Synthesis of Titania Doped Copper Ferrite Photocatalyst and Its Photoactivity towards Methylene Blue Degradation under Visible Light Irradiation

This paper reports the photocatalytic decomposition of methylene blue (MB) over titania doped copper ferrite, CuFe2O4/TiO2 with 50 wt% loading, synthesized via sol-gel method. The synthesized photocatalyst was characterized by X-ray diffraction, UV-vis diffuse reflectance, and photoluminescence, Mott-Schottky (MS) analysis and linear sweep voltammetry (LSV). The catalyst loadings were varied from 0.25 – 1.0 g/L and the optimum catalyst loading found to be 0.5 g/L. At the optimum loading, the conversion achieved was 83.7%. The other loadings produced slightly lower conversions at 82.7%, 80.6% and 80.0%, corresponding to 0.25, 1 and 0.75 g/L after 3 hours of irradiation. The study on the effect of initial concentration indicated that 20 ppm as the optimum concentration, tested with 0.5 g/L catalyst loading. The spent catalyst was used for the recyclability test and demonstrated a high longevity with a degradation efficiency less than 6 % for each time interval. The novelty of this study lies on the new application of photocatalytic material, CuFe2O4/TiO2 on thiazine dye that shows remarkable activity and reusability performance under visible light irradiation. Copyright © 2019 BCREC Group. All rights reserve

Electrochemical Study of Copper Ferrite as a Catalyst for CO2 Photoelectrochemical Reduction

In this work, p-type CuFe2O4 was synthesized by sol gel method. The prepared CuFe2O4 was used as photocathode catalyst for photoelectrochemical (PEC) CO2 reduction. The XRD, UV-Visible Spectroscopy (UV-Vis), and Mott-Schottky (MS) experiments were done to characterize the catalyst. Linear sweep voltammetry (LSV) was employed to evaluate the visible light (λ>400 nm) effect of this catalyst for CO2 reduction.  The band gap energy of the catalyst was calculated from the UV-Vis and was found 1.30 eV. Flat band potential of the prepared CuFe2O4 was also calculated and found 0.27 V versus Ag/AgCl. Under light irradiation in the CO2-saturated NaHCO3 solution, a remarkable current development associated with CO2 reduction was found during LSV for the prepared electrode from onset potential -0.89 V with a peak current emerged at -1.01 V (vs Ag/AgCl) representing the occurrence of CO2 reduction reaction. In addition, the mechanism of PEC was proposed for the photocathode where the necessity of a bias potential in the range of 0.27 to ~ -1.0 V vs Ag/AgCl was identified which could effectively inhibit the electron-hole (e-/h+) recombination process leading to an enhancement of CO2 reduction reactions.

Photoelectrochemical activity of CuO-CdS heterostructured catalyst for CO2 reduction

The present study explored the efficiency of a p-n heterostructured hybrid catalyst CuO-CdS to convert CO2 selectively into methanol by photoelectrochemical (PEC) method under concurrent visible light irradiation and a bias potential -0.4 V vs. NHE. The results showed that the inclusion of CdS with CuO significantly enhanced the activity of PEC CO2 reduction to produce methanol by facilitating the separation of photogenerated electron-hole (e-/h+) pairs through the p-n heterostructured architectures. The yield of methanol, the incident photon current efficiency (IPCE) and quantum efficiency (QE) in PEC CO2 reduction were achieved 35.65 μmoleL-1cm-2, 20.24% and 24.11%, respectively. The present work bears a new understanding into the fabrication of high-performable artificial p-n type heterostructured catalyst which is capable to function as a catalyst for photocathode for the reduction of CO2 and remarkable improvement in methanol yield under visible light illumination

Catalytic gasification of empty palm fruit bunches using charcoal and bismuth oxide for syngas production

The purpose of this research is to evaluate the intent of empty fruit bunches of palm oil (EFBpalm oil) to catalytic gasification of wood produced charcoal (Woodcharcoal) in order to notify the large-scale application of Woodcharcoal as a possible gasification feedstock. In this study, co-catalyst of bismuth oxide (Bi2O3) was also used to obtain syngas. The raw samples were characterized by proximate and ultimate analyses, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analyses. The produced syngas was analyzed by online portable gas analyzer and gas chromatography-thermal conductivity detector (GC-TCD). The syngas composition of H2 increased from 3.91 to 4.70% (increased 20.20%), CO increased from 5.73 to 6.30% (increased 10.53%), whereas CO2 decreased from 20.60 to 12.67% (decreased 38.50%) and CH4 concentration increased insignificantly from 0.35 to 0.37% (increased 5.7%) which was happened due to the use of WoodCharcoal and Bi2O3 with EFBpalm oil during gasification. According to the findings, carbon is abundant in WoodCharcoal, which may considerably boost the gasification reactivity with Bi2O3. The yield of syngas (H2 and CO) increased when WoodCharcoal and Bi2O3 were used instead of single EFBppo gasification, indicating that catalyst (WoodCharcoal) and co-catalyst (Bi2O3) have a high potential for thermal decomposition and dehydrogenation of volatile matter. Therefore, catalytic gasification of empty palm fruit bunches will be the prospective energy sources for the production of syngas with the utilization of WoodCharcoal and Bi2O3

Hetero-structure CdS-CuFe2O4 as an efficient visible light active photocatalyst for photoelectrochemical reduction of CO2 to methanol

In the present paper, hetero-structured CdS–CuFe2O4 nanocomposite was synthesized by a facial method to convert CO2 to methanol in the photoelectrochemical (PEC) system. The synthesized catalysts were characterised by XRD, Raman spectroscopy, TEM, FESEM, EDX, XPS, UV–vis and PL spectroscopy. The CdS–CuFe2O4 photocatalyst showed ~6 times higher photocurrent compared to the CuFe2O4 at −0.35 V vs. NHE of bias potential under CO2 environment as revealed by chronoamperometry results. Incident photon to current efficiency (IPCE) for CuFe2O4 and CdS–CuFe2O4 at 470 nm were found as 7.28 and 12.09%, respectively which clearly indicates the proficiency of CdS–CuFe2O4 heterojunction to absorb the visible light resulting in e−/h+ generation and the charge transfer during PEC CO2 reduction. Products in aqueous and gas phases were analysed which confirmed the selective production of methanol with trace amounts of H2 and CO. The CdS–CuFe2O4 catalyst demonstrated 72% and 16.9% of Faradaic and quantum efficiencies, respectively in terms of methanol production where a methanol yield of 23.80 μmole/Lcm2 was achieved in CO2 saturated aqueous solution of NaHCO3 (0.1 M). Detailed investigation revealed that the conduction band (CB) of the CdS in the heterojunction catalyst could act as a CO2 reduction site by trapping photogenerated electrons from the highly photosensitive CuFe2O4 while the water oxidation could take place at the valance band (VB) of CuFe2O4

Synthesis of titania doped copper ferrite photocatalyst and its photoactivity towards methylene blue degradation under visible light irradiation

This paper reports the photocatalytic decomposition of methylene blue (MB) over titania doped copper ferrite, CuFe2O4/TiO2 with 50 wt% loading, synthesized via sol-gel method. The synthesized photocatalyst was characterized by X-ray diffraction, UV-vis diffuse reflectance, and photoluminescence, Mott-Schottky (MS) analysis and linear sweep voltammetry (LSV). The catalyst loadings were varied from 0.25 – 1.0 g/L and the optimum catalyst loading found to be 0.5 g/L. At the optimum loading, the conversion achieved was 83.7%. The other loadings produced slightly lower conversions at 82.7%, 80.6% and 80.0%, corresponding to 0.25, 1 and 0.75 g/L after 3 hours of irradiation. The study on the effect of initial concentration indicated that 20 ppm as the optimum concentration, tested with 0.5 g/L catalyst loading. The spent catalyst was used for the recyclability test and demonstrated a high longevity with a degradation efficiency less than 6 % for each time interval. The novelty of this study lies on the new application of photocatalytic material, CuFe2O4/TiO2 on thiazine dye that shows remarkable activity and reusability performance under visible light irradiation

Photoelectrochemical reduction of carbon dioxide to methanol on p-type CuFe2O4 under visible light irradiation

Artificial photosynthesis has the potential to produce solar fuels from CO2 and H2O using an efficient photocatalyst. Semiconductor with low band gap and high stability is always the right candidate to be used as photocatalyst. Photocatalytic (PC) reduction of CO2 suffers from slow reaction kinetics and poor yield of product. Photocatalytic reaction in assistance with judicious bias potential is a solution to increase the catalytic activity and reduce the electron/hole (e−/h+) recombination rate. In the present work, a p-type CuFe2O4 was synthesized and used for photoelectrochemical (PEC) CO2 reduction. The catalyst was characterized by UV-visible spectroscopy (UV-vis), Mott-Schottky (MS), chronoamperometry, X-Ray powder diffraction (XRD), X-Ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Methanol was found as only product in liquid phase produced by photoelectrochemical reduction of CO2 at a bias potential of −0.5 V (vs NHE) under light irradiation (at 470 nm). The quantum efficiency and incident photon to current efficiency(IPCE) were found as 14.4% and 5.1% respectively revealed that, CuFe2O4 is a potential photocathode for PEC of CO2 reduction

Green synthesis of bismuth nanoparticles using green coffee beans extract

Abstract A green synthetic process based on plant sources could be an alternative option to conventional chemical one to synthesize nanostructured bismuth. This study explored a facile and green synthetic protocol for synthesizing bismuth nanoparticles (BiNPs) in an aqueous solution employing green coffee bean extract as a key reducing and capping agent. Several techniques, including X-ray diffraction, electron microscopy, energy dispersive X-ray and Fourier-transform infrared spectroscopy, and thermogravimetric analysis, have been used to characterize the resultant product. The outcomes show that crystalline BiNPs are successfully produced using the green synthesis method based on plant sources. The obtained BiNPs have a spherical shape, a diameter ranges of 20 to 40 nm, and are stabilized by phytochemicals. The purpose of the current study is to ascertain the potential impact of plant sources on the environmentally friendly synthesis of BiNPs

CuO-TiO2 as a visible light responsive photocatalyst for the photoelectroreduction of CO2 to methanol

As rising atmospheric CO2 levels change Earth’s climate change, CO2 reduction has become an increasingly active area in energy research over the past several years. The present work is developing artificial photosynthesis technologies that use visible light to convert CO2 and water into methanol. In this study, TiO2 loaded copper oxide (CuO-TiO2) was synthesized, characterized and studied for photoelectrochemical (PEC) reduction of CO2 into methanol under visible light (λ > 470 nm) irradiation. In this perspective, the catalyst was synthesized via Sol-gel method. Catalyst characterization was done by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis absorption spectra, and Mott-Schottky (MS). Linear sweep voltammetry (LSV) was employed to evaluate the photocatalytic activity of the prepared photocatalyst under visible light (λ >420 nm) irradiation for CO2 reduction reactions. XRD results indicated that the particle size of the as-prepared photocatalyst was 65 nm. The oxidation state of Cu2+ and Ti4+ were confirmed by XPS results. The band gap of CuO-TiO2 composite characterization results indicated that the band gap energy of the CuO-TiO2 catalyst was 1.68 eV. The flat band potential was calculated from the MS data and was found at 0.83 V vs NHE. During LSV, the onset potential was shifted positively (~100 mV) under the light on condition than the dark condition in CO2 saturated solution suggests an increase in photocurrent and occurrence CO2 photoreduction reaction. The PEC performance of CuO-TiO2 photocatalyst showed an increased methanol formation and found the optimum yield of 20.1 μmol.L-1cm-2 under visible light irradiation

Electrochemical study of copper ferrite as a catalyst for CO2 photoelectrochemical reduction

In this work, p-type CuFe2O4 was synthesized by sol gel method. The prepared CuFe2O4 was used as photocathode catalyst for photoelectrochemical (PEC) CO2 reduction. The XRD, UV-Visible Spectroscopy (UV-Vis), and Mott-Schottky (MS) experiments were done to characterize the catalyst. Linear sweep voltammetry (LSV) was employed to evaluate the visible light (λ>400 nm) effect of this catalyst for CO2 reduction. The band gap energy of the catalyst was calculated from the UV-Vis and was found 1.30 eV. Flat band potential of the prepared CuFe2O4 was also calculated and found 0.27 V versus Ag/AgCl. Under light irradiation in the CO2-saturated NaHCO3 solution, a remarkable current development associated with CO2 reduction was found during LSV for the prepared electrode from onset potential -0.89 V with a peak current emerged at -1.01 V (vs Ag/AgCl) representing the occurrence of CO2 reduction reaction. In addition, the mechanism of PEC was proposed for the photocathode where the necessity of a bias potential in the range of 0.27 to ~ -1.0 V vs Ag/AgCl was identified which could effectively inhibit the electron-hole (e-/h+) recombination process leading to an enhancement of CO2 reduction reactions