Efficient Separation Of Photogenerated Charges Research Articles

Construction of Ag3PO4/g-C3N4 Z-Scheme Heterojunction Composites with Visible Light Response for Enhanced Photocatalytic Degradation.

Ag3PO4/g-C3N4 photocatalytic composites were synthesized via calcination and hydrothermal synthesis for the degradation of rhodamine B (RhB) in wastewater, and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and diffuse reflectance spectroscopy (DRS). The degradation of RhB by Ag3PO4/g-C3N4 composites was investigated to evaluate their photocatalytic performance and cyclic degradation stability. The experimental results showed that the composites demonstrated notable photocatalytic activity and stability during degradation. Their high degradation efficiency is attributed to the Z-scheme transfer mechanism, in which the electrons in the Ag3PO4 conduction band and the holes in the g-C3N4 valence band are annihilated by heterojunction recombination, which greatly limits the recombination of photogenerated electrons and holes in the catalyst and enhances the activity of the composite photocatalyst. In addition, measurements of photocurrent (PC) and electrochemical impedance spectroscopy (EIS) confirmed that the efficient charge separation of photo-generated charges stemmed from strong interactions at the close contact interface. Finally, the mechanism for catalytic enhancement in the composite photocatalysts was proposed based on hole and radical trapping experiments, electron paramagnetic resonance (EPR) analysis, and work function evaluation.

Visible Light-Activated Room Temperature NO2 Gas Sensing Based on the In2O3@ZnO Heterostructure with a Hollow Microtube Structure.

The persistent challenge of poor recovery characteristics of NO2 sensors operated at room temperature remains significant. However, the development of In2O3-based gas sensing materials provides a promising approach to accelerate response and recovery for sub-ppm of NO2 detection at room temperature. Herein, we propose a simple two-step method to synthesize a one-dimensional (1D) In2O3@ZnO heterostructure material with hollow microtubes, by coupling metal-organic frameworks (MOFs) (MIL-68 (In)) and zinc ions. Meanwhile, the In2O3@ZnO composite-based gas sensor exhibits superior sensitivity performance to NO2 under visible light activation. The response value to 5 ppm of NO2 at room temperature is as high as 1800, which is 35 times higher than that of the pure In2O3-based sensor. Additionally, the gas sensor based on the In2O3@ZnO heterostructure demonstrates a significantly reduced response/recovery time of 30 s/67 s compared to the sensor based on pure In2O3 (74 s/235 s). The outstanding gas sensing properties of the In2O3@ZnO heterostructure-based sensors can be attributed to the enhanced photogenerated charge separation efficiency resulting from the heterostructure effect, and the improved receptor function toward NO2, which can increase the reactive sites and gas adsorption capacity. In summary, this work proposes a low-cost and efficient method to synthesize a 1D heterostructure material with microtube structures, which can serve as a fundamental technique for developing high-performance room-temperature gas sensors.

Coupling Cu Coordination Polymers with CdS Forming an S-Scheme Heterojunction for Rapid Charge Separation and High Photocatalytic Activity.

Energy and the environment are significant impacting factors for the future development of humankind. In order to improve the corrosion resistance of CdS and decrease the recombination of photogenerated carriers, a novel Cu-CPs@CdS heterojunction with high efficiency mesopores was constructed by a simple hydrothermal method. The effective interfacial contact formation between nano-CdS and Cu-CPs promotes the transfer of photogenerated carriers while exhibiting a high spatial separation rate of charges. The photocatalytic performance of the heterojunction was evaluated by the photocatalytic degradation of organic pollutants and photocatalytic hydrogen generation. The photocatalytic degradation of ciprofloxacin (CIP) could reach 90.34%, and the hydrogen generation was high as 9227.82 μmol·g-1 under simulated sunlight irradiation. The boosted photocatalytic activity of Cu-CPs@CdS results from (i) the formation of coordination bonds, which not only enhanced the stability of heterojunctions but also provided a path for photogenerated carrier migration, (ii) integrating Cu-CPs, which provided more active sites, and (iii) the matched energy band structure between CdS and Cu-CPs that promoted speedy S-scheme interfacial charge-transfer pathways, culminating in efficient photogenerated charge separation and transfer. This research offered a fresh tactic to restrict photocorrosion and enhance the production of photocatalytic H2 over CdS-based catalysts.

Heterojunction composites of covalent organic frameworks grown on the surface of persistent luminescent nanoparticles for photocatalytic hydrogen evolution and degradation of organic pollutants

Covalent organic frameworks (COFs) have shown great promise for photocatalytic hydrogen evolution from water and photocatalytic degradation of organic pollutants. However, a single COFs suffers from poor photogenerated charge separation efficiency. In this study, we synthesized persistent luminescent nanoparticles (PLNPs)@COFs composites with core–shell heterostructures by the in situ growth of COFs on the surface of PLNPs. The PLNPs@COFs composites demonstrated better photocatalytic performance than pure PLNPs and COFs. The hydrogen production rate of PLNPs@COFs (1:6) was about 35 mmol h−1 g−1, and the photodegradation efficiency of Rhodamine B by PLNPs@COFs (3:1) reached 100 % in 50 min. Evidently, the combination of COFs with PLNPs to form a core–shell heterostructure with a tight contact interface can effectively improve the photogenerated charge separation efficiency. Our covalent bonding and in situ growth approach is more conducive to the formation of stable core-shell heterostructures. A good match between the persistent luminescence emission spectrum of the PLNPs and the absorption range of the COFs improves the potential of PLNPs@COFs to function as a round-the-clock photocatalyst. This strategy holds excellent promise in the efficient use of solar photocatalytic hydrogen evolution and in environmental purification in the future.

Cu-Al co-doped BiFeO3 photo-fenton synergy for highly efficient degradation of organic pollutant

Cu-Al co-doped bismuth ferrite catalyst (Cu-Al-BFO) was prepared by hydrothermal method. The strong interaction between Cu-Al and BFO formed in the Cu-Al-BFO catalyst not only improved the stability of the catalyst, but also enhanced the photo-generated charge separation efficiency. The photocurrent of the composite catalyst is 6.3 times higher than that of BFO. In addition, Cu-Al co-doping effectively improves the electronic structure of the catalyst and promotes the generation of hydroxyl oxygen, which enhances the degradation activity of the catalyst. The 5 %Cu-Al-BFO catalyst for photo-fenton synergistic degradation of pollutants was up to 99 %, which is 93 % higher than that of BFO.

Insights into the function of metallic 1T phase tungsten disulfide as cocatalyst decorated zinc indium sulfide for enhanced photocatalytic hydrogen production activity

Improving the separation efficiency of carriers is an important part of enhancing photocatalytic activity. Herein, we successfully decorated metallic 1T phase tungsten disulfide (1T-WS2) on the surface of zinc indium sulfide (ZnIn2S4) and investigated the synergistic effect of 1T-WS2 on ZnIn2S4. The characterization results show that 1T-WS2 improves the light absorption capacity and utilization efficiency, increases the catalytic active site, improves the photogenerated charge separation efficiency, and optimizes the reduction potential of ZnIn2S4. Theoretical calculations show that compared with ZnIn2S4, 1T-WS2/ZnIn2S4 has a smaller adsorption Gibbs free energy of the intermediate state H*, which is conducive to the catalytic reaction. Under simulated solar irradiation, the hydrogen (H2) production rate of 1T-WS2/ZnIn2S4 with a loading of 12 wt% reaches 30.90 mmol h−1 g−1, which is 3.38 times higher than that of single ZnIn2S4 (9.13 mmol h−1 g−1). In addition, the apparent quantum efficiency of 1T-WS2/ZnIn2S4 with a loading of 12 wt% reaches 21.14 % under monochromatic light at a wavelength of λ = 370 nm. This work analyzes the light absorption and carrier separation to the catalytic site, and elucidates the mechanism for the enhancement of the photocatalytic hydrogen production performance.

Efficient Proton Transfer and Charge Separation within Covalent Organic Frameworks via Hydrogen-Bonding Network to Boost H2O2 Photosynthesis.

Photocatalytic synthesis based on the oxygen reduction reaction (ORR) has shown great promise for H2O2 production. However, the low activity and selectivity of 2e- ORR result in a fairly low efficiency of H2O2 production. Herein, we propose a strategy to enhance the proton-coupled electron transfer (PCET) process in covalent organic frameworks (COFs), thereby significantly boosting H2O2 photosynthesis. We demonstrated that the construction of a hydrogen-bonding network, achieved by anchoring the H3PO4 molecular network on COF nanochannels, can greatly improve both proton conductivity and photogenerated charge separation efficiency of COFs. Thus, COF@H3PO4 exhibited superior photocatalytic performance in generating H2O2 without sacrificial agents, with a solar-to-chemical conversion efficiency as high as 0.69%. Results indicated that a much more localized spatial distribution of energy band charge density on COF@H3PO4 led to efficient charge separation, and the small energy barrier of the rate-limiting step from *OOH to H2O2 endowed COF@H3PO4 with higher 2e- ORR selectivity.

Enhanced Light Absorption and Photo-Generated Charge Separation Efficiency for Boosting Photocatalytic H2 Evolution through TiO2 Quantum Dots with N-Doping and Concomitant Oxygen Vacancy.

Low-range light absorption and rapid recombination of photo-generated charge carriers have prevented the occurrence of effective and applicable photocatalysis for decades. Quantum dots (QDs) offer a solution due to their size-controlled photon properties and charge separation capabilities. Herein, well-dispersed interstitial nitrogen-doped TiO2 QDs with stable oxygen vacancies (N-TiO2-x-VO) are fabricated by using a low-temperature, annealing-assisted hydrothermal method. Remarkably, electrostatic repulsion prevented aggregation arising from negative charges accumulated in situ on the surface of N-TiO2-x-VO, enabling complete solar spectrum utilization (200-800 nm) with a 2.5 eV bandgap. Enhanced UV-vis photocatalytic H2 evolution rate (HER) reached2757µmol g-1 h-1, 41.6 times higher than commercial TiO2 (66µmol g-1 h-1). Strikingly, under visible light, HER rate was 189µmol g-1 h-1. Experimental and simulated studies of mechanisms reveal that VO can serve as an electron reservoir of photo-generated charge carriers on N-doped active sites, and consequently, enhance the separation rate of exciton pairs. Moreover, the negative free energy (-0.35 V) indicates more favorable thermodynamics for HER as compared with bulk TiO2 (0.66 V). This research work paves a new way of developing efficient photocatalytic strategies of HER that are applicable in the sustainable carbon-zero energy supply.

0D/2D dual Fenton α-Fe2O3/Fe-doped g-C3N4 photocatalyst and the synergistic photo-Fenton catalytic mechanism insight

A novel dual Photo-Fenton photocatalyst Fe2O3–Fe–CN with excellent Fe(III)/Fe(II) conversion efficiency and trace metal ion leaching rate has been fabricated by in-situ deposition of α-Fe2O3 quantum dots on ultrathin porous Fe-doped carbon nitride (Fe–CN) nanosheets. The iron species in Fe–CN and α-Fe2O3 QDs constitute a mutually reinforcing dual Photo-Fenton effect. The 4% Fe2O3–Fe–CN showed superior performance with kobs values 8.60 and 4.80 folders greater than pure CN and Fe–CN, respectively. The synergistic effect between α-Fe2O3 QDs and the ultrathin porous structure of Fe–CN is the primary reason for the outstanding catalytic performance exhibited by α-Fe2O3/Fe–CN. On one hand, the ultrathin porous structure of Fe–CN promotes the rapid transfer of photogenerated electrons. On the other hand, the efficient photogenerated charge separation at the α-Fe2O3/Fe–CN interface enables more photogenerated electrons to participate in the Fe3+/Fe2+ conversion and H2O2 activation. The trapping experiments demonstrate that •OH and •O2− are the primary active species in TC degradation. This work presents novel insights into the design of efficient heterogeneous Fenton catalysts for practical applications.

Ternary heterojunction of cross-linked benzene Polymer/Bi2MoO6-Graphene oxide catalysts promote efficient adsorption and photocatalytic removal of oxytetracycline

Antibiotics are refractory degradable organic pollutants that present a significant hazard to water environments. In this work, a ternary composite (KB/BMO-GO) comprising of graphene oxide (GO), Bi2MoO6 (BMO), and a cross-linked benzene polymer (KB) was synthesized and applied to promote the synergistic adsorption-photocatalytic degradation of the refractory pollutant, oxytetracycline (OTC). The inclusion of GO and KB in the composite enhanced the OTC adsorption performance of the catalysts, and the construction of Z-scheme heterojunction promoted the photogenerated charge separation efficiency and broadened the range of light absorption, thereby enhancing the photocatalytic performance. Moreover, we compared the performance of catalysts loaded with different mass ratios of KB (x% KB/BMO-GO). Among them, the 15 % KB/BMO-GO catalyst sample had the best OTC degradation performance. Specifically, 15 % KB/BMO-GO could adsorb 69.7 % of OTC in 30 min, reaching an OTC degradation rate of 93.3 % under visible light irradiation. h+ and 1O2 are the main active substances in the photocatalytic process. In addition, the catalysts are acid-alkali and salt-resistant, as well as good reusability. This study provides a valuable reference for the preparation of highly efficient photocatalysts for synergistic adsorption-photodegradation processes.

S-scheme heterojunction Cu-porphyrin/TiO2 nanosheets with highly efficient photocatalytic reduction of CO2 in ambient air

Directly capturing CO2 in ambient air and converting it into value-added fuels using photocatalysis is a potentially valuable technology. In this study, Cu-porphyrin (tetrakis-carboxyphenyl porphyrin copper, CuTCPP) was innovatively anchored on the surface of TiO2 (titanium dioxide) nanosheets to form an S-scheme heterojunction. Based on this, a photocatalytic reaction system for stably converting CO2 in ambient air into value-added fuels at the gas–solid interface was constructed without addition of sacrificial agents and alkaline liquids. Under the illumination of visible light and sunlight, the evolution rate of CO is 56 μmol·g−1·h−1 and 73 μmol·g−1·h−1, respectively, with a potential CO2 conversion rate of 35.8 % and 50.4 %. The enhanced of photocatalytic performance is attributed to the introduction of CuTCPP, which provides additional active sites, significantly improves capture capacity of CO2 and the utilization of electrons. Additionally, the formation of S-scheme heterojunction expands the redox range and improves the separation efficiency of photo-generated charges.

Enhanced photocatalytic ammonia oxidation over WO3@TiO2 heterostructures by constructing an interfacial electric field

WO3 nanorods and xWO3@TiO2 (WO3/TiO2 mass ratio (x) = 1−5) photocatalysts were synthesized using the hydrothermal and sol-gel methods, respectively. The photocatalytic activities of xWO3@TiO2 for NH3 oxidation first increased and then decreased with a rise in TiO2 content. Among them, the heterostructured 3WO3@TiO2 photocatalyst showed the highest NH3 conversion (58 %) under the simulated sunlight irradiation, which was about two times higher than those of WO3 and TiO2. Furthermore, the smallest amounts of by-products (i.e., NO and NO2) were produced over 3WO3@TiO2. The enhancement in photocatalytic performance (i.e., NH3 conversion and N2 selectivity) of 3WO3@TiO2 was mainly attributed to the formed interfacial electric field between WO3 and TiO2, which promoted efficient separation and transfer of photogenerated charge carriers. Based on the results of reactive species trapping and active radical detection, photocatalytic oxidation of NH3 over 3WO3@TiO2 was governed by the photogenerated holes and superoxide radicals. This work combines two strategies of morphological regulation and interfacial electric field construction to simultaneously improve light utilization and photogenerated charge separation efficiency, which promotes the development of full-spectrum photocatalysts for the removal of ammonia.

Amine-Rich Hydrogels for Molecular Nanoarchitectonics of Photosystem II and Inverse Opal TiO2 toward Solar Water Oxidation.

Solar water oxidation is a crucial process in light-driven reductive synthesis, providing electrons and protons for various chemical reductions. Despite advances in light-harvesting materials and cocatalysts, achieving high efficiency and stability remains challenging. In this study, we present a simple yet effective strategy for immobilizing natural photosystems (PS) made of abundant and inexpensive elements, using amine-rich polyethylenimine (PEI) hydrogels, to fabricate organic/inorganic hybrid photoanodes. Natural PS II extracted from spinach was successfully immobilized on inverse opal TiO2 photoanodes in the presence of PEI hydrogels, leading to greatly enhanced solar water oxidation activity. Photoelectrochemical (PEC) analyses reveal that PS II can be immobilized in specific orientations through electrostatic interactions between the positively charged amine groups of PEI and the negatively charged stromal side of PS II. This specific orientation ensures efficient photogenerated charge separation and suppresses undesired side reactions such as the production of reactive oxygen species. Our study provides an effective immobilization platform and sheds light on the potential utilization of PS II in PEC water oxidation.

Amino Acid Modified Hyper‐Cross‐Linked Polymer Enabling High‐efficient Photocatalytic Amines Oxidation Coupled with H2O2 Production

AbstractThe simultaneous production of imine and hydrogen peroxide (H2O2) via photocatalytic aerobic amine oxidation is a bright way to obtain value added products, however, rapid recombination of photogenerated charge leads to low conversion efficiency and selectivity. Herein, a metal‐free amino acid modified hyper‐cross‐linked polymer (H3LP‐HCPs) photocatalyst was synthesized for photocatalytic amines oxidation by regulating the ratio of L‐phenylalanine (L‐Phe) and hexaphenylbenzene (Hex). The results showed that the H3LP‐HCPs photocatalyst with 1 : 3 molar ratio of L‐Phe and Hex achieves close to 100 % conversion efficiency and 100 % selectivity toward benzylamine oxidation under 455 nm blue LED lamp irradiation. Furthermore, a high yield of H2O2 (9.2 mmol ⋅ gcat−1 ⋅ h−1) was synchronously obtained in benzylamine oxidation. Experiments and time‐dependent density functional theory calculation results revealed that the N‐functional groups in H3LP‐HCPs photocatalyst not only remarkably broadens light‐response range, but also facilitates electrons transfer from L‐Phe to the Hex, thus accelerating photogenerated charge separation efficiency and the formation of reactive oxygen species (ROS).

Facile synthesis of self-nitrogen-doped carbon spheres for high-efficient photocatalytic CO2 reduction to CO

In this work, self-nitrogen-doped carbon microsphere photocatalysts were prepared by hydrothermal and carbonation pyrolysis with first application in photocatalytic CO2 reduction. Coupled with relevant characterization, nitrogen-doped carbon microspheres were successfully prepared and the introduction of nitrogen significantly improved the photogenerated charge separation efficiency and CO2 photoreduction to CO activity, leading to the highest photocatalytic reduction activity with a CO yield of 185.71 μmol g−1 (9 h) under simulated sunlight irradiation. More importantly, its performance remains at about 98 % after ten consecutive cycle tests, indicating the excellent active stability of self-nitrogen-doped carbon spheres. Possible mechanisms for photocatalytic reduction and the role of nitrogen in photocatalytic adsorption and reduction processes are analyzed and proposed. The research provides novel strategies for the design of bifunctional catalysts that offer robust adsorption and efficient reduction, enabling the sustainable conversion of CO2.

Enhanced Charge Transfer Process and Photocatalytic Activity over a Phosphonate-based MOF via Amorphization Strategy.

Recently, amorphous materials have gained great attention as an emerging kind of functional material, and their characteristics such as isotropy, absence of grain boundaries, and abundant defects are very likely to outrun the disadvantages of crystalline counterparts, such as low conductivity, and ultimately lead to improved charge transfer efficiency. Herein, we investigated the effect of amorphization on the charge transfer process and photocatalytic performance with a phosphonate-based metal-organic framework (FePPA) as the research object. Comprehensive experimental results suggest that compared to crystalline FePPA, amorphous FePPA has more distorted metal nodes, which affects the electron distribution and consequently improves the photogenerated charge separation efficiency. Meanwhile, the distorted metal nodes in amorphous FePPA also greatly promote the adsorption and activation of O2. Hence, amorphous FePPA exhibits a better performance of photocatalytic C(sp3)-H bond activation for selective oxidation of toluene to benzaldehyde. This work illustrates the advantages of amorphous MOFs in the charge transfer process, which is conducive to the further development of high performance MOFs-based photocatalysts.

Enhanced Charge Transfer Process and Photocatalytic Activity over a Phosphonate‐based MOF via Amorphization Strategy

AbstractRecently, amorphous materials have gained great attention as an emerging kind of functional material, and their characteristics such as isotropy, absence of grain boundaries, and abundant defects are very likely to outrun the disadvantages of crystalline counterparts, such as low conductivity, and ultimately lead to improved charge transfer efficiency. Herein, we investigated the effect of amorphization on the charge transfer process and photocatalytic performance with a phosphonate‐based metal–organic framework (FePPA) as the research object. Comprehensive experimental results suggest that compared to crystalline FePPA, amorphous FePPA has more distorted metal nodes, which affects the electron distribution and consequently improves the photogenerated charge separation efficiency. Meanwhile, the distorted metal nodes in amorphous FePPA also greatly promote the adsorption and activation of O2. Hence, amorphous FePPA exhibits a better performance of photocatalytic C(sp3)−H bond activation for selective oxidation of toluene to benzaldehyde. This work illustrates the advantages of amorphous MOFs in the charge transfer process, which is conducive to the further development of high performance MOFs‐based photocatalysts.

Promoting the carrier mobility of Nb2SiTe4 through cation coordination engineering

Ternary two-dimensional (2D) monoclinic Nb2SiTe4 has garnered significant attention for its potential applications in anisotropic photoelectronics. Yet, its intrinsic indirect bandgap nature and low hole mobility, attributed to the short Nb–Nb dimer configurations, hinder the efficient photogenerated carrier separation and transport. In this Letter, using density functional theory calculations, we demonstrate the interlayer intercalation of Si results in the formation of a metastable orthorhombic Nb2SiTe4 structure devoid of detrimental short Nb–Nb dimers. Notably, this Si intercalation leads to a remarkable reduction of hole effective masses of orthorhombic Nb2SiX4 (X = S, Se, and Te), a crucial factor for achieving high carrier mobility. Taking the orthorhombic Nb2SiTe4 monolayer as an example, the calculated hole mobility (>100 cm2 V−1 s−1) is comparable in magnitude to the respectable hole mobility observed in multiple layers of the monoclinic Nb2SiTe4. To simultaneously enhance electron and hole mobility, we establish a van der Waals junction between the monoclinic and orthorhombic Nb2SiTe4 structures, achieving high and comparable carrier mobilities. The Nb2SiTe4 junction exhibits a nearly direct bandgap of 0.35 eV, rendering it suitable for infrared light harvesting. Furthermore, carriers within the Nb2SiTe4 junction become spatially separated across different layers, resulting in an intrinsic built-in electric field, which is superior for efficient photo-generated charge separation and decreases the potential nonradiative carrier recombination. Our findings highlight the impact of cation coordination engineering on the electronic and optical properties of 2D Nb2SiTe4 and provide a feasible solution to achieve better carrier transport in low-dimensional photovoltaic functionalities.

Self-Powered and Broadband Photodetectors Based on High-performance Mixed Dimensional Sb2O3/PdTe2/Si Heterojunction for Multiplex Environmental Monitoring.

Solar-blind ultraviolet (SBUV) to near-infrared (NIR) broadband photodetectors (BB-PD) have important applications in environmental monitoring and other applications. However, it is challenging to prepare SBUV-IR photosensitive materials via simple steps and to construct SBUV-IR broadband devices for multiplex detection with high sensitivity at different wavelengths. Here, self-powered and broadband photodetectors using a high-performance mixed dimensional Sb2O3 nanorod 1-dimension (1D)/monodisperse microdiamond-like PdTe2 3-dimension (3D)/Si (3D) heterojunction for multiplex detection of environmental pollutants with high sensitivity at broadband wavelength are developed. The 1D/3D mixed dimensional Sb2O3/PdTe2/Si structure combines the advantages of strong light absorption, high carrier transport efficiency of 1D Sb2O3 nanorods, and expansion of interface barrier caused by 3D microdiamond-like PdTe2 interlayer to improve the photocurrent density and self-powered ability. The efficient photogenerated charge separation enables anon/off ratio of more than 5×106. The device exhibits excellent photoelectric properties from 255 to 980nm with the responsivity from 4.56×10-2 to 6.55×10-1AW-1, the detectivity from 2.36×1012 to 3.39×1013Jones, and the sensitivity from 3.90×107 to 1.10×1010cm2W-1 without external bias. Finally, the proposed device is applied for the multiplex monitoring of environmental pollution gases NO2 with the detection limit of 200ppb and PM2.5 particles at mild pollution at broadband wavelength. The proposed BB-PD has great potential for multiplex detection of environmental pollutants and other analytes at broadband wavelength.

Stabilizing electron-rich Ni single-atoms on black phosphorus nanosheets boosts photocatalytic carbon dioxide reduction

The development of unique single-atom catalysts with electron-rich feature is essential to promoting the photocatalytic CO2 reduction, yet remains a big challenge. Here, a conceptionally new single-atom catalyst constructed from atomically dispersed Ni–P3 species on black phosphorus (BP) nanosheets (BP-Ni) is synthesized for realizing highly efficient visible-light-driven CO2 reduction when trapping photogenerated electrons from homogeneous light absorbers in the presence of triethanolamine as the sacrificial agent. Both the experimental and theoretical calculation data reveal that the Ni–P3 species on BP nanosheets own the electron-rich feature that can improve the photogenerated charge separation efficiency and lower the activation barrier of CO2 conversion. This unique feature makes BP-Ni exhibit the much higher activity as cocatalyst in the photocatalytic CO2 reduction than BP nanosheets. The BP-Ni can also be applied as a cocatalyst for enhanced photocatalytic CO2 reduction after combining with CdSe/S colloidal crystal photocatalyst. The present study offers valuable inspirations for the design and construction of effective catalytic sites toward photocatalytic CO2 reduction reactions.