Synthesis of fatty acid methyl esters via the methanolysis of palm oil over Ca3.5xZr0.5yAlxO3 mixed oxide catalyst

Novel mixed metal oxide catalyst Ca_3.5xZr_0.5yAl_xO₃ was synthesized through the coprecipitation of metal hydroxides. The textural, morphological, and surface properties of the synthesized catalysts were characterized via Brunauer–Emmett–Teller method, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy. The catalytic performance of the as-synthesized catalyst series was evaluated during the transesterification of cooking palm oil with methanol to produce fatty acid methyl esters (FAME). The influence of different parameters, including the calcination temperature (300–700 °C), methanol to oil molar ratio (6:1–25:1), catalyst amount (0.5–6.5 wt%), reaction time (0.5–12 h) and temperature (70–180 °C), on the process was thoroughly investigated. The metal oxide composite catalyst with a Ca:Zr ratio of 7:1 showed good catalytic activity toward methyl esters. Over 87% of FAME content was obtained when the methanol to oil molar ratio was 12:1, reaction temperature 150 °C, reaction time 5 h and 2.5 wt% of catalyst loading. The catalyst could also be reused for over four cycles.     

Hydrogen production from waste-derived synthesis gas over Ni(x)Fe(3-x)-CeO2 catalyst: optimization of Ni/Fe ratio

In this study, the effect of the Ni/Fe molar ratio on the Ni_(x)Fe_(3-x)-CeO₂ catalyst was investigated for the high-temperature water-gas shift reaction, which produces hydrogen from waste-derived synthesis gas. The catalysts were synthesized via a co-precipitation method, using different Ni/Fe molar ratios (0.5:2.5, 1.0:2.0, 1.5:1.5, 2.0:1.0, and 2.5:0.5). The physicochemical properties of these catalysts were analyzed by Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), temperature-programmed reduction using hydrogen (H₂-TPR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and H₂-O₂ pulse analyses to determine their reaction performance. The Ni_1.0Fe_2.0-CeO₂ catalyst exhibited the highest activity (X_co = 88%, T = 500 °C) without any side reactions at a high gas hourly space velocity of 41,823 mL·g⁻¹ h⁻¹, compared to the other catalysts tested, owing to its high oxygen vacancies and oxygen storage capacity (OSC). In addition, when the Ni/Fe molar ratio was higher than 1, a side reaction (methanation) occurred. Therefore, it was concluded that the Ni_1.0Fe_2.0-CeO₂ catalyst is optimal for hydrogen production via the high-temperature water-gas shift reaction from waste-derived synthesis gas.     

A bronsted basic ionic liquid as an efficient and environmentally benign catalyst for biodiesel synthesis from soybean oil and methanol

Morpholine basic ionic liquid was synthesized with N-methyl morpholine, N-butyl bromide, and KOH by two-step method and was used to catalyze the transesterification of soybean oil with methanol to biodiesel. The structure of the catalyst were examined by ¹H nuclear magnetic resonance. The effects of the molar ratio of methanol to oil, reaction temperature, and amount of catalyst on the biodiesel yield were investigated. Optimized biodiesel yield of 94.5% was achieved with catalyst amount of 3.0 wt%, and methanol to soybean oil molar ratio of 14:1 at reaction temperature of 60 °C for 6 h. The catalyst has maintained sustained activity after being employed to six cycles. The prepared biodiesel component was analyzed by gas chromatography-mass spectrometry (GC-MS) and the results showed that the biodiesel comprised of hexadecanoic acid methyl ester, 10, 13-octadecadienoic acid methyl ester, 9-octadecenoic acid methyl ester, and octadecanoic acid methyl ester, illustrating that fatty acids of soybean oil were converted completely.     

Ni2Zn0.5Fe-LDH modified carbon paste electrode as an efficient electrocatalyst for water oxidation in neutral media

In this study, the ternary-component nickel-zinc-iron layered double hydroxides (Ni_xZn_yFe_z-LDHs) were synthesized by co-precipitation process and characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy and atomic absorption spectroscopy. The Ni_xZn_yFe_z-LDHs were then used as the efficient electrocatalyst materials to fabricate the modified carbon paste electrodes (CPEs) for water oxidation in neutral media. The effect of Zn²⁺ ions on the electrocatalytic activity of the ternary-component Ni_xZn_yFe_z-LDHs modified CPE was studied under suggested optimum condition. In this condition, the ternary-component Ni₂Zn_0.5Fe-LDH modified CPE displayed improved electrocatalytic activity in comparison with other ternary-component LDHs, and also binary-component LDHs, Ni₂Fe-LDH and ZnFe-LDH modified CPEs due to high crystallinity and low band gap energy which enhanced the conductivity of the synthesized LDH. Furthermore, the ternary-component Ni₂Zn_0.5Fe-LDH modified CPE had good structural stability with no significant deactivation of the electrocatalytic properties in neutral media after 13 h oxygen evolution reaction at room temperature.     

Cd0.5Zn0.5S/Ni2P noble-metal-free photocatalyst for high-efficient photocatalytic hydrogen production: Ni2P boosting separation of photocarriers

Establishing efficient co-catalytic loaded semiconductors for efficient charge separation is a hopeful way for enhance photocatalytic water splitting hydrogen evolution. Herein, we successfully constructed the Cd_0.5Zn_0.5S/Ni₂P (CZS/Ni₂P) nanocomposites via two-step hydrothermal method. The CZS/Ni₂P composites show much improved activity than the origin CZS for photocatalytic H₂ generation. When the content of Ni₂P loaded on the Cd_0.5Zn_0.5S (CZS) is 0.3 mol%, the photocatalyst achieves the highest photocatalytic hydrogen generation rate of 41.26 mmol g⁻¹ h⁻¹ under visible light. The Ni–S bonds on the close contact interface between CZS and Ni₂P can be act as electron-bridge to provide a channel for electron transfer. During the photocatalysis processing, Ni₂P can be used as electron traps to attract electrons from CZS, resulting in the improvement of the photocatalytic performance.     

Highly efficient Ni0.5Fe0.5Se2/MWCNT electrocatatalyst for hydrogen evolution reaction in acid media

In the present energy scenario of the world, hydrogen with high energy content seems to be a better green alternative to depleting fossil fuels. Here we describe an innovative and efficient iron nickel diselenide (Ni_0.5Fe_0.5Se₂) as a potential electrocatalyst for hydrogen evolution reaction in acid media. Ni_0.5Fe_0.5Se₂ has been fabricated by means of one-step hydrothermal process supported by multi walled carbon nanotubes (MWCNTs). Ni_0.5Fe_0.5Se₂/MWCNTs electrocatalyst has been prepared from cost-effective and highly available earth-abundant elements. The crystalline structure, morphology and elemental composition of Ni_0.5Fe_0.5Se₂/MWCNTs with different weight percentage (1, 3, 5, 7%) of MWCNTs in the composite. The electrocatalysts has been successfully evaluated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), field emission scanning electron microscopy (FE-SEM). Cyclic voltammetry (CV), Tafel and electrochemical impedance analysis have been utilized to investigate. Among the investigated weight percentages, the electrocatalyst with 3 wt% of MWCNT exhibited high hydrogen evolution activity with a current density of 10 mA/cm² at an overpotential 200 mV with a Tafel slope of 71 mVdec⁻¹. The synergistic efforts between Ni_0.5Fe_0.5Se₂ and MWCNTs in the promotion of hydrogen evolution activity is ascribed to active sites, low electron transfer resistance and superior electrochemical kinetics of molecular hydrogen (H₂) production.     

Synthesis of bimetallic iron ferrite Co0.5Zn0.5Fe2O4 as a superior catalyst for oxygen reduction reaction to replace noble metal catalysts in microbial fuel cell

A low-cost electrochemically active oxygen reduction reaction (ORR) catalyst is obligatory for making microbial fuel cells (MFCs) sustainable and economically viable. In this endeavour, a highly active surface modified ferrite, with Co and Zn bimetal in the ratio of 1:1 (w/w), Co_0.5Zn_0.5Fe₂O₄ was synthesised using simple sol-gel auto combustion method. Physical characterisation methods revealed a successful synthesis of nano-scaled Co_0.5Zn_0.5Fe₂O₄. For determination of ORR kinetics of cathode, using Co_0.5Zn_0.5Fe₂O₄ catalyst, electrochemical studies viz. cyclic voltammetry and electrochemical impedance spectroscopy were conducted, which demonstrated excellent reduction current response with less charge transfer resistance. These electrochemical properties were observed to be comparable with the results obtained for cathode using 10% Pt/C as a catalyst on the cathode. The MFC using Co_0.5Zn_0.5Fe₂O₄ catalysed cathode could produce a maximum power density of 21.3 ± 0.5 W/m³ (176.9 ± 4.2 mW/m²) with a coulombic efficiency of 43.3%, which was found to be substantially higher than MFC using no catalyst on the cathode 1.8 ± 0.2 W/m³ (15.2 ± 1.3 mW/m²). Also, the specific power recovery per unit cost for MFC with Co_0.5Zn_0.5Fe₂O₄ catalysed cathode was found to be 4 times higher as compared to Pt/C based MFC. This exceptionally low-cost cathode catalyst has enough merit to replace costly cathode catalyst, like platinum, for scaling up of the MFCs.     

Enzymatic transesterification of soybean oil by using immobilized lipase on magnetic nano-particles

Lipase was covalently immobilized onto magnetic Fe₃O₄ nano-particles by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as an activating agent, and the bound lipase was used to catalyze the transesterification of vegetable oils with methanol to produce fatty acid methyl esters. The binding of lipase to magnetic particles was confirmed by enzyme assays, transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectra. It was determined that the immobilized lipase exhibited better resistance to temperature and pH inactivation in comparison to free lipase. Using the immobilized lipase, the major parameters affecting the transesterification reaction, such as the alcohol/oil molar ratio, enzyme loading and free fatty acid present in reactants were investigated to obtain the optimum reaction condition. The conversion of soybean oil to methyl esters reached over 90% in the three-step transesterification when 40% immobilized lipase was used. Moreover, the lipase catalyst could be used for 3 times without significant decrease of the activity.     

Synthesis of fatty acid methyl esters via the transesterification of waste cooking oil by methanol with a barium-modified montmorillonite K10 catalyst

The transesterification of waste cooking oil (WCO) with methanol to produce fatty acid methyl esters (FAMEs) in the presence of barium-modified montmorillonite K10 (BMK10) catalyst was investigated in a batch reactor. The influence of the reaction parameters on the yield of FAME was investigated. The highest value of 83.38% was obtained with 3.5 wt% catalyst loading at 150 °C with a methanol: oil molar ratio of 12:1 during a reaction time of 5 h. BMK10 is a promising low-cost catalyst for the transesterification of WCO to produce FAME.     

Biodiesel production from soybean and Jatropha oils using cesium impregnated sodium zirconate as a heterogeneous base catalyst

Cesium modified sodium zirconate (Cs-Na₂ZrO₃) was prepared by ionic exchange from sodium zirconate (Na₂ZrO₃), which was synthesized via a solid state reaction. Both ceramics, i.e., pristine Na₂ZrO₃ and the Cs-Na₂ZrO₃, were used as basic heterogeneous catalysts in biodiesel production. Soybean and Jatropha oils were used as triglyceride sources for transesterification reactions. Parameters, such as catalyst concentration (between 0.5 and 3 wt%), reaction time, different methanol/vegetable oil molar ratios, and temperature of the reaction, were evaluated. The cesium cation influence was evaluated from the basic transesterification reactivity. The results showed that the introduction of cesium significantly modified the catalytic activity in biodiesel production. Cs enhanced the reaction kinetics in obtaining biodiesel and reduced the reaction time in comparison with pristine Na₂ZrO₃. The results showed that Cs-Na₂ZrO₃ as a basic heterogeneous catalyst exhibited the best fatty acid methyl esters (FAME) conversion for soybean oil (98.8%) at 1 wt%, 30:1 methanol/oil ratio, 65 °C, and 15 min. The best conditions for Jatropha oil (90.8%) were 3 wt%, 15:1 methanol/oil ratio, 65 °C, and 1 h. The impregnation of Na₂ZrO₃ with cesium represents a very exciting alternative heterogeneous base catalyst for biodiesel production.     

Optimization of heterogeneous biodiesel production from waste cooking palm oil via response surface methodology

Heterogeneous transesterification of waste cooking palm oil (WCPO) to biodiesel over Sr/ZrO₂ catalyst and the optimization of the process have been investigated. Response surface methodology (RSM) was employed to study the relationships of methanol to oil molar ratio, catalyst loading, reaction time, and reaction temperature on methyl ester yield and free fatty acid conversion. The experiments were designed using central composite by applying 2⁴ full factorial designs with two centre points. Transesterification of WCPO produced 79.7% maximum methyl ester yield at the optimum methanol to oil molar ratio = 29:1, catalyst loading = 2.7 wt%, reaction time = 87 min and reaction temperature = 115.5 °C.     

CoPtx‐loaded Zn0.5Cd0.5S nanocomposites for enhanced visible light photocatalytic H2 production

Zn_0.5Cd_0.5S solid solution, modified with bimetallic CoPt_x nanoparticles, has been prepared using a two‐step organic solution method. The photocatalytic H₂ production rate of CoPt_x–Zn_0.5Cd_0.5S nanocomposites with different composition and percentage of CoPt_x was investigated. The results showed that the 1 wt% CoPt₃–Zn_0.5Cd_0.5S sample had the best activity which was 4.7 times higher than that of pure Zn_0.5Cd_0.5S and 1.2 times higher than that of Pt–Zn_0.5Cd_0.5S for photocatalytic H₂ production. The transient photocurrent response of the Zn_0.5Cd_0.5S showed an obvious increase in the current density after CoPt_x loading. Electrochemical impedance spectra measurements showed that the CoPt_x–Zn_0.5Cd_0.5S nanocomposites with x = 2 and 3 had lower charge transfer resistance R_t than that of Pt–Zn_0.5Cd_0.5S. The enhanced catalytic properties of the CoPt_x–Zn_0.5Cd_0.5S nanocomposites are attributed to their better accumulation ability for photoexcited electrons and higher rate for charge separation and transportation. Copyright © 2016 John Wiley & Sons, Ltd.     

Production of biodiesel from food processing waste using response surface methodology

The optimum conditions for biodiesel production by the transesterification of waste oil form the pork grilling process in the food factory in Udon Thani, Thailand, using NaOH and KOH as catalysts, has been investigated. A Box–Behnken Design (BBD) followed by a Response Surface Methodology (RSM) with 30 runs was used to assess the significance of three factors: the methanol to oil molar ratio, the amount of NaOH and KOH used, and the reaction time required to achieve the optimum percent fatty acid methyl ester (%FAME). The measured %FAME following transesterification using NaOH as a catalyst was an optimum 95.6% with a methanol to oil molar ratio of 12.2:1, a NaOH percentage mass fraction of 0.49% and a reaction time of 63 min. Using KOH as a catalyst, the %FAME was an optimum 93.0% with a methanol to oil molar ratio of 12:1, a KOH percentage mass fraction of 0.61% and a reaction time of 72 min. The coefficient of determination (R²) for regression equations were 98.55% and 93.99%, respectively. The probability value (P<0.05) demonstrated a very good significance for the regression model. The physicochemical properties of the biodiesel obtained from the waste oil met the ASTM 6751 biodiesel standard, illustrating that waste oil from the pork grilling process can be used as a raw material for biodiesel production by transesterification.     

Biodiesel from crude Pongamia pinnata oil under subcritical methanol conditions with calcium methoxide catalyst

Crude Pongamia pinnata oil was subjected to a transesterification reaction with a calcium methoxide (Ca(OCH₃)₂) catalyst in subcritical methanol to obtain biodiesel. The variables affecting the methyl ester conversion were investigated. The obtained results were compared with non-catalyst and two-step reaction runs. The test results showed that the catalyst could improve the methyl ester conversion of biodiesel in subcritical methanol. A conversion rate of 99.50% was achieved with a 50:1 methanol-to-oil molar ratio, 1.0 %wt catalyst, and 2.0 h reaction time at 175°C. In addition, the important fuel properties of the biodiesel satisfied the biodiesel standards.     

Biodiesel production over copper vanadium phosphate

In the present study, copper vanadium phosphate (CuVOP) with three-dimensional network structure was synthesized by hydrothermal method, and was characterized by Infrared spectrum (IR), elemental analysis (EA), EDXRF (energy dispersive X ray fluorescence) etc. Moreover, soybean oil was used as feedstock for producing biodiesel, and biodiesel was produced by CuVOP-catalyzed transesterification process. Response surface methodology was employed to statistically evaluate and optimize the conditions for the maximum conversion to biodiesel, and the effects of amount of catalyst, ratio of methanol to oil, reaction time and reaction temperature were investigated by the 2⁴ full-factorial central composite design. The maximum conversion is obtained at amount of catalyst of 1.5%, methanol/oil molar ratio of 6.75, reaction temperature of 65 °C and reaction time of 5 h. Copper vanadium phosphate CuVOP resulted very active in the transesterification reaction for biodiesel production.     

Application of β-MnO2 nanorods as catalyst in single step production of biodiesel from palm oil

Fatty acid methyl ester, which is known as biodiesel obtained from vegetable oils, has been considered as a promising remedy for fossil fuel depletion and environmental degradation. In the present research, fatty acid methyl ester is produced by transesterification of palm oil using β-MnO₂ nano rods. The catalyst was synthesized and characterized by X-ray powder diffraction, Fourier Transform Infrared, and scanning electron microscope analysis. Catalyst activity towards transesterification of palm oil was examined. The reaction parameters were optimized by the classical method and were found to be 60°C, 0.5% catalyst, and methanol to oil molar ratio of 9:1. Kinetic and thermodynamic studies were also performed.     

PVP-assisted synthesis of hollow Ni0.75Zn0.25Fe2O4 nanospheres for lithium-ion batteries

Hollow Ni_0.75Zn_0.25Fe₂O₄ nanospheres with a diameter of about 250–300 nm and thickness of 30–40 nm have been successfully fabricated through a PVP (polyvinylpyrrolidone)-assisted hydrothermal strategy. PVP plays an important role in the formation of hollow structure and a plausible formation mechanism of hollow Ni_0.75Zn_0.25Fe₂O₄ nanospheres is also proposed in this paper. The as-fabricated hollow Ni_0.75Zn_0.25Fe₂O₄ nanospheres display a good dispersibility and high specific surface area of 34.7 m² g⁻¹. Hollow Ni_0.75Zn_0.25Fe₂O₄ nanospheres also demonstrate satisfactory cycle life and rate performance when evaluated as a lithium ion battery negative electrode. Namely, after 120 cycles, the discharge specific capacity is 1321.3 mAh g⁻¹ at 200 mA g⁻¹, and the capacity retention rate is as high as 99.2%. Furthermore, the average discharge capacities are 1482.5, 1451.5, 1330.9, 1232.3, 1031.2 and 944.8 mAh g⁻¹ under the current densities of 100, 200, 500, 1000, 2000 and 4000 mA g⁻¹, respectively. The promising electrochemical performance of the hollow Ni_0.75Zn_0.25Fe₂O₄ nanosphere could be attributed to the unique hollow structure of nanospheres, which offers a higher specific surface area and shorten transmission pathways of electrons and ions, buffering the volume expansion during the Li⁺ insertion/desorption process.     

Highly efficient visible-light-assisted photocatalytic hydrogen generation from water splitting catalyzed by Zn0.5Cd0.5S/Ni2P heterostructures

Development of heterostructured photocatalysts which can facilitate spatial separation of photo-generated charge carriers is crucial for achieving improved photocatalytic H₂ production. Consequently, herein, we report the synthesis of Zn_0.5Cd_0.5S/Ni₂P heterojunction photocatalysts with varying amount of Ni₂P, 0.5 (S1), 1 (S2), 3 (S3), 5 (S4) and 10wt% (S5) for the efficient visible-light-assisted H₂ generation by water splitting. The heterostructures were characterized thoroughly by PXRD, FE-SEM, EDS, HR-TEM and XPS studies. FE-SEM and HR-TEM analyses of the samples unveiled the presence of Zn_0.5Cd_0.5S microspheres composed of smaller nanocrystals with the surface of the microspheres covered with Ni₂P nanosheets and the intimate contact between the Zn_0.5Cd_0.5S and the Ni₂P. Further, visible-light-assisted photocatalytic investigation of the samples showed excellent water splitting activity of the heterostructure, Zn_0.5Cd_0.5S/1wt%Ni₂P (S2) with very high H₂ generation rate of 21.19 mmol h^?1g^?1 and the AQY of 21.16% at 450 nm with turnover number (TON) and turnover frequency (TOF) of 251,516 and 62,879 h^?1 respectively. Interestingly, H₂ generation activity of S2 was found to be about four times higher than that of pure Zn_0.5Cd_0.5S (5.0 mmol h^?1g^?1) and about 240 times higher than that of CdS/1wt%Ni₂P. The enhanced H₂ generation activity of S2 has been attributed to efficient spatial separation of photogenerated charge carriers and the presence of highly reactive Ni₂P sites on the surface of Zn_0.5Cd_0.5S microspheres. A possible mechanism for the enhanced photocatalytic H₂ generation activity of Zn_0.5Cd_0.5S/1wt%Ni₂P (S2) has been proposed and is further supported by photoluminescence and photocurrent measurements. Furthermore, the catalyst, S2 can be recycled for several cycles without significant loss of catalytic activity and photostability. Remarkably, the H₂ generation activity of S2 was found to be even higher than the reported examples of Zn_xCd_1-xS doped with noble metal cocatalysts. Hence, the present study highlights the importance of Zn_0.5Cd_0.5S/Ni₂P heterostructures based on non-noble metal co-catalyst for efficient visible-light-driven H₂ production from water splitting.     

Enhanced discharged energy density in poly(vinylidene fluoride) composites with a small loading of (K0.5Na0.5)NbO3 particles

Dielectric composites are regarded as potential energy storage materials for electric power systems and advanced electronics because of the tunable permittivity, excellent flexibility, and high electric breakdown strengths. However, for the moment, it is still a challenge to fabricate dielectric composites combining large electrical breakdown strength and high discharged energy density. Ferroelectric (K_0.5Na_0.5)NbO₃ (KNN) particles are fabricated by solid-state reaction and introduced into poly(vinylidene fluoride) to improve energy storage capability. Particularly, the properties such as dielectric constant (ε_r), electric displacement, breakdown strength (E_b) and discharged energy density (U_dis) are enhanced with the introduction of KNN particles. The composite containing 3 vol% KNN particles exhibits an ultrahigh U_dis of 14.70 J·cm⁻³ at 480 kV·mm⁻¹, which is approximately three times that of pure PVDF of 4.80 J·cm⁻³ at the applied electric field of 350 kV·mm⁻¹. This research is of critical significance for proposing a convenient and effective way to design high discharged energy storage dielectric composites for future flexible portable capacitors. Keywords: dielectric composite, (K_0.5Na_0.5)NbO₃ particle, breakdown strength, discharged energy density.     

In-situ construction of Mo3S4/Cd0.5Zn0.5S heterojunction: An efficient and stable photocatalyst for H2 evolution

In this work, Mo₃S₄/Cd_0.5Zn_0.5S heterojunction with abundant porosity was in-situ synthesized by one-step hydrothermal method. Characterization results clearly indicate that the composite material are composed of nanoparticles with an average particle diameter about 65 nm and abundant inter-particle pores are present in between. The XPS analysis found that when Mo₃S₄ was introduced, the XPS peak positions of Cd²⁺ and Zn²⁺ were shifted from the XPS peak positions of Cd²⁺ and Zn²⁺ in pristine Cd_0.5Zn_0.5S, which indicates that there is an interaction between Mo₃S₄ and Cd_0.5Zn_0.5S at the interface. Subsequently, the Mo₃S₄/Cd_0.5Zn_0.5S (72.1 mmol h⁻¹ g⁻¹) heterojunction can achieve much higher photocatalytic hydrogen production rate than the pristine Cd_0.5Zn_0.5S (7.54 mmol h⁻¹ g⁻¹), and even higher than Cd_0.5Zn_0.5S (56.44 mmol h⁻¹ g⁻¹) loaded with the noble metal Pt (2.0%), indicating that heterojunction can effectively enhance photocatalytic activity. In addition, the improvement in photocatalytic activity of Mo₃S₄/Cd_0.5Zn_0.5S is highly related with enhanced absorption and utilization of light due to the presence of the inter-particle pores which inhibit recombination of electron-hole pairs, promote charge separation and accelerate the migration of photogenerated carriers.