1 Introduction

Recently, nanotechnology has been standing as one of the most advanced and studied fields of science and technology for manipulating and describing matter’s properties on the nanoscale [1]. R. P. Feynman first introduced this technology in the year 1959 in his Nobel prize-winning speech, i.e., “There’s a Plenty of Room at the Bottom,” in the annual gathering of APS (American Physical Society) at CIT, California [2]. Nanomaterial has gained significance in the galaxy of research and development and has also caught the eyes of industrial and pharmaceutical persons throughout the world [3, 4]. Primarily it can be defined by its associated tremendous functional properties, which suggest its interaction with other branches of science. [5]. In the current era, it has become a developing platform in materials processing technology, material science, mechanics, optics, electronics, medicine, textiles and plastics, aerospace and energy, etc. [6]. These technologies create a multidisciplinary field that includes engineering, chemistry, and physics [7] and contribute to disease diagnosis, better treatment options, and significantly decreased health care costs [8].

A hybrid nanomaterial is a composite made up of two or more different materials, typically inorganic elements such as metal clusters or particles, metal ions, oxides, salts, sulfides and other nonmetal components or derivatives, and organic elements such as organic molecules or groups, ligands, polymers, biomolecules, and other pharmaceutical components. These materials are integrated through direct interaction, resulting in the improvement of their functional properties. The various interactions involved in the construction of hybrid materials may be π-complexations, covalent bonds, a wide variety of non-covalent interactions, including H-bonding, electrostatic interactions, Van der Waal’s interaction, dispersion, and other cooperative interactions involving multiple modes. The grouping of diverse parts and structural elements accompanying different interactions results in an almost endless diversity of elements specific to a particular task. [9]

The organic molecules chosen to form hybrid materials include simple organic entities to advanced molecular frameworks and polymers of organic origin [10,11,12]. Similarly, the inorganic component of the hybrid may be composed of a wide range of simple inorganic entities that can be tuneable at their atomic level ranges, including materials of mono-metallic elements to clusters and from nanosized inorganic particles up to extended phases form particles [9, 11, 12]. The process of merging inorganic components into organic polymers represents a simple and straightforward approach to the development of versatile materials with innovative extendable properties [11, 12]

The use of hybrid systems in catalysis, environmental protection, and adsorption is very important and challenging. The shape and size of nanoparticles, i.e., the type of “core–shell” or their decoration with other sub-nanoparticles and matrix interactions, significantly impact catalyst performance, i.e., its stability, activity, and selectivity [13,14,15].

Catalytic processes are essential in the industrial production of products derived from cheap raw materials (e.g., transport fuels, bulk chemicals, and pharmaceuticals) and catalysts [16]. Among the various types of catalysts, chemical industries specifically rely on heterogeneous catalysts (where the reaction of a liquid or gas phase is formed over a solid supported catalyst) for several reasons such as easy separation of catalyst, consistent performance, and longevity. However, because of their complex morphology and limited idea about the active centers, the derivation of the rational framework of a solid catalyst is not that much easy and straightforward process [17]. This information is essential for generating qualitative amounts of solid heterogeneous catalysts in a repetitive manner. Though a huge number of advancements are made in the field of the generation of catalysis, there is still a limitation. Therefore, the development of catalytic systems with a multidimensional application, often known as an art of science, is the most important call of the day [18].

Therefore, the desire to produce a stable, efficient and the selective catalytic system allows scientists to use nanoparticles in the catalytic process. The main advantageous feature associated with the nanoparticles as a catalyst is their large size to volume ratio, resulting in a large surface area with a number of surface-active particles and ultimately leading to a highly efficient catalytic environment. Overall, the effect of a large, highly active catalytic surface area, dispersibility, quantum confinement, durability, and stability are the main parameters possessed by the N.P.s play a vital role in developing dynamic, efficient, and eco-friendly catalytic systems [19].

Additionally, the surface-associated features of the N.P.s can also be modified accordingly with respect to functionalization by different organic (surfactant, polymers) as well as inorganic (Silica, carbon, metals, and its oxides) components [20]. Nanocatalysts have superior performance, selectivity, and stability and have convenient separation and recovery. So, nanocatalyst fills up the space between homogeneous and heterogeneous catalysis and maintains both systems’ desirable characteristics, as shown in Fig. 1 [20,21,22].

Fig. 1
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Dual behavior of nano catalyst

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The functionalization of silica-based hybrid N.P.s with organic moieties has been a long-enduring focus of research, i.e., to get an extendable version of the heterogeneous form of silica from inactive silica following hybridization possessing a broad range of applicability, particularly in the area of catalysis. Today, numerous reports of SiO2 NPs are available describing their practical use to build up the exceedingly active, prominent, selective, and recyclable catalyst for many organic conversions [23].

SiO2 NPs are usually affordable to manufacture on a large scale, are hydrophobic, have a large surface area, pore-volume, and are biocompatible, therefore, they have a wide range of applications. For example, SiO2 NPs have been used for medication administration because of their non-toxic nature and high adsorption ability [24, 25]. Researchers have recently effectively used SiO2 NPs as cargo loading for a variety of cargo, ranging from medicines to macromolecules like RNA, DNA, and proteins [26, 27]. Biomedicine, biotechnology, medication delivery, food, personal care items, insecticides, adsorption, semiconductors, and ceramics are now just several fields where silica nanoparticles have been used [28]. SiO2 NPs have recently been used to absorb oil spills during oil exploration, transportation, and storage [29, 30]. The research to investigate and exploit the new conceivable applicability of silica nanoparticles is still ongoing [28]. This review article focuses on Silica-based hybrid nanoparticles’ advancements and their application in catalysis.

2 Silica-Based Hybrid Nanoparticle

Silicon is a widely explored element among many other plentiful elements on the earth core. Most of the silicon properties generally resemble “carbon” as both belong to the similar family of the periodic desk. “Si” is commonly considered chemically inert; however, it has a great affinity for oxygen and other high electronegative elements. Among the different compounds of Si, Si–O compounds are generally the most studied and familiar. Si’s most common available compounds include clay, silica, silicates, and POSS (polyhedral oligomeric silsesquioxanes) [31]. Recently, Si and SiO2 have been found to be fabricated over various sizes ranging from micro size up to nanoscale. The main feature found in them is their large surface by volume ratio. Because of this unique and marvelous aspect, N.P.s of Si and its derivatives were found to possess a profound number of popularities in different sectors, i.e., from catalysis to electronics and other pharmacological purposes [32]. Similarly, the hybrid materials of Si can also be formulated by incorporating Si with some other organic and inorganic materials. The hybridization process makes the nanomaterials more divergent with multiple applications in single-core, which found to exhibit extensive job in catalysis due to their more durable and improved thermal and chemical stability and selectivity. [20]

The earth’s crust is rich with Si or SiO2, which may occur either in amorphous or crystalline forms [33]. It possesses a 3D-network like structure, made up [SiO4] as a packing unit and a bulk structure that terminates near the surface via two different paths, that is, by -O- on the surface through -Si–O–Si- (siloxane) functional or by -Si–OH (silanol) functional. Three different kinds of -Si–OH functionals, namely vicinal (H-bonded -Si–OH), geminal (one Si-atom firmed with two silanol groups), and isolated (there are no H-bonds possible at -Si–OH sites), as presented in Fig. 2.

Fig. 2
figure 2

Different ways of attachment of silanol groups on the surface of silica

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A wide range of techniques has been invented to prepare SiO2 NPs, such as flame synthesis, sol–gel method, hydrothermal synthesis, and the reverse microemulsion technique.

The reason for supporting the active form in SiO2 NPs is to construct a heterogeneous catalytic process that can cite the transition metal-based catalyst’s reusability by resisting its unaltered performance. Variation of SiO2 NP by combining certain active groups can make them appropriate for the catalytic exploit accomplished by chemical and physical treatment. Chemical treatment alters the chemical properties of the SiO2 surface, while physical treatment changes the ratio of Si–OH to –Si–O-Si- groups. In addition, it has been demonstrated that the physical interaction between the solid supports and the modifier occurs by the insertion of the supporting material or by an electrostatic process [34]. Surfactants usually get adsorbed to silica through electrostatic interactions through a polar group, ultimately reducing the interaction between each SiO2 NPs and preventing their agglomeration[35].

The substantial adsorption of molecules over SiO2 can be illustrated by the pioneering work disclosed by Zidki et al., which incorporates a well stable and efficient water-oxidation catalyst using pH-controlled Co(II) adsorption on SiO2 NPs with 10 nm diameter [36]. The catalyst showed both enhanced selectivity and water oxidation function. However, the process of adsorption was found to be reversible, as the interaction between them was the weak physical forces.

Since metal leaching is a significant problem in an industrial sense, such a practice is far from ideal. Thus, modification of nano-silica surfaces has now been observed via chemical bonding. It may lead to strong chemical interactions between the modifiers and SiO2, thereby ultimately decreasing the leaching of active catalytic species used to alter the surface of SiO2 NPs [37]. Various altering and grafting polymers are being used to transform the surface of SiO2 NPs chemically. The traditional process of alteration using the chemical route includes silane blend agents, which are the familiar altering mediators, as they usually have hydrolyzable organo-functional assemblies. These silylating groups react with –Si–OH group of SiO2, allowing the surface to get the targeted functional entities by acting as precursors for more immobilization of molecules of choice.

These connecting reagents are usually cited as RSiX3 (X = any hydrolyzable group such as -Cl, -OMe, or -OEt groups, and R = different functionals selected to meet the requirements of the polymer) Fig. 3. Functionals of X react with -O.H. group of SiO2 NPs, and the alkyl chain may interact with polymer. If there are three leaving groups attached with the silylating agent, anchoring can be possible by exchanging one or two groups.

Fig. 3
figure 3

Modification of surface of silica nanoparticle

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Silane with –NH2 groups such as 3-aminopropyltriethoxysilane (APTS) [38, 39] can participate in polycondensation and uncontrolled hydrolytic reaction in the aqueous medium. Thus, a non-aqueous medium is generally chosen to avoid hydrolysis during the grafting of APTS on Silica. On the other hand, in an aqueous environment that allows for large-scale manufacture, alkoxy groups get first hydrolyzed by contact with H2O, following a self-condensation reaction between the hydrolyzed silanes molecules. After that, the silane molecules get adsorbed on the SiO2 surface by forming –Si–O-Si- bonds between the –Si–OH and hydrolyzed silane groups by removing water molecules. Apart from the silylating agents, additives such as 2-(methacryloyloxy) ethyl isocyanate, epichlorohydrin, octadecylamine, glycidyl phenyl ether, and others have also been used for surface alterations.

3 Silica-Based Hybrid Nanoparticle Catalysed Reaction

The unique properties of nanosized materials, due to their nano size, large surface area, large pore volume, and stability, are ideal candidates for every chemical reaction’s catalytic application. A specific catalyst is required for a specific reaction. Often the use of catalysts can increase the rate and selectivity of a reaction. [20]

As previously stated, the primary need of a catalyst is its stability, ease of separation, and recycling. To facilitate the recovery of catalyst easier, the production of active magnetic nanocatalyst was developed by Kaur et al. and used in various organic transformations reactions [40]. The use of silica N.P.s in various organic transformation reactions has increased significantly in recent years, owing to their unique properties, which include nanoscale size, large surface area, large pore volume, excellent thermal and mechanical stability, and the presence of silanol groups on their surfaces, which enable an extremely broad range of functionalities to be achieved. SiO2 NPs have risen as flexible supports for anchoring metal complexes, heteropolyacids, etc., therefore opening the way for the development of hybrid nanocatalysts. While the interactions between the functional groups of silica and metals play an essential part in making efficient and versatile catalysts were previously discussed. [23]

Therefore, all these factors and the significance of various types of hybrid silica N.P.s based catalysts for promoting diverse reactions, including coupling, oxidation, reduction, and multicomponent reactions (MCR), have been reported recently. This review discussed the current significant development in this regard.

3.1 Coupling Reaction

The coupling reactions are the essential synthetic tools widely used in industry to synthesize valuable chemicals. These are mainly employed to synthesize C–C, C-N, and C-S bonds. Sonogashira cross-coupling reaction [41] is the most commonly used reaction in natural product synthesis to synthesize C–C bonds. This coupling reaction was applicable for the synthesis of active pharmaceutical compounds and optoelectronic substances [42]. The original Sonogashira cross-coupling is carried out in Palladium and copper as a co-catalyst [43] which is economical. Then Cassar and Heck developed a copper-free Sonogashira cross-coupling reaction [44, 45]. However, an efficient catalytic system and new techniques have been developed to improve the Sonogashira cross-coupling reaction’s efficiency [46,47,48]. Nowadays, diverse hybrid catalysts have been used for coupling reaction, which exhibits good stability and recoverability and shows good activity towards the coupling reaction [49, 50].

Ferlin et al. prepared a Si-Gly-CD-PdNP hybrid catalyst for the Sonogashira cross-coupling reaction. Here, the catalyst’s efficiency was improved by using the β-Cyclodextrin (β-CD) ligand due to their hydrophilicity, allowing cyclopentyl methyl ether (CPME)/water azeotropic mixture. The reaction method enhanced the stability and durability of the catalyst, as shown in Fig. 4 [51].

Fig. 4
figure 4

Si-Gly-CD-PdNPs and β-CD catalyzed Sonogashira cross-coupling reaction

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Sudharsan et al. has demonstrated benzoyl chloride and phenylboronic acid cross-coupling reaction using K2CO3 in methanol catalyzed by Pd-TPMO catalyst. The co-condensation method prepared the Thiazoline functionalized mesoporous organosilica (TPMO). The palladium nanoparticle (Pd N.P.s) was immobilized on TPMO using a double solvent to form a (Pd-TPMO) catalyst. The catalytic efficiency of Pd-TPMO was tested for cross-coupling reaction, as shown in Fig. 5 [52].

Fig. 5
figure 5

Coupling reaction using Pd-TPMO catalyst

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Veisi and his co-worker investigated the use of green tea extract in catalysis and reported green tea extracted-encapsulated silica gel nanocomposite catalyzed coupling reaction. The reducing properties of the green tea open the door for the anchoring of Pd N.P.s on the green tea surface. The SiO2@green tea/Pd nanocatalyst was deployed for the amination reaction, the Buchwald Hartwig reaction used to form a C-N bond. This is a green method for synthesizing the C-N bond [53]. This catalyst exhibits excellent yield, easy separation of products, and excellent reusability with less loss in its efficiency, as shown in Fig. 6.

Fig. 6
figure 6

SiO2@green tea/Pd catalyzed C-N cross-coupling reaction

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However, glycerol functionalized Fe3O4@SiO2 immobilized copper complex was an efficient catalyst for synthesizing the C-S and C-O bond. The Fe3O4@SiO2-Glycerol-Cu(II) catalyst exhibits excellent reusability. The C-O bond formation is essential in the cosmetic, medicine, and dye industries and critical for various organic reactions, as shown in Fig. 7 [54].

Fig. 7
figure 7

Fe3O4@SiO2-Glycerol-Cu(II) catalyzed cross-coupling reactions

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3.2 Oxidation Reactions

Oxidation reactions in chemistry play a crucial role in designing and synthesizing various value-added products. The traditional oxidant used in stoichiometric quantities generates toxic and hazardous waste. Instead, modern oxidation reactions are carried out using molecular oxygen or hydrogen peroxide as oxidant and recyclable catalysts and green solvents, thus promoting green processes [55,56,57,58].

Jia and his co-worker have reported that Ag-doped hexagonal mesoporous silica catalyzed oxidation reaction, with excellent yield (96%) at 240 °C. Still, the main demerit of the catalyst was its use at high temperature [59]. To overcome this drawback, Thomas et al. reported novel silver nanoparticles (AgNPs) anchored mesoporous silica SBA‒15/copolymer hybrid catalyst. The N,-N-dimethylaminoethyl methacrylate and 2-hydroxyethyl acrylate (p(DMAEMA-co-HEA)) grafted modified SBA‒15 (M.S.) was prepared then the AgNPs were dispersed on grafted SBA‒15. The catalytic activity of the prepared catalyst was tested for oxidation of various alcohols to carbonyl compounds, which shows the highest activity for oxidation of alcohol, as shown in Fig. 8 [60].

Fig. 8
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oxidation of benzyl alcohol using AgNPs/p(DMAEMA-co-HEA)/MS

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3.3 Multicomponent Reaction

Multicomponent reactions (MCRs) are powerful tools for constructing molecular architecture from readily available raw materials. These reactions are economical, require less time and energy, and are carried out in one step. It is one of the newest strategies for making chemical processes more environmentally friendly. The advantages of MCRs over other chemical reactions include their atom economy and efficiency, which lowers the byproduct. MCRs would be more frugal and greener using various heterogeneous catalysts. Several MCRs have been reported using silica-based nanohybrids as catalysts [61].

Due to the diverse biological properties of dihydropyrimidinones (DHPMs) and their derivatives, they have been the subject of research in medicinal chemistry [61,62,63,64]. At the same time, traditional synthesis methods involve Brønsted or Lewis acids catalysts by the Biginelli reaction [65,66,67,68,69]. Among the different catalysts, the supported catalysts like silica-supported catalysts enhanced the rate and selectivity of the response [66,67,68,69,70]. However, research should be carried out to develop new versatile catalysts for MCRs. [70,71,72,73,74,75,76,77].

Valiey and his co-worker have reported the synthesis of novel hybrid catalyst MCM-41 -functionalized sulfamic acid and pyromellitic diamide denoted as MCM-41-APS-PMDA-NHSO3H. This catalyst was an efficient nanocatalyst for the preparation of 3,4-dihydropyrimidin-2-(1H)-one derivative using solventless environments. This catalyst is acidic and provides a large surface area, which initiates the Biginelli reaction to prepare 3,4-dihydropyrimidin-2-(1H)-ones which is an active molecule in the Pharma industry, as shown in Fig. 9 [79].

Fig. 9
figure 9

Preparation of 3,4-dihydropyrimidin-2-(1H)-one derivatives using MCM-41-APS-PMDA-NHSO3H catalyst

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In another example, Sharma and his co-worker reported the preparation of TiO2 SiO2 NPs by immobilized TiO2 Nano Particles on SiO2 Nanoparticles using the “sol–gel” technique. This catalyst was efficient for one-pot synthesis of 2,3-diaryl- 3,4-dihydroimidazo[4,5-b] indole scaffolds via reaction between isatin and anilines aldehydes and ammonium acetate using methanol, as shown in Fig. 10 [78].

Fig. 10
figure 10

TiO2.SiO2 NPs as catalyst for one-pot synthesis of 2,3-diaryl-3,4-dihydroimidazo[4,5-b] indole derivatives MCRs

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Kohzadian et al. introduced an effective way for one-pot synthesis of pyrido[2,3-d:6,5-d’]dipyrimidines. The one-pot synthesis involves using aryl aldehydes, 2-thiobarbutaric acid, and NH4OAc under solvent-less conditions. The mesoporous silica based nanocatalyst denoted as Nano-[SiO2-R-NMe2SO3H] [Cl] were employed for preparation of pyrido [2,3-d:6,5-d’] dipyrimidines via one-pot method as shown in Fig. 11. The key features of this catalyst were the mild reaction condition, less reaction time, high product yield, and ease of separation [79].

Fig. 11
figure 11

Nano-[SiO2-R-NMe2SO3H][Cl] catalyzed One-pot synthesis of pyrido[2,3-d:6,5-d0] dipyrimidines

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3.4 Reduction Reaction

The reduction reactions are a powerful tool for the chemical industry. These are extensively used to synthesize many organic compounds and useful chemicals. However, the traditional reduction reactions are carried out using transition metal catalysts. So the separation and recyclability of these catalysts can be challenging. Various types of heterogeneous catalysts have been developed for reduction reaction using mild reducing agents [80, 81].

Zao and his co-worker prepared a size-uniformed mesoporous Ag@SiO2 nanospheres’ catalyst. This catalyst was prepared in a one-pot step via reducing AgNO3 with various aldehyde via one-pot synthesis that controls the size of Ag@SiO2 NPs. The performance of the nanocatalyst was tested in the hydrogenation of nitrobenzene, as shown in Fig. 12. It serves as a highly active catalyst for the reaction [82].

Fig. 12
figure 12

Ag@SiO2 Catalyzed Reduction of nitrobenzene

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Lu et al. synthesized nickel phosphide (Ni2P) nanoclusters functionalized mesoporous SiO2 catalyst in a two-step synthetic process that regulates the size of Ni2P. “The process of functionalization of Ni onto the MCM-41 matrix was carried out via one-pot synthesis, followed by phosphorization reaction between oleylamine and trioctylphosphine, which transform Ni to Ni2P”. The Ni2P@SiO2catalyst can serve as an efficient catalyst for reducing SO2, as shown in Fig. 13 [83].

Fig. 13
figure 13

Reduction of SO2 using Ni2P@ SiO2 Catalyst

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Sudharsan et al. introduced another application of Pd-TPMO for the catalytic reduction reaction. Thiazoline fabricated mesoporous organosilica (TPMO) anchored metal nanocatalyst was employed to hydrogenation of Phenylethylene oxide, Furfural, and nitrobenzene as shown in Fig. 14, shows better yields and selectivity [52].

Fig. 14
figure 14

Pd-TPMO Catalyzed Reduction reaction

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3.5 Carbon Dioxide Conversion

Due to anthropogenic emissions, carbon dioxide (CO2) concentration increases day by day. Decreasing the concentration of CO2 in the atmosphere is currently a serious environmental issue recently. Increasing research has been done to design a new approach to solve this issue [84, 85]. Nowadays synthesis of value-added chemicals from carbon is an effective method for the utilization of CO2. A diverse range of homogeneous and heterogeneous catalysts was developed to utilize CO2. Cyclic carbonates are well known in the chemical industry due to their applications as fuel additives, electrolytes in batteries, reagents, solvents, the monomer for polymer, etc. Thus the cyclic carbonates synthesis by the reaction between CO2 and epoxide has witnessed enormous attention for the utilization of CO2. Several recent works have explored the development of numerous catalysts (homogeneous and heterogeneous) that are efficient for converting CO2 to cyclic carbonate. [86]

Tan and his co-worker recently designed functionalized benzotriazolium ionic liquid functionalized periodic mesoporous organosilica nanoparticles (PMOs) as a catalyst denoted as PMO-ILTiCl5. This nanocatalyst was successfully employed to transform CO2 to cyclic carbonates without any solvents and co-catalysts. Figure 15 The PMO-ILTiCl5 was an excellent catalyst for the synthesis of cyclic carbonates from CO2 with high yields and selectivities. The synthesized PMO-ILTiCl5 nanocatalyst showed remarkable recovery, activity, and reusability (used five times with no significant decrease in its efficiency). This is because of the intramolecular synergic effect between active hydroxyl sites, and TiCl5which provide the most stable catalytic sites [87].

Fig. 15
figure 15

Conversion of CO2 to Cyclic Carbonate using PMO-ILTiCl5 catalyst

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4 Conclusion and Outlook

This review has highlighted current improvements in methods for the production of silica nanoparticles due to their widespread use as a catalyst in response to various transformation reactions. This protocol provides a large surface area, excellent stability, and nanoscale size of silica. Its surface contains silanol groups that promote the fabrication of different groups to the surface of silica. The hybrid nanocatalysts were a burgeoning tool for synthesizing valuable added products in chemical and pharma industries. This review aims to provide information about the recently published work on silica-based hybrid Nanocatalyst for various organic reactions, such as coupling reaction, oxidation, reduction, multicomponent reaction, and CO2 conversion reaction. The essential features of this hybrid nanocatalyst were its excellent activity, selectivity, reasonable recovery, and excellent reusability. While numerous works have been done to synthesize hybrid nanocatalysis, there is still a requirement to develop a more promising, Green, and viable hybrid catalyst for the organic reaction. These nanoparticles have made significant contributions to agricultural production, preservation of food, biomedical research, and catalytic reactions, among other domains. SNPs have been proved to be effective encapsulating agents for a wide range of bioactive compounds, and they have already been proven to be safe for targeted medication delivery. Furthermore, the ability of SNPs to combine with various polymeric and non-polymeric materials to generate hybrid composites has broadened the range of functionalities. MSNPs (mesoporous Silica nanoparticles) have already demonstrated outstanding carrier qualities, allowing them to be used in chemotherapy to target specific cancer cells.

As a result, additional study is needed to develop a flexible, environmentally friendly, recyclable, and recoverable silica-based nanohybrid catalyst that can catalyze the green reaction and serve as a critical step toward developing a more environmentally friendly method. The Nanohybrids catalyst is an emerging field of research and less explored with vast potential for the future. Yet, this type of material will remain at the forefront for decades.