**1. Introduction**

Since ancient times, the importance of porous solid materials and fine powders has been recognized when porous coal used for its medicinal properties [1]. Research on porous solid materials and fine powders, which have various applications such as catalysis, separation, isolation, sensors, chromatography, etc., have reinforced the global interest [2] in environmental sustainability and energy storage. In the above - referenced applications, the outperformance of different porous solid materials and fine powders is extremely dependent on each material's internal porous structure. Therefore, the internal geometry, size, connectivity, etc. such as porous materials of different properties were fully characterized to better understand a particular physical process taking place in a porous medium [3]. Gas adsorption is one of many experimental methods available to characterize porous materials by the surface and pore size. These include ray and neutron scattering of small angles (SAXS and SANS), porosimetry of mercury, electron microscopy (scanning and transmission), thermoporometry, nuclear magnetic resonance methods, and others. Each method has a limited application scale for analyzing pore size. IUPAC recently provided an overview of different methods for characterizing pore size and their range of application [4]. Among these methods, gas adsorption is the most popular because it enables the evaluation of a wide range of pore sizes (from 0.35 nm to >100 nm), including the full range of micro-and mesopores and even macropores. Moreover, the techniques of gas adsorption are convenient to use and are not that cost-intensive compared to some of the other methods [5].

Adsorption finds very extensive potential application in the research laboratory and industry. Adsorption plays a very important role in various aspects of the catalysis of gases reactions by solid surfaces. As applications of adsorption from solutions may be mentioned the clarification of sugar liquors by charcoal, the removal of coloring materials from various types of solutions, and recovery of dyes from dilute solutions in several solvents. Adsorption has also been employed for the recovery and concentration of vitamins and other biological substances and finds immense utility in the chromatographic analysis [6]. The importance of the adsorption can be assessed in the sense that Langmuir was awarded Nobel Prize in Chemistry for his seminal contribution to surface science. Since then, two more Nobel Prizes Has been given in this area (Ertl in 1992 for his studies of chemical processes on solid surfaces and Marcus in 1992 for his theory and mechanism of electron transfer reactions on surfaces).

The materials comprising of pore size lying between Micro- and Macro-porous materials are regarded as mesoporous materials [7–9]. Mesoporous materials are the materials that have their pore size in between Micro- and Macro-porous materials. Meso a Greek prefix – "in-between" - micro and macroporous system. Following the IUPAC standard, microporous material has pore smaller than 2 nm while macroporous material possesses pores larger than 50 nm. Mesoporous material has high specific surface area due to high porosity within the mesopore range which forms the basis of their applications in varying fields. They possess high surface area -400-1000 m2 /g, large pore volume and high stability −500-600°C. A very common mesoporous material is customary activated carbon which is typically composed of a carbon framework having both mesoporosity and microporosity depending on the conditions under which it was manufactured. According to IUPAC, a mesoporous material can be deliberately ordered or disordered in a mesostructure [10–13]. In crystalline inorganic materials, mesoporous structure noticeably limits the number of lattice units, and this significantly changes the physics and chemistry. For example, the battery performance of mesoporous electroactive materials is significantly different from that of their bulk structure. "The overwhelming tendency for solids to minimize void space within their structure" is inherent, porous materials are difficult to make naturally. But Einstein says "In the middle of difficulty lies opportunity". The above statement was made true by the Mobil scientist in the year 1992 by successfully synthesizing the Mesoporous materials i.e. Mobil Crystalline Materials (MCM-41 and MCM-48) employing soft template strategy. This has opened new potentialities for Mesoporous materials, and extensive research has been contributed in this field.

Material can be classified as porous if its internal voids can be filled with gases. The history of porous materials began with the zeolites having an aluminosilicates *Application of Titanium Dioxide in the Synthesis of Mesoporous Activated Carbon Derived… DOI: http://dx.doi.org/10.5772/intechopen.98395*

framework which was synthesized employing a single template molecule with a small pore. Usually, they are synthesized by the use of the soft template method. Since then, research and development in this field have grown steadily. Notable examples of prospective industrial applications are catalysis, sorption, gas sensing, ion exchange, optics, and photovoltaics. Gas adsorption is the most effective and corroborative method for the characterization of the texture of porous solids and fine powders. The analysis was done on "Reporting Physisorption Data for Gas/ Solid Systems" on the surface area and porosity [14, 15].

### **2. Materials and methods**

The agriculture waste namely mustard cake (sample) was purchased from the local mill (Sai Enterprise, Lucknow, India). Sodium hydroxide (98%), hydrochloric acid (35.5%), potassium chloride (99.5%), sulfuric acid (98%) and TiO2-Degussa P25 (ca.80% anatase, 20% rutile) chemicals were used and supplied by Bionic Enterprises, Lucknow, India. High-purity grade nitrogen gas (99.999%) and helium gas (99.9999%) were used for physicochemical characterization of the sample supplied by Krishna Gas Agencies, Lucknow, India. The double-distilled water (DDW) was prepared using a double distillation unit (Glassco Laboratory Equipment Pvt. Ltd., Ambala Cantt., India) and used for the preparation of modified material. All the reagents used for synthesis and experimental studies were of analytical and laboratory grade.

The agricultural waste sample was crushed and washed with double distilled water (DDW) and then sun-dried. This material was treated with 20 wt% H2O2 at 60°C for 24 h to oxidize the adhering organic matter and it was washed several times using DDW. This material was calcinated in the presence of O2 gas at 715°C for 25 min. The material, powdered activated carbon (PAC) was grounded and sieved to desired particle sizes. To get TiO2-MMC, TiO2-Degussa P25 (ca.80% anatase, 20% rutile) was added to PAC in a 5:1 weight ratio, in NaOH 2 N alkaline solution; in the 1000 ml, volumetric flask with a reflux condenser, the new potential material (TiO2-MMC) was obtained from the slurry under stirring (300 ppm) for 24 h, at atmospheric pressure and 100°C, on a thermostat heating plate. After filtration, washing and drying at 105–120°C till a constant mass, the dried TiO2-MMC was ground and passed through a 100 mesh sieve and stored in a desiccator. The material was characterized employing ATR- FTIR, SEM, XRD, BET and XPS [6, 7].

For the functional group analysis, the sample was directly (without any preparation) scanned in transmittance mode with a wave region ranging from 4000 to 500 cm−1 by ATR-FTIR (Bruker-Tensor 27) [16, 17]. The particle morphologies of samples were studied using SEM (JEOL JSM 6490LV). The sample was mounted on an aluminum stub with the help of double-sided tape. Mounted stubs were coated with gold–palladium for analysis using a Polaron sputter coater [16, 17]. The specific surface area, size and pore diameter of the materials were measured using a surface area analyzer (Belsorp-Mini-II, Japan). A definite amount of the adsorbent materials (0.20 g) were heated under pre-treatment at 120°C under vacuum for approximate 5–6 hrs. Subsequently, the process of N2 adsorption and desorption was performed. The surface area and pore diameter were calculated using the standard Brunauer–Emmett–Teller (BET) equation and pore size was obtained employing a method of Barrett–Joyner–Halenda (BJH) and T-plot [16, 17]. The crystalline nature of the sample was examined by powder X-ray diffraction (PXRD) (PAN analytical X'pert, Powder, Malvern Panalytical, UK) in 2-theta(degree) angle range 5°-80° at 45 kV using CuK radiation with 148.92 times per step [6, 7]. The XPS experiments were performed in an ultrahigh vacuum (UHV) using a high-resolution X-ray photoelectron spectrophotometer (HR-XPS), (PHI 5000 Versa Prob II). All samples

were dehydrated under vacuum before XPS analysis. All Data of XPS analysis were plotted using Casa XPS Version 2.3.17PRI. I and Origin Pro 8 SRO v8.0724 (B724) software [16, 17].
