Hydrothermal Process Research Articles

Study on the hydrothermal gradient extraction of hemicellulose by a flow-through reactor

The hydrothermal gradient extraction process based on the hemicellulose constituent units is important for obtaining high quality hemicellulose products. The hydrothermal extraction of sawdust hemicellulose was performed under both non-isothermal and isothermal operations using a flow-through reactor for investigating the extraction patterns. The results show that there were significant differences in the major forms of hemicellulose units at different extraction stages. For glucose, xylose, and galactose units, the selectivity of oligomeric form decreased gradually with increasing temperature, whereas it decreased and then increased under thermostatic operation. The selectivity of the mannose oligomeric form decreased and then increased in both operation modes, reaching a trough at 170 °C (96.81 %) and 60 min (55.21 %), respectively. The molecular weight of extracted hemicelluloses were mainly distributed below 70,000 Da, and gradually decreased with temperature, but increased with time. The results contribute to the quantitative and qualitative understanding of the hemicellulose gradient extraction process.

Facile construction of a novel dual Z-scheme mixed phases BiFeO3 heterojunction: For peroxymonosulfate activation toward efficient photodegradation of 4-nitrophenol and mechanistic insights

This study proposes a novel approach for preparing bismuth ferrite (BiFeO3, BFO) with controlled crystal phase purity and morphology via a one-pot hydrothermal process using specific mineralizers (NaOH or KOH). The effects of these mineralizers on the crystal purity and photocatalytic efficiency of the catalyst were investigated. The XRD results revealed that KOH produced pure BFO, whereas NaOH yielded mixed-phase BFO (m-BFO) with secondary phases, including Bi2O3 and Bi2Fe4O9. SEM analysis revealed that m-BFO exhibited a flake-like structure assembled into cubes, whereas pure BFO consisted of irregularly shaped agglomerated nanoparticles. The photocatalytic efficiency of the two catalysts was evaluated for the degradation of 4-nitrophenol (4-NP). The results showed that m-BFO exhibited outstanding photocatalytic degradation performance (92%) for 4-NP compared with pure BFO (22%). The enhanced photocatalytic efficiency of m-BFO was attributed to the construction of a dual-heterojunction Z-scheme within its structure and the presence of abundant surface oxygen vacancies. This study provides valuable insights into the synthesis of efficient dual-heterojunction Z-scheme photocatalysts via one-pot hydrothermal synthesis.

Integration of orange peel derived carbon quantum dots with TiO2 for enhanced photocatalytic degradation of brilliant green dye

Brilliant green (BG) dye is a non-biodegradable, highly venomous and coloured pigment. BG dye possesses remarkably high visibility even at small concentration that causes diarrhea and abdominal pain in humans when being ingested. In addition, it is harmful to living organisms and polluting aquatic environments. Hence, eliminating BG dye from contaminated water is an urgent need. In this report, a photocatalyst encompasses hydrothermally prepared titanium dioxide (TiO2) integrated with orange peel derived oxygenated carbon quantum dots (O-CQDs) was developed for effective removal of BG dye. The O-CQDs were prepared using a single step eco-friendly hydrothermal process and an intense green fluorescence was observed upon exposing the O-CQDs to far UV light irradiation (254 nm). The formation of TiO2/O-CQDs nanohybrid was confirmed through UV–Visible spectrophotometer, X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS) analyses. A random distribution of spherical shaped O-CQDs on the surface of TiO2 was clearly observed in FESEM images. The carboxyl groups present in O-CQDs not only increased interlayer spacing but also led to the attachment of TiO2 effectively. The TiO2/O-CQDs nanohybrid showed 94.70 % efficiency towards photocatalytic degradation of BG dye under UV light irradiation that was ∼20 % higher than the efficiency of pristine TiO2 photocatalyst. The presence of O-CQDs in the TiO2/O-CQDs nanohybrid boosted the photocatalytic degradation efficiency by enhancing UV light absorption and suppressing photo-generated electron–hole recombination. The integration of agricultural waste derived carbon with TiO2 by a facile synthesis method paves a way for large scale synthesis of TiO2/O-CQDs nanohybrid, which is anticipated to broaden its application potential in environmental remediation through photocatalytic degradation of organic compounds.

Tungsten based nanostructured hybrid electrocatalysts in neutral medium for hydrogen evolution reaction

Generating a clean and sustainable hydrogen using the naturally available electrocatalysts to split water is among the primary energy resources adopted by the global industries. Transition metal dichalcogenides such as tungsten disulfide (WS2) provide abundant active sites to foster hydrogen evolution reaction (HER). A simple hydrothermal process was employed to synthesize WO3·H2O (hydrated tungsten trioxide) and WO3 nanoparticles. The inclusion of WS2 into the oxide has enhanced the ionic movement, which has improved the catalytic performance of the composite. The hydrophilic nature of WO3 has facilitated the conversion of water molecules into adsorbed hydrogen, which was then spilled over the HER active sites of WS2 to produce hydrogen. Thus, the WO3·H2O/WS2 catalyst achieved a current density of 10 mA cm−2 at an overpotential of 383 mV with Tafel slope of 77 mV dec−1 under neutral conditions and a hydrogen evolution rate of 0.33 mmol h−1 cm−2 at −0.5 V versus RHE.

Synergising hydrothermal pre-treatment and biological processes for enhancing biohydrogen production from palm oil mill effluent

The high quantity of nutrient-rich palm oil mill effluent (POME) waste in the industry will have a severe negative environmental impact and a high cost of treatment. However, POME waste could be converted into bioenergy via environmentally sustainable processes. Several studies have explored using hydrothermal carbonisation for solid biomass products in biofuel production, but the potential of the liquid phase produced during these processes has received less attention. Therefore, this study aims to assess the potential of biohydrogen production from treated POME as a substrate by hydrothermal process. This study is presented in two phases: the first phase involves substrate pre-treatment using a hydrothermal process to improve biomass properties at different temperatures, and the second phase explores the potential for biohydrogen production from treated POME through dark fermentation. Substrate pre-treatment was conducted at 180, 210, and 240 °C using 100% raw POME. Next, the treated POME was incubated for biohydrogen production at 50 °C for 24hours. A microbial analysis was conducted to determine the most dominant species present in the sample. Our findings show that at 180 °C, the total chemical oxygen demand (COD) removal efficiency was 80%, and acetic acid concentration was 28%. Compared to raw POME, treated POME generated a maximum hydrogen yield and rate (HPR) of 52.19mL H2 g-1 CODrem and 0.59mL H2 mL POME-1 day-1 with a 2.32-fold and 1.59-fold increase, respectively. Meanwhile, Clostridium was a dominant bacterial species identified in the treated POME. These findings demonstrated the feasibility of implementing a hydrothermal process to treat POME and improve its biohydrogen production efficiency. The treated POME from the hydrothermal process is more homogenous and readily consumable by microorganisms used in dark fermentation. Hydrothermal pre-treatment could potentially increase the rate and efficiency of microbial digestion, leading to enhanced hydrogen production. The high COD removal efficiency during the process significantly reduces the environmental impact of POME discharge, and converting POME into a valuable resource through the hydrothermal and dark fermentation process aligns with sustainable waste management practices.

Biomass hydrothermal gasification characteristics study: based on deep learning for data generation and screening strategies

Hydrothermal gasification is an import-ant way to utilize biomass resources, and accurate prediction of the biomass hydrothermal gasification process is of great significance for the formulation and optimization of process parameters and equipment. Data is a key factor in machine learning, but due to the high experimental costs associated with hydrothermal gasification processes, acquiring a large amount of experimental data for machine learning modeling is a major challenge. To address this issue, this study proposes a data generation and screening strategy based on generative adversarial networks (GAN). The data generation and screening strategy primarily rely on GAN networks trained with real data as data generators and random forest models trained with real data as data screeners. High-quality synthetic data is selected through screening criteria to augment the dataset. Four machine learning models are used to model the biomass hydrothermal gasification process based on synthetic data to validate this strategy. The results show that, compared to the original data, modeling with synthetic data leads to a significant increase in the evaluation metrics for predicting H2, CH4, and CO2, especially during the testing phase. This indicates the rationality of the proposed data generation and screening strategy.

Multistage magmatic and post-magmatic evolution of the Neoarchaean Closepet Batholith of Dharwar Craton in southern India - insights from the texture and chemical composition of titanite

Titanite is often used to describe the path of igneous, metamorphic, and hydrothermal processes. Therefore, titanite can unravel the multistage magmatic and post-magmatic evolution of granitoids. In this study, we present a comprehensive study of the ca. 2.57–2.51 Ga Closepet Batholith in the Dharwar Craton of southern India using titanite. This granitoid body provides a unique opportunity as various structural levels of the batholith are continuously outcropping. The textural and geochemical studies of titanite, supported by UPb isotopic dating, allowed us to distinguish five generations of magmatic and hydrothermal titanite. Three types of magmatic titanite demonstrate stage-growth crystallization (type I) and a change from reduced, high-temperature (type II) to oxidised, low-temperature conditions (type III). Hydrothermal titanite is recorded as altered titanite with zoned to patchy textures and secondary fractures and veinlets (type IV) and titanite inclusions within biotite (type V). Hydrothermal titanite (type IV) shows depletion in rare earth elements and high-field strength elements, indicating mobilization of those elements by a fluid. UPb dating by LA-ICP-MS of magmatic titanite type I yielded ages of ca. 2.5 Ga, consistent with the timing of formation of the Closepet Batholith. The relationship between titanite textures and chemistry indicates that titanite serves as a recorder of the multistage magmatic and post-magmatic evolution of the Closepet Batholith. In addition, our study shows that hydrothermal activity affected a large area, with fluids circulating over long distances within the upper structural levels of the Closepet Batholith.

Enhancement of capacitance retention of ZnCo2S4@Metal organic framework composite electrodes by hydrothermal process

Metal organic framework-derived materials are promising electrodes for electrochemical supercapacitors due to their surface area, porosity, and excellent redox behaviors. In the present study the fabrication of ZnCo2S4 and ZnCo2S4@ZIF-67 composites synthesized by solid-state grinding and hydrothermal processing for supercapacitor utilization. Studies using XRD, XPS, FTIR, BET, FE-SEM, and HR-TEM are employed to validate the morphological, surface, and structural characteristics. Highly conductive ZnCo2S4 nanostructured materials are intercalated with MOF surfaces to enhance electron transport. The high number of active sites involved in the rapid electrochemical phase fluctuation using 1 M KOH electrolyte may be the cause of this. ZnCo2S4 and ZnCo2S4@ZIF-67 composites are used to create the working electrode, while a 1 M KOH electrolyte is used for the supercapacitor. By employing a three-electrode design, the created composite electrodes improve cyclic retention with specific capacitances of 245 and 447.14F/g at 1 A/g, respectively. Two electrode configurations are used to build ZnCo2S4@ZIF-67/1M KOH/SSC, which produced results of 151.42F/g at 1 A/g, 85.2 % capacitance retention at 7 A g−1 of 6000 cycles, and 18.93 Wh kg−1 energy density at 642.85 W kg−1 power density. Thus, the fabricated composite electrodes may find application in electrochemical symmetric supercapacitor via two electrode configuration systems.

Bio-inspired fabrication of Ag-ZnO nanoparticle decorated Nylon 11 nanofibers: Multifunctional membrane for environmental remediation

Traditional wastewater treatment methods using nanoparticles encounter challenges with catalyst recovery. In this study, we fabricated a Nylon 11 nanofibrous membrane (NFM) via electrospinning and functionalized it with polydopamine to immobilize Ag-ZnO nanoparticles for photocatalytic degradation of organic pollutants. The Nylon 11 NFM was treated with a dopamine tris buffer solution for polydopamine (PDA) coating, which facilitated mussel-inspired attachment of the ZnO nanoparticles. These nanoparticles served as a nucleation site for the biomimetic nucleation of Ag-ZnONPs during the hydrothermal process. The synthesized composite membrane was characterized by various microscopic and spectroscopic techniques. The water contact angle decreased from 135° (Nylon 11 NFM) to 41° (PDA/Nylon 11 NFM) and the filtration efficiency improved 10 folds (from 15.92 Lm-2 hr-1 to 170.60 Lm-2hr-1) at ambient conditions. The Ag-ZnO/PDA/Nylon 11 NFM showed strong antimicrobial activity against different bacterial strains and excellent photocatalytic degradation for methyl orange with a rate constant of 0.0431 min-1, significantly surpassing other configurations. The membrane exhibited excellent stability, reusability and consistent photocatalytic efficiency over multiple cycles. It is easily recoverable from the reaction mixture, and suitable for repeated use, making it a promising candidate for environmental remediation due to its antibacterial properties, photocatalytic activity, enhanced filtration efficiency, and reusability.

Eco-friendly synthesis and applications of graphene-titanium dioxide nanocomposites for pollutant degradation and energy storage

An innovative, eco-friendly method has been developed to synthesize reduced graphene oxide (rGO) sheets using orange peel extract. Following this, TiO2 nanoparticles are anchored to the rGO sheets through a hydrothermal process, resulting in an rGO/TiO2 nanocomposite (GTO/NC). This study utilized standard characterization techniques to confirm the formation of GTO/NC-1 and GTO/NC-2. Comparative analysis demonstrated that orange peel extract exhibits reducing capabilities compared to other natural reducers. The resulting GTO/NC-1 and GTO/NC-2, specifically GTO/NC-2, enhanced catalytic performance in degrading methyl orange a prevalent organic pollutant in various industrial applications. This nanocomposite achieved a turnover frequency of 0.003 mg MO/mg catalyst/min and displayed remarkable durability, enduring 3.0 cycles with robust first-order rate constants of 0.0193 min−1. Additionally, the electrochemical properties of GTO/NC-1 and GTO/NC-2 as electrode materials were assessed, revealing a specific capacitance of 320.0 Fg−1 at a current density of 1.0 Ag−1 and maintaining about 86.8 % of its initial capacitance after various charge–discharge cycles. These properties highlight the potential of GTO/NC-1 and GTO/NC-2 as both efficient catalysts for environmental remediation and durable materials for energy storage applications, offering substantial benefits for sustainable technology solutions.

Synthesis of isolated ZnO nanorods on introducing g-C3N4 for improved photoelectrocatalytic methanol production by CO2 reduction

The photoelectrocatalytic (PEC) CO2 reduction into fuels has been developed as a prospective approach to resolve the environmental and energy concerns. Herein, a composite catalyst comprising ZnO nanorods dispersed on the g-C3N4 surface (g-C3N4/ZnO) was successfully obtained by simple ZnO seed layer formation and then hydrothermal processes. The synthesized and characterized g-C3N4/ZnO catalytic composite showed 2.8 times enhanced photocurrent density at −1 V applied potential than the bare g-C3N4. The g-C3N4/ZnO catalyst exhibited 2.86 times enhanced the PEC CO2 reduction to methanol than the prepared bare ZnO catalyst. The catalyst’s enhanced the PEC CO2 reduction performance was ascribed to the high surface area, and higher generation and lower recombination of e−/h+ pairs. For the first time, this study showed the enhanced methanol production by the PEC reduction of CO2 over the prepared g-C3N4/ZnO catalytic composite.

Molybdenum Disulfide–Zinc Oxide Mixed Phase Network as Water Purifier

AbstractThe present work reports the development of oxide‐sulfide hybrid by simple hydrothermal process where zinc oxide (ZnO) prepared by simple chemical process is added in situ during the growth of molybdenum disulfide (MoS2) by hydrothermal process. The as prepared sample is characterized by X‐ray diffraction (XRD), field emission scanning electron microscope (FESEM), and energy dispersive X‐ray analysis (EDX). XRD confirms the coexistence of both ZnO and MoS2 in the sample whereas FESEM shows that fractal kind of sulfide structures get developed over ZnO rod. EDX carries the information regarding the stoichiometry of the sample. The sample is proven to be an excellent remover of textile dyes by synergistic effect of photocatalysis and adsorption with almost 100% efficiency following simple first‐order reaction kinetics. When the porous structure of the sample helps the process of adsorption, the charge transfer mechanism has been assumed to be responsible for photocatalytic dye degradation. The latter involves the transferring of electrons or holes between the photocatalyst and the dye molecules, leading to the generation of reactive species that initiate the degradation process. The combined effect of these two processes takes only 30 min to degrade textile dyes like Bengal rose (BR) and methylene blue (MB). Thus, the present work is supposed to serve as milestone in the associated field.

A 2D open framework zinc phosphate and its high proton conductance properties at medium and low temperature

A 2D open-framework zinc phosphate [C3N2H12][Zn2(HPO4)3] (1) was synthesized by solvothermal method. The inorganic anion layer is constructed from Zn2P2O12 cluster units and the interlayer spaces are filled by the diprotonated DAP molecules. The resultant compound had high purity and thermal stability by PXRD and TG analysis. This compound exhibited strongly temperature and humidity dependent proton conductivity, and its highest proton conductivity achieves 2.36 × 10−2 S.cm−1 at 100 %RH and 333 K. Moreover, the important effect of the dense hydrogen bond network in elevating the proton conductivity was explored through comparing the structure and proton conduction behavior between 1 and [C3N2H12][Zn(HPO4)2] (2), which synthesized via the same hydrothermal reaction process, and only a slight difference in the amount of DAP.

Investigating the role of fibre-matrix interfacial degradation on the ageing process of carbon fibre-reinforced polymer under hydrothermal conditions

The aqueous environment can deteriorate the fibre-matrix interface of carbon fibre-reinforced polymer (CFRP), significantly impairing the non-fibre-dominated mechanical properties. Thus, this study aimed to quantitatively analyse the impact of interfacial degradation on the hydrothermal ageing mechanism and process of the CFRP. Firstly, entire water absorption process of the CFRP under hydrothermal conditions was divided into three stages according to experimental measurement of its water content. Based on this division of stages, a novel water diffusion model was established for the hydrothermally aged CFRP. To measure the mechanical degradation, tensile tests were conducted on unaged, aged, and redried neat epoxy and transversely positioned unidirectional (UD) CFRP specimens. It was found that the transverse tensile strength degradation of UD CFRP was irreversible due to the permanent interfacial debonding between the fibres and matrix, in contrast to the reversible ageing of the epoxy matrix. To further quantify the fibre-matrix interfacial ageing, physically-based models were established for the degraded interfacial strength of CFRP subjected to hydrothermal conditions. After the characterization of the modelling coefficients, the physically-based models can be employed to predict interfacial strength inside the aged CFRP for various ageing durations. The prediction error was only 4.57% for the transverse tensile strength of degraded UD CFRP with various ageing durations from the representative volume element (RVE) simulation with its interfacial strength provided by the physically-based models, validating the effectiveness of the proposed physically-based models for degraded fibre-matrix interface under various ageing conditions.

Hierarchical porous MXene film with diffusion path optimization for supercapacitor

MXenes have immense potential in electrochemical energy storage owing to their outstanding physicochemical properties such as their oxygen-containing groups that impart additional pseudocapacitance to acidic electrolytes. However, during electrode assembly, MXene nanosheets undergo restacking because of hydrogen bonding and van der Waals forces, which causes electrolyte ions to traverse long diffusion pathways between the long and narrow nanosheets. Exploiting the oxidative properties of Ti3C2Tx, a hierarchical porous MXene film with micro-, meso- and macroporous structures was successfully prepared using a simple hydrothermal oxidation and etching process to create micro- and mesoporous structures, followed by ice templating to prepare three-dimensional (3D) linked macroporous structures. Because these hierarchical pores have synergistic effects on electrochemical activity and electrolyte ion diffusion, the film attained a specific capacitance of 539F/g at a current density of 2 A/g when it was used as a supercapacitor electrode, which corresponds to one of the highest values reported for MXene-based electrodes. The film retained 83% of its specific capacitance when the current density was increased to 40 A/g, and exhibited excellent cycling stability. By using this multi-porous MXene design, synergistic improvement in ion diffusion was successfully realized and thus a new strategy to prepare high-performance supercapacitor electrode materials was developed.

Enrichment of Chlorophyta growth via cerium oxide and utilized for hydrogen production via hydrothermal gasification process

Abstract The growing interest in alternative fuels stems from the need to address energy security and economic challenges. Hydrogen fuel is considered a promising solution due to its versatility, efficiency, and potential for zero emissions, as well as continuous technological advancements and increasing policy support. This study intends to enhance Chlorophyta growth by incorporating different volume percentages of cerium oxide (CeO2) as feedstock for hydrogen production through hydrothermal gasification. The research findings indicate that the highest concentration (0.2 vol %) of CeO2 resulted in the maximum growth of 0.63 μ/day, which was utilized for hydrogen extraction. Additionally, the investigation explored the impact of Chlorophyta algae loading (0.05-0.15 g/mL) and processing temperature (500-650°C) on molar fraction, hydrogen yield, gasification efficiency, carbon efficiency, and total hydrogen production. Higher feedstock (0.15 g/mL) and gasification temperature (650°C) were found to improve hydrogen fraction (61.8%), yield (10.2 mol/kg), gasification efficiency (43.8 %), and total hydrogen production (62.5%).

Manipulating the d-band center of bimetallic molybdenum vanadate for high performance aqueous zinc-ion battery

Vanadium-based oxides have good application prospects in aqueous zinc ion batteries (AZIBs) due to their structures suitable for zinc ion extraction and intercalation. However, their poor conductivity limits their further development. The d-band center plays a key role in promoting adsorption of ions, which promotes the development of electrode materials. Here, a series of MoV2O8 compounds with oxygen defect (Od-MoV2O8) were synthesized by a simple hydrothermal process and a subsequent vacuum calcination process through strict control of the deoxidation time. Theoretical calculations reveal that the abundant oxygen vacancies in MoV2O8 effectively regulate the d-band center of the zinc ion adsorption site. This precise control of the d-band center enhances the zinc ion adsorption energy of MoV2O8, lowers the migration energy barrier for zinc ions, and ultimately significantly boosts zinc storage performance. The specific capacity is as high as 282.4 mAh/g after 100 cycles at 0.1 A/g, and it also shows excellent performance and outstanding cycle life. In addition, the maximum energy density of Od-MVO-0.5 (MoV2O8 sample deoxidized for 0.5 h) is 343.3 Wh kg−1. Importantly, the mechanism of Zn2+ storage in Od-MoV2O8 was revealed by the combination of in situ and ex situ characterization techniques.

A pH visual sensing platform based on dual-emission chiral carbon dots for discrimination of normal/cancer cells and monitoring food freshness

Accurate detection of pH is important in pathological processes and food freshness. Developing sensors of sensitive response and visualization for pH is highly demanded. In this work, Chiral carbon dots(CCDs) was synthesized via one-pot hydrothermal process using o-phenylenediamine and L-Tryptophan, which displayed circular dichroism (CD) signals at 200–255 nm and 255–300 nm. The CCDs exhibited dual-emission peaks with blue and red emission bands when excited at 360 nm. The ratiometric signals of UV–vis absorption and fluorescence intensity of L-CDs were responsive over the pH range of 2.0 to 11.0 with significant color changes in solution. Fluorescence imaging of live cells displayed different signals related to pH in both the blue and red channels, allowing accurate measurement of the pH of the cellular environment. Furthermore, the pH test paper based on L-CDs enabled monitoring the freshness of shrimp and pork under 365 nm UV light. Therefore, L-CDs provided a multifunctional visual pH sensing platform for environmental monitoring and biosensing.

40Ar/39Ar Dating of Hydrothermal Processes in Large Gold Deposits of the Kochkar Anticlinorium (South Urals, Russia)

The age restrictions for productive mineral associations of the two largest gold deposits of the Southern Urals—Svetlinsk and Kochkar, which are located in the East Uralian megazone—are discussed. The 40Ar/39Ar dating method was performed for the first time for potassium-containing hydrothermal minerals (micas and amphiboles) from the ore veins and ore-host alteration, as well as from marbles. The age estimates obtained are in the range of 290–276 Ma; the weighted average value for the Svetlinsk deposit is 276 ± 2 Ma; for the Kochkar field, 284 ± 2 Ma. It is supposed that the studied mineral assemblages of the Svetlinsk and Kochkar deposits were formed in the beginning of the postcollision stage corresponding to the tectonic relaxation regime. Age of hydrothermal mineral formation in the gold fields of the Kochkar anticlinorium are consistent with the time of post-tectonic plutonic activity, which was expressed in the Middle–Southern Urals in large-scale granitization (~300 Ma). The ore-bearing alteration of a femic profile (of the same age for two deposits), which are most likely basificates, are near-synchronous with the granitization.

Facile synthesis of transition metal-selenides@CNTs for electrochemical oxygen evolution reactions

The fabrication of carbon based efficient electrocatalysts for hydrogen production during electrochemical water splitting could be a great achievement to fulfill the future renewable energy demand. In this study, one-step hydrothermal process was used to develop composites of multi-metal selenides with carbon nanotubes (MnSe@CNTs, MnCuSe@CNTs, MnCoNiSe@CNTs) as electrocatalysts for OER during electrolytic water splitting. XRD and SEM with EDS analysis confirm the successful fabrication of proposed catalyst and their crystalline morphology. Among the synthesized functionalized CNTs composites, bimetallic selenide composite gives a better electrocatalytic activity with the reduce overpotential, lower Tafel slope and reduced charge transfer resistance in 1 M KOH. By using this catalyst, water oxidation starts at 1.4 V onset potential with a very low overpotential of 245 mV and the Tafel slope was only 107 mV dec−1. Metal based selenides composites with CNTs introduces a lot of active sites, subsequent nanoparticles of MnSe, MnCuSe, & MnCoNiSe, causes to boost the surface area and electrocatalysis towards oxygen evolution reactions.