Green Synthetic Fuels: Renewable Routes for the Conversion of Non-Fossil Feedstocks into Gaseous Fuels and Their End Uses

Innovative renewable routes are potentially able to sustain the transition to a decarbonized energy economy. Green synthetic fuels, including hydrogen and natural gas, are considered viable alternatives to fossil fuels. Indeed, they play a fundamental role in those sectors that are difficult to electrify (e.g., road mobility or high-heat industrial processes), are capable of mitigating problems related to flexibility and instantaneous balance of the electric grid, are suitable for large-size and long-term storage and can be transported through the gas network. This article is an overview of the overall supply chain, including production, transport, storage and end uses. Available fuel conversion technologies use renewable energy for the catalytic conversion of non-fossil feedstocks into hydrogen and syngas. We will show how relevant technologies involve thermochemical, electrochemical and photochemical processes. The syngas quality can be improved by catalytic CO and CO2 methanation reactions for the generation of synthetic natural gas. Finally, the produced gaseous fuels could follow several pathways for transport and lead to different final uses. Therefore, storage alternatives and gas interchangeability requirements for the safe injection of green fuels in the natural gas network and fuel cells are outlined. Nevertheless, the effects of gas quality on combustion emissions and safety are considered.

Polaronic structure of excess electrons and holes for a series of bulk iron oxides

With the use of a gap-optimized hybrid functional and large supercells, it is found that while the electron hole polaron generally localises onto a single iron site, the electron polaron localises across two iron sites of the same spin layer.

Study of the GaAs/SiH van der Waals type-II heterostructure: a high efficiency photocatalyst promoted by a built-in electric field

The built-in electric field promotes GaAs/SiH as a high efficiency photocatalyst for water splitting in visible light.

Photoelectrocatalytic production of solar fuels with semiconductor oxides: materials, activity and modeling

Transition metal oxides keep on being excellent candidates as electrode materials for the photoelectrochemical conversion of solar energy into chemical energy.

Photosensitized H2 Evolution and NADPH Formation by Photosensitizer/Carbon Nitride Hybrid Nanoparticles

The broadband C₃N₄ semiconductor absorbs in the UV region, λ = 330-380 nm, a feature limiting its application for light-to-energy conversion. The unique surface adsorption properties of C₃N₄ allow, however, the binding of a photosensitizer, operating in the visible-solar spectrum to the surface of C₃N₄. Coupling of the energy levels of the photosensitizer with the energy levels of C₃N₄ allows effective photoinduced electron-transfer quenching and subsequent charge separation in the hybrid structures. Two methods to adsorb a photosensitizer on the C₃N₄ nanoparticles are described. One is exemplified by the adsorption of Zn(II)-protoporphyrin IX on C₃N₄ using π-π interactions. The second method utilizes the specific binding interactions of single-stranded nucleic acids on C₃N₄ and involves the binding of a Ru(II)-tris-bipyridine-modified nucleic acid on the C₃N₄ nanoparticles. Effective electron-transfer quenching of the photoexcited photosensitizers by C₃N₄ proceeds in the two hybrid systems. The two hybrid photosystems induce the effective photosensitized reduction of N,N'-dimethyl-4,4'-bipyridinium, MV²⁺, to MV^+•, in the presence of Na₂EDTA as a sacrificial electron donor. The generation of MV^+• is ca. 5-fold higher as compared to the formation of MV^+• in the presence of the photosensitizer alone (in the absence of C₃N₄). The effective generation of MV^+• in the photosystems is attributed to the efficient quenching of the photosensitizers, followed by effective charge separation of the electrons in the conduction band of C₃N₄ and the holes in the oxidized photosensitizer. The subsequent transfer of the conduction-band electrons to MV²⁺ and the oxidation of Na₂EDTA by the oxidized photosensitizers lead to the effective formation of MV^+•. The photogenerated MV^+• by the two hybrid photosystems is used to catalyze H₂ evolution in the presence of Pt nanoparticle catalysts and to mediate the reduction of NADP⁺ to NADPH, in the presence of ferredoxin-NADP⁺ reductase, FNR. The ability to couple the photogenerated NADPH to drive NADP⁺-dependent biocatalytic transformations is demonstrated.

Water Oxidation Catalysts for Artificial Photosynthesis

Water oxidation is the primary reaction of both natural and artificial photosynthesis. Developing active and robust water oxidation catalysts (WOCs) is the key to constructing efficient artificial photosynthesis systems, but it is still facing enormous challenges in both fundamental and applied aspects. Here, the recent developments in molecular catalysts and heterogeneous nanoparticle catalysts are reviewed with special emphasis on biomimetic catalysts and the integration of WOCs into artificial photosystems. The highly efficient artificial photosynthesis depends largely on active WOCs integrated into light harvesting materials via rational interface engineering based on in-depth understanding of charge dynamics and the reaction mechanism.

Growth and photocatalytic behavior of transparent reduced GO-ZnO nanocomposite sheets

Reduced graphene oxide-zinc oxide (rGO-ZnO) nanocomposites were grown on solid substrates by rapid thermal treatment of Langmuir-Blodgett transferred GO-Zn composite sheets in oxygen ambient. The changes induced by uptake of Zn²⁺ ions and subsequent thermal treatment on surface morphology, micro-structure, composition and optical properties of composite sheets were investigated by atomic force microscopy, high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared (FT-IR) and Raman measurements. The morphological features of composites are practically independent of subphase Zn concentration and are largely determined by the temperature of rapid thermal treatment. FT-IR results indicate the presence of zinc carboxylate in composites and HR-TEM results confirm the formation of ZnO nanoparticles upon subsequent oxidation. XPS and Raman measurements show that rapid thermal treatment in oxygen ambient results in decrease of carbon-oxygen functional groups and increase in graphitic carbon content leading to the reduction of GO in the composites. The average optical transmittance of rGO-ZnO composites in the visible region is found to be ∼87%. Photocatalytic studies carried out on methylene blue (MB) overlayer coated rGO-ZnO composites show reduction in concentration of MB with increasing duration of UV irradiation. The transparent two-dimensional rGO-ZnO composite solid state structures thus facilitate efficient adsorption and degradation of MB molecules, without any composite aggregation.

Carbon Dioxide Photoreduction on the Bi2S3/MoS2 Catalyst

The photocatalytic activity of a material is contingent on efficient light absorption, fast electron excitation, and control of the recombination rate by effective charge separation. Inorganic materials manufactured in unique shapes via controlled synthesis can exhibit significantly improved properties. Here, n-type Bi2S3 nanorods (with good optical activity) were wrapped with two-dimensional (2D) p-type MoS2 sheets, which have good light absorption properties. The designed p-n junction Bi2S3/MoS2 composite exhibited enhanced light absorption over the entire wavelength range, and higher carbon dioxide adsorption capacity and photocurrent density compared to the single catalysts. Consequently, the activity of the 1Bi2S3/1MoS2 composite catalyst for the photocatalytic reduction of carbon dioxide was more than 20 times higher than that of the single catalysts under visible-light irradiation at ≤400 nm, with partial selectivity for CO conversion. This is attributed to the p-n heterojunction Bi2S3/MoS2 composite designed in this study, the high light absorption of n-Bi2S3, accelerated electron excitation, and the electron affinity of the 2D sheet-p-MoS2, which quickly absorbed excited electrons, resulting in effective charge separation. This ultimately improved the catalytic performance by continuously supplying catalytically active sites to the heterojunction interfaces.

Enhanced photocatalytic water splitting of a SILAR deposited α-Fe2O3 film on TiO2 nanoparticles

We have investigated the effect of deposition of a α-Fe2O3 thin layer on a substrate of TiO2 nanoparticles for photoelectrochemical (PEC) water splitting. The TiO2 layer was coated on an FTO substrate using the paste of TiO2 nanoparticles. The α-Fe2O3 layer was deposited on the TiO2 thin film, using the method of Successive Ionic Layer Adsorption and Reaction (SILAR) with different cycles. Various characterizations including XRD, EDX and FE-SEM confirm the formation of α-Fe2O3 and TiO2 nanoparticles on the electrode. The UV-visible absorption spectrum confirms a remarkable enhancement of the absorption of the α-Fe2O3/TiO2/FTO composite relative to the bare TiO2/FTO. In addition, the photocurrents of the composite samples are remarkably higher than the bare TiO2/FTO. This is mainly due to the low band gap of α-Fe2O3, which extends the absorption spectrum of the α-Fe2O3/TiO2 composite toward the visible region. In addition, the impedance spectroscopy analysis shows that the recombination rate of the charge carriers in the α-Fe2O3/TiO2 is lower than that for the bare TiO2. The best PEC performance of the α-Fe2O3/TiO2 sample was achieved by the sample of 70 cycles of α-Fe2O3 deposition with about 7.5 times higher photocurrent relative to the bare TiO2.

A precursor-approach in constructing 3D ITO electrodes for the improved performance of photosystem I-cyt c photobioelectrodes

In recent years the use of photoelectrodes based on conductive metal oxides has become very popular in the field of photovoltaics. The application of 3D electrodes holds great promise since they can integrate large amounts of photoactive proteins. In this study photosystem I (PSI) from the thermophilic cyanobacterium Thermosynechococcus elongatus was immobilized on 3D ITO electrodes and electrically wired via the redox protein cytochrome c (cyt c). The main goal, however, was the investigation of construction parameters of such electrodes for achieving a high performance. For this, ITO electrodes were constructed from liquid precursors resulting in improved transmission compared to previous nanoparticle-based preparation protocols. First, the doping level of Sn was varied for establishing suitable conditions for a fast cyt c electrochemistry on such 3D electrodes. In a second step the pore diameter was varied in order to elucidate optimal conditions. Third, the scalability of the template-based preparation was studied from 3 to 15 layers during spin coating and the subsequent baking step. In the thickness range from 3 to 17 μm no limitation in the protein immobilization and also in the photocurrent generation was found. Consequently, a photocurrent of about 270 μA cm-2 and a turnover number (Te) of 30 e- s-1 at PSI were achieved. Because of the high current flow the withdrawal of electrons at the stromal side of PSI becomes clearly rate limiting. Here improved transport conditions and alternative electron acceptors were studied to overcome this limitation.

An Insulating Al2O3 Overlayer Prevents Lateral Hole Hopping Across Dye-Sensitized TiO2 Surfaces

Three chromophores of the general form [Ru(bpy')₂(4,4'-(PO₃H₂)₂-2,2'-bipyridine)]²⁺, where bpy' is 4,4'-(C(CH₃)₃)₂-2,2'-bipyridine (Ru(dtb)₂P); 4,4'-(CH₃O)₂-2,2'-bipyridine (Ru(OMe)₂P), and 2,2'-bipyridine (RuP) were anchored to mesoporous thin films of TiO₂ nanocrystallites at saturation surface coverages to investigate lateral self-exchange Ru^III/II intermolecular hole hopping in 0.1 M LiClO₄/CH₃CN electrolytes. Hole hopping was initiated by a potential step 500 mV positive of the E_1/2 (Ru^III/II) potential or by pulsed laser (532 nm, 8 ns fwhm) excitation and monitored by visible absorption chronoabsorptometry and time-resolved absorption anisotropy measurements, respectively. The hole hopping rate constant k_R extracted from the potential step data revealed self-exchange rate constants that followed the trend: TiO₂|Ru(OMe)₂P (k_et = 1.4 × 10⁶ s^-1) > TiO₂|RuP (7.1 × 10⁵ s^-1) > TiO₂|Ru(dtb)₂P (6.5 × 10⁴ s^-1). Analysis of the anisotropy data with Monte Carlo simulations provided hole hopping rate constants for TiO₂|RuP and TiO₂|Ru(dtb)₂P that were within experimental error the same as that measured with the potential step. The hole hopping rate constants were found to trend with the TiO₂(e^-)|Ru^III → TiO₂|Ru^II charge recombination rate constants. The atomic layer deposition of an ∼10 Å layer of Al₂O₃ on top of the dye-sensitized films was found to prevent hole hopping by both initiation methods even though the chromophore surface coverage exceeded the percolation threshold and excited-state injection was efficient. The dramatic hole hopping turnoff was attributed to a larger outer-sphere reorganization energy for self-exchange due to the restricted access of electrolyte to the redox active chromophores. The implications of these findings for solar energy conversion applications are discussed.

Nanostructuring Confinement for Controllable Interfacial Charge Transfer

Carbon nanostructures supported semiconductors are common in photocatalytic and photoelectrochemical applications, as it is expected that the nanoconductors can improve the spatial separation and transport of photogenerated charge carriers. Transfer of charge carriers through the carbon-semiconductor interface is the key electronic process, which determines the role of charge separation channels, and is sensitively influenced by band structures of the semiconductor near the contacts. Usually, this electronic process suffers from excessive energy dissipation by thermionic emission, which will undesirably prevent the interfacial charge transfer and eventually aggravate the recombination of photogenerated charge carriers. Unfortunately, this critical issue has hardly been consciously considered. Here, ultrathin dopant-free tunneling interlayers coated on the surface of graphene and sandwiched between the carbon sheets and the semiconductor nanostructures are adopted as a model system to demonstrate energy saving for the interfacial charge transfer. The nanostructuring confinement of band bending within the ultrathin interlayers in contact with the graphene sheets effectively narrows the width of the potential barriers, which enables tunneling of a substantial number of photogenerated electrons to the co-catalysts without unduly consuming energy. Besides, the dopant-free tunneling interlayers simultaneously block the transferred electrons in the sandwiched graphene sheets from leakage.

Recent advances on photocatalytic fuel cell for environmental applications-The marriage of photocatalysis and fuel cells

Environmental pollution and energy crisis have become recent worldwide concerns. Huge amounts of organic wastes are discharged into water bodies, causing serious environmental pollution. Meanwhile, these organic compounds are important carbon and energy sources that could be utilized instead of being discarded. A smart design of a photocatalytic fuel cell (PFC) can achieve double benefits: it can degrade organic pollutants and at the same time generate energy. In this review article, we discuss recent progress in the development of PFC systems, and summarize the principles for constructing advanced PFC systems. We particularly focus on the rational design of electrode materials in terms of surface, morphology, facet, and interfacial reaction engineering. The impact of important operational parameters on PFC performance is further discussed in detail. We then discuss the major limitations and opportunities for future PFCs research. The development of smart and advanced PFC systems depends on highly interdisciplinary collaborations, which require concerted efforts from the communities of materials science, chemistry, engineering, and environmental science.

Nanocomposite Metamaterials Based on Self-assembled Titanium Dioxide Rolls with Embedded Gold Nanoparticles

An experimental method for fabrication of a nanocomposite metamaterial based on a self-assembly of titanium dioxide microtubes with encapsulated gold nanoparticles (NPs) is proposed. The formation of microtubes is induced by laser irradiation in the presence of an external magnetic field. It is shown that the variation of the metal NP concentration leads to the increase of the optical absorption of the metamaterial. The possibility of using arrays of oriented microtubes as absorbing n-doped layers for solar cells is demonstrated.

Metal Nanoclusters: New Paradigm in Catalysis for Water Splitting, Solar and Chemical Energy Conversion

A sustainable future demands innovative breakthroughs in science and technology today, especially in the energy sector. Earth-abundant resources can be explored and used to develop renewable and sustainable resources of energy to meet the ever-increasing global energy demand. Efficient solar-powered conversion systems exploiting inexpensive and robust catalytic materials for the photo- and photo-electro-catalytic water splitting, photovoltaic cells, fuel cells, and usage of waste products (such as CO₂ ) as chemical fuels are appealing solutions. Many electrocatalysts and nanomaterials have been extensively studied in this regard. Low overpotentials, catalytic stability, and accessibility remain major challenges. Metal nanoclusters (NCs, ≤3 nm) with dimensions between molecule and nanoparticles (NPs) are innovative materials in catalysis. They behave like a "superatom" with exciting size- and facet-dependent properties and dynamic intrinsic characteristics. Being an emerging field in recent scientific endeavors, metal NCs are believed to replace the natural photosystem II for the generation of green electrons in a viable way to facilitate the challenging catalytic processes in energy-conversion schemes. This Review aims to discuss metal NCs in terms of their unique physicochemical properties, possible synthetic approaches by wet chemistry, and various applications (mostly recent advances in the electrochemical and photo-electrochemical water splitting cycle and the oxygen reduction reaction in fuel cells). Moreover, the significant role that MNCs play in dye-sensitized solar cells and nanoarrays as a light-harvesting antenna, the electrochemical reduction of CO₂ into fuels, and concluding remarks about the present and future perspectives of MNCs in the frontiers of surface science are also critically reviewed.

Epitaxial Bi2FeCrO6 Multiferroic Thin-Film Photoanodes with Ultrathin p-Type NiO Layers for Improved Solar Water Oxidation

The photoelectric properties of multiferroic double-perovskite Bi₂FeCrO₆ (BFCO), such as above-band gap photovoltages, switchable photocurrents, and bulk photovoltaic effects, have recently been explored for potential applications in solar technology. Here, we report the fabrication of photoelectrodes based on n-type ferroelectric (FE) semiconductor BFCO heterojunctions coated with p-type transparent conducting oxides (TCOs) by pulsed laser deposition and their application for photoelectrochemical (PEC) water oxidation. The photocatalytic properties of the bare BFCO photoanodes can be improved by controlling the FE polarization state. However, the charge recombination as well as the limited charge transfer kinetics in the photoanode/electrolyte cause major energy loss and thus hinder the PEC performance. We show that this problem may be addressed by the deposition of an ultrathin p-type NiO layer on the photoanode to enhance the charge transport kinetics and reduce charge recombination at surface-trapped states for increased surface band bending. A fourfold enhancement of photocurrent density, up to 0.4 mA cm^-2 (at +1.23 V vs RHE), a best performance of stability over 4 h, and a high incident photon-to-current efficiency (∼3.7%) were achieved under 1 sun illumination in such p-NiO/n-BFCO heterojunction photoanodes. These studies reveal the optimization of PEC performance by polarization switching of BFCO and the successful achievement of p-TCOs/n-FE heterojunction photoanodes that are able to sustain water oxidation that is stable for many hours.

Surface-Controlled Photocatalysis and Chemical Sensing of TiO2, α-Fe2O3, and Cu2O Nanocrystals

A relatively new approach to the design of photocatalytic and gas sensing materials is to use the shape-controlled nanocrystals with well-defined facets exposed to light or gas molecules. An abrupt increase in a number of papers on the synthesis and characterization of metal oxide semiconductors such as a TiO2, α-Fe2O3, Cu2O of low-dimensionality, applied to surface-controlled photocatalysis and gas sensing, has been recently observed. The aim of this paper is to review the work performed in this field of research. Here, the focus is on the mechanism and processes that affect the growth of nanocrystals, their morphological, electrical, and optical properties and finally their photocatalytic as well as gas sensing performance.

Metal/Semiconductor Nanocomposites for Photocatalysis: Fundamentals, Structures, Applications and Properties

Due to the capability of utilizing light energy to drive chemical reactions, photocatalysis has been widely accepted as a green technology to help us address the increasingly severe environment and energy issues facing human society. To date, a large amount of research has been devoted to enhancing the properties of photocatalysts. As reported, coupling semiconductors with metals is one of the most effective methods to achieve high-performance photocatalysts. The excellent properties of metal/semiconductor (M/S) nanocomposite photocatalysts originate in two aspects: (i) improved charge separation at the metal-semiconductor interface; and (ii) increased absorption of visible light due to the surface plasmon resonance of metals. So far, many M/S nanocomposite photocatalysts with different structures have been developed for the application in environmental remediation, selective organic transformation, hydrogen evolution, and disinfection. Herein, we will give a review on the M/S nanocomposite photocatalysts, regarding their fundamentals, structures (as well as their typical synthetic approaches), applications and properties. Finally, we will also present our perspective on the future development of M/S nanocomposite photocatalysts.

Carbon-Based Photocathode Materials for Solar Hydrogen Production

Hydrogen is considered a promising environmentally friendly energy carrier for replacing traditional fossil fuels. In this context, photoelectrochemical cells effectively convert solar energy directly to H₂ fuel by water photoelectrolysis, thereby monolitically combining the functions of both light harvesting and electrolysis. In such devices, photocathodes and photoanodes carry out the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. Here, the focus is on photocathodes for HER, traditionally based on metal oxides, III-V group and II-VI group semiconductors, silicon, and copper-based chalcogenides as photoactive material. Recently, carbon-based materials have emerged as reliable alternatives to the aforementioned materials. A perspective on carbon-based photocathodes is provided here, critically analyzing recent research progress and outlining the major guidelines for the development of efficient and stable photocathode architectures. In particular, the functional role of charge-selective and protective layers, which enhance both the efficiency and the durability of the photocathodes, is discussed. An in-depth evaluation of the state-of-the-art fabrication of photocathodes through scalable, high-troughput, cost-effective methods is presented. The major aspects on the development of light-trapping nanostructured architectures are also addressed. Finally, the key challenges on future research directions in terms of potential performance and manufacturability of photocathodes are analyzed.

Effects of Se Incorporation in La5Ti2CuS5O7 by Annealing on Physical Properties and Photocatalytic H2 Evolution Activity

Oxysulfoselenide semiconductor photocatalysts absorb light at longer wavelengths than the corresponding oxysulfides. However, the synthesis of oxysulfoselenides is challenging due to excessive particle growth and the limited availability of metal selenide precursors. In this study, a La₅Ti₂CuS₅O₇ (LTCSO) oxysulfide was annealed with Se powder in sealed, evacuated quartz tubes to obtain LTCSO:Se photocatalysts, and the properties of these materials were investigated. Se was found to be incorporated into the LTCSO upon heating at 973 K or higher, and the Se/(S + Se) ratio was increased to a maximum of 0.3 upon repeating the heat treatment twice. The addition of Se extended the absorption edge of the LTCSO and thus increased its photocatalytic H₂ evolution activity at longer wavelength. Even so, the apparent quantum yield at shorter wavelengths was reduced, which is similar to the results obtained for La₅Ti₂Cu(S_{1- x}Se _x)₅O₇ (LTCS_{1- x}Se _xO) solid solutions. Overall water splitting was achieved by constructing photocatalyst sheets using LTCSO:Se and LTCS_{1- x}Se _xO as hydrogen evolution photocatalysts and BiVO₄ as an oxygen evolution photocatalyst. Heat treatment with Se is evidently an effective method for the transformation of oxysulfide photocatalysts to oxysulfoselenides that promote photocatalytic H₂ evolution and have longer absorption edge wavelengths.

Rational Design and Construction of Cocatalysts for Semiconductor-Based Photo-Electrochemical Oxygen Evolution: A Comprehensive Review

Photo-electrochemical (PEC) water splitting, as an essential and indispensable research branch of solar energy applications, has achieved increasing attention in the past decades. Between the two photoelectrodes, the photoanodes for PEC water oxidation are mostly studied for the facile selection of n-type semiconductors. Initially, the efficiency of the PEC process is rather limited, which mainly results from the existing drawbacks of photoanodes such as instability and serious charge-carrier recombination. To improve PEC performances, researchers gradually focus on exploring many strategies, among which engineering photoelectrodes with suitable cocatalysts is one of the most feasible and promising methods to lower reaction obstacles and boost PEC water splitting ability. Here, the basic principles, modules of the PEC system, evaluation parameters in PEC water oxidation reactions occurring on the surface of photoanodes, and the basic functions of cocatalysts on the promotion of PEC performance are demonstrated. Then, the key progress of cocatalyst design and construction applied to photoanodes for PEC oxygen evolution is emphatically introduced and the influences of different kinds of water oxidation cocatalysts are elucidated in detail. Finally, the outlook of highly active cocatalysts for the photosynthesis process is also included.

Recent advances in metal sulfides: from controlled fabrication to electrocatalytic, photocatalytic and photoelectrochemical water splitting and beyond

This review describes an in-depth overview and knowledge on the variety of synthetic strategies for forming metal sulfides and their potential use to achieve effective hydrogen generation and beyond.

Electron injection into titanium dioxide by panchromatic dirhodium photosensitizers with low energy red light

Two new Rh₂(ii,ii) dyes were synthesized and anchored to TiO₂ for charge injection upon low energy irradiation.

Development of a tubular continuous flow reactor for the investigation of improved gas–solid interaction in photocatalytic CO2 reduction on TiO2

Newly developed tubular reactor geometry allows intensive gas–solid interaction in photocatalytic gas-phase CO₂ reduction.

The fate of O2 in photocatalytic CO2 reduction on TiO2 under conditions of highest purity

Modification of P25-TiO₂ with IrO_x allowed the detection of gas-phase O₂ during photocatalytic CO₂ reduction with H₂O. The effect on the overall CO₂ conversion on P25 is discussed.

ZnO@CdS heterostructures: an efficient photoanode for photoelectrochemical water splitting

CdS nanoparticles attached to ZnO 2D sheets help to improve light absorbance, leading to enhanced photoelectrochemical water splitting performance.

Recent Progress in Constructing Plasmonic Metal/Semiconductor Hetero-Nanostructures for Improved Photocatalysis

Hetero-nanomaterials constructed by plasmonic metals and functional semiconductors show enormous potential in photocatalytic applications, such as in hydrogen production, CO2 reduction, and treatment of pollutants. Their photocatalytic performances can be better regulated through adjusting structure, composition, and components’ arrangement. Therefore, the reasonable design and synthesis of metal/semiconductor hetero-nanostructures is of vital significance. In this mini-review, we laconically summarize the recent progress in efficiently establishing metal/semiconductor nanomaterials for improved photocatalysis. The defined photocatalysts mainly include traditional binary hybrids, ternary multi-metals/semiconductor, and metal/multi-semiconductors heterojunctions. The underlying physical mechanism for the enhanced photocatalysis of the established photocatalysts is highlighted. In the end, a brief summary and possible future perspectives for further development in this field are demonstrated.