MoS2 Cocatalyst Research Articles

Anchored MoS2 co-catalysts on ZnxCd1-xS solid solution for photocatalytic reduction of U(VI)

In recent years, a great deal of attention has focused on achieving higher photocatalytic performance by modifications. However, external modification methods, such as heterojunction, defect engineering and doping, bring the disadvantage of mismatch of energy band positions or uncontrollable defects and doping positions, resulting in different photocatalytic efficiencies for different batches of materials. As a result, the search for new modification methods is currently the focus of photocatalytic reduction of U(VI). In this work, the modification method of forming a solid solution between Zn, Cd and S by adjusting the ratio of Zn /Cd precursors, i.e., the internal modification method, is proposed to solve the problem of matching the energy band structure, keeping the conduction band in the right position and facilitating efficient charge separation, and complexing with MoS2 co-catalysts to improve the catalytic performance of the catalyst. A novel complex, MoS2/Zn0.2Cd0.8S, has been designed and synthesized. And the photocatalytic reduction of U(VI) by Zn0.2Cd0.8S was 27 and 373 times higher than that of pure CdS and ZnS, respectively, and MoS2/Zn0.2Cd0.8S was 24.45 % higher than that of Zn0.2Cd0.8S (74.75 %), with a reduction rate of 99.20 % under 60 min of illumination. Gladly, its photocatalytic activity remained above 95.67 % after five cycles, and there was no difference in the performance of catalysts synthesised in different batches, showing excellent stability and reproducibility. Moreover, the mechanism of U(VI) reduction was investigated by MoS2/Zn0.2Cd0.8S. This study provides a new strategy to guarantee the preparation of photocatalysis with stable performance and improve photocatalytic performance.

CdS/ZnS core–shell nanorod heterostructures co-deposited with ultrathin MoS2 cocatalyst for competent hydrogen evolution under visible-light irradiation

Hydrogen generation via semiconductor photocatalysts has gained significant attention as a sustainable fuel generation process. To demonstrate the performance of nanoscale core–shell heterostructure in photocatalytic hydrogen production, we have fabricated CdS nanorods coated with ZnS photocatalyst via wet-chemical reaction followed by deposition of ultrathin MoS2 nanosheets by photo reduction process. The effect of ZnS content and suitable amount of MoS2 loading over the visible-light induced photocatalytic hydrogen evolution was examined in Na2S and Na2SO3 aqueous solutions. Interestingly, it is apparent that a close connection (or heterojunction) between CdS and ZnS is believed to easily tunnel the charge carriers to the surplus surface states, making its electrons and holes energetically favourable to transfer from ZnS to MoS2 for photocatalytic reactions and subsequently, enhances the H2 evolution activity in CdS/ZnS type I core–shell heterostructures. The optimal MoS2 concentration is resolved to be 7 mol% and the subsequent visible-light induced H2 generation rate was 13589 μmol h−1g−1, which is 19 and 158 fold higher than pristine CdS and ZnS respectively. The probable photocatalytic mechanism of CdS/ZnS type I core–shell heterostructure with MoS2 cocatalyst is proposed. Our inexpensive and convenient preparation strategy may offer novel prospects in the engineering of desirable nanoheterostructures with better performance.

Photodeposition of highly dispersed MoS2 nanosheets on CdS nanorods with enhanced photocatalytic activity for reduction of p-nitroaniline to p-phenylenediamine

So far, the significant effect of different assembly methods on the microstructures and photocatalytic properties of MoS2/CdS nanocomposite photocatalysts has rarely been reported. In the study, single-crystalline CdS nanorods (NRs) were prepared by a solvothermal method. MoS2 cocatalyst was decorated on the CdS NRs to obtain MoS2/CdS-PD and MoS2/CdS-HT photocatalysts by an in situ photodeposition (PD) technique and a hydrothermal (HT) method, respectively. Under visible light irradiation, the photocatalytic activity of MoS2/CdS-PD and MoS2/CdS-HT for reduction of p-nitroaniline (p-NA) to p-phenylenediamine (p-PDA) was comparatively studied. Results indicate: i) When MoS2 was attached on CdS NRs by the in situ PD, ultrathin MoS2 nanosheets could be uniformly and tightly tethered to CdS NRs to form core-shell MoS2/CdS-PD composite, whereas MoS2 nanosheets were aggregated to form stacked multilayered structure and loosely coupled to CdS NRs to produce non-core-shell MoS2/CdS-HT by the HT method. ii) MoS2/CdS-PD exhibits higher photocatalytic efficiency for p-NA reduction than MoS2/CdS-HT, which can be ascribed to the fact that the interfacial contact between MoS2 and CdS is more intimate and the electron transfer from CdS to MoS2 is more efficient in MoS2/CdS-PD than that in MoS2/CdS-HT.

Rational construction of carbon nitride homojunction photocatalyst for enhanced hydrogen evolution from water splitting

Solar energy-driven photocatalytic H2 evolution is a clean and sustainable energy conversion technology, in which the hinge lies on developing an efficient photocatalyst. Homojunction is an effective manner to improve photocatalytic performance, however, its successful design and construction have always been a challenge. Herein, a facile approach of molten-salt assisted two-step thermal polymerization strategy is innovatively developed to prepare a unique polymer carbon nitride (PCN)-based homojunction photocatalyst (HLPCN), which not only creates different PCN regions with high and low crystallization but also the closely combined homo-interface. As a consequence, the as-prepared HLPCN homojunction exhibits Z-scheme mechanism, accelerating the separation of photocarriers and reserving photogenerated electrons with a strong reducibility. Plus the help of MoS2 cocatalyst, the optimized HLPCN shows a photocatalytic H2 evolution rate of 8193 µmol∙g−1·h−1, which is up to 27.2 and 17.2 times of the low crystalline PCN (LPCN) and high crystalline PCN (HPCN), respectively, and exceeds many well-designed PCN-based photocatalytic system using Pt as cocatalyst. Besides that, HLPCN also shows high H2 evolution from seawater splitting of 5694 µmol∙g−1·h−1 in the simulated seawater and 6318 µmol∙g−1·h−1 in the real seawater. This work showcases a novel method to design and construct PCN homojunction with great potential in the application of solar to energy photocatalysis.

High-valent metal-oxo species heterogeneous activation making use of MoS2 in a novel Electro-Fenton System: pH-independent catalytic environment and nonradical generation mechanism

High-valent metal-oxo (HVMO) species emerge as promising reactive species for decontamination owing to its long and stable life expectancy. Nevertheless, it is challenging to generate HVMO using solid-phase catalysts, considering high orbital occupancy of transition metals disfavor electron migrations. Herein, we propose a universal MoS2 co-catalyst capable of inducing electronic delocalization in a layered double hydroxide composite of Co and Fe, in turn acting as a HVMO evolution booster. In this heterogeneous electro-Fenton system, the spontaneous generation of high-valent cobalt-oxo (CoIV = O) and high-valent iron-oxo (FeIV = O, FeV = O and FeVI = O) was facilitated by MoS2 configuration, accepting self-motivated electron transfer, pivotally shifting d-band centers and lowering the energy barrier by 2.81–11.62 eV. Noteworthy, HVMO production at pH 9 compensated for the sluggish Fenton’s reaction rate in alkaline, increasing over 20 % contaminant decay and shortening treatment time by ∼ 4 h even in practical aqueous matrices (tap and river water). Depending upon the pH, HVMO exhibits a distinct degradation pathway of norfloxacin (model organics), compared with other reactive oxygen species, yielding different intermediates of varying toxicity levels. This study comprehensively showcased the feasibility of activating HVMO generation by MoS2 in heterogeneous mediation, unveiled a pH-independent strategy to degrade pollutants, thereby expanding the applicability of Fenton’s technology.

Step-by-step tuning of morphology and band gap of ZnS/MoS2 photocatalyst for enhanced visible light to hydrogen fuel conversion

To address the inherent limitations of ZnS and MoS2 as visible light photocatalysts, herein, we report a step-by-step tuning of mixed sulfide composite system (ZnS/MoS2) to achieve enhanced visible light to hydrogen fuel conversion efficiency in the absence of any sacrificial agents. In the first stage, ZnS/MoS2 composite was synthesized by using a single step hydrothermal route and the photocatalytic activity of the synthesized ZnS/MoS2 composite was tuned by varying the ratio of Zn and Mo in the composite. In the second stage, the photocatalytic efficiency of the composite was further enhanced by tuning the band gap and visible light absorption characteristics of the material through cobalt doping (Co-doping) in the MoS2 co-catalyst. The hydrogen generation activity of the tuned composition (1:1.3 ratio of Zn and Mo) of the ZnS/MoS2 composite with 3% Co-doping is obtained as the best (1256 μmol of H2 in 1 h) as compared to the other compositions of the doped composites (1%, 3% and 5% Co doping). The enhanced hydrogen generation through visible light induced water splitting of the developed mixed sulfide composite systems (ZnS/MoS2 and ZnS/Co-doped MoS2) even in the absence of any sacrificial agents is ascribed to their tuned band gap and low electron-hole recombination rate.

Organic-inorganic p-type PEDOT:PSS/CuO/MoS2 photocathode with in-built antipodal photogenerated holes and electrons transfer pathways for efficient solar-driven photoelectrochemical water splitting

Organic PEDOT:PSS thin film and n-type MoS2 flakes were incorporated on CuO photocathode as the underlying layer and surface co-catalysts, respectively, establishing a rationally-designed novel integrated structure of PEDOT:PSS/CuO/MoS2. The organic-inorganic interface of PEDOT:PSS/CuO effectively shuttles photogenerated holes towards the FTO/PEDOT:PSS junction. Furthermore, the surface MoS2 co-catalysts form a p-n junction with CuO, which accelerates the transport of photogenerated electrons towards the photocathode/electrolyte junction, in addition to providing more reactive sites for the H2 evolution reaction. These synergistically formed antipodal charge transfer pathways have led to improved charge separation, rapid interfacial charge transfer kinetics and impeded electron-hole recombination in the PEDOT:PSS/CuO/MoS2 photocathode, which can achieve a photocurrent density of – 2.26 mA/cm2 at −0.6 V vs Ag/AgCl (2.1 times higher than that of the bare CuO photocathode). Analytical characterisations, electrochemical impedance spectroscopy (EIS) and intensity-modulated photocurrent spectroscopy (IMPS), also provide supporting evidence for its dramatically enhanced PEC water splitting performance.

Highly active Co2P/2H-1T MoS2 cocatalyst with fast charge transfer and H2 production reaction toward effective photocatalytic activity of P-TiO2

Cobalt phosphide (Co2P) and molybdenum sulfide (MoS2) have been shown to be efficient cocatalysts for photocatalytic H2O splitting reactions in hydrogen (H2) production. However, maintaining remarkable stability while obtaining high photocatalytic efficiency remains challenging due to the limited optical absorption. Herein, Co2P and MoS2 nanospecies were securely mounted as cocatalysts on phosphorous-titanium dioxide (TiO2) nanobelts to achieve increased activity and stability for photocatalytic H2 evolution. The photocatalytic H2 yield of the 2Co2P/P-TiO2/2H-1T MoS2 material driven by visible light was 4156 μmol/g, which was 129 and 2.3 times higher compared to those of TiO2 (32 μmol/g) and 2H-1T MoS2/TiO2 (1800 μmol/g), respectively. In particular, 2Co2P/P-TiO2/2H-1T MoS2 exhibited consistently stable photocatalytic H2 evolution while undergoing more than eight cycles of reactions for a total of 8 h. A thorough understanding of the modification effect of the Co2P and 2H-1T MoS2 nanospecies reveals that the modification strongly promotes the migration and separation of photoinduced electron-hole pairs and increases the interaction at the heterointerfaces between the Co2P and 2H-1T MoS2 nanospecies and P-TiO2 nanobelts. This study broadens the potential use of Co2P and 2H-1T MoS2 as co-catalysts for the photocatalytic conversion of solar energy to chemical energy.

Spatially Isolated Noble-Metal-Free Redox Cocatalysts on CdS Nanorods for Increased Photocatalytic Hydrogen Generation

Spatially isolated oxidation and reduction cocatalysts on a semiconductor can realize efficient charge separation and thereby lead to increased photo-catalytic hydrogen generation. However, the effective preparation of such photocatalysts has proven challenging. Herein, we report the facile synthesis of a novel noble-metal-free CdS/MoS2/CoPi ternary photocatalyst via a visible light-induced synthesis route, in which MoS2 reduction cocatalysts were precisely grown on the two terminals of CdS nanorods, while CoPi oxidation cocatalysts were preferentially anchored onto the sidewalls of CdS nanorods. Such spatially isolated MoS2 and CoPi redox cocatalysts endow CdS nanorods with a rapid charge separation, which enhances their hydrogen generation activity. The CdS/MoS2/CoPi photocatalyst with optimized CoPi amount achieves the highest H2 generation rate of 206 μmol/h, which is 21 and 2 times higher than that achieved by using CdS alone (9.7 μmol/h) and CdS/MoS2 (105 μmol/h), respectively. The present work highlights the effectiveness of the spatial isolation of reduction and oxidation sites for efficient charge separation and thereby provides a promising strategy for the preparation of highly active photocatalysts.

Rational design 2D/3D MoS2/In2O3 composites for great boosting photocatalytic H2 production coupled with dye degradation

BackgroundCurrently, the solar-driven photocatalytic H2 evolution coupled with pollutants photodegradation is a promising strategy for the developing sustainable solar energy and environmental processes. Thus, development of the high-efficiency, robust, and low-cost photocatalysts for photocatalytic H2 production combined with pollutants photodegradation in a one-pot system is urgently needed. MethodsIn this study, the two-dimension (2D) thin-layered molybdenum disulfide (MoS2) was decorated on the surface of three-dimension (3D) cube-like indium oxide (In2O3) to forming the new 2D/3D MoS2/In2O3 composites by a hydrothermal method. The photoreactivities of as-obtained MoS2/In2O3 composites were carefully studied by the photocatalytic H2 generation coupled with dye (Rhodamine B, RhB) degradation. Significant findingsThe photocatalysis results suggested that all of the as-formed composites could greatly boost photocatalytic H2 production simultaneous with RhB degradation performance with respect to pristine In2O3. Moreover, it was found that the 10 wt% MoS2 content of sample (10-MoS2/In2O3) showed the optimum activities both in H2 generation and RhB photodegradation under simulated sunlight irradiation. The H2 evolved rate of 10-MoS2/In2O3 was 15.5 μmol/g/h, which was 77.5 times higher than that of pure In2O3. Meanwhile, The RhB photodegraded efficiency of 10-MoS2/In2O3 could achieve nearly 100%, and the total organic carbon (TOC) removal rate was 12.1-folds greater than that of single In2O3. Eventually, the charge carrier's transferring from In2O3 photocatalyst to MoS2 co-catalyst was evidenced by density functional theory (DFT) calculations, and further a dramatical improvement of photocatalytic mechanism was proposed.

Synergistic effect of phosphorus doping and MoS2 co-catalysts on g-C3N4 photocatalysts for enhanced solar water splitting

Carbon nitride (g-C3N4) is a promising metal-free and visible-light-responsive photocatalyst. However, its photocatalytic efficiency still suffers from high recombination rates of photoinduced charge carriers, slow kinetics of surface redox reactions, and relatively poor light absorption. Herein, a non-noble metal photocatalyst of MoS2 nanodots anchored on P-doped g-C3N4 via in situ photodeposition was constructed. With the synergetic effect of the P-doping and MoS2 co-catalyst, the as-prepared P-doped g-C3N4/MoS2 catalyst has achieved efficient photocatalytic overall water splitting with a hydrogen evolution rate of 121.7 μmol h−1 g−1. Experimental results and Density functional theory (DFT) simulations indicate that the enhanced photo-absorption capacity originates from the reduced band gaps by P doping. Meanwhile, the MoS2 reduces the overpotential of the water oxidation process and improves hydrogen adsorption capability in the hydrogen evolution reaction. This work can pave a new avenue to design and develop noble-metal-free water-splitting photocatalysts for future large-scale applications.

Dual non-metal atom doping enabled 2D 1T-MoS2 cocatalyst with abundant edge-S active sites for efficient photocatalytic H2 evolution

Metal–organic frameworks (MOFs) materials featured large specific surface area, unique porous structure and highly crystalline nature which rendered them ideal catalysts in solar light conversion. Generally, the catalytic H2 generation activity of the MOFs was rather low which restricted its application. The effective co-catalyst introduction could enhance its overall performance via reducing the overpotential of hydrogen production while facilitating charges transfer and increasing reactive sites. Herein, an two-dimensional (2D) O,P–MoS2 nanosheets cocatalyst with adequate edge-S active sites and high 1T-phase content were fabricated via co-doping of O and P atoms. Rational coupling the 2D O, P–MoS2 nanosheets with 2D NH2-MIL-125(Ti) nanoplate can afford greatly improved photocatalytic H2 production rate of 339.3 μmol⋅g−1⋅h−1, which was 11.6 and 6.7 times of pure NH2-MIL-125(Ti) and NH2-MIL-125(Ti)/commercial MoS2 composite, respectively. DFT calculation revealed that the edge-S serve as the active sites for H∗ adsorption rather than the plane-S and O sites in O, P–MoS2 or the O and S sites in O–MoS2. Compared with the commercial MoS2 with completely 2H-phase, the dual-doping can create higher-density unsaturated edge-S atoms and more 1T phase which can improve the reactivity of NH2-MIL-125(Ti) via inducing the breaking of Mo–S bonds and providing higher electrical conductivity. Dual non-metal atom doping of MoS2 cocatalyst featured abundant edge-S active centers and high concentration of 1T-phase offered a facile and effective method to developing highly efficient catalysts toward solar-energy conversion.

Modulating light absorption and charge recombination in photoelectrochemical water oxidation with spin-coated MoS2 co-catalyst on ZnO nanorods

Efficient oxygen evolution reaction (OER) on a photoanode is until today considered a major challenge. In the case of ZnO, one of the most investigated semiconductors, the limitation is due to its low visible light absorption and severe charge recombination. Combining ZnO with catalytically active 2D materials such as MoS2 has been proven to increase its water oxidation performance, but they are still often produced using complex methods. Here, we present a simple and low-cost method of spin-coating to fabricate ZnO nanorods/MoS2 nanosheets (ZRM) heterostructures for OER photoanode. Using this method, we successfully produce heterostructures with improved performance, that is, measured photocurrent density (Jph) of 0.61 mA cm−2 at 1.23 V vs. RHE, about threefold than that of pure ZnO, with excellent photostability, which is on par with similar heterostructures synthesized using more complex methods. Beyond benchmarking the performance, we also unravel the mechanism by which MoS2 improves the water oxidation process, that is, through the efficient light-harvesting (ηLHE), charge separation (ηsep), and charge injection (ηinj). Our findings provide a straightforward route to produce metal oxide/2D materials heterostructure-based photoanodes for photoelectrochemical water splitting.

Carbon intercalated MoS2 cocatalyst on g-C3N4 photo-absorber for enhanced photocatalytic H2 evolution under the simulated solar light

Despite MoS2 being a promising non-precious-metal cocatalyst, poor electronic conductivity and low activity for hydrogen evolution caused by serious agglomeration have been identified as critical roadblocks to further developing MoS2 cocatalyst for photocatalytic water splitting using solar energy. In this work, the density functional theory calculations reveal that carbon intercalated MoS2 (C-MoS2) has excellent electronic transport properties and could effectively improve catalytic activity. The experiment results show that the prepared tremella-like C-MoS2 nanoparticles have large interlayer spacing along the c-axis direction and high dispersion because of intercalation of the carbon between adjacent MoS2 layers. Furthermore, the heterostructure photocatalyst of C-MoS2@g-C3N4 formed by loading the cocatalyst of C-MoS2 onto g-C3N4 nanosheets exhibits the H2 evolution rate of 157.14 μmolg−1h−1 when containing 5 wt% C-MoS2. The high photocatalytic H2 production activity of the 5 wt% C-MoS2@g-C3N4 can be attributed to the intercalated conductive carbon layers in MoS2, which leads to efficient charge separation and transfer as well as increased activities of the edge S atoms for H2 evolution. We believe that the C-MoS2 will offer great potential as a photocatalytic H2 evolution reaction cocatalyst with high efficiency and low cost.

Carbon-Protected BiVO4—Cu2O Thin Film Tandem Cell for Solar Water Splitting Applications

Carbon-protected BiVO4 photoanode and Cu2O photocathode tandem photoelectrochemical (PEC) system has been explored to reduce surface recombination and enhance the stability of the photoelectrodes. In addition to the carbon layer, the electrodeposited FeOOH nanolayer and drop-casted MoS2 co-catalyst layer on the photoanode and photocathode, respectively improve the reaction kinetics. The optimized photoanode (Mo-BiVO4/C/FeOOH) and photocathode (Cu2O/C/MoS2) produces current densities of ~1.22 mA cm−2 at 1.23 V vs. RHE and ~−1.48 mA cm−2 at 0 V vs. RHE, respectively. The obtained photocurrent is higher than bare photoelectrodes without a carbon layer. Finally, a tandem cell has been constructed, and an unassisted current density of ~0.107 mA cm−2 is obtained for a carbon-protected BiVO4–Cu2O tandem PEC cell at zero bias. The improved stability and enhanced photocurrent of the carbon protective layer are attributed to its better charge transfer resistance and minimized surface defects. Carbon protective layer can be a viable option to improve the stability of photoelectrodes in aqueous media.

Role of carbon protective layer on the photoelectrochemical performance of drop-casted CuBi2O4 photocathodes for water splitting

Multinay p-type semiconductor oxide CuBi2O4 is a potential photocathode for solar water splitting due to its favorable band gap (1.5 to 1.8 eV) and positive flat band potential of above 1 VRHE. In this work, we report a facile drop-casted CuBi2O4 photocathode protected with low-cost carbon layer for improving its stability as well as enhancing charge carrier transfer. The drop-casted CuBi2O4 was annealed at three different temperatures (450 °C, 550 °C, and 650 °C) to optimize its crystallinity and morphology. The sample annealed at 550 °C exhibited better photoelectrochemical activity compared to other annealed temperatures due to its better crystallinity and morphology as revealed by XRD and FESEM, respectively. A thin protective carbon film of about 100 nm to 150 nm coated on CuBi2O4 showed an improved photoelectrochemical performance compared to bare CuBi2O4 with better stability. The optimized photocathodes at 550 °C produced maximum photocurrents of up to − 0.32 mA/cm2 and −0.56 mA/cm2 at +0.35 VRHE in pH 12.5 for CuBi2O4 and CuBi2O4/Carbon, respectively. The enhanced photocurrent was further supported by EIS spectra showing a better interfacial charge transfer as a result of minimized surface defects for CuBi2O4/Carbon. The photocurrent was further improved after depositing MoS2 co-catalyst but the stability of co-catalyst was inferior due to dissolution of the co-catalyst. The results show a promising low-cost route for protecting copper-based photocathodes for improving their stability in aqueous environment.

Constructing MoS2-coupled carbon/g-C3N4 heterointerface to optimize charge delivery for enhanced photocatalytic capacity

It is appealing to design targeted integrating photocatalysts for solar energy conversion reaction. Currently in-situ synthesizing method is no doubt a more progressive way to obtain hybrid catalyst with strong connection compared with mixing chemical composition directly. The heterointerface status is becoming essential during photocatalytic reaction for studying photo-generated charge transfers between different components. Here, a simple coordination process using Mo-dopamine is introduced to form integrating g-C3N4@MoS2/C nanosheets by subsequent treatment. An excellent photocatalytic hydrogen production performance (712.90 μmol/g*h) is finally shown and it exhibits negligible degradation for 20 h. The large surface area of g-C3N4, function of high dispersed MoS2 cocatalyst, conductive route of carbon structure and synergism during the whole charge transfer process contribute to the improved catalytic ability, which is confirmed via further measurement and DFT calculation. The study highlights the advantage of coordination system in catalyst interface design and provides a universal approach to build multiple-photocatalysts.

Boosting solar-driven water splitting via spatially separated noble-metal-free-based dual reaction sites in cactus-like hollow TiO2

Noble-metal-free sulfides have certain photocatalytic activities and can be used as cocatalysts in reduction reactions. Metal sulfides have a catalytic mechanism similar to that of noble metals, and S ions can exert a force on H+ in water, improving the adsorption capacity of the catalyst for water molecules; this is beneficial to the hydrogen evolution reaction. Moreover, metal oxides can accelerate the consumption of holes and improve the efficiency of electron-hole separation. Herein, a novel TiO2 nanomaterial with a cactus-like hollow structure and with spatially separated MoS2 and NiO dual cocatalysts (denoted as NiO/TiO2/MoS2) is reported for use in catalytic hydrogen evolution under solar light irradiation. Space-separated dual reaction sites (MoS2 and NiO) with redox capability can efficiently promote the separation of photogenerated carriers of the catalyst. Furthermore, the special hollow structure enhances the solar light absorption efficiency by reducing the penetration loss to narrow the band gap. The density functional theory (DFT) calculation results show that, compared to Pt, the MoS2 cocatalyst loaded on the TiO2 surface is more conducive to efficient proton/electron transfer and easier molecular hydrogen release. As a result, the supported MoS2 cocatalyst on TiO2 has comparable photocatalytic hydrogen evolution performance to the noble metal Pt.

A Rapid Effervescent Route to Rational Activation of Cu/g‐C3N4 and bulk MoS2 Cocatalyst for Highly Efficient and Robust Photo‐Fenton Process

AbstractHeterogeneous Fenton‐like process with a wide pH range is a promising alternative to traditional homogeneous Fenton reactions. Recently, the boosting effect of MoS2 cocatalysts is widely recognized in Fenton reactions, and the primary mechanism is the promotion of the reduction and recycling of high‐valence metal ions. Unfortunately, integrating heterogeneous Fenton‐like catalysts and MoS2 cocatalyst to form an efficient system remains challenging due to the severe deactivation of MoS2 and the inability of simple physical mixing to speed up the reaction. For the first time, the direct activation of commercially available bulk MoS2 powder in a durable acidic microenvironment is achieved. The foam‐modified photo‐Fenton catalyst (Cu‐CN‐ef) promotes the rapid activation and formed an ideal MoS2‐excited photo‐Fenton system. The significant synergistic effect of the system is ascribed to the outstanding sustainability of Cu‐Mo redox cycling and favorable local acidic microenvironment on the surface of Cu‐CN‐ef. This system works well in outdoor cases with a tiny amount of commercially available Cu‐CN/MoS2 powder, promising a new route for portable and rapid solar‐powered wastewater treatment. The unique effervescence modification method shows great potential in the rational reconstruction of the affinity interface of composite catalysts and efficient solar energy utilization systems.

Amorphization-crystallization synergism on MoSx homojunction for boosting photocatalytic H2 production of TiO2 in alkaline medium

Low-cost molybdenum sulfide (MoS2) has been widely regarded as a potential H2-production cocatalyst for various photocatalysts. However, compared with neutral or acidic medium, MoS2 cocatalyst generally exhibits a very limited H2-production activity in alkaline medium owing to the complex progress, including the H2O adsorption and activation, OH desorption and evolution of hydrogen. In this study, an amorphous-crystalline MoSx homojunction (ac-MoSx) is synthesized and anchored on TiO2 surface to greatly enhance its photocatalytic hydrogen production efficiency in alkaline medium. Herein, the ratio of amorphous to crystalline MoSx phase in the ac-MoSx homojunction can be regulated by controlling the calcination temperature (100–700 °C). Photocatalytic results show that the resultant ac-MoSx/TiO2(300 °C) has the highest hydrogen-production activity (3.43 mmol h−1 g−1, AQE = 16.3 %) in alkaline medium, which is higher compared to that of a-MoSx/TiO2 by 4 times. An amorphization-crystallization synergism of MoSx homojunction was proposed for the improved photocatalytic hydrogen-production activity of TiO2 in alkaline medium, where the Mo atom of crystalline MoS2 can act as the excellent water-activation site, while the unsaturated S atom of amorphous MoSx works as the outstanding H2-evolution active center. This work offers a new and innovative strategy to construct highly-active alkaline H2-production catalysts in photocatalysis and electrochemistry fields.