higher than that of pristine Cs3Sb2Br9.

Facile fabrication of carbon supported Bi2O3-BiOCl-Bi heterostructure to boost ammonia under visible light

In this paper, carbon supported Bi2O3-BiOCl-Bi heterostructures were successfully synthesized via a facile and simple hydrothermal method. A series of structure and morphology testing clearly showed that carbon and metallic Bi were deposited on the surface margin of Bi2O3-BiOCl, which benefited the rapid transfer of internal photogenerated electrons. Photophysical experiments including electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) indicated that the amount of surface oxygen vacancies (OVs) was significantly increased, which act as reactive active sites and therefore effectively enhance the photocatalytic performance. The photocatalytic N2 reduction yield of C@Bi2O3-BiOCl-Bi was remarkably improved to 400 μg·L−1, which was 3.63 times higher than that of BiOCl. This research demonstrated a feasible strategy to construct advanced photocatalyst by incorporating defect-rich structures and surface engineering.

Coupling of BiOCl Ultrathin Nanosheets with Carbon Quantum Dots for Enhanced Photocatalytic Performance

AbstractOver the past few decades, photocatalysis technology has received extensive attention because of its potential to mitigate or solve energy and environmental pollution problems.Designing novel materials with outstanding photocatalytic activities has become a research hotspot in this field. In this study, we prepared a series of photocatalysts in which BiOCl nanosheets were modified with carbon quantum dots (CQDs) to form CQDs/BiOCl composites by using a simple solvothermal method. The photocatalytic performance of the resulting CQDs/BiOCl composite photocatalysts was assessed by rhodamine B and tetracycline degradation under visible-light irradiation. Compared with bare BiOCl, the photocatalytic activity of the CQDs/BiOCl composites was significantly enhanced, and the 5 wt% CQDs/BiOCl composite exhibited the highest photocatalytic activity with a degradation efficiency of 94.5% after 30 min of irradiation. Moreover, photocatalytic N2 reduction performance was significantly improved after introducing CQDs. The 5 wt% CQDs/BiOCl composite displayed the highest photocatalytic N2 reduction performance to yield NH3 (346.25 μmol/(g h)), which is significantly higher than those of 3 wt% CQDs/BiOCl (256.04 μmol/(g h)), 7 wt% CQDs/BiOCl (254.07 μmol/(g h)), and bare BiOCl (240.19 μmol/(g h)). Our systematic characterizations revealed that the key role of CQDs in improving photocatalytic performance is due to their increased light harvesting capacity, remarkable electron transfer ability, and higher photocatalytic activity sites. Graphical Abstract This work reports a novel CQDs/BiOCl composite photocatalyst for efficiently removing contaminants from water.

Modelling Photocatalytic N2 Reduction: Where We Stand and Where We Are Going.

Artificial ammonia synthesis via the Haber-Bosch process is environmentally problematic due to the high energy consumption and corresponding CO2 emissions, produced during the reaction and before hand in hydrogen production upon methane steam reforming. Photocatalytic nitrogen fixation as a greener alternative to the conventional Haber-Bosch process enables us to perform nitrogen reduction reaction (NRR) under mild conditions, harnessing light as the energy source. Herein, we systematically review first-principles calculations used to determine the electronic/optical properties of photocatalysts, N2 adsorption and to expound possible NRR mechanisms. The most commonly studied photocatalysts for nitrogen fixation are usually modified with dopants, defects, co-catalysts and Z-scheme heterojunctions to prevent charge carrier recombination, improve charge separation efficiency and adjust a band gap to for utilizing a broader light spectrum. Most studies at the atomistic level of modeling are grounded upon DFT calculations, wholly foregoing excitation effects paramount in photocatalysis. Hence, there is a dire need to consider methods beyond DFT to study the excited state properties more accurately. Furthermore, a few studies have been examined, which include higher level kinetics and macroscale simulations. Ultimately, we show there is still ample room for improvement with regard to first principles calculations and their integration in multiscale models.

Bimetallic NH2-MIL-101(Fe, Co) as highly efficient photocatalyst for nitrogen fixation

Developing effective catalysts for N2 photofixation at ambient conditions is highly desirable but still challenging. Herein, we reported a novel Co-doped NH2-MIL-101(Fe) (NM-Fe) bimetallic organic framework (BMOF) for visible-light-driven catalytic N2 fixation. It was found that the doping of Co ions could effectively enhance light-harvesting, reduce the conduction band potential, suppress the recombination of photogenerated carriers, and promote the activation of N2. Consequently, the photocatalytic N2 reduction efficiency of bimetallic NH2-MIL-101(Fe, Co) (NM-Fe-Co) was obviously boosted. The sample with the optical Co/Fe molar ratio of 0.15, namely NM-Fe-0.15Co, enabled an ammonia evolution rate up to 335.7 µmol g−1 h−1 without the aid of any sacrificial agents, a 4.4-fold increase over the monometallic NM-Fe baseline. Additionally, the bimetallic NM-Fe-Co displayed excellent stability. The possible reaction mechanism of nitrogen fixation over NM-Fe-Co was proposed based on in-situ infrared analysis. Our study demonstrates a promising strategy for designing potent MOF-based catalysts for N2 photofixation.

Engineering of local electron properties optimization in single-atom catalysts enabling sustainable photocatalytic conversion of N2 into NH3

Photocatalytic synthesis of ammonia (NH3) from nitrogen (N2) offers a promising strategy for carbon neutrality, as it avoids the energy-intensive and carbon-emitting industrial processes. The exploration of high-efficiency N2 photofixation systems for photocatalytic N2 reduction reaction (pNRR) is critical but it remains a challenge since the lack of rational structural design and atomic-level insights into molecular N2 activation mechanism. Herein, an atomically dispersed single-atom palladium (Pd) active sites decorated oxygen-deficient molybdenum oxide (Pd/MoO3-x) was creatively designed for assessing pNRR performance. Interestingly, the integration of single-atom Pd active sites in MoO3-x can significantly weaken the N≡N bond of adsorbed N2 and effectively lower the activation energy barrier during the pNRR process. This is attributed to the fact that the modified Pd single-atom sites of Pd/MoO3-x play a dominant role in the N2 spontaneous adsorption process as well as possess a remarkable photogenerated electron trapping ability, which could be assisted to inject electrons into N2 antibonding orbital, thus significantly accelerates the reaction kinetics. Consequently, the Pd/MoO3-x photocatalyst reaches an impressive NH3 yield rate of 103.2 μggcat.−1h−1, which is superior to that of pristine MoO3-x (21.2 μggcat.−1h−1) and commercial MoO3 (6.5 μggcat.−1h−1), respectively. The present study not only creates a reliable approach to expand efficient N2 photofixation system under mild conditions through the fabrication of atomically dispersed monometallic active sites, but also offers atomic-level insights into the underlying mechanism of pNRR catalytic process.

Fast Joule heating for transformation of Fe-MIL-125(Ti) to Fe/TiO2 with enhanced photocatalytic activity in N2 fixation

It is critical to develop a highly efficient catalyst for the photocatalytic fixation of nitrogen to produce ammonia under ambient conditions. Herein, we reported on a fast Joule heating (FJH) method to synthesize 1.0 wt% Fe-doped TiO2 (JH Fe/TiO2) derived from MIL-125(Ti). For comparison, Fe/TiO2 calcined in a tube furnace was also prepared (TF Fe/TiO2). The photocatalytic production rate of ammonia on JH Fe/TiO2 was increased to 56.87 μmol g−1 h−1, which was 1.5 times higher than that of TF Fe/TiO2. As detected, FJH might lead to the formation of lattice defects with oxygen vacancies (OVs) formation. These OVs and defects had the potential to act as adsorption and reactive sites for N2. Furthermore, in-situ infrared (FT-IR) along with Density Functional Theory (DFT) simulation were applied to study the possible reaction pathways of photocatalytic reduction of N2. As calculated, the substitution of Feδ+ for Ti4+ with the formation of Fe-Ti dual active sites synergistically interacted with the OVs to facilitate the photocatalytic reduction process. Moreover, an alternative pathway was more favorable for the production of NH3. The reasonable design of Fe-doped transition metal oxides and the proposed Fe-Ti dual active sites opened a new approach for highly efficient photocatalytic N2 fixation.

Bi2WO6 Incorporation of g‐C3N4 to Enhance the Photocatalytic N2 Reduction Reaction and Antibiotic Pollutants Removal

Synthesis of ammonia from photocatalytic N2 reduction is challenging due to the fast recombination of electron–hole pairs and the low selectivity of N2 on catalysts. This can be addressed by creating heterojunctions to separate the photogenerated carriers adequately. In this regard, BW/g‐C3N4 is synthesized and the weight percentage of g‐C3N4 is varied. The best photocatalytic activity for N2 reduction reaction (N2RR) is achieved with a ratio of BW/gC3N4 in 3.5:2 ratio, deemed to be the optimized heterojunction. N2‐temperature programmed desorption analysis shows outstanding chemisorption of N2 adsorbed on the BW/g‐C3N4 surface compared to pristine g‐C3N4 and BW. Additionally, forming a heterojunction enhances the charge transfer process and well‐separated electron–hole pairs, significantly boosting the water oxidation process on the catalytic surface. Photoelectrochemical analysis reveals that BW/g‐C3N4 exhibits the shortest hole relaxation lifetime and higher current density than its pristine counterparts. The robust contact between g‐C3N4 and BW reduces the work function of BW/g‐C3N4 based on ultraviolet photoelectron spectroscopy data. Ammonia production with the optimized BW/gC3N4‐3.5:2 is 5.3 and 2.1 times higher than pure g‐C3N4 and Bi2WO6, respectively. Meanwhile, BW/g‐C3N4 demonstrates excellent photocatalytic activity toward antibiotic pollutant degradation as well. After 150 min of visible light irradiation, the removal of 94% ciprofloxacin (CIP) is observed. Finally, a possible mechanism is proposed for photocatalytic N2RR and CIP degradation.

Fluorinated phosphonium ionic liquid boosts the N2-adsorbing ability of TiO2 for efficient photocatalytic NH3 synthesis

A novel ionic liquid ([P4,4,4,4][PF6])–water reaction solution system was constructed, transforming the TiO2−x surface to aerophilic. N2 dissolution and adsorption were promoted, greatly improving N2 fixation performance.

Construction of a BiVO4/VS-MoS2 S-scheme heterojunction for efficient photocatalytic nitrogen fixation.

Photocatalytic nitrogen (N2) reduction to ammonia (NH3), adopting H2O as the electron source, suffers from low efficiency owing to the sluggish kinetics of N2 reduction and the requirement of a substantial thermodynamic driving force. Herein, we present a straightforward approach for the construction of an S-scheme heterojunction of BiVO4/VS-MoS2 to successfully achieve photocatalytic N2 fixation, which is manufactured by coupling an N2-activation component (VS-MoS2 nanosheet) and water-oxidation module (BiVO4 nanocrystal) through electrostatic self-assembly. The VS-MoS2 nanosheet, enriched with sulfur vacancies, plays a pivotal role in facilitating N2 adsorption and activation. Additionally, the construction of the S-scheme heterojunction enhances the driving force for water oxidation and improves charge separation. Under simulated sunlight irradiation (100 mW cm-2), BiVO4/VS-MoS2 exhibits efficient photocatalytic N2 reduction activity with H2O as the proton source, yielding NH3 at a rate of 132.8 μmol g-1 h-1, nearly 7 times higher than that of pure VS-MoS2. This study serves as a noteworthy example of efficient N2 reduction to NH3 under mild conditions.

Au Nanoparticle-Loaded UiO-66 Metal–Organic Framework for Efficient Photocatalytic N2 Fixation

In order to achieve efficient photocatalytic N2 reduction activity for ammonia synthesis, a photochemical strategy was used in this work. UiO-66 was prepared through the solvothermal method and further loaded with Au nanoparticles (Au NPs) onto the UiO-66 (Zr) framework. The experimental results verified that there were metal–support interactions between Au NPs and UiO-66; this could facilitate charge transfer among Au NPs and UiO-66, which was beneficial to enhance the photocatalytic activity. The best N2 fixation effect of Au/UiO-66 with a loading of 1.5 wt% was tested, with a photocatalytic yield of ammonia of 66.28 μmol g−1 h−1 while maintaining good stability. The present work provides a novel approach to enhancing photocatalytic N2 fixation activity by loading NPs onto UiO-66.

Defects-Induced Single-Atom Anchoring on Metal-Organic Frameworks for High-Efficiency Photocatalytic Nitrogen Reduction.

Aiming to improve the photocatalytic activity in N2 fixation to produce ammonia, herein, we proposed a photochemical strategy to fabricate defects, and further deposition of Ru single atoms onto UiO-66 (Zr) framework. Electron-metal-support interactions (EMSI) were built between Ru single atoms and the support via a covalently bonding. EMSI were capable of accelerating charge transfer between Ru SAs and UiO-66, which was favorable for highly-efficiently photocatalytic activity. The photocatalytic production rate of ammonia improved from 4.57 μmol g-1  h-1 to 16.28 μmol g-1  h-1 with the fabrication of defects onto UiO-66, and further to 53.28 μmol g-1  h-1 with Ru-single atoms loading. From the DFT results, it was found that d-orbital electrons of Ru were donated to N2 π✶-antibonding orbital, facilitating the activation of the N≡N triple bond. A distal reaction pathway was probably occurred for the photocatalytic N2 reduction to ammonia on Ru1 /d-UiO-66 (single Ru sites decorated onto the nodes of defective UiO-66), and the first step of hydrogenation of N2 was the reaction determination step. This work shed a light on improving the photocatalytic activity via feasibly anchoring single atoms on MOF, and provided more evidences to understand the reaction mechanism in photocatalytic reduction of N2 .

Defects‐Induced Single‐Atom Anchoring on Metal–Organic Frameworks for High‐Efficiency Photocatalytic Nitrogen Reduction

AbstractAiming to improve the photocatalytic activity in N2 fixation to produce ammonia, herein, we proposed a photochemical strategy to fabricate defects, and further deposition of Ru single atoms onto UiO‐66 (Zr) framework. Electron‐metal‐support interactions (EMSI) were built between Ru single atoms and the support via a covalently bonding. EMSI were capable of accelerating charge transfer between Ru SAs and UiO‐66, which was favorable for highly‐efficiently photocatalytic activity. The photocatalytic production rate of ammonia improved from 4.57 μmol g−1 h−1 to 16.28 μmol g−1 h−1 with the fabrication of defects onto UiO‐66, and further to 53.28 μmol g−1 h−1 with Ru‐single atoms loading. From the DFT results, it was found that d‐orbital electrons of Ru were donated to N2 π✶‐antibonding orbital, facilitating the activation of the N≡N triple bond. A distal reaction pathway was probably occurred for the photocatalytic N2 reduction to ammonia on Ru1/d‐UiO‐66 (single Ru sites decorated onto the nodes of defective UiO‐66), and the first step of hydrogenation of N2 was the reaction determination step. This work shed a light on improving the photocatalytic activity via feasibly anchoring single atoms on MOF, and provided more evidences to understand the reaction mechanism in photocatalytic reduction of N2.

Multifunctional metal (Ag, Bi)-organic frameworks: a versatile platform for photocatalytic degradation, CO2 and N2 reduction, and enhanced antibacterial applications

The facile synthesis of a bimetallic-organic framework is successfully established to portray an efficient catalyst in photocatalytic degradation and photoreduction of nitrogen (N2) and carbon dioxide (CO2) and with antibacterial properties. In the current study, a novel B-BTC (where B represents Ag and Bi) organic framework was successfully synthesized and opted for advanced characterizations. The high-resolution transmission electron microscopy and X-ray photon spectroscopy illustrate the heterostructure formation, whereas X-ray diffraction spectroscopy, zeta sizer, and zeta potential were used to reveal the crystallinity, polydispersity, and average size of the nanomaterial. The material was characterized for photoluminescence analysis to understand the recombination rate and has been compared with the Bi-organic framework. B-BTC was further opted to determine the photocatalytic efficacy, through photocatalytic degradation of amoxicillin (AMX), photocatalytic reduction of N2 to ammonia (NH3), photoreduction of CO2, and antibacterial disinfection. The catalyst showcased ∼90% degradation of AMX under light-emitting diode light irradiation for 60 min. Successful photoreduction of N2 and CO2 showcases a fair generation of NH3 and value-added hydrocarbons, respectively. For each photocatalytic application, a mechanism has been knitted for understanding the overall reactions concerning the proposed reactions. Interestingly, the catalyst also showcased excellent antibacterial activity toward Escherichia coli and Staphylococcus aureus, with a proposed mechanism.

Efficient photocatalytic nitrogen fixation over novel 2D/2D Bi12O17Br2/ZnCr layered double hydroxide heterojunction

Herein, a novel ultrathin 2D/2D heterostructure, Bi12O17Br2 with oxygen vacancies/ZnCr layered double hydroxides (Vo-Bi12O17Br2/ZnCr-LDHs, Vo-BZ) is prepared by solvothermal and coprecipitation methods for photocatalytic reduction of N2 to NH3. The optimal 2D/2D Vo-BZ heterostructure photocatalyst shows production rate of ammonia production of 286.0 μmol·g−1·h−1. It is 12.5 and 3.6 times higher than that of pure ZnCr-LDHs and Vo-Bi12O17Br2. The improved photocatalytic nitrogen reduction performance is attributed to the intimate contact interface, matching bandgap structure, the shortened migration distance, and thus significantly improved separation and transfer efficiency of hole-electron pairs and light adsorption ability. The large number of oxygen vacancies and high specific surface promote the absorption, activation and deionization of N2 molecules. The theoretical simulation calculation indicates that the free energy of nitrogen molecules on the surface of Vo-BZ is favorable for the absorption and activation of N2 molecules. The existence of oxygen vacancies and formation of heterojunctions can dramatically reduce energy barrier of nitrogen molecule hydrogenation process to boost photocatalytic N2 reduction. This study provides a new idea for the development of efficient photocatalytic nitrogen fixing catalysts.

One‐step supramolecular pre‐organizational synthesis of copper‐doped porous carbon nitride for high photocatalytic nitrogen fixation

AbstractSolar‐driven reduction of nitrogen to ammonia is a promising green approach and is considered as a sustainable alternative to the Haber–Bosch process. Carbon nitride (g‐C3N4) is an ideal non‐metallic semiconductor photocatalyst for photocatalytic N2 reduction reaction (p‐NRR). In this work, we designed a simple supramolecular self‐assembly method to prepare copper‐doped porous graphitic nitride (Cu@pg‐C3N4) photocatalysts. The synergistic semiconductor and metal interactions enabled the obtained Cu@pg‐C3N4 to achieve larger specific surface area, more efficient photogenerated carrier separation, and stronger photoreduction ability. The specific surface area of Cu@pg‐C3N4 increased from 5.69 to 75.76 μmol/L, exposing more active sites compared to bulk g‐C3N4. The NH4+ production rate of the obtained Cu@pg‐C3N4 was 150.47 μmol/L, which is 20 times higher than that of the bulk carbon nitride, exhibiting excellent N2 photofixation ability. These findings highlight the significant progress that can be achieved by metal supramolecular network modification strategies in harnessing the potential of carbon nitride for photocatalytic reduction applications.

Electro- and Photocatalytic Conversion of N2 to NH3 by Chemically Modified Transition Metal Dichalcogenides, MoS2, and WS2

Electro- and photocatalytic reduction of N2 to NH3—the nitrogen reduction reaction (NRR)—is an environmentally- and energy-friendly alternative to the Haber-Bosch process for ammonia production. There is a great demand for the development of novel semiconductor-based electrocatalysts with high efficiency and stability for the direct conversion of inert substrates—including N2 to ammonia—using visible light irradiation under ambient conditions. Herein we report electro-, and photocatalytic NRR with transition metal dichalcogenides (TMDCs), viz MoS2 and WS2. Improved acid treatment of bulk TMDCs yields exfoliated TMDCs (exTMDCs) only a few layers thick with ∼10% S vacancies. Linear scan voltammograms on exMoS2 and exWS2 electrodes reveal significant NRR activity for exTMDC-modified electrodes, which is greatly enhanced by visible light illumination. Spectral measurements confirm ammonia as the main reaction product of electrocatalytic and photocatalytic NRR, and the absence of hydrazine byproduct. Femtosecond-resolved transient absorption studies provide direct evidence of interaction between photo-generated excitons/trions with N2 adsorbed at S vacancies. DFT calculations corroborate N2 binding to exMoS2 at S-vacancies, with substantial π-backbonding to activate dinitrogen. Our findings suggest that chemically functionalized exTMDC materials could fulfill the need for highly-desired, inexpensive catalysts for the sustainable production of NH3 using Sunlight under neutral pH conditions without appreciable competing production of H2.

Electronic metal-support interaction via defective-induced platinum modified BiOBr for photocatalytic N2 fixation

Designing atomic-scale catalytic sites to facilitate N2 adsorption and transport of photogenerated electrons to the target active sites offers new opportunities to achieve highly-efficiently photocatalytic N2 reduction reactions. Herein, Pt was photodeposited on BiOBr along with formation of oxygen vacancies (OVs) under ultraviolet light. The modulation of chemical states of Pt and the formation of electron metal-support interactions (EMSI) between BOB and Pt facilitated the charge transfer between the modifiers (i.e. Pt and OVs) and the support (i.e. BiOBr). The production rate of ammonia on Pt and OVs co-modified BiOBr reached 23.8 μmol g−1 h−1, which was much higher than that either on OVs-BiOBr or pristine BiOBr. Density functional theory (DFT) calculations showed that EMSI effect led to a significant charge redistribution between Pt and BOBr carriers, whereby Pt doping could significantly reduce energy barrier of N2 hydrogenation process to facilitate photocatalytic N2 reduction.

Semiconducting Quantum Dots for Energy Conversion and Storage

AbstractSemiconducting quantum dots (QDs) have received huge attention for energy conversion and storage due to their unique characteristics, such as quantum size effect, multiple exciton generation effect, large surface‐to‐volume ratio, high density of active sites, and so on. However, the holistic and systematic understanding of the energy conversion and storage mechanism centering on QDs in specific application is still lacking. Herein, a comprehensive introduction of these extraordinary 0D materials, e.g., metal oxide, metal dichalcogenide, metal halides, multinary oxides, and nonmetal QDs, is presented. It starts with the synthetic strategies and unique properties of QDs. Highlights are focused on the rational design and development of advanced QDs‐based materials for the various applications in energy‐related fields, including photocatalytic H2 production, photocatalytic CO2 reduction, photocatalytic N2 reduction, electrocatalytic H2 evolution, electrocatalytic CO2 reduction, electrocatalytic N2 fixation, electrocatalytic O2 evolution, electrocatalytic O2 reduction, solar cells, metal‐ion batteries, lithium–sulfur batteries, metal–air batteries, and supercapacitors. At last, challenges and perspectives of semiconducting QDs for energy conversion and storage are detailedly proposed.

Recent progress in research and design concepts for the characterization, testing, and photocatalysts for nitrogen reduction reaction

AbstractThe reduction of molecular nitrogen (N2) to ammonia (NH3) under mild conditions is one of the most promising studies in the energy field due to the important role of NH3 in modern industry, production, and life. The photocatalytic reduction of N2 is expected to achieve clean and sustainable NH3 production by using clean solar energy. To date, the new photocatalysts for photocatalytic reduction of N2 to NH3 at room temperature and atmospheric pressure have not been fully developed. The major challenge is to achieve high light‐absorption efficiency, conversion efficiency, and stability of photocatalysts. Herein, the methods for measuring produced NH3 are compared, and the problems related to possible NH3 pollution in photocatalytic systems are mentioned to provide accurate ideas for measuring photocatalytic efficiency. The recent progress of nitrogen reduction reaction (NRR) photocatalysts at ambient temperature and pressure is summarized by introducing charge transfer, migration, and separation in photocatalytic NRR, which provides guidance for the selection of future photocatalyst selection. More importantly, we introduce the latest research strategies of photocatalysts in detail, which can guide the preparation and design of photocatalysts with high NRR activity.