Slow Photon Effect Research Articles

Coupling Bifunctional Scaffolds with Slow Photon Effect for Synergistically Enhanced Photoassisted Lithium-Sulfur Battery Properties.

Photoassisted lithium-sulfur (Li-S) batteries offer a promising approach to enhance the catalytic transformation kinetics of polysulfide. However, the development is greatly hindered by inadequate photo absorption and severe photoexcited carriers recombination. Herein, a photonic crystal sulfide heterojunction structure is designed as a bifunctional electrode scaffold for photoassisted Li-S batteries. Inverse opal (IO) structures utilize a slow photon effect that originates from their adjustable photonic band gaps, giving them distinctive optical response characteristics. The incorporation of a SnS/ZnS heterojunction within these IO frameworks further broadens the light absorption spectrum and enhances the charge transfer process. This efficient IO hybrid bifunctional electrode not only enhances the adsorption and conversion of polysulfides at the cathode but also induces uniform Li nucleation at the anode. These contribute the full batteries to output a high reversible capability of 1072 mAh g-1 and maintain stable cycling for 50 cycles. Additionally, a specific capacity of 698.8 mAh g-1 is still obtained even under a sulfur loading of up to 4 mg cm-2. The present strategy on SnS/ZnS IO to enhance photoassisted Li-S battery properties can be extended to rationally construct other energy storage devices.

Vertical flow immunoassay for multiplex mycotoxins based on photonic nitrocellulose and SERS nanotags.

Here, we report a SERS based VFA using PNC as a sensing substrate for highly sensitive multiplex mycotoxins detection. The PNC was fabricated by filtration-based self-assembled monodisperse SiO2 NPs on a filter membrane as a template, and the obtained PNC had an ordered complementary inverse opal structure. In parallel, three kinds of Raman dyes encoding Au@NBAAg, Au@4-MBAAg and Au@DNTBAg SERS nanotags were synthesized for the detection of OTA, AFB1 and ZON. In the immunoassay, because of the slow-photon effect of the PNC substrate, which facilitates the light coupling with SERS nanotags, the SERS signal was highly enhanced. The LODs of 8.2, 13.7 and 47.6fgmL-1 were achieved for simultaneous detection of OTA, AFB1 and ZON, respectively, which were lower than the tolerable cutoff values recommended by the EC. Therefore, this proposed PNC based SERS VFA is expected to be a powerful method for multiplex mycotoxins detection.

ZIF-8-CdS photonic crystal beads for slow photon effect induced enhanced photocatalysts

The unique periodic structure of photonic crystals demonstrates an effective slow photon effect that enhances the interaction between light and matter. This study designed and prepared MOF photonic crystal beads, and significantly improved the photocatalytic efficiency by utilizing the slow light effect. Utilizing microfluidic technology, ZIF-8 was self-assembled to form photonic crystal beads (PCB-Z) to enhance adsorption properties and light absorption. The surface of PCB-Z is modified with CdS to form a heterostructure (PCB-ZC), which widens the absorption spectrum, reduces the carrier recombination rate, and increases the specific surface area, while the photocurrent intensity of PCB-ZC is about 1.8 and 29 times that of CdS and PCB-Z. Under the combined effect of photonic crystal structure, ZIF-8/CdS heterojunction and slow photon effect, the degradation rate of Rhodamine B by PCB-ZC was 15.22 times higher than the disordered ZIF-8 powder, and the photocatalytic performance was significantly improved. The dominant role of holes in Rhodamine B degradation was confirmed by free radical trapping experiments and EPR tests. This research confirms that MOF-based photonic crystals can be assembled into periodic structures to enhance adsorption properties and light absorption, which provides a new paradigm for the development of MOF-based photocatalysts.

Advances in hybrid strategies for enhanced photocatalytic water splitting: Bridging conventional and emerging methods

Significant efforts have been dedicated to hydrogen production through photocatalytic water splitting (PWS) over the past five decades. However, achieving commercially viable solar-to-hydrogen conversion efficiency in PWS systems remains elusive. These systems face intrinsic and extrinsic challenges, such as inadequate light absorption, insufficient charge separation, limited redox active sites, low surface area, and scalability issues in practical designs. To address these issues, conventional strategies including heterojunction engineering, plasmonics, hybridization, lattice defects, sensitization, and upconversion processes have been extensively employed. More recently, innovative hybrid strategies like photonic crystal-assisted and polarization field-assisted PWS have emerged, which improve light absorption and charge separation by harnessing the slow photon effect, multiple light scattering, and the piezoelectric, pyroelectric, and ferroelectric properties of materials. This review article aims to provide a comprehensive examination and summary of these new synergistic hybrid approaches, integrating plasmonic effects, upconversion processes, and photonic crystal photocatalysis. It also explores the role of temperature in suppressing exciton recombination during photothermic photocatalysis. This article also highlights emerging strategies such as the effects of magnetic fields, periodic illumination, many-body large-hole polaron, and anapole excitations, which hold significant potential to advance PWS technology and facilitate renewable hydrogen generation.

Semiconductor Nanoporous Anodic Alumina Photonic Crystals as a Model Photoelectrocatalytic Platform for Solar Light‐Driven Reactions

In this study, nanoporous anodic alumina distributed‐Bragg reflectors (NAA–DBRs) functionalized with tungsten trioxide (WO3) are used as prototype photoelectrocatalysts (PEC) for harnessing the slow photon effect to maximize photon‐to‐electron conversion efficiency under UV–visible–NIR illumination. NAA–DBR structures are structurally engineered by anodization, where their characteristic photonic stopband is precisely tuned along specific positions of the UV–visible spectrum. Subsequent atomic layer deposition is employed to coat the inner surface of these porous structures with WO3 semiconductor layers. Upon the application of overpotential bias, these platforms reveal excellent electron–hole pair separation to boost photoelectrocatalytic reactions. Photoelectrochemical degradation of methylene blue is used as a model reaction to elucidate enhancements associated with structural and optoelectronic arrangements. Notably, precise spectral alignment between the photonic stopband's red edge and the absorbance band of methylene blue enhances the degradation performance through the slow photon effect. Applying an overpotential bias further improves the photodegradation performance through efficient charge separation. These systems outperform comparable structures in this model reaction, achieving a maximum kinetic rate of 13.7 ± 2.0 h−1. The findings create new opportunities to develop high‐performing PEC technologies harnessing light–matter interactions.

A Stable Perovskite Sensitized Photonic Crystal P-N Junction with Enhanced Photoelectrochemical Hydrogen Production.

The slow photon effect in inverse opal photonic crystals represents a promising approach to manipulate the interactions between light and matter through the design of material structures. This study introduces a novel ordered inverse opal photonic crystal (IOPC) sensitized with perovskite quantum dots (PQDs), demonstrating its efficacy for efficient visible-light-driven H2 generation via water splitting. The rational structural design contributes to enhanced light harvesting. The sensitization of the IOPC with PQDs improves optical response performance and enhances photocatalytic H2 generation under visible light irradiation compared to the IOPC alone. The designed photoanode exhibits a photocurrent density of 3.42 mA cm-2 at 1.23 V vs RHE. This work advances the rational design of visible light-responsive photocatalytic heterostructure materials based on wide band gap metal oxides for photoelectrochemical applications.

Hydroxyl Defects-Mediated Hydrolytic Activation of Peroxydisulfate Under Nanoconfinement: Role of Lewis Basic Sites for Altering the Photosensitized Species and Pathways.

Herein, the pivotal mechanism of defect engineering-mediated triazine-based conjugated polymers (TCPs) is comprehensively elucidated for photosensitized activation of peroxydisulfate (PDS) under nanoconfinement by encapsulating the defective polymer framework into the nanochannel of SBA-15 (d-TCPs@SBA-15). The incorporated hydroxyl defects (-OH defects) substantially accelerate the accumulation of electrons at -OH defects, forming the Lewis basic sites. Due to the facilitated elongation of the S─O bond and reduced energy barrier of SO5* generation, the captured PDS undergo prehydrolysis process, oxidized into O2 - and 1O2 by surrounding h+, thereby setting apart from the conventional reductive activation of SO4 -/•OH generation occurred in pristine TCPs (p-TCPs). Crucially, this work represents a pioneering effort in exploring the PDS activation pathway upon the defective polymer under the nanoconfinement to leverage kinetic merits of slow photon effect and reactive oxygen species (ROSs) enrichment, and the novel prehydrolysis activation mechanism involved may catalyze the rational design of photocatalysts featuring Lewis-acid/base centers.

Synthesis of Doped g‐C3N4 Photonic Crystals for Enhanced Light‐Driven Hydrogen Production from Catalytic Water‐Splitting

Dopants are frequently used to improve graphitic carbon nitride (gCN) photoactivity. As a doping source, phosphomolybdic acid (PMA) can activate doping sites inside the gCN lattice, resulting in 2D Mo:P‐gCN porous material. However, the gradual loading of the PMA fraction has no systematic improvement in the Mo:P‐gCN photoactivity. For improving the optoelectronic properties of Mo:P‐gCN, its textural geometry is a controllable parameter that can provide enhanced photonic properties, achievable by shaping its morphology through a crystalline template structure, namely, photonic crystals (PCs). Herein, a doped PC material is made of Mo:P‐gCN and PCs and labeled as Mo:P‐gCN/PCs. The impact of PCs is highlighted in the structural, electronic, and optical performances of Mo:P‐gCN. A well‐defined 3D crystalline network is evidenced by microscopic measurements (scanning electron microscopy, AFM, focused ion beam). Mo:P‐gCN/PCs shows a hydrogen production rate (750 μmol g−1 h−1) one time higher than Mo:P‐gCN and 6 times higher than pure gCN. The synthesis strategy proposed in this work leads simultaneously to the Mo:P codoping effect provided by PMA and the slow photon effect due to the PC structure, offering a novel strategy to improve the gCN photoactivity by simultaneously applying polyoxometalates as modifiers and polystyrene opals as templates.

Preparation of Ag@Au core-shell nanoparticles embedded in TiO2 inverse opal for light harvesting and efficiency enhancement in quantum dot sensitized solar cells

In the fabrication of Quantum dot sensitized solar cells (QDSSCs), it is important to fabricate a photoanode with a high ability to trap photons as well as transfer photogenerated electrons. TiO2 inverse opal (TIO) photonic crystals with their organized porous structures, besides their chemical nature, have unique optical features such as the slow-photon effect, photon localization, and photonic bandgap (PBG). Herein, to improve the efficiency of QDSSCs, gold, silver, and silver/gold core-shell (Ag@Au) plasmonic nanoparticles (nps) are loaded on TIO. The plasmonic nanoparticle-decorated inverse opal improves the light scattering process and provides direct charge transfer tunnels, which can effectively prevent the recombination of electron-hole pairs. In this work, fabricated QDSSCs with TIO (double-layer)/ZnS/CdS/CdSe/ZnSe/ZnS photoanode, and a 6 μm total thickness of the TIO multilayer, has an open circuit voltage (Voc) of 0.745 V and short-circuit current density (JSC) of 16.22 mA/cm2. The obtained results are higher than the common anatase TiO2 (TiO2-A)/ rutile TiO2 (TiO2-R)/QD photoanode. Also, the TIO (double-layer)/Ag@Au/QDs photoanode exhibits JSC=20.3283 mA/cm2, Voc= 0.75 V, and a power conversion efficiency (PCE) of ƞ=10.79 %.

Ti[sbnd]F bridged IL-CuCQDs-F/TiO2 inverse opal composite for boosting CO2 visible-photo reduction via slow photon effect

Photocatalytic reduction of CO2 exhibits unsatisfactory photocatalytic performance owing to the inefficient separation of photogenerated electron-hole pairs, low CO2 capture efficiency and limited visible light absorption on most photo-catalysts. Herein, TiF bridged IL-CuCQDs-F/TiO2 inverse opal composite (IO-CFTi) was constructed for boosting CO2 visible-photo reduction via slow photo effect. In this work, ethylenediaminetetraacetic acid (EDTA(Cu)) and imidazole ionic liquid 1-(2-Hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([HOEtMIM][BF4]) were employed to confine grow of IL-CuCQDs-F within TiO2 inverse opal supporter via TiF bonds connection. Unique IL-CuCQDs-F efficiently expended light absorption towards visible region, and the confined growth of IL-CuCQDs-F within the TiO2 inverse opal cavity achieved the photoelectric conversion and efficient CO2 capture. Moreover, their TiF bonding interface of IO-CFTi assisted photogenerated electron transportation from TiO2 to CO2 for its reduction in this system. Consequently, IO-CFTi achieved a substantially increased CO production rate of 78.1 μmol·h−1·g−1 with 98 % selectivity. This improved performance in CO2 photoreduction positions the nanocomposite as a promising material for preservation of the environment and conversion of energy.

Photothermal Oxidation of Volatile Organic Compounds Over Co3O4‐Based Inverse Opal

AbstractThe growing preference for photothermal catalysis stems from its minimal energy consumption and heightened catalytic efficacy. Nonetheless, material photon utilization efficiency is frequently hindered by catalyst structural design constraints and bandgap limitations. Herein, we present a Co3O4‐based inverse opal featuring a three‐dimensional ordered macroporous (3DOM‐Co3O4) architecture tailored for photothermal VOCs oxidation. The 3DOM‐Co3O4 exhibits superior catalytic performance in carbon monoxide oxidation, methane oxidation, and toluene oxidation, with a photothermal enhancement of more than 100 %. Further experimental and theoretical analyses reveal that the three‐dimensional periodic array of pores facilitates the slow photon effect, augmenting the light absorption capabilities of the catalyst. Thus, it generates more photoexcited electrons, promoting VOCs molecular activation. Additionally, the well‐ordered porous structure facilitates the diffusion of reactants and products, further accelerating the catalytic reaction. This work highlights promising prospects for leveraging inverse opals as an innovative strategy towards enhancing photothermal catalytic VOCs oxidization efficiency.

Enhanced Photocatalytic Properties and Photoinduced Crystallization of TiO2-Fe2O3 Inverse Opals Fabricated by Atomic Layer Deposition.

The use of solar energy for photocatalysis holds great potential for sustainable pollution reduction. Titanium dioxide (TiO2) is a benchmark material, effective under ultraviolet light but limited in visible light utilization, restricting its application in solar-driven photocatalysis. Previous studies have shown that semiconductor heterojunctions and nanostructuring can broaden the TiO2's photocatalytic spectral range. Semiconductor heterojunctions are interfaces formed between two different semiconductor materials that can be engineered. Especially, type II heterojunctions facilitate charge separation, and they can be obtained by combining TiO2 with, for example, iron(III) oxide (Fe2O3). Nanostructuring in the form of 3D inverse opals (IOs) demonstrated increased TiO2 light absorption efficiency of the material, by tailoring light-matter interactions through their photonic crystal structure and specifically their photonic stopband, which can give rise to a slow photon effect. Such effect is hypothesized to enhance the generation of free charges. This work focuses on the above-described effects simultaneously, through the synthesis of TiO2-Fe2O3 IOs via multilayer atomic layer deposition (ALD) and the characterization of their photocatalytic activities. Our results reveal that the complete functionalization of TiO2 IOs with Fe2O3 increases the photocatalytic activity through the slow photon effect and semiconductor heterojunction formation. We systematically explore the influence of Fe2O3 thickness on photocatalytic performance, and a maximum photocatalytic rate constant of 1.38 ± 0.09 h-1 is observed for a 252 nm template TiO2-Fe2O3 bilayer IO consisting of 16 nm TiO2 and 2 nm Fe2O3. Further tailoring the performance by overcoating with additional TiO2 layers enhances photoinduced crystallization and tunes photocatalytic properties. These findings highlight the potential of TiO2-Fe2O3 IOs for efficient water pollutant removal and the importance of precise nanostructuring and heterojunction engineering in advancing photocatalytic technologies.

Highly efficient and sustainable photocatalytic Fenton reactions utilizing catalyst-embedded inverse-opal structured membranes

The inverse opal (IO) structure, known for its photonic crystal properties and uniform pores, promotes multiple internal light scatterings and reflections. This leads to a decrease in photon group velocity, generating a slow photon effect. When integrated with photocatalysts, this effect enhances light absorption by extending photon interaction with the catalyst, thereby significantly enhancing the efficacy of IO structures in photocatalytic applications. However, the integration of inorganic photocatalysts into IO structures presents challenges, such as mechanical brittleness and a tendency to form powders. To overcome these obstacles, we have engineered IO-structured polymeric membranes coated with graphitic carbon nitride tailored for photocatalytic Fenton reactions. These membranes, which encapsulate photocatalysts within the polymeric porous IO framework, facilitate the straightforward reaction and separation of catalysts from byproducts. They demonstrated superior photocatalytic performance, as evidenced by Rhodamine B degradation (∼7.1 %) and benzene hydroxylation (∼7.3 %). Extensive durability (>30 days) and recyclability tests (>5 times) confirmed their robustness, establishing their utility for various organic conversion reactions. By combining the advantages of the IO structure with tailored photocatalytic properties, these membranes offer promising potential for sustainable and efficient water treatment and the production of fine chemicals in industrial settings.

Fabrication of ZnO–Al2O3 inverse opals with atomic layer deposited Amorphous-Al2O3 for enhanced photocatalysis

Zinc oxide inverse opal (IO) has excellent photocatalytic properties, while Al2O3 has high chemical stability and negligible photocatalytic activity. However, combining these materials creates a crystalline ZnO-amorphous Al2O3 composite IO photonic crystal material with improved photocatalytic performance. In this study, ZnO IO and ZnO–Al2O3 combined structures were grown on self-assembled polystyrene (PS) nanosphere templates. ZnO layer was coated by thermal atomic layer deposition (TALD) in the pores of the template, and the template was then removed by annealing to yield a self-standing ZnO IO nanostructure. An ultra-thin film of Al2O3 was coated on the top of ZnO IO by TALD or plasma-enhanced ALD (PEALD). SEM imaging, Raman spectroscopy, and XRD analysis confirmed the presence of a periodically arranged, and wurtzite ZnO IO structure, with an amorphous Al2O3 layer on top. The UV–Vis results demonstrated distinctive absorption bands in both regions, with a notable increase in visible light absorption attributed to the slow photon effect within the near-bandgap region of the photonic materials. The ZnO/Al2O3-TALD photocatalyst exhibited enhanced photocatalytic performance in degrading various pollutants including methylene blue, rhodamine 6G, and 4-nitrophenol under visible light illumination compared to its pristine IO and PEALD composite counterparts. This is attributed to its periodic arrangement of the IO structure that acts as a photonic crystal, precisely controlling light interaction through photonic band gap manipulation and the slow photon effect. This tailored light manipulation within the visible spectrum significantly enhances photodegradation efficiency.

High-efficiency solar-driven H2 generation by three-dimensionally ordered macroporous heterojunction structure

Development of high-efficiency photocatalyst for solar-driven hydrogen (H2) generation still encounters significant challenges. The biomimetic materials with a multistage structure are advantageous for enhancing light harvesting and utilization, as well as facilitating the efficient separation of photon-generated electron-hole pairs, thus play a crucial role in improving photocatalytic efficiency. Herein, the present study demonstrates the design of ZnIn2S4-TiO2 (ZIS/T) biomimetic multistage heterostructure with three-dimensionally ordered macroporous (3DOM) structure for efficient H2 generation. The optimal ZIS/T heterostructure photocatalyst by carefully regulating the interface structure exhibits the superior H2 generation rate of 9.05 mmol·h−1·g−1, surpassing the rates observed in 3DOM TiO2 and ZnIn2S4 samples by 11 and 4.1 times, respectively. The significantly improved photocatalytic efficiency was primarily attributed to the unique multistage structure that provide with abundant reactive sites and excellent mass transfer ability. Furthermore, the slow photon effect induced by the particular 3DOM multistage heterojunctions promote separation of photon-generated carriers. This resultant work provides a novel strategy for the construction of photo-confined heterojunction photocatalysts with enhanced photocatalytic performance through interfacial engineering.

Slow Photonic Effect Inducing Improved H2 Generation in Photonic Films with Chiral Nematic Structure

AbstractIntegrating photonic crystals (PCs) into the design of a photocatalyst can significantly enhance its light‐harvesting capability. PCs can manipulate the propagation of light uniquely within a material and reduce its group velocity, thereby enhancing the absorption factor for photocatalysts. However, the slow photon effect in photoactive films with chiral nematic structures has not been reported yet, especially at the blue edge of the photonic bandgap. This work proposes a straightforward one‐pot method to fabricate various photonic films with chiral nematic, namely g‐C3N4/SiO2, TiO2/SiO2, and g‐C3N4/TiO2/SiO2. The sol‐gel biotemplating formulation using cellulose nanocrystals successfully leads to the elaboration of films exhibiting variable iridescent colors with photonic bandgap from UV to visible range. The tunable wavelength of the Bragg peak reflection offers the opportunity to access a region with a slow photonic effect, which directly impacts the light‐harvesting properties of the photoactive material. It is demonstrated that the H2 generation is significantly enhanced when the blue edge of the photonic bandgap position overlapped with the absorbance band of the photocatalyst. These results offer the opportunity to design photonic materials with chiral nematic structure and optimize the photocatalytic performance for energy application.

Construction of Inverse-Opal ZnIn2S4 with Well-Defined 3D Porous Structure for Enhancing Photocatalytic H2 Production.

The conversion of solar energy into hydrogen using photocatalysts is a pivotal solution to the ongoing energy and environmental challenges. In this study, inverse opal (IO) ZnIn2S4 (ZIS) with varying pore sizes is synthesized for the first time via a template method. The experimental results indicate that the constructed inverse opal ZnIn2S4 has a unique photonic bandgap, and its slow photon effect can enhance the interaction between light and matter, thereby improving the efficiency of light utilization. ZnIn2S4 with voids of 200 nm (ZIS-200) achieved the highest hydrogen production rate of 14.32 μ mol h-1. The normalized rate with a specific surface area is five times higher than that of the broken structures (B-ZIS), as the red edge of ZIS-200 is coupled with the intrinsic absorption edge of the ZIS. This study not only developed an approach for constructing inverse opal multi-metallic sulfides, but also provides a new strategy for enriching efficient ZnIn2S4-based photocatalysts for hydrogen evolution from water.

Photon Management Enabled by Opal and Inverse Opal Photonic Crystals: from Photocatalysis to Photoluminescence Regulation.

Light is a promising renewable energy source and can be converted into heat, electricity, and chemical energy. However, the efficiency of light-energy conversion is largely hindered by limited light-absorption coefficients and the low quantum yield of current-generation materials. Photonic crystals (PCs) can adjust the propagation and distribution of photons because of their unique periodic structures, which offers a compelling platform for photon management. The periodicity of materials with an alternating refractive index can be used to manipulate the dispersion of photons to generate the photonic bandgap (PBG), in which light is reflected. The slow photon effect, i. e., photon propagation at a reduced group velocity near the edges of the PBG, is widely regarded as another valuable optical property for manipulating light. Furthermore, multiple light scattering can increase the optical path, which is a vital optical property for PCs. Recently, the light reflected by PBG, the slow photon effect, and multiple light scattering have been exploited to improve light utilization efficiency in photoelectrochemistry, materials chemistry, and biomedicine to enhance light-energy conversion efficiency. In this review, the fabrication of opal or inverse opal PCs and the theory for improving the light utilization efficiency of photocatalysis, solar cells, and photoluminescence regulation are discussed. We envision photon management of opal or inverse opal PCs may provide a promising avenue for light-assisted applications to improve light-energy-conversion efficiency.

Enhanced antibiofilm photodynamic therapy: Leveraging the slow photon effect for maximized efficacy with minimal photosensitizer and light doses

The persistent and recurrent nature of biofilm infections, coupled with their increased resistance to antibiotics, poses a significant health risk. Photodynamic therapy has emerged as a promising strategy against biofilms, and it is crucial to fully harness the optimal potential of photosensitizers for generating reactive oxygen species (ROS) in order to prevent the development of resistance through insufficient ROS induction. The present study describes the fabrication of a photodynamic platform through the conjugation of photosensitizer chlorine e6 (Ce6) into inverse opal photonic crystal (IOPC) with a matching photonic band edge. The resulting slow photon effect of IOPC improves the light-harvesting capacity of Ce6 and ensures a 370% enhancement in the production of high levels of ROS at low Ce6 dosage (nanomolar levels) and light intensity (3 mW cm−2). In vitro experiments demonstrate that IOPC enhances the photodynamic antibiofilm efficacy of Ce6 by an impressive 375%. Furthermore, in vivo experiments confirm that IOPC expedites wound healing in mice infected with biofilm through photodynamic treatment. This work provides valuable insights into the phenomenon of slow photon effect in enhancing photodynamic therapy and presents a recommended design principle for achieving efficient antibiofilm treatment.

Au@ZnS core–shell nanoparticles decorated 3D hierarchical porous TiO2 photocatalysts for visible-light-driven CO2 reduction into CH4

Hereby, the core–shell structured Au@ZnS nanoparticles were precipitated on three-dimensionally ordered macro-mesoporous TiO2 (Au@ZnS/3DOMm-TiO2) by GBMR/P method. The slow photon effect of 3DOM structure leads to increase the light trapping and absorption efficiency. The hierarchical porous structure improves the specific surface area of the carrier, providing a larger internal void for desorption of reaction products and additional activation sites for the CO2 reduction. In the all-solid Z-scheme system, electrons are transferred along the direction from TiO2 to Au and finally to the surface of ZnS is realized to participate in the reaction of CO2 reduction. Under irradiation of visible light, ternary Au@ZnS/3DOMm-TiO2-2 catalyst exhibits the highest catalytic activity for CO2 photoreduction with H2O, i.e., the formation rate and selectivity of CH4 product is 33.2 µmol g-1h−1 and 91.5 %, respectively. The design of Z-scheme heterojunctions on 3D macro-mesoporous oxide surfaces are expected to expand new ideas for the preparation of efficient photocatalysts.