Photoelectrocatalytic Oxidation of Diuron in Ethanol: Performance, Synergy, and Toxicity Assessment of Ti-Based Mixed-Metal-Oxides Anodes Julia Faria, Michel Z. Fidelis, William Santacruz, Lucas Siqueira, Azam Pirkarami, Diego D. Silva, Artur J. Motheo Advanced Sustainable Systems, 2026 This work evaluates Ti/Ti 0.7 Ru 0.3 O 2 , Ti/Ti 0.7 Ir 0.3 O 2 , and Ti/Ti 0.7 Nb 0.3 O 2 mixed‐metal‐oxide (MMO) anodes for the degradation of the herbicide diuron in a non‐aqueous ethanolic medium using electrocatalysis, photocatalysis, and photoelectrocatalysis. Except for the commercial Ti/RuO 2 DSA, all anodes were prepared by thermal decomposition and characterized by XRD, UV–Vis DRS, and FEG‐SEM/EDS to correlate crystalline, optical, and morphological features with electrochemical behavior. Degradation performance was assessed by removal efficiency, pseudo‐first‐order kinetics, synergy index, and energy consumption. Electrocatalysis, Ti/RuO 2 , achieved the highest diuron removal (60.3%). Under photocatalytic conditions, removals of 98.2%, 87.2%, and 91.5% were obtained for Ti/RuO 2 , Ti/IrO 2 , and Ti/Nb 2 O 5 , respectively. Photoelectrocatalysis, Ti/RuO 2 , and Ti/IrO 2 reached 98.5% and 98.2% removal, whereas Ti/Nb 2 O 5 attained only 78.6%, indicating limited benefit from process coupling due to poor conductivity. Only Ti/IrO 2 exhibited a pronounced synergistic effect (SI = 1.45), enhancing degradation kinetics without additional energy demand, while Ti/RuO 2 and Ti/Nb 2 O 5 showed non‐synergistic behavior (SI < 1). LC–MS revealed several intermediates, including ethoxylated and hydroxylated species and the more toxic 3,4‐dichloroaniline, suggesting that high degradation efficiency is not directly correlated with a reduction in ecotoxicological risk. Overall, Ti/RuO 2 is an efficient benchmark, and Ti/IrO 2 is a promising MMO for ethanol‐based photoelectrocatalytic treatment when toxicity evolution is carefully monitored.
Nb-MOG as a High-Performance Photocatalyst for Cr(VI) Remediation: Optimization and Reuse Cycles Eduardo Abreu, Onelia A. A. dos Santos, Maria E. K. Fuziki, Angelo M. Tusset, Michel Z. Fidelis, Artur J. Motheo, Giane G. Lenzi Catalysts, 2026 This study describes the removal of Cr(VI) using Nb-MOG (Niobium Metal–Organic Gel) as a photocatalyst. The characterization was performed using various techniques: Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy (SEM–EDS), Point charge zero charge (PZC) determination, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TG). The characterization results indicated an amorphous structure with predominance of Nb on the catalytic surface. Photoreduction tests were performed under different experimental conditions, following a two-factor central composite design with 11 experiments—including triplicates of the central point—to evaluate the influence of catalyst concentration (0.146 to 0.854 g L−1) and pH (1.46 to 8.54) on the Cr(VI) removal efficiency after 60 min of photocatalytic treatment. Experimentally, complete Cr(VI) removal was achieved at pH 5.00 using 0.854 g·L−1 of Nb-MOG, and the response surface analysis indicated optimal performance at higher catalyst concentrations and pH values around 5.00. In contrast, lower efficiencies were observed at extreme pH values, particularly at higher pH and lower catalyst concentrations. These results suggest that the photocatalytic performance of Nb-MOG for Cr(VI) removal is very susceptible to operating conditions, underscoring the importance of optimizing pH and catalyst concentration for effective treatment.
Niobium-Based Catalysts in Advanced Oxidation Processes: A Systematic Review of Mechanisms, Material Engineering, and Environmental Applications Michel Z. Fidelis, Julia Faria, William Santacruz, Thays S. Lima, Giane G. Lenzi, Artur J. Motheo Environments Mdpi, 2025 Water contamination by emerging pollutants poses a significant environmental challenge, demanding innovative treatment technologies beyond conventional methods. Advanced oxidation processes (AOPs) utilizing niobium-based catalysts, particularly niobium oxide (Nb2O5) and its modified forms, are prominent due to their high chemical stability, effective reactive oxygen species (ROS) generation, and versatility. This review systematically examines recent advancements in Nb2O5-based catalysts across various AOPs, including heterogeneous photocatalysis, electrocatalysis, and Fenton-like reactions, highlighting their mechanisms, material modifications, and performance. Following PRISMA and InOrdinatio guidelines, 381 papers were selected for this synthesis. The main findings indicate that niobium incorporation enhances pollutant degradation by extending light absorption, reducing electron–hole recombination, and increasing ROS generation. Structural modifications such as crystalline phase tuning, defect engineering, and the formation of heterostructures further amplify catalytic efficiency and stability. These catalysts demonstrate considerable potential for water treatment, effectively degrading a broad range of persistent contaminants such as dyes, pharmaceuticals, pesticides, and personal care products. This review underscores the environmental benefits and practical relevance of Nb2O5-based systems, identifying critical areas for future research to advance sustainable water remediation technologies.
Application of Magnetic Separation in Catalyst Reuse Applied in Paracetamol Degradation Jessica R. P. Oliveira, Eduardo Abreu, Maria E. K. Fuziki, Elaine T. de Paula, Michel Z. Fidelis, Rodrigo Brackmann, Angelo M. Tusset, Odivaldo C. Alves, Giane G. Lenzi Magnetism, 2024 This work presents an investigation of the degradation of paracetamol via heterogeneous photocatalysis, aiming to magnetically immobilize the catalyst in a continuous process. Catalyst immobilization was conducted on aggregated flower-like structures. The CoFe2O4@Nb5O2 catalyst was characterized using a Vibrating Sample Magnetometer (VSM). The effects of the magnetic immobilization of the catalyst, flow, residence time, adsorption, and photolysis were evaluated. Additionally, catalyst reuse cycles were analyzed. The results indicated that a longer residence time favors the degradation of paracetamol due to the increase in the contact time of the effluent catalyst. At a flow rate of 20 mL·min−1, a degradation of 27% was obtained. Photolysis and adsorption tests indicated that residence time was not an important factor for paracetamol degradation. For the photolysis test, in the first cycle, the values obtained were in the range of 6.0–8.5%. The adsorption results indicated ~10% removal.
Paraquat degradation by photocatalysis: experimental desing and optimization Giane G. Lenzi, Paula Freitas, Michel Z. Fidelis, Mauricio A. Ribeiro, Rodrigo Brackmann, Leda M. S. Colpini, Angelo M. Tusset Journal of Environmental Science and Health Part B Pesticides Food Contaminants and Agricultural Wastes, 2021
Photoelectrocatalytic Oxidation of Diuron in Ethanol: Performance, Synergy, and Toxicity Assessment of Ti‐Based Mixed‐Metal‐Oxides Anodes J Faria, MZ Fidelis, W Santacruz, L Siqueira, A Pirkarami, DD Silva, ... Advanced Sustainable Systems 10 (5), e70502 , 2026 2026
Nb-MOG as a high-performance photocatalyst for Cr (VI) remediation: optimization and reuse cycles E Abreu, OAA Santos, MEK Fuziki, AM Tusset, MZ Fidelis, AJ Motheo, ... Catalysts 16 (1), 60 , 2026 2026 Citations: 1
Advanced hybrid and electrochemical techniques for emerging water pollutants AJ Motheo, MZ Fidelis 2026
Drug Quantification by Simultaneous HPLC Analysis E Abreu, MZ Fidelis, MEK Fuziki, JRP Oliveira, R Brackmann, AM Tusset, ... Fine Chemical Engineering, 75-86 , 2026 2026 Citations: 1
Wastewater treatment and oxygen evolution via oxygen vacancy-engineered CeO₂-NiAl-LDH@ MIL-88A eectrocatalyst supported on low-grade charcoal A Pirkarami, J Faria, MZ Fidelis, L Siqueira, A de Jesus Motheo Journal of Water Process Engineering 80, 109095 , 2025 2025 Citations: 2
Niobium-Based Catalysts in Advanced Oxidation Processes: A Systematic Review of Mechanisms, Material Engineering, and Environmental Applications MZ Fidelis, J Faria, W Santacruz, TS Lima, GG Lenzi, AJ Motheo Environments 12 (9), 311 , 2025 2025 Citations: 8
Magnetically recyclable CuFe2O4/TiO2 photocatalysts for UV-driven degradation of reactive Yellow BF-4G in aqueous media MZ Fidelis, PH Lazzaroto, AJ Motheo, R Brackmann Physica B: Condensed Matter, 417660 , 2025 2025 Citations: 2
TiO 2 /Fe 2 O 3 and Fe 2 O 3 /TiO 2 heterojunction nanocomposites applied to As(III) decontamination MZ Fidelis, GB Baroncello, E Abreu, E dos Santos Filho, ÉCF de Souza, ... Environmental Science and Pollution Research 32 (11), 6839-6855 , 2025 2025 Citations: 6
Exploring the unique physicochemical properties of Fe3O4@ TiO2-Nd magnetic nanocomposites synthesized via hydrothermal coprecipitation MA Dariz, JE Marmentini, GL Colpani, MA Fiori, AAC Recco, OC Alves, ... Journal of Magnetism and Magnetic Materials 614, 172752 , 2025 2025 Citations: 5
Photocatalytic degradation of propranolol hydrochloride in aqueous medium employing bentonite-TiO2 nanocomposites TP Rosa, GL Colpani, MA Fiori, NRC Huaman, GG Lenzi, MZ Fidelis, ... Journal of Photochemistry and Photobiology A: Chemistry 459, 116080 , 2025 2025 Citations: 4
Progress in the combination of advanced oxidative processes for the degradation of emerging pollutants WS Parra, MM Mendanha, DS Ribeiro, JF Silva, MZ Fidelis, AJ Motheo Abstract Book , 2025 2025
Synergistic effect of combined electrocatalysis and ozonation for efficient tetracycline removal in different media MZ Fidelis, WS Parra, JF Silva, AJ Motheo Resumos , 2025 2025
Evaluation of Ti/RuO2, Ti/IrO2 and Ti/Nb2O5 anodes for photoelectrocatalytic degradation of diuron in ethanolic medium JF Silva, MZ Fidelis, WS Parra, AJ Motheo Resumos , 2025 2025
Evaluation of CuFe2O4/TiO2 heterojunctions in the photocatalytic degradation of reactive yellow BF-4G dye MZ Fidelis, PH Lazzaroto, GG Lenzi, OB Andreo, AJ Motheo, ... Abstract Book , 2025 2025
Application of Magnetic Separation in Catalyst Reuse Applied in Paracetamol Degradation JRP Oliveira, E Abreu, MEK Fuziki, ET Paula, MZ Fidelis, R Brackmann, ... Magnetism 4 (3), 240-251 , 2024 2024
Magnetic NiFe2O4/TiO2 heterostructures for the photocatalytic decontamination of glyphosate in water IR Verdi, AJM Neto, IS de Gois Garcia, GG Lenzi, MA Villetti, OC Alves, ... Materials Science in Semiconductor Processing 174, 108205 , 2024 2024 Citations: 10
Application of Structured Sol-Gel Nb 2 O 5 Catalyst in Photocatalytic Continuous Process Prototype for Ibuprofen Degradation MZ Fidelis, E Abreu, OAB Andreo, OSGP Soares, FC Janzen, GG Lenzi Topics in Catalysis 67 (9), 828-842 , 2024 2024 Citations: 3
Nb2O5/MWCNT nanocomposites for the degradation of ibuprofen via photocatalysis and catalytic ozonation MZ Fidelis, ASGG dos Santos, ET de Paula, GG Lenzi, OSGP Soares, ... Catalysis Communications 187, 106853 , 2024 2024 Citations: 20
Sol-gel and Pechini niobium modified: synthesis, characterization and application in the 2, 4-D herbicide degradation YB Fávaro, MEK Fuziki, MZ Fidelis, E Abreu, AM Tusset, R Brackmann, ... Journal of Environmental Science and Health, Part B 59 (2), 50-61 , 2024 2024 Citations: 4
Magnetic heterostructures of NiFe2O4 and TiO2: Pechini synthesis, characterization and photocatalytic performance in arsenite oxidation GC de Cristo Borges, IR Verdi, MZ Fidelis, HEZ Junior, GG Lenzi, ... Journal of Water Process Engineering 56, 104352 , 2023 2023 Citations: 10
MOST CITED SCHOLAR PUBLICATIONS
Degradation of emerging contaminants: Effect of thermal treatment on nb2o5 as photocatalyst E Abreu, MZ Fidelis, ME Fuziki, RM Malikoski, MC Mastsubara, RE Imada, ... Journal of Photochemistry and Photobiology A: Chemistry 419, 113484 , 2021 2021 Citations: 41
Enhancing Ibuprofen and 4-Isobutylacetophenone degradation: Exploiting the potential of Nb2O5 sol-gel catalysts in photocatalysis, catalytic ozonation, and photocatalytic ozonation MZ Fidelis, YB Favaro, ASGG dos Santos, MFR Pereira, R Brackmann, ... Journal of Environmental Chemical Engineering 11 (5), 110690 , 2023 2023 Citations: 26
Experimental Design and Optimization of Triclosan and 2.8-Diclorodibenzeno-p-dioxina Degradation by the Fe/Nb 2 O 5 /UV System MZ Fidelis, E Abreu, OAA Dos Santos, ES Chaves, R Brackmann, DT Dias, ... Catalysts 9 (4), 343 , 2019 2019 Citations: 26
Process Comparison for Caffeine Degradation: Fenton, Photo-Fenton, UV/H 2 O 2 and UV/Fe 3+ LNB De Almeida, TG Josué, MZ Fidelis, E Abreu, MA Bechlin, ... Water, Air, & Soil Pollution 232 (4), 147 , 2021 2021 Citations: 22
Nb2O5/MWCNT nanocomposites for the degradation of ibuprofen via photocatalysis and catalytic ozonation MZ Fidelis, ASGG dos Santos, ET de Paula, GG Lenzi, OSGP Soares, ... Catalysis Communications 187, 106853 , 2024 2024 Citations: 20
Sol–gel Fe/TiO 2 Magnetic Catalysts Applied to Selenium Photoreduction MEK Fuziki, E Abreu, AE De Carvalho, L Silva, MZ Fidelis, AM Tusset, ... Topics in Catalysis 63 (11), 1131-1144 , 2020 2020 Citations: 13
Continuous process applied to degradation of triclosan and 2.8-dichlorodibenzene-p-dioxin MZ Fidelis, E Abreu, TG Josué, LNB de Almeida, GG Lenzi, OAAD Santos Environmental Science and Pollution Research 28 (19), 23675-23683 , 2021 2021 Citations: 11
Magnetic NiFe2O4/TiO2 heterostructures for the photocatalytic decontamination of glyphosate in water IR Verdi, AJM Neto, IS de Gois Garcia, GG Lenzi, MA Villetti, OC Alves, ... Materials Science in Semiconductor Processing 174, 108205 , 2024 2024 Citations: 10
Magnetic heterostructures of NiFe2O4 and TiO2: Pechini synthesis, characterization and photocatalytic performance in arsenite oxidation GC de Cristo Borges, IR Verdi, MZ Fidelis, HEZ Junior, GG Lenzi, ... Journal of Water Process Engineering 56, 104352 , 2023 2023 Citations: 10
Paraquat degradation by photocatalysis: experimental desing and optimization GG Lenzi, P Freitas, MZ Fidelis, MA Ribeiro, R Brackmann, LMS Colpini, ... Journal of Environmental Science and Health, Part B 56 (6), 523-531 , 2021 2021 Citations: 9
Niobium-Based Catalysts in Advanced Oxidation Processes: A Systematic Review of Mechanisms, Material Engineering, and Environmental Applications MZ Fidelis, J Faria, W Santacruz, TS Lima, GG Lenzi, AJ Motheo Environments 12 (9), 311 , 2025 2025 Citations: 8
Caffeine adsorption onto bentonite clay in suspension and immobilized GG Lenzi, MEK Fuziki, MZ Fidelis, YB Fávaro, MA Ribeiro, ES Chaves, ... Brazilian Archives of Biology and Technology 63, e20180637 , 2020 2020 Citations: 8
Experimental design and optimization of triclosan and 2.8-diclorodibenzenop-dioxina degradation by the Fe/Nb2O5/UV system. Catalysts 9: 343 MZ Fidelis, E Abreu, O Dos Santos 2019 Citations: 8
17 α-Ethinylestradiol Degradation in Continuous Process by Photocatalysis Using Ag/Nb 2 O 5 Immobilized in Biopolymer as Catalyst GG Lenzi, E Abreu, MEK Fuziki, MZ Fidelis, R Brackmann, JLD de Tuesta, ... Topics in Catalysis 65 (13), 1225-1234 , 2022 2022 Citations: 7
TiO 2 /Fe 2 O 3 and Fe 2 O 3 /TiO 2 heterojunction nanocomposites applied to As(III) decontamination MZ Fidelis, GB Baroncello, E Abreu, E dos Santos Filho, ÉCF de Souza, ... Environmental Science and Pollution Research 32 (11), 6839-6855 , 2025 2025 Citations: 6
Exploring the unique physicochemical properties of Fe3O4@ TiO2-Nd magnetic nanocomposites synthesized via hydrothermal coprecipitation MA Dariz, JE Marmentini, GL Colpani, MA Fiori, AAC Recco, OC Alves, ... Journal of Magnetism and Magnetic Materials 614, 172752 , 2025 2025 Citations: 5
Photocatalytic degradation of propranolol hydrochloride in aqueous medium employing bentonite-TiO2 nanocomposites TP Rosa, GL Colpani, MA Fiori, NRC Huaman, GG Lenzi, MZ Fidelis, ... Journal of Photochemistry and Photobiology A: Chemistry 459, 116080 , 2025 2025 Citations: 4
Sol-gel and Pechini niobium modified: synthesis, characterization and application in the 2, 4-D herbicide degradation YB Fávaro, MEK Fuziki, MZ Fidelis, E Abreu, AM Tusset, R Brackmann, ... Journal of Environmental Science and Health, Part B 59 (2), 50-61 , 2024 2024 Citations: 4
Nb2O5: Percentage Effect of T/H Phase and Evaluation of Catalytic Activity, a Preliminary Study MZ Fidelis, ET de Paula, E Abreu, MEK Fuziki, OAA dos Santos, ... Catalysis Research 3 (3), 1-13 , 2023 2023 Citations: 4
Application of Structured Sol-Gel Nb 2 O 5 Catalyst in Photocatalytic Continuous Process Prototype for Ibuprofen Degradation MZ Fidelis, E Abreu, OAB Andreo, OSGP Soares, FC Janzen, GG Lenzi Topics in Catalysis 67 (9), 828-842 , 2024 2024 Citations: 3
