Catalyst For Degradation Of Dyes Research Articles

Structural, electronic and optical properties of SrMnO3 photocatalyst for dye degradation; experimental and DFT study

Perovskite oxides (PO) are versatile multi-functional materials with wide range of applications. In current study, highly-crystalline perovskite manganite (PM) SrMnO3 has been synthesized via ultrasonic method followed by calcination at 600 °C. Morphology of PM with irregular shape and size was assessed by FESEM and hexagonal geometry with a crystallite size of 13.67nm was determined by XRD studies. As-synthesized PM was further tested as photocatalyst for its dye degradation potential against malachite green (MG) and methylene blue (MB). In the presence of synthesized perovskites, degradation of both the dyes MG and MB was achieved in 12min and 4.5min with the percentage degradation of 80.26% and 89.35% respectively. The factors including pH and temperature affecting degradation of both the dyes were also studied. Additionally, calculations based on simulated DFT (density function theory) have been employed to explore the optical, electronic and structural attributes of SrMnO3 PM through generalized gradient approximation (GGA). The total and partial density of states have been evaluated by GGA confirms the Fermi level (Ef) characteristics of metallic Sr and Mn and found that ‘d’ and ‘p’ orbitals of Sr, Mn and O were responsible for the band formation. The results of the current study advocate the synthesis of PM and related compounds followed by their successful applications as catalyst for dye degradation as well as many other fields involving the use of nanomaterials.

Na0.5Bi0.5TiO3 as an efficient catalyst for degradation of Dyes, Cr (VI) reduction and biomedical applications

In present study, we prepared Na0.5Bi0.5TiO3 (NBTO3) having perovskite structure via solid-state route. NBTO3 sample was characterized to examine the physico-chemical, optical and photoelectrochemical assets of samples using various analytical techniques. Photocatalytic activity of NBTO3 was investigated for methylene blue and rose Bengal dye degradation and toxic Cr (VI) reduction. Furthermore, NBTO3 was evaluated for antimicrobial and antioxidant activity. These findings highlight the versatile role of the prepared NBTO3 as an efficient catalyst for environmental remediation making it a promising material for various applications. The rate and mechanism related with photodegradation reaction were evaluated by kinetics and radical trap based quenching experiment. Moreover, the reusability study confirmed that even after four cycles, the material’s photocatalytic activity was still high.

A novel photocatalytic degradation of mixed dye through chemically synthesized ZnO/Fe2O3 nanocomposite.

This study reported the synthesis and assessment of zinc oxide/iron oxide (ZnO/Fe2O3) nanocomposite as photocatalysts for the degradation of a mixture of methylene red and methylene blue dyes. X-ray diffraction analysis confirms that the crystallite of zinc oxide (ZnO) has a hexagonal wurtzite phase and iron oxide (Fe2O3) has a rhombohedral phase. Fourier Transform Infra-Red spectrum confirms the presence of Zn-O vibration stretching at 428, 480 and 543cm-1 stretching confirming Fe-O bond formation. Scanning Electron Microscope images exhibited a diverse size and shape of the nanocomposites. The ZnO-90%/Fe2O3-10% and ZnO-10%/Fe2O3-90% nanocomposites reveal good photocatalytic activity with reaction rate constants of 1.5 × 10-2 and 0.66 × 10-2; and 1.3 × 10-2 and 0.60 × 10-2 for methylene blue and methyl red dye respectively. The results revealed that the synthesized ZnO/Fe2O3 nanocomposite is the best catalyst for dye degradation and can be used for industrial applications in future.

Synthesis of nano-crystalline K2NiF4-type phases La1+xSr1-xCoO4 (x = 0.0, 0.2, and 0.5): Effect of mixed valence state of Co on structural, magnetic and photocatalytic properties

A lot of work has already been reported on bulk K2NiF4-type layered perovskite oxides but hardly is known about their nano-crystalline state as they are generally prepared at high temperatures. In this connection, we have synthesized nanocrystalline La1+xSr1-xCoO4 layered perovskites oxides via sol-gel Pechini method. Efforts were also done to synthesize phases with x > 0.5 but remained unsuccessful. The Rietveld refinement investigation has confirmed the successful formation of single-phase compounds that crystallize in the I4/mmm space group with tetragonal symmetry. The X-ray photoelectron spectroscopy (XPS) analysis revealed that Co in La1+xSr1-xCoO4 has mixed valence states of +2 and + 3. Dominant anti-ferromagnetic (AFM) super-exchange Co2+―O―Co2+ and Co3+―O―Co3+ interactions were observed in all the synthesized nanophases and the existence of weak ferromagnetic (FM) interactions due to the generation of double-exchange Co2+―O―Co3+ interaction because of mixed valent state of Co. The increase in Néel temperature (TN) values with La doping has been attributed by the increased prevalence of anti-ferromagnetic (AFM) super-exchange Co2+―O―Co2+ and Co3+―O―Co3+ interactions. The band gap energy values (Eg) for all the prepared nano samples vary from 1.57 to 1.64 eV, rendering them highly competent catalysts for degradation of dyes. Additionally, the photocatalytic performance of the prepared nano photocatalysts was evaluated using cationic (MB & RhB) and anionic (MO) dye contaminants as well as their ternary mixture. LaSrCoO4 photocatalyst has been found to efficiently and swiftly degrade all three dye pollutants separately as well as in mixtures, with outstanding recyclability and durability. It has been observed that the x = 0.0 photocatalyst showed best degradation efficacy for RhB dye, i.e., ∼99 % in 100 min, compared to ∼91 % and ∼84 % for the x = 0.2 and 0.5 photocatalysts in the same time interval, respectively. These results suggest that LaSrCoO4 nano powder can be considered a promising photocatalyst in the dyes degradation.

Enhanced Photocatalytic Degradation of Methyl Orange Using Nitrogen‐Functionalized MesoporousTiO2 Decorated with Au9 Nanoclusters

A novel catalyst for dye degradation is fabricated through attaching Au9 nanoclusters (Au9 NCs) to N functionalized mesoporous TiO2 (NMTiO2). The NMTiO2 is created through chitosan‐assisted soft templating resulting in an N terminated surface preventing the agglomeration of the Au9 NCs adsorbed surface and enhancing the overall loading with Au9. The calcination atmosphere influenced the surface properties of the NMTiO2 and its capability to adsorb the Au9 NCs. The photocatalytic effectiveness of these materials was probed through methyl orange (MO) dye degradation. The black coloured Au9/NMTiO2 catalyst is highly effective to completely degrade MO dyes within 20 min due to its large reaction constant (0.176 min−1). Parameter interactions for the dye degradation process were explored using response surface methodology (RSM) and the dependency of MO degradation on the affecting parameters was evaluated based on the statistical analysis and 3D plots.

Cobalt Ferrite (CoFe2O4) Spinel as a New Efficient Magnetic Heterogeneous Fenton-like Catalyst for Wastewater Treatment

For the first time, cobalt ferrite spinel (CoFe2O4) was used as a catalyst in the Fenton process for Remazol Red RR dye degradation in water. CoFe2O4 was synthesized via gel combustion using tris(hydroxymethyl)aminomethane as an alternative fuel in one step with a ratio of Ψ = 0.8. Its structural, surface optics, magnetic properties, and the optimal conditions of the Fenton reagents for dye degradation were evaluated. The saturation magnetization and remanence (Ms and Mr, respectively) for the as-prepared powder were 65.7 emu/g and 30.4 emu/g, respectively, and the coercivity (Hc) was 1243 Oe, indicating its ferromagnetic nature and suitability as a magnetic catalyst. Red Remazol RR dye degradation tests were performed using the Fenton process to evaluate the influence of the catalyst dosage and H2O2 concentration. The tests were performed in a batch reactor in the dark with constant agitation for 24 h. The best result was obtained using 1 g/L of catalyst with a dye degradation of 80.6%. The optimal concentration of H2O2 (1.0 M) resulted in 96.5% dye degradation. Nanoparticle recyclability testing indicated that the material could be satisfactorily reused as a catalyst for at least three cycles. The potential use of the CoFe2O4 synthesized in this study as a catalyst for dye degradation by the Fenton process was demonstrated.

Activation of peroxymonosulfate by a novel stratiform Co-MOF as catalyst for degradation of dyes in water

Cobalt-based metal-organic frameworks (MOFs) have been used as catalysts to remove macromolecular organic pollutants from wastewater. In this work, a novel type of cobalt-based MOF, CUST-593, was synthesized from cobalt nitrate hexahydrate (Co(NO3)2·6H2O), 2,2-bipyridine (BIPY), and 4,4ˊ,4ˊˊ-nitrilotrisbenzoic acid (NTB) using solvothermal method. The catalytic properties of CUST-593 for degrading dyes in water were then investigated. CUST-593, with the chemical formula {Co(NTB)(BIPY)(H2O)·0.5H2O·0.1DMA}, exhibited excellent catalytic activity in degrading dyes such as methyl orange (MO) and rhodamine B (RhB) in aqueous solutions. CUST-593 has a multi-layered structure, connected by carboxylate hydrogen bonds, which is beneficial to improving its water stability. Synthetic test results showed that CUST-593 effectively attacked dyes by primarily generating sulfate radicals (SO4•−) and a portion of hydroxyl radicals (•OH). Under the testing conditions, MO removal efficiency reached approximately 95 %. Moreover, CUST-593 exhibited remarkable cycling catalytic properties, broad pH range applicability, and long-term effectiveness. A mechanism for the degradation of dyes by CUST-593 was proposed. The experimental findings in this study collectively support the conclusion that CUST-593 serves as a green and environmentally friendly catalyst for the degradation of dyes in polluted water.

Synthesis of calcium-bismuth layered double hydroxide (LADH) nanoparticles: Applications as photo-catalyst and fuel additive

The development of calcium-bismuth layered double hydroxide [(Ca-Bi) LADH] microflowers for catalyzing degradation of Congo red (CR) and combustion of fuel is significant and highly desirable. Ca-Bi LADH microflowers are prepared by hydrothermal method with intercalated nitrates ions in inter lamellar spaces with 3–4 µm diameter and exposed active sites. After hydrothermal heating, the product is calcined at 400 °C for 4 and 7 hr to study the effect of calcination time on morphology of LADH. Prepared LADH is characterized by X-Ray diffraction and scanning electron microscopy (SEM). It is clear from XRD pattern that product is consist of hexagonal unit cell and highly crystalline. Synthesized LADH is used as catalyst for degradation of dye and combustion of fuel. The values of apparent rate constant (kapp) of catalytic degradation of CR are 0.0528, 0.0550, 0.0550 and 0.0557 min−1 for 1.0, 1.5, 2.0 and 2.5 mg/mL catalyst dosage respectively. Different parameters like flash point, fire point, kinematic viscosity and cloud point of fuel are increased by increasing additive dosage due to high surface area of LADH. LADH degrades dye in aqueous medium due to large number of adsorption sites. Synthesis of Ca-Bi LADH microflowers involves low cost and environmental friendly materials that can be used for different applications.

CdS Semiconductor Quantum Dots; Facile Synthesis, Application as Off Fluorescent Sensor for Detection of Lead (Pb2+) Ions and Catalyst for Degradation of Dyes from Water.

The CdS quantum dots (QDs) were prepared by rapid, one-pot, and novel photochemical method, which used Thioglycolic acid (TGA) molecules as both stabilizer and sulfur source. The structure and morphology of the prepared CdS QDs were characterized by different analyses such as XRD, FT-IR, Raman, EDS, TEM, PL, and absorption. In this work, was used of CdS QDs as off fluorescence sensor for rapid and simple detection of lead (Pb2+) ions in water. The PL intensity of CdS QDs in the presence of lead ions decreased gradually and in the presence of 100μM lead ions, photo emission completely quenched. The photocatalyst performance of CdS QDs was investigated by methylene blue (MB), methylene orange (MO), and rhodamine b (RB) pollutant dyes under both UV and sun lights. The obtained results showed that CdS QDs had excellent photocatalyst activity with dyes under UV light and 94.9% of MO dye, 94.4% of RB dye, and 81.2% of MB was degraded after 60min UV irradiation. For understanding about which parameter have a key role in the photodegradation process of MO by CdS QDs under UV illumination, several radical scavengers were used, and results showed that holes have a key role in the degradation process.

Ag coated CuS core/shell nanoparticles to harness the full Vis-NIR spectrum for photocatalysis

Photocatalysis has broad applications in pollution and related environmental issues. CuS shows broad absorption (600–1000 nm) and has application in dye photodegradation for toxic pollutants. In this study, CuS nanoparticles were synthesized using two copper precursors: CuCl2 and Cu(OAc)2. These nanoparticles were further coated with Ag using AgNO3 under light irradiation. The pure CuS and CuS/Ag core–shell nanoparticles were characterized by XRD, FESEM, UV–vis absorption, photoluminescence, and XPS. The results confirmed the formation of core–shell nanostructured CuS/Ag. The photocatalytic activity tested using methyl-blue dye. The enhanced degradation with core–shell nanoparticles shows their potential application as a catalyst for dye degradation.

New transition metal(II) complexes with naphthoate and aminoguanidine-based ligands: a combined spectroscopic and theoretical study with its applications

A new series of transition metal complexes of Mn(ΙΙ), Fe(ΙΙ), Co(ΙΙ) and Ni(ΙΙ) is synthesized from aminoguanidine and 3-hydroxy-2-naphthoic acid ligands with the formula (N4H7C)2[M{(C10H6(O)(COO)}2]·2H2O. The synthesized complexes were characterized by analytical, spectral and thermal studies. The elemental analysis confirms the composition of the complexes. The XRD studies show that all the complexes are isostructural in nature. The complexes were screened for antimicrobial activity against a Gram-positive, Bacillus subtilis (B. subtilis), and a Gram-negative, Escherichia coli (E. coli), bacterial species. The antibacterial results were concurrent with the output of the DFT investigation of metal complex, showing that the aminoguanidine moiety plays a key role in biological activity. Molecular docking studies have been carried out to identify the binding affinity and the mode of interaction of metal complexes with E. coli protein (2FUM). Further the synthesized complex is used as a single source precursor for preparation of nano metal oxides. The photocatalytic activity was carried out using the metal oxide as catalyst for degradation of dye materials. The metal oxide is found to be an efficient catalyst for degradation of methyl orange dye.

Synthesis of MnO2 Particles via One Step Localized Heating Method as Catalyst for Dye Degradation

This work demonstrated the synthesis of MnO2 particles via a rapid one-step localized heating method. The heat was transferred directly from the wire into the precursor solution, hence minimized the heat loss to the surrounding. As a result, the precursor solution was heated up rapidly and MnO2 particles with different morphologies were successfully synthesized in short duration within 10 to 15 min. These MnO2 particles were used as catalyst in the degradation of Rhodamine B (RhB) organic dye. Particularly, MnO2 particles synthesized at 10 min possessed outstanding catalytic activity with 99% degradation efficiency of RhB dye in 10 min of reaction time. This was greatly contributed by its 3D nanoflowers morphology that provided more active sites for catalytic activities to occur. The promising catalytic activity, synthesizing by a simple and affordable synthesis setup could provide an alternative in the development of MnO2 catalyst for organic pollutants removal.

Ceria nanoparticles anchored on graphitic oxide sheets (CeO2-GOS) as an efficient catalyst for degradation of dyes and textile effluents

Herein, we report a Ceria-graphitic oxide sheets (CeO2-GOS) nanocomposites photo catalyst synthesized by simple and green methods for the degradation of textile effluents and dyes. In the first step, green treated CeO2 NPs were synthesized through a simple organic reduction method. Further, green synthesized CeO2 NPs were anchored with GOS to produce CeO2-GOS nanocomposites by a sol-gel method. The phase morphology and structure of CeO2-GOS nanocomposites was systematically characterized through X-ray diffraction, Raman spectroscopy, zeta potential, Fourier transform infrared spectroscopy (FT-IR), High-Resolution Transmission Electron Microscope (HR-TEM), and X-ray photoelectron spectroscopy (XPS) analysis. Under visible light irradiation, the CeO2-GOS nanocomposites photo catalyst exhibited 83%, 78%, and 70% degradation efficiencies for rhodamine B, methylene blue, and textile effluent, respectively. Due to the synergistic impact of GO, it act as an elastic conductive channel permitting improved charge transport, the fabricated CeO2-GOS nanocomposites showed a significant retort to photo catalysis of rhodamine B, methylene blue, and textile effluent. CeO2-GOS nanocomposites may yield unique insight into the synthesis of green nanocomposites and their application in environmental remediation due to their better photo catalytic activity.

A novel heterogeneous photo-Fenton Fe/Al2O3 catalyst for dye degradation

The activity of heterogeneous photo-Fenton catalysts based on iron and supported on commercial alumina was studied for the degradation of rhodamine B, methyl orange and methylene blue under UV irradiation. The catalysts were prepared by impregnation, drying, and calcination or omitting this last step and referred to as dried or calcined samples. All samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption, diffuse reflectance UV–vis absorption spectroscopy and X-ray photoelectron spectroscopy (XPS). The XRD results revealed that all catalysts showed peaks of α-Al2O3 and FeSO4. The band gap of the catalysts compared with alumina decreased, due to the presences of Fe species which functioned as traps inhibiting the electron-hole recombination. The XPS results revealed the presence hydroxyl groups on the surface and the presence of both Fe3+ and Fe2+ in both catalysts. The photodegradation experiments showed that the heterogeneous photo-Fenton process was much faster compared with the heterogenous photocatalyst on all the tested dyes. The dried Fe/Al2O3 with the presence of H2O2 under UV irradiation showed the best degradation of rhodamine B, methyl orange, and methylene blue at 99.6, 100, and 99.1% at 5, 10, and 5 min, respectively. This could probably be ascribed to a good dispersion of Fe particle species on Al2O3, a low band gap and a proper concentration of hydroxyl groups and sulfate groups on the surface. The scavenger test revealed that the hydroxyl radicals played the main role in the photodegradation of dyes in this process compared with the superoxide radicals and positive holes.

Cellulose-zeolitic imidazolate frameworks (CelloZIFs) for multifunctional environmental remediation: Adsorption and catalytic degradation

The crystal growth of zeolitic imidazolate frameworks (ZIFs) on biopolymers such as cellulose is a promising method for obtaining hybrid materials that combinenatural and synthetic materials. Cellulose derivative viz. 2,2,6,6‐tetramethylpiperidine‐1‐oxylradical (TEMPO)-mediated oxidized nanocellulose (TOCNF) was used to modulate the crystal growth of ZIF-8 (denoted as CelloZIF-8) and ZIF-L (CelloZIF-L). The synthesis procedure occurred in water at room temperature with and without NaOH. The reaction parameters such as the sequence of the chemical's addition and reactant molar ratio were investigated. The phases formed during the crystal growth were monitored. The data analysis ensured the presence of zinc hydroxide nitrate nanosheets modified TOCNF during the crystallization of CelloZIFs. These phases were converted to pure phases ofCelloZIF-8 and CelloZIF-L. The resultant CelloZIFs materials were used for the adsorption ofcarbon dioxide (CO2), metal ions, and dyes. The materials exhibited high selectivity with reasonable efficiency (100%) toward the adsorption of anionic dyes such as methyl blue (MeB). They can also be used as a catalyst for dye degradation via hydrogenation with an efficiency of 100%. CelloZIF crystals can be loaded into a filter paper for simple, fast, and selective adsorption of MeB from a dye mixture. The materials are recyclable for five cycles without significant loss of their performance. The mechanisms of adsorption and catalysis were also investigated.

Fenton-Type Bimetallic Catalysts for Degradation of Dyes in Aqueous Solutions

Dye compounds are becoming a problematic class of pollutants for the environment, so it is important to develop stable catalysts for their elimination. First, several studies were performed with different Y zeolites (NaY, (NH4)Y and USY) in order to select the best support for the preparation of the bimetallic catalysts. In particular, NaY zeolite was used as the support for Fe, Cu and Mn metals to prepare mono and bimetallic Fenton-type catalysts by the ion exchange method. The catalysts were characterized by several techniques, such as chemical analysis, nitrogen physisorption, X-ray diffraction (XRD), scanning electron microscopy (SEM) and cyclic voltammetry studies. Characterization results revealed that the metals were successfully ion-exchanged within the NaY zeolite. The prepared catalysts were tested for the aqueous-phase degradation of dye compounds (Procion yellow (PY) and Tartrazine (Tar)) at atmospheric pressure and different temperatures, using H2O2 as the oxidant. All the investigated samples were found to be active in degrading the dyes through the Fenton-type process; however, the oxidation rate was found to be higher in the presence of the bimetallic catalysts. CuFe-NaY displays the best mineralization rate for PY oxidation while MnFe-NaY shows the highest activity for Tar degradation. This work may provide further insight into the design of Fenton-type bimetallic catalysts with improved catalytic properties for environmental remediation.

Zinc-bearing dust derived non-toxic mixed iron oxides as magnetically recyclable photo-Fenton catalyst for degradation of dye.

In this paper, comprehensive utilization of hazardous zinc-bearing dust for preparation of non-toxic mixed iron oxides as a magnetically recyclable photo-Fenton catalyst for degradation of dye by a facile solid state reaction process was proposed. The as-prepared samples were characterized by X-ray diffraction (XRD), Raman spectra, ultraviolet and visible (UV-Vis) spectra and Physical Property Measurement System (PPMS), and the degradation performance of as-prepared catalysts was also tested and analyzed. The results show that spinel ferrite coexisting with or without Fe2O3 was the predominant phase in the as-prepared samples, which were confirmed by Raman analysis. The as-prepared samples presented high degradation efficiency (about 90%) of rhodamine B (RhB) in the presence of hydrogen peroxide (H2O2) with visible light irradiation, owing to the synergistic effect of photocatalyst reaction and Fenton-like catalyst reaction during the degradation process. The mixed iron oxides also presented stable structure and exhibited excellent reusability with a degradation efficiency of 87% after the fifth cycle of reuse. Importantly, the heavy metals in the zinc-bearing dust could be fixed in the stable spinel structure. This paper could provide a simple approach for comprehensive utilization of zinc-bearing dust to synthesize non-toxic mixed iron oxides as a magnetically recyclable photo-Fenton catalyst for degradation of dye.

Evolution of Surface Catalytic Sites on Bimetal Silica-Based Fenton-Like Catalysts for Degradation of Dyes with Different Molecular Charges.

We present here important new findings on the direct synthesis of bimetal Cu-Mn containing porous silica catalyst and the effects of structure-directing agent removal from the prepared nanomaterial on the evolution of surface catalytic sites. The extraction-calcination procedure of the structure-directing agent removal led to the formation of Cu and Mn oxo-clusters and Cu and Mn oxide nanoparticles smaller than 5 nm, while the solely calcination procedure led to the mentioned species and in addition to the appearance of CuO nanoparticles 20 nm in size. Catalysts were tested in the Fenton-like catalytic degradation of dyes with different molecular charge (cationic, anionic, and zwitterionic) as model organic pollutants in wastewater at neutral pH. Significantly faster degradation of cationic and anionic dyes in the first 60 min was observed with the catalyst containing larger CuO nanoparticles (>20 nm) due to the less hindered generation of •OH radicals and slower obstructing of the active sites on the catalysts surface by intermediates. However, this was not found beneficial for zwitterionic dye with no adsorption on the catalysts surface, where the catalyst with smaller Cu species performed better.

Fe3O4 Based Nanoparticles as a Catalyst in Degradation of Dyes: A Short Review

Dye is a chemical substance which is used for coloring of a substance. For better coloration of substance it is made chemically stable and persistence to light, and biodegradation process. After applied to a substrate the waste generated in water causes very toxic effect and hazardous for aquatic ecosystem so it is necessary to degrade or decolorize dyes from waste water. In present review degradation of different dyes using Fe3O4 based nanoparticles were cited and their catalytic properties for degradation studied in this review.

A new solution route for the synthesis of CuFeO2 and Mg-doped CuFeO2 as catalysts for dye degradation and CO2 conversion

In this study, CuFeO2 and Mg-doped CuFeO2 powders are synthesized by using a novel chemical solution route under an ambient atmosphere. By regulating the pH of the reaction solution, on the basis of Pourbaix diagrams, and the stoichiometric ratio of copper to iron ions, delafossite CuFeO2 powders are formed at 363 K in an aqueous solution. Mg-doped CuFeO2 powders are also synthesized by using the same chemical route with the trace addition of Mg(II) ions. From the powder X-ray diffraction results, all diffraction peaks are of the delafossite structure with dominated 3R phase and few 2H phase. X-ray photoelectron spectroscopy measurements show that the chemical environments of the Cu and Fe ions are consistent with the binding energies of Cu(I) and Fe(III) in the delafossite structure of CuFeO2. The UV–vis spectra show that the CuFeO2 and Mg-doped CuFeO2 powders are both able to absorb light with wavelengths ranging from 300 to 700 nm. The calculated optical band gaps of the CuFeO2 and Mg-doped CuFeO2 powders are 1.35 and 1.5 eV, respectively. With regard to the application of the powders in the photodegradation of 50 ppm methylene blue, the results suggest that at an incident light irradiation of AM 1.5G, the photodegradation efficiency of the Mg-doped CuFeO2 powder is remarkably better than that of the CuFeO2 powder, which can be attributed to its higher carrier concentration. Furthermore, at an external bias of −1.2 V, these delafossite catalysts are able to convert CO2 to ethylene glycol through an electrocatalytic reaction.